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Sample records for cultured rat skeletal

  1. Receptor Expression in Rat Skeletal Muscle Cell Cultures

    Science.gov (United States)

    Young, Ronald B.

    1996-01-01

    One on the most persistent problems with long-term space flight is atrophy of skeletal muscles. Skeletal muscle is unique as a tissue in the body in that its ability to undergo atrophy or hypertrophy is controlled exclusively by cues from the extracellular environment. The mechanism of communication between muscle cells and their environment is through a group of membrane-bound and soluble receptors, each of which carries out unique, but often interrelated, functions. The primary receptors include acetyl choline receptors, beta-adrenergic receptors, glucocorticoid receptors, insulin receptors, growth hormone (i.e., somatotropin) receptors, insulin-like growth factor receptors, and steroid receptors. This project has been initiated to develop an integrated approach toward muscle atrophy and hypertrophy that takes into account information on the populations of the entire group of receptors (and their respective hormone concentrations), and it is hypothesized that this information can form the basis for a predictive computer model for muscle atrophy and hypertrophy. The conceptual basis for this project is illustrated in the figure below. The individual receptors are shown as membrane-bound, with the exception of the glucocorticoid receptor which is a soluble intracellular receptor. Each of these receptors has an extracellular signalling component (e.g., innervation, glucocorticoids, epinephrine, etc.), and following the interaction of the extracellular component with the receptor itself, an intracellular signal is generated. Each of these intracellular signals is unique in its own way; however, they are often interrelated.

  2. Discoordinate regulation of different K channels in cultured rat skeletal muscle by nerve growth factor.

    Science.gov (United States)

    Vigdor-Alboim, S; Rothman, C; Braiman, L; Bak, A; Langzam, L; Yosef, O; Sterengarz, B B; Nawrath, H; Brodie, C; Sampson, S R

    1999-05-01

    We investigated the effects of nerve growth factor (NGF) on expression of K+ channels in cultured skeletal muscle. The channels studied were (1) charybdotoxin (ChTx)-sensitive channels by using a polyclonal antibody raised in rabbits against ChTx, (2) Kv1.5 voltage-sensitive channels, and (3) apamin-sensitive (afterhyperpolarization) channels. Crude homogenates were prepared from cultures made from limb muscles of 1-2-day-old rat pups for identification of ChTx-sensitive and Kv1.5 channels by Western blotting techniques. Apamin-sensitive K+ channels were studied by measurement of specific [125I]-apamin binding by whole cell preparations. ChTx-sensitive channels display a fusion-related increase in expression, and NGF downregulates these channels in both myoblasts and myotubes. Voltage-dependent Kv1.5 channel expression is low in myoblasts and increases dramatically with fusion; NGF induces early expression of these channels and causes expression after fusion to increase even further. NGF downregulates apamin-sensitive channels. NGF increases the rate of fall of the action potential recorded intracellularly from single myotubes with intracellular microelectrodes. The results confirm and extend those of previous studies in showing a functional role for NGF in the regulation of membrane properties of skeletal muscle. Moreover, the findings demonstrate that the different K+ channels in this preparation are regulated in a discoordinate manner. The divergent effects of NGF on expression of different K+ channels, however, do not appear sufficient to explain the NGF-induced increase in the rate of fall of the action potential. The changes during the falling phase may rather be due to increases in channel properties or may result from an increased driving force on the membrane potential secondary to the NGF-induced hyperpolarization.

  3. Effect of electrical stimulation on beta-adrenergic receptor population and cyclic amp production in chicken and rat skeletal muscle cell cultures

    Science.gov (United States)

    Young, R. B.; Bridge, K. Y.; Strietzel, C. J.

    2000-01-01

    Expression of the beta-adrenergic receptor (betaAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the betaAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the betaAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the betaAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

  4. Effect of electrical stimulation on beta-adrenergic receptor population and cyclic amp production in chicken and rat skeletal muscle cell cultures

    Science.gov (United States)

    Young, R. B.; Bridge, K. Y.; Strietzel, C. J.

    2000-01-01

    Expression of the beta-adrenergic receptor (betaAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the betaAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the betaAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the betaAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

  5. Proliferation of bone marrow mesenchymal stem cells, skeletal muscle cells and co-culture of both for cell myocardium therapy in Wistar rats.

    Science.gov (United States)

    Carvalho, K A T; Guarita-Souza, L C; Simeone, R B; Francisco, J C; Olandoski, M; Gremski, W

    2006-01-01

    The best results of cell therapy are achieved by a greater quantity of cells, delivery to the correct place, and cell conditions of viability with proliferation and without apoptosis. The quantification of cellular growth, including proliferation and viability, has become an essential tool. The objective of this study was to analyze cell proliferation in 14-day cultures of bone marrow mesenchymal stem cells (BMMSC), skeletal muscle cells (SMC), and co-culture of both types of cells (CO). Forty-four adult Wistar male rats (250-300g) received cultured cells CO (n = 22), BMMSC (n = 10), and SMC (n = 12). All cultured cells were started with the same concentration: 5 x 10(5)/mL, under similar conditions and maintained in an incubator with 5% CO(2) at 37 degrees C, which was changed every 48 hours for 14 days. The cell count was performed in Neubauer's chamber to calculate the proliferation index (IP). Statistical analysis was performed by the nonparametric Kruskal-Wallis and Wilcoxon tests. P values statistically significant. The results showed that IP was positive in all groups. In conclusion, proliferation capacity was demonstrated in all groups. SMC IP was greater than the others, although it was the most heterogeneous.

  6. Establishment of bipotent progenitor cell clone from rat skeletal muscle.

    Science.gov (United States)

    Murakami, Yousuke; Yada, Erica; Nakano, Shin-ichi; Miyagoe-Suzuki, Yuko; Hosoyama, Tohru; Matsuwaki, Takashi; Yamanouchi, Keitaro; Nishihara, Masugi

    2011-12-01

    The present study describes the isolation, cloning and characterization of adipogenic progenitor cells from rat skeletal muscle. Among the obtained 10 clones, the most highly adipogenic progenitor, 2G11 cells, were further characterized. In addition to their adipogenicity, 2G11 cells retain myogenic potential as revealed by formation of multinucleated myotubes when co-cultured with myoblasts. 2G11 cells were resistant to an inhibitory effect of basic fibroblast growth factor on adipogenesis, while adipogenesis of widely used preadipogenic cell line, 3T3-L1 cells, was suppressed almost completely by the same treatment. In vivo transplantation experiments revealed that 2G11 cells are able to possess both adipogenicity and myogenicity in vivo. These results indicate the presence of bipotent progenitor cells in rat skeletal muscle, and suggest that such cells may contribute to ectopic fat formation in skeletal muscle.

  7. 大鼠肌源性干细胞的培养与鉴定%Primary culture and identification of rat skeletal muscle-derived stem cells

    Institute of Scientific and Technical Information of China (English)

    李爱斌; 王玲珑; 金化民; 李晶晶

    2006-01-01

    BACKGROUND: Skeletal muscle-derived stem cells (MDSCs), another adult pluripotent stem cells, have become a hot topic in the field of gene therapy and cell-based tissue engineering. It has wide prospect in treating stress incontinence by periurethral injection of patients' MDSCs.OBJECTIVE: To investigate the method of culturing MDSCs in vitro so as to provide experimental basis for treating stress incotinence by injecting MDSCs.DESIGN: Repeated observation.SETTING: Department of Reproductive Medical Center and Department of Urology, Renmin Hospital of Wuhan University.MATERIALS: This experiment was conducted at the Laboratory of Department of Urology , Renmin Hospital , wuhan University from December 2003 to May 2004. Totally 20 female SD rats , aged 4 to 6 weeks , were involved . Type- Ⅺ pancreatin, collgenase , pancreatin ,polylysine (Sigma), dispase enzyme (Gibco) , chick embryo extract (self made).METHODS: ① Rats were anesthetized intraperitoneally with 10 g/Lpentobarbital sodium (30 g/kg). Under aspetic condition, gastroeneminus were isolated and immediately put into pre-cooled DMEM media (Gibco)containing antibiotics and then removed into the hood. After washed with D-hank's solution three times, muscle biopsies were removed of fascia,tendon, nerve and blood vessels and minced into small pieces about 1-3 mm3,and then transferred into a centrifugation tube. 0.2% collgenase-type Ⅺ(Sigma) and 0.1% pancreatin were added to the left tissue . Skeletal muscle cells of the rats were isolated with collagenase. ② Differential attachment was used to purify the skeletal muscle cells of the rats. After screened with cell screen cloth , cell suspension was transferred into a polylysine-coated flask and cultured at 37 ℃ in a humid atmosphere with 0.05 CO2 in air for 1 hour. All the cells that did not adhere to the flask were then transferred to another flask with new culture medium and cultured for approximately 1 hour at 37 ℃ .Again,the non-adhering cells were

  8. Effects of two medicinal plants Psidium guajava L. (Myrtaceae) and Diospyros mespiliformis L. (Ebenaceae) leaf extracts on rat skeletal muscle cells in primary culture

    Institute of Scientific and Technical Information of China (English)

    BELEMTOUGRI R.G.; CONSTANTIN B.; COGNARD C.; RAYMOND G.; SAWADOGO L.

    2006-01-01

    Crude decoction, aqueous and ethanolic extracts of two medicinal plants (Psidium guajava and Diospyros mespiliformis), widely used in the central plateau of Burkina Faso to treat many diseases were evaluated for their antagonistic effects on caffeine induced calcium release from sarcoplasmic reticulum of rat skeletal muscle cells. These different extracts showed a decrease of caffeine induced calcium release in a dose dependent manner. Comparison of the results showed that Psidium guajava leaf extracts are more active than extracts ofDiospyros mespiliformis and that crude decoctions show better inhibitory activity.The observed results could explaine their use as antihypertensive and antidiarrhoeal agents in traditional medicine, by inhibiting intracellular calcium release.

  9. Thalidomide affects the skeletal system of ovariectomized rats.

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    Kaczmarczyk-Sedlak, Ilona; Folwarczna, Joanna; Trzeciak, Henryk I

    2009-01-01

    Apart from having written an inglorious chapter in the history of medicine, thalidomide is currently being intensely studied because of its multidimensional activity. The aim of this study was to examine the effects of thalidomide on the skeletal system in ovariectomized and non-ovariectomized rats. The experiments were carried out with female Wistar rats, divided into eight groups: sham-operated control rats; sham-operated rats receiving thalidomide at doses of 15, 30 or 60 mg/kg, po; ovariectomized control rats; ovariectomized rats receiving thalidomide at doses of 15, 30 or 60 mg/kg, po. The drug was administered for 4 weeks. Body mass gain and the mass of the uterus, liver, spleen and thymus were studied. Macrometric parameters and content of mineral substances, calcium and phosphorus in the femur, tibia and L-4 vertebra and histomorphometric parameters of the femur and tibia were examined. In the femur, the mechanical properties of the whole bone and of the femoral neck were examined. Thalidomide did not affect the skeletal system of the non-ovariectomized rats. Bilateral ovariectomy induced osteoporotic skeletal changes in mature female rats. The effects of thalidomide on the skeletal system of ovariectomized rats depended on the dose used. With a dose of 15 mg/kg, po, thalidomide counteracted some osteoporotic changes induced by estrogen deficiency. With a dose of 60 mg/kg, po, thalidomide intensified the destructive effects of estrogen deficiency on the rat skeletal system.

  10. Formation of hydrogen peroxide and nitric oxide in rat skeletal muscle cells during contractions

    DEFF Research Database (Denmark)

    Silveira, Leonardo R.; Pereira-Da-Silva, Lucia; Juel, Carsten

    2003-01-01

    We examined intra- and extracellular H(2)O(2) and NO formation during contractions in primary rat skeletal muscle cell culture. The fluorescent probes DCFH-DA/DCFH (2,7-dichlorofluorescein-diacetate/2,7-dichlorofluorescein) and DAF-2-DA/DAF-2 (4,5-diaminofluorescein-diacetate/4,5-diaminofluoresce...

  11. Carboxylic ester hydrolases in mitochondria from rat skeletal muscle

    DEFF Research Database (Denmark)

    Kirkeby, S; Moe, D; Zelander, T

    1990-01-01

    A mitochondrial pellet, prepared from rat skeletal muscle, contained a number of carboxylic ester hydrolase isoenzymes. The esterases which split alpha-naphthyl acetate were organophosphate sensitive, whereas two out of three indoxyl acetate hydrolysing enzymes were resistant to both organophosph......A mitochondrial pellet, prepared from rat skeletal muscle, contained a number of carboxylic ester hydrolase isoenzymes. The esterases which split alpha-naphthyl acetate were organophosphate sensitive, whereas two out of three indoxyl acetate hydrolysing enzymes were resistant to both...

  12. 大鼠骨骼肌卫星细胞的原代培养鉴定和体外分化特点%Study on culture, identification and differentiation of primary rat skeletal muscle satellite cells

    Institute of Scientific and Technical Information of China (English)

    冯永强; 李峥; 褚万立; 郁永辉; 马丽; 柴家科

    2016-01-01

    目的 建立骨骼肌卫星细胞(SMSC)的体外分离、原代培养、鉴定方法,观察细胞的成肌分化特点.方法 采用组织块法结合差速贴壁法获得SMSC.采用免疫荧光和流式细胞仪以Pax7为标志物鉴定分离获得的卫星细胞纯度,用分化培养基诱导SMSC的体外分化,实时定量PCR法检测分化标志基因成肌决定因子(MyoD)和生肌素的mRNA相对表达量.结果 组织块法培养约1周,可见细胞从组织块边缘爬出.经差速贴壁法纯化后,流式细胞仪检测所获得的原代SMSC纯度可达97.6%.细胞体外诱导分化后,MyoD和生肌素基因呈时序性表达.结论 组织块法可成功获得高纯度的SMSC,在体外具有良好的分化能力.%Objective To establish the isolation,culture and identification methods of primary rat skeletal muscle satellite cells (SMSC) and observe its characterization of differentiation in vitro.Methods Skeletal muscle satellite cells were obtained by tissue block culture method in combination with pre-plating techniques,and the purity of these cells was detected by both immunocytochemistry and fluorescence activated cell sorter (FACS) with Pax7 as marker of SMSC.Myogenesis of these cells was induced in differentiation medium and the mRNA expressions of myogenic differentiation gene (MyoD) and Myogenin were determined by Real-time polymerase chain reaction (PCR).Results Cells crawled out from the edge of tissue blocks after 1 week of culture.After purification by pre-plating techniques,more than 97.6% of the cells expressed Pax7,a unique marker of satellite cells.The mRNA of MyoD and Myogenin showed timespecific expression in the myogenesis induction process in vitro.Conclusion Skeletal muscle satellite cells with high purity and strong differentiation ability can be obtained by means of tissue block culture method.

  13. Culturing rat hippocampal neurons.

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    Audesirk, G; Audesirk, T; Ferguson, C

    2001-01-01

    Cultured neurons are widely used to investigate the mechanisms of neurotoxicity. Embryonic rat hippocampal neurons may be grown as described under a wide variety of conditions to suit differing experimental procedures, including electrophysiology, morphological analysis of neurite development, and various biochemical and molecular analyses.

  14. Teratogenic effects of Gentamicin on skeletal system of rat fetuses

    Directory of Open Access Journals (Sweden)

    Marzban H

    1999-09-01

    Full Text Available Gentamicin was evaluated for developmental toxicity in pregnant Sprague-Dawley rat. Gentamicin was administered subcutaneously on days 6-15 gestation at dose of 100 mg/kg. On gestation day 21, all live fetuses were examined for external and skeletal malformations and variations. Increased resorptions and dead fetuses, and reduced fetal body weight were observed at dose of 100 mg/kg. Gentamicin caused severe skeletal anomalies, such as: wavy ribs, incomplete ossification of sternebrae, tail vertebra, metacarpus, metatarsus and calvaria. These results indicate the nature and extent of embryotoxicity and teratogenicity of gentamicin in Sprague-Dawley rats.

  15. Prolonged Culture of Aligned Skeletal Myotubes on Micromolded Gelatin Hydrogels

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    Bettadapur, Archana; Suh, Gio C.; Geisse, Nicholas A.; Wang, Evelyn R.; Hua, Clara; Huber, Holly A.; Viscio, Alyssa A.; Kim, Joon Young; Strickland, Julie B.; McCain, Megan L.

    2016-06-01

    In vitro models of skeletal muscle are critically needed to elucidate disease mechanisms, identify therapeutic targets, and test drugs pre-clinically. However, culturing skeletal muscle has been challenging due to myotube delamination from synthetic culture substrates approximately one week after initiating differentiation from myoblasts. In this study, we successfully maintained aligned skeletal myotubes differentiated from C2C12 mouse skeletal myoblasts for three weeks by utilizing micromolded (μmolded) gelatin hydrogels as culture substrates, which we thoroughly characterized using atomic force microscopy (AFM). Compared to polydimethylsiloxane (PDMS) microcontact printed (μprinted) with fibronectin (FN), cell adhesion on gelatin hydrogel constructs was significantly higher one week and three weeks after initiating differentiation. Delamination from FN-μprinted PDMS precluded robust detection of myotubes. Compared to a softer blend of PDMS μprinted with FN, myogenic index, myotube width, and myotube length on μmolded gelatin hydrogels was similar one week after initiating differentiation. However, three weeks after initiating differentiation, these parameters were significantly higher on μmolded gelatin hydrogels compared to FN-μprinted soft PDMS constructs. Similar results were observed on isotropic versions of each substrate, suggesting that these findings are independent of substrate patterning. Our platform enables novel studies into skeletal muscle development and disease and chronic drug testing in vitro.

  16. Isolation and Culture of Satellite Cells from Mouse Skeletal Muscle.

    Science.gov (United States)

    Musarò, Antonio; Carosio, Silvia

    2017-01-01

    Skeletal muscle tissue is characterized by a population of quiescent mononucleated myoblasts, localized between the basal lamina and sarcolemma of myofibers, known as satellite cells. Satellite cells play a pivotal role in muscle homeostasis and are the major source of myogenic precursors in mammalian muscle regeneration.This chapter describes protocols for isolation and culturing satellite cells isolated from mouse skeletal muscles. The classical procedure, which will be discussed extensively in this chapter, involves the enzymatic dissociation of skeletal muscles, while the alternative method involves isolation of satellite cells from isolated myofibers in which the satellite cells remain in their in situ position underneath the myofiber basal lamina.In particular, we discuss the technical aspect of satellite cell isolation, the methods necessary to enrich the satellite cell fraction and the culture conditions that optimize proliferation and myotube formation of mouse satellite cells.

  17. Kinetics of lactate and pyruvate transport in cultured rat myotubes

    DEFF Research Database (Denmark)

    von Grumbckow, Lena; Elsner, Peter; Hellsten, Ylva;

    1999-01-01

    Skeletal muscle transport of lactate and pyruvate was studied in primary cultures of rat myotubes, applying the pH-sensitive fluorescent indicator 2', 7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. The initial rate of decrease in intracellular pH (pHi) upon lactate or pyruvate incubation was used...

  18. Angiotensin II induces differential insulin action in rat skeletal muscle.

    Science.gov (United States)

    Surapongchai, Juthamard; Prasannarong, Mujalin; Bupha-Intr, Tepmanas; Saengsirisuwan, Vitoon

    2017-03-01

    Angiotensin II (ANGII) is reportedly involved in the development of skeletal muscle insulin resistance. The present investigation evaluated the effects of two ANGII doses on the phenotypic characteristics of insulin resistance syndrome and insulin action and signaling in rat skeletal muscle. Male Sprague-Dawley rats were infused with either saline (SHAM) or ANGII at a commonly used pressor dose (100 ng/kg/min; ANGII-100) or a higher pressor dose (500 ng/kg/min; ANGII-500) via osmotic minipumps for 14 days. We demonstrated that ANGII-100-infused rats exhibited the phenotypic features of non-obese insulin resistance syndrome, including hypertension, impaired glucose tolerance and insulin resistance of glucose uptake in the soleus muscle, whereas ANGII-500-treated rats exhibited diabetes-like symptoms, such as post-prandial hyperglycemia, impaired insulin secretion and hypertriglyceridemia. At the cellular level, insulin-stimulated glucose uptake in the soleus muscle of the ANGII-100 group was 33% lower (P study demonstrates for the first time that chronic infusion with these two pressor doses of ANGII induced differential metabolic responses at both the systemic and skeletal muscle levels.

  19. Mechanically induced alterations in cultured skeletal muscle growth

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    Vandenburgh, H. H.; Hatfaludy, S.; Karlisch, P.; Shansky, J.

    1991-01-01

    Model systems are available for mechanically stimulating cultured skeletal muscle cells by passive tensile forces which simulate those found in vivo. When applied to embryonic muscle cells in vitro these forces induce tissue organogenesis, metabolic adaptations, and muscle cell growth. The mechanical stimulation of muscle cell growth correlates with stretch-induced increases in the efflux of prostaglandins PGE2 and PGF2(alpha) in a time and frequency dependent manner. These prostaglandins act as mechanical 'second messengers' regulating skeletal muscle protein turnover rates. Since they also effect bone remodelling in response to tissue loading and unloading, secreted prostaglandins may serve as paracrine growth factors, coordinating the growth rates of muscle and bone in response to external mechanical forces. Cell culture model systems will supplement other models in understanding mechanical transduction processes at the molecular level.

  20. Improved Cell Culture Method for Growing Contracting Skeletal Muscle Models

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    Marquette, Michele L.; Sognier, Marguerite A.

    2013-01-01

    An improved method for culturing immature muscle cells (myoblasts) into a mature skeletal muscle overcomes some of the notable limitations of prior culture methods. The development of the method is a major advance in tissue engineering in that, for the first time, a cell-based model spontaneously fuses and differentiates into masses of highly aligned, contracting myotubes. This method enables (1) the construction of improved two-dimensional (monolayer) skeletal muscle test beds; (2) development of contracting three-dimensional tissue models; and (3) improved transplantable tissues for biomedical and regenerative medicine applications. With adaptation, this method also offers potential application for production of other tissue types (i.e., bone and cardiac) from corresponding precursor cells.

  1. Mechanically induced alterations in cultured skeletal muscle growth

    Science.gov (United States)

    Vandenburgh, H. H.; Hatfaludy, S.; Karlisch, P.; Shansky, J.

    1991-01-01

    Model systems are available for mechanically stimulating cultured skeletal muscle cells by passive tensile forces which simulate those found in vivo. When applied to embryonic muscle cells in vitro these forces induce tissue organogenesis, metabolic adaptations, and muscle cell growth. The mechanical stimulation of muscle cell growth correlates with stretch-induced increases in the efflux of prostaglandins PGE2 and PGF2(alpha) in a time and frequency dependent manner. These prostaglandins act as mechanical 'second messengers' regulating skeletal muscle protein turnover rates. Since they also effect bone remodelling in response to tissue loading and unloading, secreted prostaglandins may serve as paracrine growth factors, coordinating the growth rates of muscle and bone in response to external mechanical forces. Cell culture model systems will supplement other models in understanding mechanical transduction processes at the molecular level.

  2. Effects of curcumin on the skeletal system in rats.

    Science.gov (United States)

    Folwarczna, Joanna; Zych, Maria; Trzeciak, Henryk I

    2010-01-01

    There is increasing interest in the discovery of natural compounds that could favorably affect the skeletal system. Curcumin is a constituent of turmeric, a plant which has been used for centuries as a dietary spice and a traditional Indian medicine. Curcumin has been reported to affect differentiation, activity and the lifespan of osteoblasts and osteoclasts in vitro. The aim of the present study was to investigate the effects of curcumin on the skeletal system of rats in vivo. Curcumin (10 mg/kg, po daily) was administered for four weeks to normal (non-ovariectomized) and bilaterally ovariectomized (estrogen-deficient) three-month-old female Wistar Cmd:(WI)WU rats. Ovariectomy was performed seven days before the start of curcumin administration. Bone mass, mineral and calcium content, macrometric and histomorphometric parameters, as well as the mechanical properties of the bone, were examined. Serum total cholesterol and estradiol levels were also determined. In rats with normal estrogen levels, curcumin decreased serum estradiol level and slightly increased cancellous bone formation, along with decreased mineralization. Estrogen deficiency induced osteoporotic changes in the skeletal system of the ovariectomized control rats. In ovariectomized rats, curcumin decreased body mass gain and serum total cholesterol level, slightly improved some bone histomorphometric parameters impaired by estrogen deficiency, but did not improve bone mineralization or mechanical properties. In conclusion, the results of the present in vivo study in rats did not support the hypothesis that curcumin, at doses that are readily achievable through dietary intake, could be useful for the prevention or treatment of osteoporosis.

  3. Passive stiffness of rat skeletal muscle undernourished during fetal development

    Directory of Open Access Journals (Sweden)

    Ana Elisa Toscano

    2010-01-01

    Full Text Available OBJECTIVES: The aim of the study was to investigate the effect of fetal undernutrition on the passive mechanical properties of skeletal muscle of weaned and young adult rats. INTRODUCTION: A poor nutrition supply during fetal development affects physiological functions of the fetus. From a mechanical point of view, skeletal muscle can be also characterized by its resistance to passive stretch. METHODS: Male Wistar rats were divided into two groups according to their mother's diet during pregnancy: a control group (mothers fed a 17% protein diet and an isocaloric low-protein group (mothers fed a 7.8% protein diet. At birth, all mothers received a standardized meal ad libitum. At the age of 25 and 90 days, the soleus muscle and extensor digitorum longus (EDL muscles were removed in order to test the passive mechanical properties. A first mechanical test consisted of an incremental stepwise extension test using fast velocity stretching (500 mm/s enabling us to measure, for each extension stepwise, the dynamic stress (σd and the steady stress (σs. A second test consisted of a slow velocity stretch in order to calculate normalized stiffness and tangent modulus from the stress-strain relationship. RESULTS: The results for the mechanical properties showed an important increase in passive stiffness in both the soleus and EDL muscles in weaned rat. In contrast, no modification was observed in young adult rats. CONCLUSIONS: The increase in passive stiffness in skeletal muscle of weaned rat submitted to intrauterine undernutrition it is most likely due to changes in muscle passive stiffness.

  4. Purinergic effects on Na,K-ATPase activity differ in rat and human skeletal muscle

    DEFF Research Database (Denmark)

    Juel, Carsten; Nordsborg, Nikolai Baastrup; Bangsbo, Jens

    2014-01-01

    P2Y receptor activation may link the effect of purines to increased maximal in vitro activity of the Na,K-ATPase in rat muscle. The hypothesis that a similar mechanism is present in human skeletal muscle was investigated with membranes from rat and human skeletal muscle.......P2Y receptor activation may link the effect of purines to increased maximal in vitro activity of the Na,K-ATPase in rat muscle. The hypothesis that a similar mechanism is present in human skeletal muscle was investigated with membranes from rat and human skeletal muscle....

  5. Osteogenic Differentiation Capacity of In Vitro Cultured Human Skeletal Muscle for Expedited Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Chunlei Miao

    2017-01-01

    Full Text Available Expedited bone tissue engineering employs the biological stimuli to harness the intrinsic regenerative potential of skeletal muscle to trigger the reparative process in situ to improve or replace biological functions. When genetically modified with adenovirus mediated BMP2 gene transfer, muscle biopsies from animals have demonstrated success in regenerating bone within rat bony defects. However, it is uncertain whether the human adult skeletal muscle displays an osteogenic potential in vitro when a suitable biological trigger is applied. In present study, human skeletal muscle cultured in a standard osteogenic medium supplemented with dexamethasone demonstrated significant increase in alkaline phosphatase activity approximately 24-fold over control at 2-week time point. More interestingly, measurement of mRNA levels revealed the dramatic results for osteoblast transcripts of alkaline phosphatase, bone sialoproteins, transcription factor CBFA1, collagen type I, and osteocalcin. Calcified mineral deposits were demonstrated on superficial layers of muscle discs after an extended 8-week osteogenic induction. Taken together, these are the first data supporting human skeletal muscle tissue as a promising potential target for expedited bone regeneration, which of the technologies is a valuable method for tissue repair, being not only effective but also inexpensive and clinically expeditious.

  6. Osteogenic Differentiation Capacity of In Vitro Cultured Human Skeletal Muscle for Expedited Bone Tissue Engineering

    Science.gov (United States)

    Miao, Chunlei; Zhou, Lulu; Tian, Lufeng; Zhang, Yingjie; Zhang, Wei; Yang, Fanghong; Liu, Tianyi

    2017-01-01

    Expedited bone tissue engineering employs the biological stimuli to harness the intrinsic regenerative potential of skeletal muscle to trigger the reparative process in situ to improve or replace biological functions. When genetically modified with adenovirus mediated BMP2 gene transfer, muscle biopsies from animals have demonstrated success in regenerating bone within rat bony defects. However, it is uncertain whether the human adult skeletal muscle displays an osteogenic potential in vitro when a suitable biological trigger is applied. In present study, human skeletal muscle cultured in a standard osteogenic medium supplemented with dexamethasone demonstrated significant increase in alkaline phosphatase activity approximately 24-fold over control at 2-week time point. More interestingly, measurement of mRNA levels revealed the dramatic results for osteoblast transcripts of alkaline phosphatase, bone sialoproteins, transcription factor CBFA1, collagen type I, and osteocalcin. Calcified mineral deposits were demonstrated on superficial layers of muscle discs after an extended 8-week osteogenic induction. Taken together, these are the first data supporting human skeletal muscle tissue as a promising potential target for expedited bone regeneration, which of the technologies is a valuable method for tissue repair, being not only effective but also inexpensive and clinically expeditious. PMID:28210626

  7. Blockades of mitogen-activated protein kinase and calcineurin both change fibre-type markers in skeletal muscle culture

    DEFF Research Database (Denmark)

    Higginson, James; Wackerhage, Henning; Woods, Niall

    2002-01-01

    A and mitogen-activated protein kinase kinase (MEK1/2) blockade with U0126 upon myosin heavy chain (MHC) isoform mRNA levels and activities of metabolic enzymes after 1 day, 3 days and 7 days of treatment in primary cultures of spontaneously twitching rat skeletal muscle. U0126 treatment significantly decreased......Activation of either the calcineurin or the extracellular signal-regulated kinase (ERK1/2) pathway increases the percentage of slow fibres in vivo suggesting that both pathways can regulate fibre phenotypes in skeletal muscle. We investigated the effect of calcineurin blockade with cyclosporin...

  8. Ectopic development of skeletal muscle induced by subcutaneous transplant of rat satellite cells

    Directory of Open Access Journals (Sweden)

    M.G. Fukushima

    2005-03-01

    Full Text Available The present study analyzes the ectopic development of the rat skeletal muscle originated from transplanted satellite cells. Satellite cells (10(6 cells obtained from hindlimb muscles of newborn female 2BAW Wistar rats were injected subcutaneously into the dorsal area of adult male rats. After 3, 7, and 14 days, the transplanted tissues (N = 4-5 were processed for histochemical analysis of peripheral nerves, inactive X-chromosome and acetylcholinesterase. Nicotinic acetylcholine receptors (nAChRs were also labeled with tetramethylrhodamine-labeled alpha-bungarotoxin. The development of ectopic muscles was successful in 86% of the implantation sites. By day 3, the transplanted cells were organized as multinucleated fibers containing multiple clusters of nAChRs (N = 2-4, resembling those from non-innervated cultured skeletal muscle fibers. After 7 days, the transplanted cells appeared as a highly vascularized tissue formed by bundles of fibers containing peripheral nuclei. The presence of X chromatin body indicated that subcutaneously developed fibers originated from female donor satellite cells. Differently from the extensor digitorum longus muscle of adult male rat (87.9 ± 1.0 µm; N = 213, the diameter of ectopic fibers (59.1 µm; N = 213 did not obey a Gaussian distribution and had a higher coefficient of variation. After 7 and 14 days, the organization of the nAChR clusters was similar to that of clusters from adult innervated extensor digitorum longus muscle. These findings indicate the histocompatibility of rats from 2BAW colony and that satellite cells transplanted into the subcutaneous space of adult animals are able to develop and fuse to form differentiated skeletal muscle fibers.

  9. Leucine supplementation improves regeneration of skeletal muscles from old rats.

    Science.gov (United States)

    Pereira, Marcelo G; Silva, Meiricris T; da Cunha, Fernanda M; Moriscot, Anselmo S; Aoki, Marcelo S; Miyabara, Elen H

    2015-12-01

    The decreased regenerative capacity of old skeletal muscles involves disrupted turnover of proteins. This study investigated whether leucine supplementation in old rats could improve muscle regenerative capacity. Young and old male Wistar rats were supplemented with leucine; then, the muscles were cryolesioned and examined after 3 and 10 days. Leucine supplementation attenuated the decrease in the expression of eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1) and eukaryotic translation initiation factor 4E (eIF4E) in young and old muscles on day 3 post-injury and promoted an increase in the cross-sectional area of regenerating myofibers from both young and old soleus muscles on day 10 post-injury. This supplementation decreased the levels of ubiquitinated proteins and increased the proteasome activity in young regenerating muscles, but the opposite effect was observed in old regenerating muscles. Moreover, leucine decreased the inflammation area and induced an increase in the number of proliferating satellite cells in both young and old muscles. Our results suggest that leucine supplementation improves the regeneration of skeletal muscles from old rats, through the preservation of certain biological responses upon leucine supplementation. Such responses comprise the decrease in the inflammation area, increase in the number of proliferating satellite cells and size of regenerating myofibers, combined with the modulation of components of the phosphoinositide 3-kinase/Akt-protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway and ubiquitin-proteasome system.

  10. Mineralization and growth of cultured embryonic skeletal tissue in microgravity

    Science.gov (United States)

    Klement, B. J.; Spooner, B. S.

    1999-01-01

    Microgravity provides a unique environment in which to study normal and pathological phenomenon. Very few studies have been done to examine the effects of microgravity on developing skeletal tissue such as growth plate formation and maintenance, elongation of bone primordia, or the mineralization of growth plate cartilage. Embryonic mouse premetatarsal triads were cultured on three space shuttle flights to study cartilage growth, differentiation, and mineralization, in a microgravity environment. The premetatarsal triads that were cultured in microgravity all formed cartilage rods and grew in length. However, the premetatarsal cartilage rods cultured in microgravity grew less in length than the ground control cartilage rods. Terminal chondrocyte differentiation also occurred during culture in microgravity, as well as in the ground controls, and the matrix around the hypertrophied chondrocytes was capable of mineralizing in both groups. The same percentage of premetatarsals mineralized in the microgravity cultures as mineralized in the ground control cultures. In addition, the sizes of the mineralized areas between the two groups were very similar. However, the amount of 45Ca incorporated into the mineralized areas was significantly lower in the microgravity cultures, suggesting that the composition or density of the mineralized regions was compromised in microgravity. There was no significant difference in the amount of 45Ca liberated from prelabeled explants in microgravity or in the ground controls.

  11. Skeletal muscle metabolism in hypokinetic rats

    Science.gov (United States)

    Tischler, Marc E.

    1993-01-01

    This grant focused on the mechanisms of metabolic changes associated with unweighting atrophy and reduced growth of hind limb muscles of juvenile rats. Metabolic studies included a number of different areas. Amino acid metabolic studies placed particular emphasis on glutamine and branched-chain amino acid metabolism. These studies were an outgrowth of understanding stress effects and the role of glucocorticoids in these animals. Investigations on protein metabolism were largely concerned with selective loss of myofibrillar proteins and the role of muscle proteolysis. These investigations lead to finding important differences from denervation and atrophy and to define the roles of cytosolic versus lysosomal proteolysis in these atrophy models. A major outgrowth of these studies was demonstrating an ability to prevent atrophy of the unweighted muscle for at least 24 hours. A large amount of work concentrated on carbohydrate metabolism and its regulation by insulin and catecholamines. Measurements focused on glucose transport, glycogen metabolism, and glucose oxidation. The grant was used to develop an important new in situ approach for studying protein metabolism, glucose transport, and hormonal effects which involves intramuscular injection of various agents for up to 24 hours. Another important consequence of this project was the development and flight of Physiological-Anatomical Rodent Experiment-1 (PARE-1), which was launched aboard Space Shuttle Discovery in September 1991. Detailed descriptions of these studies can be found in the 30 peer-reviewed publications, 15 non-reviewed publications, 4 reviews and 33 abstracts (total 82 publications) which were or are scheduled to be published as a result of this project. A listing of these publications grouped by area (i.e. amino acid metabolism, protein metabolism, carbohydrate metabolism, and space flight studies) are included.

  12. Quercetin protects rat skeletal muscle from ischemia reperfusion injury.

    Science.gov (United States)

    Ekinci Akdemir, Fazile Nur; Gülçin, İlhami; Karagöz, Berna; Soslu, Recep

    2016-01-01

    In this study, we investigated the potential beneficial effects of quercetin on skeletal muscle ischemia reperfusion injury. Twenty-four Sprague-Dawley type rats were randomly divided into four groups. In the sham group, only gastrocnemius muscle were removed and given no quercetin. In ischemia group, all the femoral artery, vein and collaterals were occluded in the left hindlimb by applying tourniquate under general anaesthesia for three hours but reperfusion was not done. In the Quercetin + Ischemia reperfusion group, quercetin (200 mg kg(-1) dose orally) was given during one-week reoperation and later ischemia reperfusion model was done. Finally, gastrocnemius muscle samples were removed to measure biochemical parameters. The biomarkers, MDA levels, SOD, CAT and GPx activities, were evaluated related to skeletal muscle ischemia reperfusion injury. MDA levels reduced and SOD, CAT and GPx activities increased significantly in Quercetin + Ischemia reperfusion group. Results clearly showed that Quercetin have a protective role against oxidative damage induced by ischemia reperfusion in rats.

  13. Effect of weak static magnetic fields on the development of cultured skeletal muscle cells.

    Science.gov (United States)

    Surma, Sergei V; Belostotskaya, Galina B; Shchegolev, Boris F; Stefanov, Vasily E

    2014-12-01

    We studied the effect produced on the development and functional activity of skeletal muscle cells from newborn Wistar rats in primary culture by weak static magnetic fields (WSMF; 60-400 µT) with a high capacity of penetrating the biological media. To reduce the impact of external magnetic fields, cells were cultured at 37 °C in a multilayered shielding chamber with the attenuation coefficient equal to 160. WSMF inside the chamber was created by a circular permanent magnet. We found that the application of WSMF with the magnetic field strength only a few times that of the geomagnetic field can accelerate the development of skeletal muscle cells, resulting in the formation of multinuclear hypertrophied myotubes. WSMF was shown to induce 1.5- to 3.5-fold rise in the concentration of intracellular calcium [Ca(2+)]i due to the release of Ca(2+) from the sarcoplasmic reticulum (SR) through ryanodine receptors (RyR), which increases in the maturation of myotubes. We also found that fully differentiated myotubes at late stages of development were less sensitive to WSMF, manifesting a gradual decrease in the frequency of contractions. However, myotubes at the stage when electromechanical coupling was forming dramatically reduced the frequency of contractions during the first minutes of their exposure to WSMF.

  14. Calcium regulation of oxidative phosphorylation in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Kavanagh, N I; Ainscow, E K; Brand, M D

    2000-02-24

    Activation of oxidative phosphorylation by physiological levels of calcium in mitochondria from rat skeletal muscle was analysed using top-down elasticity and regulation analysis. Oxidative phosphorylation was conceptually divided into three subsystems (substrate oxidation, proton leak and phosphorylation) connected by the membrane potential or the protonmotive force. Calcium directly activated the phosphorylation subsystem and (with sub-saturating 2-oxoglutarate) the substrate oxidation subsystem but had no effect on the proton leak kinetics. The response of mitochondria respiring on 2-oxoglutarate at two physiological concentrations of free calcium was quantified using control and regulation analysis. The partial integrated response coefficients showed that direct stimulation of substrate oxidation contributed 86% of the effect of calcium on state 3 oxygen consumption, and direct activation of the phosphorylation reactions caused 37% of the increase in phosphorylation flux. Calcium directly activated phosphorylation more strongly than substrate oxidation (78% compared to 45%) to achieve homeostasis of mitochondrial membrane potential during large increases in flux.

  15. Culture of cryopreserved rat hepatocyte

    Institute of Scientific and Technical Information of China (English)

    Haitao Yin; Gaojun Teng; Lifeng Wang; Baorui Liu; Xiaoping Qian

    2006-01-01

    Objective: To study the method of cryopreserving rat hepatocytes and double collagen gel culture measurement after its cryopreservation. Methods: Rat hepatocytes, isolated by two-step perfusion with collagenase using an extra corporeal perfusion apparatus, were cryopreserved in double collagen gel with culture medium added by epidermal growth factor(EGF).The expression of cell function and cellular morphology were examined during culture. Results: The hepatocytes cryopreserved in double collagen gel concluding EGF showed good morphology and biological characteristics. After thawing, the MTT metabolism and protein synthesis of hepatocytes in sandwich ± EGF groups were better than those in control group. And the morphology and function of hepatocytes in sandwich group was better than that in EGF group(P < 0.05). Conclusion: Double collagen gel culture can keep hepatocyte's activities. Thawed hepatocytes can be cultivated with collagenous matrix, which provides an environment that more closely resembles that in vivo and maintain the expression of certain liver-specific function of hepatocytes.

  16. Alpha-adrenergic receptors in rat skeletal muscle

    DEFF Research Database (Denmark)

    Rattigan, S; Appleby, G J; Edwards, S J;

    1986-01-01

    Sarcolemma-enriched preparations from muscles rich in slow oxidative red fibres contained specific binding sites for the alpha 1 antagonist, prazosin (e.g. soleus Kd 0.13 nM, Bmax 29 fmol/mg protein). Binding sites for prazosin were almost absent from white muscle. Displacement of prazosin bindin...... adrenergic receptors are present on the sarcolemma of slow oxidative red fibres of rat skeletal muscle. The presence provides the mechanistic basis for apparent alpha-adrenergic effects to increase glucose and oxygen uptake in perfused rat hindquarter.......Sarcolemma-enriched preparations from muscles rich in slow oxidative red fibres contained specific binding sites for the alpha 1 antagonist, prazosin (e.g. soleus Kd 0.13 nM, Bmax 29 fmol/mg protein). Binding sites for prazosin were almost absent from white muscle. Displacement of prazosin binding...... from sarcolemma of soleus muscle (phentolamine greater than phenylephrine greater than idazoxan greater than yohimbine) suggested that the receptors were alpha 1. Binding sites for dihydroalprenolol (beta antagonist) were also more concentrated on red than white muscle and outnumbered prazosin sites...

  17. Dexamethasone regulates glutamine synthetase expression in rat skeletal muscles

    Science.gov (United States)

    Max, Stephen R.; Konagaya, Masaaki; Konagaya, Yoko; Thomas, John W.; Banner, Carl; Vitkovic, Ljubisa

    1986-01-01

    The regulation of glutamine synthetase by glucocorticoids in rat skeletal muscles was studied. Administration of dexamethasone strikingly enhanced glutamine synthetase activity in plantaris and soleus muscles. The dexamethasone-mediated induction of glutamine synthetase activity was blocked to a significant extent by orally administered RU38486, a glucocorticoid antagonist, indicating the involvement of intracellular glucocorticoid receptors in the induction. Northern blot analysis revealed that dexamethasone-mediated enhancement of glutamine synthetase activity involves dramatically increased levels of glutamine synthetase mRNA. The induction of glutamine synthetase was selective in that glutaminase activity of soleus and plantaris muscles was not increased by dexamethasone. Furthermore, dexamethasone treatment resulted in only a small increase in glutamine synthetase activity in the heart. Accordingly, there was only a slight change in glutamine synthetase mRNA level in this tissue. Thus, glucocorticoids regulate glutamine synthetase gene expression in rat muscles at the transcriptional level via interaction with intracellular glutamine production by muscle and to mechanisms underlying glucocorticoid-induced muscle atrophy.

  18. Preservation of rat skeletal muscle energy metabolism by illumination.

    Science.gov (United States)

    Lindgård, Ann; Lundberg, Jonas; Rakotonirainy, Olivier; Elander, Anna; Soussi, Bassam

    2003-04-25

    Skeletal muscle viability is crucially dependent on the tissue levels of its high energy phosphates. In this study we investigated the effect of the preservation medium Perfadex and illumination with Singlet Oxygen Energy (SOE). Singlet oxygen can be produced photochemically by energy transfer from an excited photosensitizer. The energy emitted from singlet oxygen upon relaxation to its triplet state is captured as photons at 634 nm and is here referred to as SOE. Rat hind limb rectus femoris muscles were preserved for five hours at 22 degrees C in Perfadex, saline, SOE illuminated Perfadex or SOE illuminated saline. Extracts of the muscles were analysed by 31P NMR. Data were analysed using two-way analysis of variance and are given as mean values micromol/g dry weight) +/- SEM. The ATP concentration was higher (p = 0.006) in saline groups (4.52) compared with Perfadex groups (2.82). There was no statistically significant difference in PCr between the saline groups (1.25) and Perfadex groups (0.82). However, there were higher (p = 0.003) ATP in the SOE illuminated groups (4.61) compared with the non-illuminated groups (2.73). The PCr was also higher (p < 0.0001) in the SOE illuminated groups (1.89) compared with the non-illuminated groups (0.18). In conclusion, Perfadex in this experimental model was incapable of preserving the high energy phosphates in skeletal muscle during 5 hours of ischemia. Illumination with SOE at 634 nm improved the preservation potential, in terms of a positive effect on the energy status of the muscle cell.

  19. Isolation, culture and biological characteristics of multipotent porcine skeletal muscle satellite cells.

    Science.gov (United States)

    Yang, Jinjuan; Liu, Hao; Wang, Kunfu; Li, Lu; Yuan, Hongyi; Liu, Xueting; Liu, Yingjie; Guan, Weijun

    2017-03-02

    Skeletal muscle has a huge regenerative potential for postnatal muscle growth and repair, which mainly depends on a kind of muscle progenitor cell population, called satellite cell. Nowadays, the majority of satellite cells were obtained from human, mouse, rat and other animals but rarely from pig. In this article, the porcine skeletal muscle satellite cells were isolated and cultured in vitro. The expression of surface markers of satellite cells was detected by immunofluorescence and RT-PCR assays. The differentiation capacity was assessed by inducing satellite cells into adipocytes, myoblasts and osteoblasts. The results showed that satellite cells isolated from porcine tibialis anterior were subcultured up to 12 passages and were positive for Pax7, Myod, c-Met, desmin, PCNA and NANOG but were negative for Myogenin. Satellite cells were also induced to differentiate into adipocytes, osteoblasts and myoblasts, respectively. These findings indicated that porcine satellite cells possess similar biological characteristics of stem cells, which may provide theoretical basis and experimental evidence for potential therapeutic application in the treatment of dystrophic muscle and other muscle injuries.

  20. Methods for the Organogenesis of Skeletal Muscle in Tissue Culture

    Science.gov (United States)

    Vandenburgh, Herman; Shansky, Janet; DelTatto, Michael; Chromiak, Joseph

    1997-01-01

    Skeletal muscle structure is regulated by many factors, including nutrition, hormones, electrical activity, and tension. The muscle cells are subjected to both passive and active mechanical forces at all stages of development and these forces play important but poorly understood roles in regulating muscle organogenesis and growth. For example, during embryogenesis, the rapidly growing skeleton places large passive mechanical forces on the attached muscle tissue. These forces not only help to organize the proliferating mononucleated myoblasts into the oriented, multinucleated myofibers of a functional muscle but also tightly couple the growth rate of muscle to that of bone. Postnatally, the actively contracting, innervated muscle fibers are subjected to different patterns of active and passive tensions which regulate longitudinal and cross sectional myofiber growth. These mechanically-induced organogenic processes have been difficult to study under normal tissue culture conditions, resulting in the development of numerous methods and specialized equipment to simulate the in vivo mechanical environment.These techniques have led to the "engineering" of bioartificial muscles (organoids) which display many of the characteristics of in vivo muscle including parallel arrays of postmitotic fibers organized into fascicle-like structures with tendon-like ends. They are contractile, express adult isoforms of contractile proteins, perform directed work, and can be maintained in culture for long periods. The in vivo-like characteristics and durability of these muscle organoids make them useful for long term in vitro studies on mechanotransduction mechanisms and on muscle atrophy induced by decreased tension. In this report, we described a simple method for generating muscle organoids from either primary embrionic avain or neonatal rodent myoblasts.

  1. Mangiferin protects against adverse skeletal muscle changes and enhances muscle oxidative capacity in obese rats.

    Science.gov (United States)

    Acevedo, Luz M; Raya, Ana I; Martínez-Moreno, Julio M; Aguilera-Tejero, Escolástico; Rivero, José-Luis L

    2017-01-01

    Obesity-related skeletal muscle changes include muscle atrophy, slow-to-fast fiber-type transformation, and impaired mitochondrial oxidative capacity. These changes relate with increased risk of insulin resistance. Mangiferin, the major component of the plant Mangifera indica, is a well-known anti-inflammatory, anti-diabetic, and antihyperlipidemic agent. This study tested the hypothesis that mangiferin treatment counteracts obesity-induced fiber atrophy and slow-to-fast fiber transition, and favors an oxidative phenotype in skeletal muscle of obese rats. Obese Zucker rats were fed gelatin pellets with (15 mg/kg BW/day) or without (placebo group) mangiferin for 8 weeks. Lean Zucker rats received the same gelatin pellets without mangiferin and served as non-obese and non-diabetic controls. Lesser diameter, fiber composition, and histochemical succinic dehydrogenase activity (an oxidative marker) of myosin-based fiber-types were assessed in soleus and tibialis cranialis muscles. A multivariate discriminant analysis encompassing all fiber-type features indicated that obese rats treated with mangiferin displayed skeletal muscle phenotypes significantly different compared with both lean and obese control rats. Mangiferin significantly decreased inflammatory cytokines, preserved skeletal muscle mass, fiber cross-sectional size, and fiber-type composition, and enhanced muscle fiber oxidative capacity. These data demonstrate that mangiferin attenuated adverse skeletal muscle changes in obese rats.

  2. Mangiferin protects against adverse skeletal muscle changes and enhances muscle oxidative capacity in obese rats

    Science.gov (United States)

    Acevedo, Luz M.; Raya, Ana I.; Martínez-Moreno, Julio M.

    2017-01-01

    Obesity-related skeletal muscle changes include muscle atrophy, slow-to-fast fiber-type transformation, and impaired mitochondrial oxidative capacity. These changes relate with increased risk of insulin resistance. Mangiferin, the major component of the plant Mangifera indica, is a well-known anti-inflammatory, anti-diabetic, and antihyperlipidemic agent. This study tested the hypothesis that mangiferin treatment counteracts obesity-induced fiber atrophy and slow-to-fast fiber transition, and favors an oxidative phenotype in skeletal muscle of obese rats. Obese Zucker rats were fed gelatin pellets with (15 mg/kg BW/day) or without (placebo group) mangiferin for 8 weeks. Lean Zucker rats received the same gelatin pellets without mangiferin and served as non-obese and non-diabetic controls. Lesser diameter, fiber composition, and histochemical succinic dehydrogenase activity (an oxidative marker) of myosin-based fiber-types were assessed in soleus and tibialis cranialis muscles. A multivariate discriminant analysis encompassing all fiber-type features indicated that obese rats treated with mangiferin displayed skeletal muscle phenotypes significantly different compared with both lean and obese control rats. Mangiferin significantly decreased inflammatory cytokines, preserved skeletal muscle mass, fiber cross-sectional size, and fiber-type composition, and enhanced muscle fiber oxidative capacity. These data demonstrate that mangiferin attenuated adverse skeletal muscle changes in obese rats. PMID:28253314

  3. Increased cellular proliferation in rat skeletal muscle and tendon in response to exercise

    DEFF Research Database (Denmark)

    Skovgaard, Dorthe; Bayer, Monika L; Mackey, Abigail

    2010-01-01

    PURPOSE: The purpose of this study is to investigate exercise-induced cellular proliferation in rat skeletal muscle/tendon with the use of 3'-[F-18]fluoro-3'deoxythymidine (FLT) and to quantitatively study concomitant changes in the proliferation-associated factor, Ki67. PROCEDURES: Wistar rats (...

  4. Glucose metabolism in rats submitted to skeletal muscle denervation

    Directory of Open Access Journals (Sweden)

    Wilton Marlindo Santana Nunes

    2005-07-01

    Full Text Available This study analyzed the local and systemic effects of immobilization by denervation of the skeletal muscle on glucose metabolism. The rats were submitted to section of the right paw sciatic nerve. A reduction was observed in glucose uptake by the isolated soleus muscle of the denervated paw after 3 and 7 days, but not after 28 days in relation to the control animals. There was no difference after 3 and 7 days in glucose uptake by the soleus muscle of the opposite intact paw in relation to the control. There was increased glucose uptake in the same paw 28 days after denervation. The rate of glucose removal in response to exogenous insulin after 28 days of denervation was significantly higher than in control animals and those observed after 3 and 7 days of denervation. These results suggest that immobilization by denervation interfered not only in glucose metabolism in the skeletal muscle involved but also in other tissues.O estudo analisou os efeitos locais e sistêmicos da imobilização por desnervação do músculo esquelético sobre o metabolismo glicidico. Ratos foram submetidos à secção do nervo ciático da pata direita. Observou-se redução da captação de glicose pelo músculo sóleo isolado da pata desnervada após 3 e 7 mas não após 28 dias em relação a animais controle. Não houve diferença após 3 e 7 dias na captação de glicose pelo músculo sóleo da pata contralateral intacta em relação ao controle. Houve aumento da captação de glicose nesta mesma pata 28 dias após a desnervação. A taxa de remoção da glicose em resposta à insulina exógena após 28 dias de desnervação foi significantemente superior à do controle e àquelas observadas após 3 e 7 dias da desnervação. Esses resultados sugerem que a imobilização por desnervação interfere não só no metabolismo da glicose no músculo esquelético envolvido como também em outros tecidos.

  5. Alterations in Skeletal Muscle Microcirculation of Head-Down Tilted Rats

    Science.gov (United States)

    Musacchia, X. J.; Stepke, Bernhard; Fleming, John T.; Joshua, Irving G.

    1992-01-01

    In this study we assessed the function of microscopic blood vessels in skeletal muscle (cremaster muscle) for alterations which may contribute to the observed elevation of blood pressure associated with head-down tilted whole body suspension (HDT/WBS), a model of weightlessness. Arteriolar baseline diameters, vasoconstrictor responses to norepinephrine (NE) and vasodilation to nitroprusside (NP) were assessed in control rats, rats suspended for 7 or 14 day HDT/WBS rats, and rats allowed to recover for 1 day after 7 days HDT/WBS. Neither baseline diameters nor ability to dilate were influenced by HDT/WBS. Maximum vasoconstriction to norepinephrine was significantly greater in arterioles of hypertensive 14 day HDT/WBS rats. This first study of the intact microvasculature in skeletal muscle indicates that an elevated contractility of arterioles to norepinephrine in suspended rats, and suggests an elevated peripheral resistance in striated muscle may contribute to the increase in blood pressures among animals subjected to HDT/WBS.

  6. The Effect of Exercise Training on Skeletal Muscle Glucose Transorter Isoform GLUT4 Concentration in the Obese Zucker Rat

    Science.gov (United States)

    1991-05-01

    NUMBERS The Effect of Exercise Training on Skeletal Muscle Glucose Transorter Isoform GLUT4 Concentration in the Obese Zucker Rat 6. AUTHOR(S) Eric A...Zr) THE EFFECT OF EXERCISE TRAINING ON SKELETAL MUSCLE GLUCOSE TRANSPORTER ISOFORM GLUT4 CONCENTRATION IN THE OBESE ZUCKER RAT by Eric Anthony Banks...laboratory for their help. Eric A. Banks v ABSTRACT THE EFFECT OF EXERCISE TRAINING ON SKELETAL MUSCLE GLUCOSE TRANSPORTER ISOFORM GLUT4 CONCENTRATION IN

  7. Prolonged exposure to resistin inhibits glucose uptake in rat skeletal muscles

    Institute of Scientific and Technical Information of China (English)

    Hong-qi FAN; Nan GU; Feng LIU; Li FEI; Xiao-qin PAN; Mei GUO; Rong-hua CHEN; Xi-rong GUO

    2007-01-01

    Aim: To assess the effects and mechanisms of the action of resistin on basal and insulin-stimulated glucose uptake in rat skeletal muscle cells. Methods: Rat myo-blasts (L6) were cultured and differentiated into myotubes followed by stimula-tion with single commercial resistin (130 ng/mL, 0-24 h) or cultured supernatant from 293-T cells transfected with resistin-expressing vectors (130 ng/mL, 0-24 h).Liquid scintillation counting was used to quantitate [3H] 2-deoxyglucose uptake.The transiocation of insulin-sensitive glucose transporters GLUT4 and GLUT1,synaptosomal-associated protein 23 (SNAP23) and GLUT protein content, as well as the tyrosine phosphorylation status and protein content of insulin receptor substrate (IRS) -1, were assessed by Western blotting. Results: Treatment of L6 myotubes with single resistin or cultured supernatant containing recombinant resistin reduced basal and insulin-stimulated 2-deoxyglucose uptake and impaired insulin-stimulated GLUT4 translocation. While SNAP23 protein content was decreased, no effects were noted in GLUT4 or GLUT1 protein content. Resistin also diminished insulin-stimulated IRS-1 tyrosine phosphorylation levels without affecting its protein content. The effects of recombinant resistin from 293-T cells transfected with resistin-expressing vectors were greater than that of single resistin treatment. Conclusion: Resistin regulated IRS-1 function and decreased GLUT4 translocation and glucose uptake in response to insulin. The downregulated expression of SNAP23 may have been partly attributed to the decrease of glucose uptake by resistin treatment. These observations highlight the potential role of resistin in the pathophysiology of type 2 diabetes related to obesity.

  8. Single molecular image of cytosolic free Ca2+ of skeletal muscle cells in rats pre- and post-exercise-induced fatigue

    Science.gov (United States)

    Liu, Yi; Zhang, Heming; Zhao, Yanping; Liu, Zhiming

    2009-08-01

    A growing body of literature indicated the cytosolic free Ca2+ concentration of skeletal muscle cells changes significantly during exercise-induced fatigue. But it is confusing whether cytosolic free Ca2+ concentration increase or decrease. Furthermore, current researches mainly adopt muscle tissue homogenate as experiment material, but the studies based on cellular and subcellular level is seldom. This study is aimed to establish rat skeletal muscle cell model of exercise-induced fatigue, and confirm the change of cytosolic free Ca2+ concentration of skeletal muscle cells in rats preand post- exercise-induced fatigue. In this research, six male Wistar rats were randomly divided into two groups: control group (n=3) and exercise-induced fatigue group (n=3). The former group were allowed to freely move and the latter were forced to loaded swimming to exhaustive. Three days later, all the rats were sacrificed, the muscle tissue from the same site of skeletal muscle were taken out and digested to cells. After primary culture of the two kinds of skeletal muscle cells from tissue, a fluorescent dye-Fluo-3 AM was used to label the cytosolic free Ca2+. The fluorescent of Ca2+ was recorded by confocal laser scanning microscopy. The results indicated that, the Ca2+ fluorescence intensity of cells from the rat of exercise-induced fatigue group was significantly higher than those in control group. In conclusion, cytosolic free Ca2+ concentration of skeletal muscle cells has a close relation with exercise-induced fatigue, and the increase of cytosolic free Ca2+ concentration may be one of the important factors of exercise-induced fatigue.

  9. Branched-chain amino acid-rich diet improves skeletal muscle wasting caused by cigarette smoke in rats.

    Science.gov (United States)

    Tomoda, Koichi; Kubo, Kaoru; Hino, Kazuo; Kondoh, Yasunori; Nishii, Yasue; Koyama, Noriko; Yamamoto, Yoshifumi; Yoshikawa, Masanori; Kimura, Hiroshi

    2014-04-01

    Cigarette smoke induces skeletal muscle wasting by a mechanism not yet fully elucidated. Branched-chain amino acids (BCAA) in the skeletal muscles are useful energy sources during exercise or systemic stresses. We investigated the relationship between skeletal muscle wasting caused by cigarette smoke and changes in BCAA levels in the plasma and skeletal muscles of rats. Furthermore, the effects of BCAA-rich diet on muscle wasting caused by cigarette smoke were also investigated. Wistar Kyoto (WKY) rats that were fed with a control or a BCAA-rich diet were exposed to cigarette smoke for four weeks. After the exposure, the skeletal muscle weight and BCAA levels in plasma and the skeletal muscles were measured. Cigarette smoke significantly decreased the skeletal muscle weight and BCAA levels in both plasma and skeletal muscles, while a BCAA-rich diet increased the skeletal muscle weight and BCAA levels in both plasma and skeletal muscles that had decreased by cigarette smoke exposure. In conclusion, skeletal muscle wasting caused by cigarette smoke was related to the decrease of BCAA levels in the skeletal muscles, while a BCAA-rich diet may improve cases of cigarette smoke-induced skeletal muscle wasting.

  10. Procedures for rat in situ skeletal muscle contractile properties.

    Science.gov (United States)

    MacIntosh, Brian R; Esau, Shane P; Holash, R John; Fletcher, Jared R

    2011-10-15

    There are many circumstances where it is desirable to obtain the contractile response of skeletal muscle under physiological circumstances: normal circulation, intact whole muscle, at body temperature. This includes the study of contractile responses like posttetanic potentiation, staircase and fatigue. Furthermore, the consequences of disease, disuse, injury, training and drug treatment can be of interest. This video demonstrates appropriate procedures to set up and use this valuable muscle preparation. To set up this preparation, the animal must be anesthetized, and the medial gastrocnemius muscle is surgically isolated, with the origin intact. Care must be taken to maintain the blood and nerve supplies. A long section of the sciatic nerve is cleared of connective tissue, and severed proximally. All branches of the distal stump that do not innervate the medial gastrocnemius muscle are severed. The distal nerve stump is inserted into a cuff lined with stainless steel stimulating wires. The calcaneus is severed, leaving a small piece of bone still attached to the Achilles tendon. Sonometric crystals and/or electrodes for electromyography can be inserted. Immobilization by metal probes in the femur and tibia prevents movement of the muscle origin. The Achilles tendon is attached to the force transducer and the loosened skin is pulled up at the sides to form a container that is filled with warmed paraffin oil. The oil distributes heat evenly and minimizes evaporative heat loss. A heat lamp is directed on the muscle, and the muscle and rat are allowed to warm up to 37°C. While it is warming, maximal voltage and optimal length can be determined. These are important initial conditions for any experiment on intact whole muscle. The experiment may include determination of standard contractile properties, like the force-frequency relationship, force-length relationship, and force-velocity relationship. With care in surgical isolation, immobilization of the origin of the

  11. Imbalance in SOD/CAT activities in rat skeletal muscles submitted to treadmill training exercise.

    Science.gov (United States)

    Pinho, Ricardo A; Andrades, Michael E; Oliveira, Marcos R; Pirola, Aline C; Zago, Morgana S; Silveira, Paulo C L; Dal-Pizzol, Felipe; Moreira, José Cláudio F

    2006-10-01

    The association between physical exercise and oxidative damage in the skeletal musculature has been the focus of many studies in literature, but the balance between superoxide dismutase and catalase activities and its relation to oxidative damage is not well established. Thus, the aim of the present study was to investigate the association between regular treadmill physical exercise, oxidative damage and antioxidant defenses in skeletal muscle of rats. Fifteen male Wistar rats (8-12 months) were randomly separated into two groups (trained n=9 and untrained n=6). Trained rats were treadmill-trained for 12 weeks in progressive exercise (velocity, time, and inclination). Training program consisted in a progressive exercise (10 m/min without inclination for 10 min/day). After 1 week the speed, time and inclination were gradually increased until 17 m/min at 10% for 50 min/day. After the training period animals were killed, and gastrocnemius and quadriceps were surgically removed to the determination of biochemical parameters. Lipid peroxidation, protein oxidative damage, catalase, superoxide dismutase and citrate synthase activities, and muscular glycogen content were measured in the isolated muscles. We demonstrated that there is a different modulation of CAT and SOD in skeletal muscle in trained rats when compared to untrained rats (increased SOD/CAT ratio). TBARS levels were significantly decreased and, in contrast, a significant increase in protein carbonylation was observed. These results suggest a non-described adaptation of skeletal muscle against exercise-induced oxidative stress.

  12. Optimizing hyaluronidase dose and plasmid DNA delivery greatly improves gene electrotransfer efficiency in rat skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Vedel, Kenneth; Needham Andersen, Josefine

    2015-01-01

    Transfection of rat skeletal muscle in vivo is a widely used research model. However, gene electrotransfer protocols have been developed for mice and yield variable results in rats. We investigated whether changes in hyaluronidase pre-treatment and plasmid DNA delivery can improve transfection...... efficiency in rat skeletal muscle. We found that pre-treating the muscle with a hyaluronidase dose suitable for rats (0.56. U/g b.w.) prior to plasmid DNA injection increased transfection efficiency by >200% whereas timing of the pre-treatment did not affect efficiency. Uniformly distributing plasmid DNA...... delivery across the muscle by increasing the number of plasmid DNA injections further enhanced transfection efficiency whereas increasing plasmid dose from 0.2 to 1.6. μg/g b.w. or vehicle volume had no effect. The optimized protocol resulted in ~80% (CI95%: 79-84%) transfected muscle fibers...

  13. Melatonin prevents mitochondrial dysfunction and insulin resistance in rat skeletal muscle.

    Science.gov (United States)

    Teodoro, Bruno G; Baraldi, Flavia G; Sampaio, Igor H; Bomfim, Lucas H M; Queiroz, André L; Passos, Madla A; Carneiro, Everardo M; Alberici, Luciane C; Gomis, Ramon; Amaral, Fernanda G; Cipolla-Neto, José; Araújo, Michel B; Lima, Tanes; Akira Uyemura, Sérgio; Silveira, Leonardo R; Vieira, Elaine

    2014-09-01

    Melatonin has a number of beneficial metabolic actions and reduced levels of melatonin may contribute to type 2 diabetes. The present study investigated the metabolic pathways involved in the effects of melatonin on mitochondrial function and insulin resistance in rat skeletal muscle. The effect of melatonin was tested both in vitro in isolated rats skeletal muscle cells and in vivo using pinealectomized rats (PNX). Insulin resistance was induced in vitro by treating primary rat skeletal muscle cells with palmitic acid for 24 hr. Insulin-stimulated glucose uptake was reduced by palmitic acid followed by decreased phosphorylation of AKT which was prevented my melatonin. Palmitic acid reduced mitochondrial respiration, genes involved in mitochondrial biogenesis and the levels of tricarboxylic acid cycle intermediates whereas melatonin counteracted all these parameters in insulin-resistant cells. Melatonin treatment increases CAMKII and p-CREB but had no effect on p-AMPK. Silencing of CREB protein by siRNA reduced mitochondrial respiration mimicking the effect of palmitic acid and prevented melatonin-induced increase in p-AKT in palmitic acid-treated cells. PNX rats exhibited mild glucose intolerance, decreased energy expenditure and decreased p-AKT, mitochondrial respiration, and p-CREB and PGC-1 alpha levels in skeletal muscle which were restored by melatonin treatment in PNX rats. In summary, we showed that melatonin could prevent mitochondrial dysfunction and insulin resistance via activation of CREB-PGC-1 alpha pathway. Thus, the present work shows that melatonin play an important role in skeletal muscle mitochondrial function which could explain some of the beneficial effects of melatonin in insulin resistance states.

  14. Wortmannin inhibits both insulin- and contraction-stimulated glucose uptake and transport in rat skeletal muscle

    DEFF Research Database (Denmark)

    Wojtaszewski, Jørgen; Hansen, B F; Ursø, Birgitte

    1996-01-01

    The role of phosphatidylinositol (PI) 3-kinase for insulin- and contraction-stimulated muscle glucose transport was investigated in rat skeletal muscle perfused with a cell-free perfusate. The insulin receptor substrate-1-associated PI 3-kinase activity was increased sixfold upon insulin stimulat...

  15. Mitochondria-targeted antioxidant preserves contractile properties and mitochondrial function of skeletal muscle in aged rats.

    Science.gov (United States)

    Javadov, Sabzali; Jang, Sehwan; Rodriguez-Reyes, Natividad; Rodriguez-Zayas, Ana E; Soto Hernandez, Jessica; Krainz, Tanja; Wipf, Peter; Frontera, Walter

    2015-11-24

    Mitochondrial dysfunction plays a central role in the pathogenesis of sarcopenia associated with a loss of mass and activity of skeletal muscle. In addition to energy deprivation, increased mitochondrial ROS damage proteins and lipids in aged skeletal muscle. Therefore, prevention of mitochondrial ROS is important for potential therapeutic strategies to delay sarcopenia. This study elucidates the pharmacological efficiency of the new developed mitochondria-targeted ROS and electron scavenger, XJB-5-131 (XJB) to restore muscle contractility and mitochondrial function in aged skeletal muscle. Male adult (5-month old) and aged (29-month old) Fischer Brown Norway (F344/BN) rats were treated with XJB for four weeks and contractile properties of single skeletal muscle fibres and activity of mitochondrial ETC complexes were determined at the end of the treatment period. XJB-treated old rats showed higher muscle contractility associated with prevention of protein oxidation in both muscle homogenate and mitochondria compared with untreated counterparts. XJB-treated animals demonstrated a high activity of the respiratory complexes I, III, and IV with no changes in citrate synthase activity. These data demonstrate that mitochondrial ROS play a causal role in muscle weakness, and that a ROS scavenger specifically targeted to mitochondria can reverse age-related alterations of mitochondrial function and improve contractile properties in skeletal muscle.

  16. A novel insulin sensitizer (S15511) enhances insulin-stimulated glucose uptake in rat skeletal muscles.

    Science.gov (United States)

    Jessen, N; Selmer Buhl, E; Pold, R; Schmitz, O; Lund, S

    2008-04-01

    Type 2 diabetes is preceded by the presence of skeletal muscle insulin resistance, and drugs that increase insulin sensitivity in skeletal muscle prevent the disease. S15511 is an original compound with demonstrated effects on insulin sensitivity in animal models of insulin resistance. However, the mechanisms behind the insulin-sensitizing effect of S15511 are unknown. The aim of our study was to explore whether S15511 improves insulin sensitivity in skeletal muscles. Insulin sensitivity was assessed in skeletal muscles from S15511-treated rats by measuring intracellular insulin-signaling activity and insulin-stimulated glucose transport in isolated muscles. In addition, GLUT4 expression and glycogen levels were assessed after treatment. S15511 treatment was associated with an increase in insulin-stimulated glucose transport in type IIb fibers, while type I fibers were unaffected. The enhanced glucose transport was mirrored by a fiber type-specific increase in GLUT4 expression, while no improvement in insulin-signaling activity was observed. S15511 is a novel insulin sensitizer that is capable of improving glucose homeostasis in nondiabetic rats. The compound enhances skeletal muscle insulin sensitivity and specifically targets type IIb muscle fibers by increasing GLUT4 expression. Together these data show S15511 to be a potentially promising new drug in the treatment and prevention of type 2 diabetes.

  17. Skeletal growth and long-term bone turnover after enterocystoplasty in a chronic rat model

    DEFF Research Database (Denmark)

    Gerharz, E.W.; Gasser, J.A.; Mosekilde, Li.

    2003-01-01

    OBJECTIVE: To investigate skeletal growth and bone metabolism in a chronic animal model of urinary diversion.MATERIALS AND METHODS: Young male Wistar rats (120) were allocated randomly to four groups undergoing: ileocystoplasty, ileocystoplasty and resection of the ileocaecal segment...... insulin-like growth factor-binding protein 3 were the only significant findings on blood analysis. Deoxypyridinoline crosslinks in urine were higher in rats with an enterocystoplasty than in controls.CONCLUSIONS: Enterocystoplasty in rats neither impairs skeletal growth nor bone quantity, but leads......, colocystoplasty, and controls. All animals received antibiotics for 1 week after surgery; half of each group remained on oral antibiotics. Bone-related biochemistry was measured in serum and urine. Dual-energy X-ray absorptiometry and peripheral quantitative computed tomography (pQCT) were used to determine bone...

  18. Optimizing hyaluronidase dose and plasmid DNA delivery greatly improves gene electrotransfer efficiency in rat skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Vedel, Kenneth; Needham Andersen, Josefine;

    2015-01-01

    delivery across the muscle by increasing the number of plasmid DNA injections further enhanced transfection efficiency whereas increasing plasmid dose from 0.2 to 1.6. μg/g b.w. or vehicle volume had no effect. The optimized protocol resulted in ~80% (CI95%: 79-84%) transfected muscle fibers......Transfection of rat skeletal muscle in vivo is a widely used research model. However, gene electrotransfer protocols have been developed for mice and yield variable results in rats. We investigated whether changes in hyaluronidase pre-treatment and plasmid DNA delivery can improve transfection...... with a homogenous distribution. We also show that transfection was stable over five weeks of regular exercise or inactivity. Our findings show that species-specific plasmid DNA delivery and hyaluronidase pre-treatment greatly improves transfection efficiency in rat skeletal muscle....

  19. Tissue specific phosphorylation of mitochondrial proteins isolated from rat liver, heart muscle, and skeletal muscle

    DEFF Research Database (Denmark)

    Bak, Steffen; León, Ileana R; Jensen, Ole Nørregaard;

    2013-01-01

    of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC-MS/MS on isolated mitochondria to investigate the tissue-specific mitochondrial phosphoproteomes of rat liver, heart, and skeletal muscle. In total, we identified 899 phosphorylation sites in 354 different mitochondrial proteins including......Phosphorylation of mitochondrial proteins in a variety of biological processes is increasingly being recognized and may contribute to the differences in function and energy demands observed in mitochondria from different tissues such as liver, heart, and skeletal muscle. Here, we used a combination...

  20. Hydrogen sulfide is endogenously generated in rat skeletal muscle and exerts a protective effect against oxidative stress

    Institute of Scientific and Technical Information of China (English)

    DU Jian-tong; LI Wei; YANG Jin-yan; TANG Chao-shu; LI Qi; JIN Hong-fang

    2013-01-01

    Background Skeletal muscle has recently been recognized as an endocrine organ that can express,synthesize and secrete a variety of bioactive molecules which exert significant regulatory effects.Hydrogen sulfide (H2S) is endogenously produced in mammalian tissues and participates in a number of physiological and pathophysiological processes.We aimed to verify whether H2S could be endogenously generated and released by rat skeletal muscle,and determine the biological effects of H2S in rat skeletal muscle.Methods The study was divided into two parts:detection of endogenous H2S generation and release in rat skeletal muscle and determination of antioxidative activity of skeletal muscle-derived H2S.H2S content and production in tissues were detected by sensitive sulfur electrode method.The expressions of H2S producing enzymes cystathionine β-synthase,cystathionine Y-lyase and mercaptopyruvate sulfurtransferase were detected by real-time PCR and western blotting and their tissue distributions were observed by immunohistochemical and immunofluorescent analysis.Rat skeletal muscular ischemia-reperfusion (I-R) injury model was created and evaluated by histological analysis under microscope.The malondialdehyde (MDA) contents,hydrogen peroxide levels,superoxide anion and superoxide dismutase (SOD) activities were detected using spectrophotometer.Results H2S could be endogenously generated and released by skeletal muscle of Sprague-Dawley rats (H2S content:(2.06±0.43) nmol/mg; H2S production:(0.17±0.06) nmol.min-1·mg-1).Gene and protein expressions of the three H2S producing enzymes were detected in skeletal muscle,as well as the liver and kidney.Endogenous H2S content and production were decreased in skeletal muscles of rats with I-R skeletal muscle injury (P <0.05).Furthermore,H2S significantly protected rat skeletal muscle against I-R injury and resulted in decreased MDA content,reduced hydrogen peroxide and superoxide anion levels,but increased SOD activity and

  1. Skeletal Muscle Regeneration in a Rat (Rattus norvegicus) Model with CorMatrix and Adipose Derived Stem Cells

    Science.gov (United States)

    2015-07-16

    not provide a regenerative scaffold for growth of skeletal muscle after volumetric muscle loss. 12. PROTOCOL OUTCOME SUMMARY: (Please provide, in...additional pages if necessary.) PROTOCOL #: FDG20130044A DATE: 16 July 2015 PROTOCOL TITLE: "Skeletal Muscle Regeneration in a Rat (Rattus no1Vegicus...volumetric muscle loss, with a clinical need for enhanced repair. Extracellular matrix (ECM) shows promise to regenerate skeletal muscle , opening a

  2. Developmental regulation of voltage-sensitive sodium channels in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, S.J.

    1985-01-01

    The developmental regulation of the voltage-sensitive Na/sup +/ channel in rat skeletal muscle was studied in vivo and in vitro. In triceps surae muscle developing in vivo the development of TTX-sensitive Na/sup +/ channel occurred primarily during the first three postnatal weeks as determined by the specific binding of (/sup 3/H)saxitoxin. This development proceeded in two separate phases. The first phase occurs independently of continuing motor neuron innervation and accounts for 60% of the adult density of TTX-sensitive Na/sup +/ channels. The second phase, which begins about day 11, requires innervation. Muscle cells in primary culture were found to have both TTX-sensitive and insensitive Na/sup +/ channels. The development of the TTX-sensitive channel, in vitro, paralleled the initial innervation-independent phase of development observed in vivo. The density of TTX-sensitive Na/sup +/ channels in cultured muscle cells was regulated by electrical activity and cytosolic Ca/sup + +/ levels. Pharmacological blockade of the spontaneous electrical activity present in these cells lead to a nearly 2-fold increase in the surface density of TTX-sensitive channels. The turnover time of the TTX-sensitive Na/sup +/ channel was measured by blocking the incorporation of newly synthesized channels with tunicamycin, an inhibitor of N-linked protein glycosylation. The regulation of channel density by electrical activity, cytosolic Ca/sup + +/levels, and agents affecting cyclic neucleotide levels had no effect on the turnover time of the TTX-sensitive Na/sup +/ channel, indicating that these regulatory agents instead affect the synthesis of the channel.

  3. Effects of magnetic stimulation on oxidative stress and skeletal muscle regeneration induced by mepivacaine in rat.

    Science.gov (United States)

    Jimena, I; Tasset, I; López-Martos, R; Rubio, A J; Luque, E; Montilla, P; Peña, J; Túnez, I

    2009-01-01

    We investigated the effect of magnetic field stimulation (MS) on oxidative damage and skeletal muscle injury prompted by mepivacaine injection in the anterior tibial muscle of Wistar rats. The effects of mepivacaine and MS on oxidative stress were evaluated by lipid peroxidation, GSH levels and catalase activity. Muscle regeneration was analyzed by haematoxylin-eosin stained, NADH-TR histochemical reaction, desmin immunostaining as well as by morphometric parameters such as fibers density and fiber area were evaluated. Our data revealed that mepivacaine induced oxidative stress, that MS prevents the harmful effects induced by mepivacaine and that it facilitates the regeneration process of skeletal muscle. In conclusion, the results show the ability of MS to modify skeletal muscle response to mepivacaine.

  4. Titin Isoform Size is Not Correlated with Thin Filament Length in Rat Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Marion Lewis Greaser

    2014-02-01

    Full Text Available The mechanisms controlling thin filament length in muscle remain controversial. It was recently reported that thin filament length was related to titin size, and that the latter might be involved in thin filament length determination. Titin plays several crucial roles in the sarcomere, but its function as it pertains to the thin filament has not been explored. We tested this relationship using several muscles from wild type rats and from a mutant rat model which results in increased titin size. Myofibrils were isolated from skeletal muscles (extensor digitorum longus, external oblique, gastrocnemius, longissimus dorsi, psoas major, and tibialis anterior using both adult wild type (WT and homozygous mutant (HM rats. Phalloidin and antibodies against tropomodulin-4 and nebulin’s N-terminus were used to determine thin filament length. The WT rats studied express skeletal muscle titin sizes ranging from 3.2 to 3.7 MDa, while the HM rats express a giant titin isoform sized at 3.7 MDa. No differences in phalloidin-based thin filament length, nebulin N terminus distances from the Z line, or tropomodulin distances from the Z line were observed across genotypes. The data indicates that, although titin performs many sarcomeric functions, its correlation with thin filament length and structure could not be demonstrated in the rat. Current models of thin filament assembly are inadequate to explain the phalloidin, nebulin N terminus, and tropomodulin staining patterns in the myofibril.

  5. Isolation, Culture and Identification of Porcine Skeletal Muscle Satellite Cells

    Directory of Open Access Journals (Sweden)

    Bo-jiang Li

    2015-08-01

    Full Text Available The objective of this study was to establish the optimum protocol for the isolation and culture of porcine muscle satellite cells. Mononuclear muscle satellite cells are a kind of adult stem cell, which is located between the basal lamina and sarcolemma of muscle fibers and is the primary source of myogenic precursor cells in postnatal muscle. Muscle satellite cells are a useful model to investigate the mechanisms of muscle growth and development. Although the isolation and culture protocols of muscle satellite cells in some species (e.g. mouse have been established successfully, the culture system for porcine muscle satellite cells is very limited. In this study, we optimized the isolation procedure of porcine muscle satellite cells and elaborated the isolation and culture process in detail. Furthermore, we characterized the porcine muscle satellite cells using the immunofluorecence. Our study provides a reference for the isolation of porcine muscle satellite cells and will be useful for studying the molecular mechanisms in these cells.

  6. Exercise at simulated high altitude facilitates the increase in capillarity in skeletal muscle of rats

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: To study the changes in capillarity of skeletal muscle during acclimation to high altitude, and explore the effects of a certain extent physical activity under hypoxia on capillary formation and the role of vascular endothelial growth factor (VEGF) in this process. METHODS: 48 Wistar rats were divided into 3 groups: Ⅰ normoxic control; Ⅱ hypoxia and Ⅲ hypoxia+exercise. Rats of Ⅱ and Ⅲ groups were subjected to hypobaric hypoxia for 5 weeks (23 h/d). They were first brought to simulated 4 000 m altitude, where rats of the Ⅲgroup were forced to swim for 1 h/d (6 d/week). Then the animals were ascent to 5 000 m. Biomicrosphere method was used to determine blood flow of skeletal muscle. The mean fiber cross-sectional area (FCSA), capillary density (CD) and capillary/fiber ratio (C/F) of red portion of the lateral head of the gastrocneminus were assayed by myofibrillar ATPase histochemistry. VEGF and its receptor KDR were assayed with immunohistochemistry method.RESULTS: By comparison with the normoxic control, 5-week hypoxic exposure resulted in a decrease in cross-sectional area of skeletal muscle fiber and an increase in CD, but the C/F remained unchanged. The blood supply to the gastrocnemius was not changed. After 5-week-exercise at high altitude, the muscle fibers did not undergo atrophy. CD, C/F, and the blood flow at rest increased significantly. VEGF protein was found primarily in the matrix between muscle fibers; KDR were shown mainly in endothelial cells of capillary. VEGF was more strongly stained in the skeletal muscle of hypoxia-exercise rats.CONCLUSION: Hypoxia itself can not induce neovascularization. While exercise during hypoxic exposure can lead to capillary formation. VEGF and KDR may play roles in it. New capillary formation benefits the blood supply, oxygen delivery and working performance at high altitude.

  7. Evaluation of the response of rat skeletal muscle to a model of weightlessness

    Science.gov (United States)

    Templeton, G. H.; Padalino, M.; Glasberg, M.; Manton, J.; Silver, P.; Sutko, J.

    1982-01-01

    Suspension of rats in a head-down tilt position such that their hind limbs are non-load bearing has been proposed as a model for weightlessness. Changes observed in metabolism, bone formation (Morey et al., 1979), and muscle catabolism (Mussachia et al., 1980) support the validity of the model. To further document this model, the effects of suspension on the mechanical, biochemical and histochemical characteristics of two hind limb skeletal muscles, the gastrocnemius and the soleus, are investigated.

  8. Impairment of Electron Transfer Chain Induced by Acute Carnosine Administration in Skeletal Muscle of Young Rats

    Directory of Open Access Journals (Sweden)

    José Roberto Macarini

    2014-01-01

    Full Text Available Serum carnosinase deficiency is an inherited disorder that leads to an accumulation of carnosine in the brain tissue, cerebrospinal fluid, skeletal muscle, and other tissues of affected patients. Considering that high levels of carnosine are associated with neurological dysfunction and that the pathophysiological mechanisms involved in serum carnosinase deficiency remain poorly understood, we investigated the in vivo effects of carnosine on bioenergetics parameters, namely, respiratory chain complexes (I–III, II, and II-III, malate dehydrogenase, succinate dehydrogenase, and creatine kinase activities and the expression of mitochondrial-specific transcription factors (NRF-1, PGC-1α, and TFAM in skeletal muscle of young Wistar rats. We observed a significant decrease of complexes I–III and II activities in animals receiving carnosine acutely, as compared to control group. However, no significant alterations in respiratory chain complexes, citric acid cycle enzymes, and creatine kinase activities were found between rats receiving carnosine chronically and control group animals. As compared to control group, mRNA levels of NRF-1, PGC-1α, and TFAM were unchanged. The present findings indicate that electron transfer through the respiratory chain is impaired in skeletal muscle of rats receiving carnosine acutely. In case these findings are confirmed by further studies and ATP depletion is also observed, impairment of bioenergetics could be considered a putative mechanism responsible for the muscle damage observed in serum carnosinase-deficient patients.

  9. Regional alterations of type I collagen in rat tibia induced by skeletal unloading

    Science.gov (United States)

    Shiiba, Masashi; Arnaud, Sara B.; Tanzawa, Hideki; Kitamura, Eiji; Yamauchi, Mitsuo

    2002-01-01

    Skeletal unloading induces loss of mineral density in weight-bearing bones that leads to inferior bone mechanical strength. This appears to be caused by a failure of bone formation; however, its mechanisms still are not well understood. The objective of this study was to characterize collagen, the predominant matrix protein in bone, in various regions of tibia of rats that were subjected to skeletal unloading by 4 weeks tail suspension. Sixteen male Sprague-Dawley rats (4 months old) were divided into tail suspension and ambulatory controls (eight rats each). After the tail suspension, tibias from each animal were collected and divided into five regions and collagen was analyzed. The collagen cross-linking and the extent of lysine (Lys) hydroxylation in unloaded bones were significantly altered in proximal epiphysis, diaphysis, and, in particular, proximal metaphysis but not in distal regions. The pool of immature/nonmineralized collagen measured by its extractability with a chaotropic solvent was significantly increased in proximal metaphysis. These results suggest that skeletal unloading induced an accumulation of post-translationally altered nonmineralized collagen and that these changes are bone region specific. These alterations might be caused by impaired osteoblastic function/differentiation resulting in a mineralization defect.

  10. Skeletal Muscle Satellite Cell Activation Following Cutaneous Burn in Rats

    Science.gov (United States)

    2013-12-01

    Satellite cell isolation and culture Satellite cells were isolated similar as described by Allen et al. [30]. Following euthanasia , muscles were...satellite cell cultures. Methods Cell Biol 1997;52:155–76. [31] Tatsumi R, Liu X, Pulido A, Morales M, Sakata T, Dial S, Hattori A, Ikeuchi Y, Allen RE

  11. Activation of estrogen response elements is mediated both via estrogen and muscle contractions in rat skeletal muscle myotubes

    DEFF Research Database (Denmark)

    Wiik, A.; Hellsten, Ylva; Berthelson, P.

    2009-01-01

    The aim of the present study was to investigate the activation of estrogen response elements (EREs) by estrogen and muscle contractions in rat myotubes in culture and to assess whether the activation is dependent on the estrogen receptors (ERs). In addition, the effect of estrogen and contraction...... increased (P estrogen and attenuated (P estrogen-induced transactivation is mediated via ERs, the effect of muscle contraction...... is ER independent. The muscle contraction-induced transactivation of ERE and increase in ERbeta mRNA were instead found to be MAP kinase (MAPK) dependent. This study demonstrates for the first time that muscle contractions have a similar functional effect as estrogen in skeletal muscle myotubes, causing...

  12. Skeletal muscle and hormonal adaptation to physical training in the rat

    DEFF Research Database (Denmark)

    Henriksson, J; Svedenhag, J; Richter, Erik

    1985-01-01

    The main purpose of the present study was to test the hypothesis that adrenergic stimulation of muscle fibres during exercise is a major stimulus for the training-induced enhancement of skeletal muscle respiratory capacity. Therefore, Sprague-Dawley rats either underwent bilateral surgical ablation...... of the adrenal medulla or were sham-operated. Furthermore, unilateral surgical extirpation of the lumbar sympathetic chain was performed. Half of the rats were then trained for 12 weeks by swimming (up to 5.5 h X day-1, 4 days X week-1) and the remaining rats were sedentary controls. In the gastrocnemius muscle......, training significantly increased the mitochondrial enzymes citrate synthase, succinate dehydrogenase, cytochrome c oxidase, and 3-hydroxyacyl-CoA dehydrogenase. In sham-operated rats, the increases were 40%, 43%, 66%, and 25%, respectively, in legs with intact sympathetic innervation. The training...

  13. Metabolic adaptations of skeletal muscle to voluntary wheel running exercise in hypertensive heart failure rats

    DEFF Research Database (Denmark)

    Schultz, R L; Kullman, E L; Waters, Ryan

    2013-01-01

    The Spontaneously Hypertensive Heart Failure (SHHF) rat mimics the human progression of hypertension from hypertrophy to heart failure. However, it is unknown whether SHHF animals can exercise at sufficient levels to observe beneficial biochemical adaptations in skeletal muscle. Thirty-seven female...... SHHF and Wistar-Furth (WF) rats were randomized to sedentary (SHHFsed and WFsed) and exercise groups (SHHFex and WFex). The exercise groups had access to running wheels from 6-22 months of age. Hindlimb muscles were obtained for metabolic measures that included mitochondrial enzyme function...... and expression, and glycogen utilization. The SHHFex rats ran a greater distance and duration as compared to the WFex rats (Pmuscle citrate synthase and beta-hydroxyacyl-CoA dehydrogenase enzyme activity was not altered in the SHHFex group...

  14. Evaluation of ubiquinone concentration and mitochondrial function relative to cerivastatin-induced skeletal myopathy in rats.

    Science.gov (United States)

    Schaefer, William H; Lawrence, Jeffery W; Loughlin, Amy F; Stoffregen, Dana A; Mixson, Lori A; Dean, Dennis C; Raab, Conrad E; Yu, Nathan X; Lankas, George R; Frederick, Clay B

    2004-01-01

    As a class, hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors can potentially cause skeletal myopathy. One statin, cerivastatin, has recently been withdrawn from the market due to an unacceptably high incidence of rhabdomyolysis. The mechanism underlying statin-induced myopathy is unknown. This paper sought to investigate the relationship among statin-induced myopathy, mitochondrial function, and muscle ubiquinone levels. Rats were administered cerivastatin at 0.1, 0.5, and 1.0 (mg/kg)/day or dose vehicle (controls) by oral gavage for 15 days. Samples of type I-predominant skeletal muscle (soleus) and type II-predominant skeletal muscle [quadriceps and extensor digitorum longus (EDL)], and blood were collected on study days 5, 10, and 15 for morphological evaluation, clinical chemistry, mitochondrial function tests, and analysis of ubiquinone levels. No histological changes were observed in any of the animals on study days 5 or 10, but on study day 15, mid- and high-dose animals had necrosis and inflammation in type II skeletal muscle. Elevated creatine kinase (CK) levels in blood (a clinical marker of myopathy) correlated with the histopathological diagnosis of myopathy. Ultrastructural characterization of skeletal muscle revealed disruption of the sarcomere and altered mitochondria only in myofibers with degeneration, while adjacent myofibers were unaffected and had normal mitochondria. Thus, mitochondrial effects appeared not to precede myofiber degeneration. Mean coenzyme Q9 (CoQ9) levels in all dose groups were slightly decreased relative to controls in type II skeletal muscle, although the difference was not significantly different in most cases. Mitochondrial function in skeletal muscle was not affected by the changes in ubiquinone levels. The ubiquinone levels in high-dose-treated animals exhibiting myopathy were not significantly different from low-dose animals with no observable toxic effects. Furthermore, ubiquinone levels did not correlate

  15. Effect of diltiazem on skeletal muscle 3-O-methylglucose transport in bacteremic rats

    Energy Technology Data Exchange (ETDEWEB)

    Westfall, M.V.; Sayeed, M.M.

    1989-03-01

    This study examined whether alterations in cellular Ca2+ regulation contribute to previously observed changes in skeletal muscle sugar transport during bacteremia. Fasted male rats received saline (control) or bacteria (4 X 10(10) Escherichia coli/kg) intraperitoneally. Twelve hours later, basal and insulin-mediated 3-O-methylglucose (3MG) transport was measured in isolated soleus muscles. Measurements of 3MG transport in the presence of cytochalasin b or at a low temperature (0.5 degree C) indicated that altered sugar transport in bacteremic rat muscles was not due to nonspecific membrane permeability changes. To determine the role of Ca2+ in the pathogenesis of altered sugar transport during bacteremia, rats were treated with the Ca2+ antagonist diltiazem (DZ, 0.6-2.4 mg/kg) at various times (0, 0 + 7.5, 10 h) after saline or bacterial injection. In bacteremic rats given 2.4 mg/kg DZ at 10 h, basal and insulin-mediated transport were similar to control values. This dose of DZ had little effect on control muscles. The addition of 20 microM DZ to the incubation media did not affect basal or insulin-mediated 3MG transport in bacteremic rat muscles. Addition of the Ca2+ agonist BAY K 8644 to the incubation media had no effect on sugar transport in bacteremic rat muscles but caused alterations in control rat muscles that were comparable to those observed in bacteremia. These results suggest that alterations in Ca2+ regulation could contribute to the previously observed changes in sugar transport in skeletal muscles from bacteremic rats.

  16. Engineering skeletal myoblasts: roles of three-dimensional culture and electrical stimulation.

    Science.gov (United States)

    Pedrotty, Dawn M; Koh, Jennifer; Davis, Bryce H; Taylor, Doris A; Wolf, Patrick; Niklason, Laura E

    2005-04-01

    Immature skeletal muscle cells, or myoblasts, have been used in cellular cardiomyoplasty in attempts to regenerate cardiac muscle tissue by injection of cells into damaged myocardium. In some studies, muscle tissue within myoblast implant sites may be morphologically similar to cardiac muscle. We hypothesized that identifiable aspects of the cardiac milieu may contribute to growth and development of implanted myoblasts in vivo. To test this hypothesis, we designed a novel in vitro system to mimic some aspects of the electrical and biochemical environment of native myocardium. This system enabled us to separate the three-dimensional (3-D) electrical and biochemical signals that may be involved in myoblast proliferation and plasticity. Myoblasts were grown on 3-D polyglycolic acid mesh scaffolds under control conditions, in the presence of cardiac-like electrical current fluxes, or in the presence of culture medium that had been conditioned by mature cardiomyocytes. Cardiac-like electrical current fluxes caused increased myoblast number in 3-D culture, as determined by DNA assay. The increase in cell number was due to increased cellular proliferation and not differences in apoptosis, as determined by proliferating cell nuclear antigen and TdT-mediated dUTP nick-end labeling. Cardiomyocyte-conditioned medium also significantly increased myoblast proliferation. Expression of transcription factors governing differentiation along skeletal or cardiac lineages was evaluated by immunoblotting. Although these assays are qualitative, no changes in differentiation state along skeletal or cardiac lineages were observed in response to electrical current fluxes. Furthermore, from these experiments, conditioned medium did not appear to alter the differentiation state of skeletal myoblasts. Hence, cardiac milieu appears to stimulate proliferation but does not affect differentiation of skeletal myoblasts.

  17. Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Yoshikazu; Fukushima, Yuji; Kaneki, Masao [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States); Martyn, J.A. Jeevendra, E-mail: jmartyn@partners.org [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States)

    2013-02-01

    Highlights: ► Propofol, as a model anesthetic drug, induced whole body insulin resistance. ► Propofol anesthesia decreased glucose infusion rate to maintain euglycemia. ► Propofol decreased insulin-mediated glucose uptake in skeletal and cardiac muscles. ► Propofol increased hepatic glucose output confirming hepatic insulin resistance. -- Abstract: Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [{sup 3}H]glucose and 2-deoxy[{sup 14}C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats.

  18. Leucine Protects Against Skeletal Muscle Atrophy in Lipopolysaccharide-Challenged Rats.

    Science.gov (United States)

    Wan, Jin; Chen, Daiwen; Yu, Bing; Luo, Yuheng; Mao, Xiangbing; Zheng, Ping; Yu, Jie; Luo, Junqiu; He, Jun

    2017-01-01

    Skeletal muscle atrophy is a decrease in muscle mass that occurs when protein degradation exceeds protein synthesis. Leucine (Leu), an essential branched-chain amino acid in animal nutrition, regulates skeletal muscle protein metabolism. Two experiments were conducted to evaluate whether Leu could alleviate lipopolysaccharide (LPS)-induced skeletal muscle wasting by modulating skeletal muscle protein synthesis and degradation. A total of 24 rats were randomly allocated into three groups (n = 8): (1) non-challenged control; (2) LPS-challenged control; and (3) LPS +3.0% Leu. Rats were fed with control or Leu-supplemented (part of the casein was replaced with 3.0% Leu) diets throughout the trial and were injected intraperitoneally with sterile saline or LPS at days 6, 11, 16, and 21. On the morning of day 22, serum samples were collected and rats were then sacrificed for liver and muscle analysis. In vitro protein degradation, nuclear factor-κB (NF-κB) activity, and proteolytic enzyme activities of the muscles from immune-challenged rats were also measured. Our results showed that the LPS challenge resulted in not only enhanced serum interleukin-1 and liver C-reactive protein (CRP) concentrations but also decreased the average daily body weight gain and muscle fiber diameter. However, dietary Leu inclusion attenuated the increase in CRP level and the decrease in muscle fiber diameter. Importantly, the LPS challenge caused a significant elevation in the muscle proteolysis rate, but dietary Leu supplementation significantly blocked the muscle proteolysis. The mRNA expression of NF-κB, muscle atrophy F-box (MAFbx), and muscle ring finger 1 (MuRF1) was upregulated by the LPS challenge in gastrocnemius muscles, but was downregulated by Leu supplementation. Interestingly, when muscles from the LPS-challenged rats were incubated with Leu in vitro, proteasome-, calpain-, and cathepsin-L-dependent muscle proteolysis and NF-κB activity were decreased. Collectively, the

  19. In vitro effects of soy phytoestrogens on rat L6 skeletal muscle cells.

    Science.gov (United States)

    Jones, K L; Harty, J; Roeder, M J; Winters, T A; Banz, W J

    2005-01-01

    Soy isoflavones display estrogenic activity in humans and animals, and thus are referred to as phytoestrogens. This study was performed to observe the effects of the soy isoflavones genistein, daidzein, and glycitein on cell cultures of rat skeletal muscles. [3H]Thymidine incorporation was used to determine cell proliferation, while protein synthesis and degradation were determined by tracking radiolabeled leucine. For the proliferation studies, insulin, estradiol, genistein, daidzein, or glycitein was supplemented at 0, 0.04, 0.08, 0.16, 0.31, 0.63, 1.25, 2.5, 5, 10, or 20 microM, respectively, or in combinations with final concentrations of 0, 0.1, 1, or 10 microM. Genistein reacted most similarly to estradiol, inhibiting proliferation at > or = 1 microM (P phytoestrogens resulted in significant inhibition of cell proliferation, but not to the extent observed with genistein alone. For the protein synthesis and degradation experiments, treatments of 0.1 microM dexamethasone or 1 microM concentrations of insulin, genistein, daidzein, or glycitein were used. Phytoestrogens did not inhibit or stimulate protein degradation or synthesis (P > .05). A one-tailed univariate analysis of variance revealed a trend (P < or = .1) in protein stimulation with genistein and glycitein treatments. These results suggest that the tyrosine kinase inhibiting activity of genistein may be affecting phosphorylation of the mitosis-promoting factor, preventing the advancement of the mitotic cell cycle. In addition, at higher total combined concentrations, daidzein and glycitein may be able to outcompete genistein for receptor sites. These results suggest that soy isoflavones in the diet may potentially modulate normal growth and development in humans and animals that ingest soy-based products.

  20. Effects of Hyperbaric Oxygen on Metabolic Capacity of the Skeletal Muscle in Type 2 Diabetic Rats with Obesity

    Directory of Open Access Journals (Sweden)

    Naoto Fujita

    2012-01-01

    Full Text Available We investigated whether hyperbaric oxygen enhances the oxidative metabolic capacity of the skeletal muscle and attenuates adipocyte hypertrophy in type 2 diabetic rats with obesity. Five-week-old male Otsuka Long-Evans Tokushima fatty (OLETF and Long-Evans Tokushima Otsuka (LETO rats were used as diabetic animals and nondiabetic controls, respectively, and assigned to control and hyperbaric oxygen groups. Animals in the hyperbaric oxygen group were exposed to an atmospheric pressure of 1.25 with an oxygen concentration of 36% for 3 h daily. The glucose level at 27 weeks of age was significantly higher in OLETF rats than in LETO rats, but the elevation was inhibited in OLETF rats exposed to hyperbaric oxygen. The slow-to-fast fiber transition in the skeletal muscle was observed in OLETF rats, but the shift was inhibited in OLETF rats exposed to hyperbaric oxygen. Additionally, the oxidative enzyme activity of muscle fibers was increased by hyperbaric oxygen. The adipocyte size was larger in OLETF rats than in LETO rats, but hypertrophied adipocytes were not observed in OLETF rats exposed to hyperbaric oxygen. Hyperbaric oxygen enhances glucose and lipid metabolism in the skeletal muscle, indicating that hyperbaric oxygen can prevent elevation of glucose and adipocyte hypertrophy in diabetic rats with obesity.

  1. The proteasome inhibitor MG132 attenuates skeletal muscle atrophy in a rat model of chronic obstructive pulmonary disease

    Institute of Scientific and Technical Information of China (English)

    马碧蔓

    2013-01-01

    Objective To investigate the effect of the proteasome inhibitor MG-132 on skeletal muscle atrophy in a rat model of chronic obstructive pulmonary disease (COPD) and is potential mechanisms.Methods The COPD rat model was established by instillation of LPS and exposure

  2. Indoxyl sulfate induces skeletal resistance to parathyroid hormone in cultured osteoblastic cells.

    Science.gov (United States)

    Nii-Kono, T; Iwasaki, Y; Uchida, M; Fujieda, A; Hosokawa, A; Motojima, M; Yamato, H; Kurokawa, K; Fukagawa, M

    2007-04-01

    Skeletal resistance to parathyroid hormone (PTH) is well known to the phenomenon in chronic renal failure patient, but the detailed mechanism has not been elucidated. In the process of analyzing an animal model of renal failure with low bone turnover, we demonstrated decreased expression of PTH receptor (PTHR) accompanying renal dysfunction in this model. In the present study, we focused on the accumulation of uremic toxins (UTx) in blood, and examined whether indoxyl sulfate (IS), a UTx, is associated with PTH resistance. We established primary osteoblast cultures from mouse calvariae and cultured the cells in the presence of IS. The intracellular cyclic adenosine 3',5' monophosphate (cAMP) production, PTHR expression, and free radical production in the primary osteoblast culture were studied. We found that the addition of IS suppressed PTH-stimulated intracellular cAMP production and decreased PTHR expression in this culture system. Free radical production in osteoblasts increased depending on the concentration of IS added. Furthermore, expression of organic anion transporter-3 (OAT-3) that is known to mediate cellular uptake of IS was identified in the primary osteoblast culture. These results suggest that IS taken up by osteoblasts via OAT-3 present in these cells augments oxidative stress to impair osteoblast function and downregulate PTHR expression. These finding strongly suggest that IS accumulated in blood due to renal dysfunction is at least one of the factors that induce skeletal resistance to PTH.

  3. Skeletal muscle afferent regulation of bioassayable growth hormone in the rat pituitary

    Science.gov (United States)

    Gosselink, K. L.; Grindeland, R. E.; Roy, R. R.; Zhong, H.; Bigbee, A. J.; Grossman, E. J.; Edgerton, V. R.

    1998-01-01

    There are forms of growth hormone (GH) in the plasma and pituitary of the rat and in the plasma of humans that are undetected by presently available immunoassays (iGH) but can be measured by bioassay (bGH). Although the regulation of iGH release is well documented, the mechanism(s) of bGH release is unclear. On the basis of changes in bGH and iGH secretion in rats that had been exposed to microgravity conditions, we hypothesized that neural afferents play a role in regulating the release of these hormones. To examine whether bGH secretion can be modulated by afferent input from skeletal muscle, the proximal or distal ends of severed hindlimb fast muscle nerves were stimulated ( approximately 2 times threshold) in anesthetized rats. Plasma bGH increased approximately 250%, and pituitary bGH decreased approximately 60% after proximal nerve trunk stimulation. The bGH response was independent of muscle mass or whether the muscles were flexors or extensors. Distal nerve stimulation had little or no effect on plasma or pituitary bGH. Plasma iGH concentrations were unchanged after proximal nerve stimulation. Although there may be multiple regulatory mechanisms of bGH, the present results demonstrate that the activation of low-threshold afferents from fast skeletal muscles can play a regulatory role in the release of bGH, but not iGH, from the pituitary in anesthetized rats.

  4. Effect of Ferula hermonis root extract on rat skeletal muscle adaptation to exercise.

    Science.gov (United States)

    Allouh, Mohammed Z

    2011-12-01

    Ferula hermonis Boiss. is an aphrodisiac plant that grows in the Mediterranean region. It has been reported that treatment with acetonic extract from the root of this plant acutely increases serum testosterone in the rat. This study investigated the effects of F. hermonis extract alone or combined with exercise on rat skeletal muscle fibers. Adult male rats were divided into four groups: control-sedentary (CS) that had no treatment or exercise; ferula-sedentary (FS) that was orally treated with ferula extract at a dose of 60 mg/kg/rat every other day over a period of 20 d; control-exercised (CE) that was trained by swimming for 40 min every other day; and ferula-exercised (FE) that received ferula and performed exercise. At the end of experiments, the fiber diameter and number of muscle nuclei of tibialis anterior were measured by using immunofluorescent techniques and software analyses. The FE group showed significant increases in muscle weight, fiber size and nuclear number compared with the other groups. However, no significant changes in the aforementioned parameters were found among the CS, FS and CE groups. Ferula treatment and exercise were additive to each other. In conclusion, short-term exercise combined with administration of F. hermonis extract was more effective in enhancing the growth of skeletal muscle fibers than exercise alone.

  5. Skeletal muscle afferent regulation of bioassayable growth hormone in the rat pituitary

    Science.gov (United States)

    Gosselink, K. L.; Grindeland, R. E.; Roy, R. R.; Zhong, H.; Bigbee, A. J.; Grossman, E. J.; Edgerton, V. R.

    1998-01-01

    There are forms of growth hormone (GH) in the plasma and pituitary of the rat and in the plasma of humans that are undetected by presently available immunoassays (iGH) but can be measured by bioassay (bGH). Although the regulation of iGH release is well documented, the mechanism(s) of bGH release is unclear. On the basis of changes in bGH and iGH secretion in rats that had been exposed to microgravity conditions, we hypothesized that neural afferents play a role in regulating the release of these hormones. To examine whether bGH secretion can be modulated by afferent input from skeletal muscle, the proximal or distal ends of severed hindlimb fast muscle nerves were stimulated ( approximately 2 times threshold) in anesthetized rats. Plasma bGH increased approximately 250%, and pituitary bGH decreased approximately 60% after proximal nerve trunk stimulation. The bGH response was independent of muscle mass or whether the muscles were flexors or extensors. Distal nerve stimulation had little or no effect on plasma or pituitary bGH. Plasma iGH concentrations were unchanged after proximal nerve stimulation. Although there may be multiple regulatory mechanisms of bGH, the present results demonstrate that the activation of low-threshold afferents from fast skeletal muscles can play a regulatory role in the release of bGH, but not iGH, from the pituitary in anesthetized rats.

  6. Influence of creatine supplementation on indicators of glucose metabolism in skeletal muscle of exercised rats

    Directory of Open Access Journals (Sweden)

    Michel Barbosa de Araújo

    2013-12-01

    Full Text Available The purpose of this study was to evaluate the effect of creatine supplementation in the diet on indicators of glucose metabolism in skeletal muscle of exercised rats. Forty Wistar adult rats were distributed into four groups for eight weeks: 1 Control: sedentary rats that received balanced diet; 2 Creatine control: sedentary rats that received supplementation of 2% creatine in the balanced diet; 3 Trained: rats that ran on a treadmill at the Maximal Lactate Steady State and received balanced diet; and 4 Supplemented-trained: rats that ran on a treadmill at the Maximal Lactate Steady State and received creatine supplementation (2% in the balanced diet. The hydric intake increased and the body weight gain decreased in the supplemented-trained group. In the soleus muscle, the glucose oxidation increased in both supplemented groups. The production of lactate and glycemia during glucose tolerance test decreased in the supplemented-trained group. Creatine supplementation in conjunction with exercise training improved muscular glycidic metabolism of rats.

  7. Oxidative stress and peripheral skeletal muscle dysfunction in rats with emphysema

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-lei; PANG Bao-sen; HOU Xiao-li; WANG Jun; WANG Chen

    2010-01-01

    Background Peripheral skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease (COPD)may be due to the disease per se or as a result of concomitant confounding factors. Although the mechanistic basis forthis functional impairment is uncertain, oxidative stress may play a role. The purpose of this study was to investigatewhether local oxidative stress is associated with the reduced peripheral skeletal muscle performance in rats withemphysema.Methods In situ mechanical properties of gastrocnemius were measured in Sprague-Dawley rats 5 months afterintratracheal instillation of either elastase (EMP, n=10) or normal saline (CON, n=10). Lipofuscin inclusions, myocyteapoptosis and antioxidant enzyme activities were examined in the gastrocnemius muscle.Results Lipofuscin inclusions were significantly higher in the gastrocnemius muscle of EMP compared with CON(3.2±0.4 vs. 1.7±0.4, P0.05). EMP decreased the fatigue endurance of gastrocnemius muscle (half-time to fatiguerecovery: (150.0±55.4) seconds vs. (55.2±29.3) seconds, P 0.05). A significantly positive correlation was found between the level of lipofuscininclusions and the half-time to fatigue recovery of gastrocnemius muscle in EMP (/to.664, P<0.05).Conclusion Local oxidative stress may have important functional consequences for peripheral skeletal muscle in ratswith EMP.

  8. Nitric oxide agents impair insulin-mediated signal transduction in rat skeletal muscle

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    Ragoobirsingh Dalip

    2006-05-01

    Full Text Available Abstract Background Evidence demonstrates that exogenously administered nitric oxide (NO can induce insulin resistance in skeletal muscle. We have investigated the modulatory effects of two NO donors, S-nitroso-N-acetyl-D, L-penicillamine (SNAP and S-nitrosoglutathione (GSNO on the early events in insulin signaling in rat skeletal myocytes. Results Skeletal muscle cells from 6–8 week old Sprague-Dawley rats were treated with SNAP or GSNO (25 ng/ml in the presence or absence of glucose (25 mM and insulin (100 nM. Cellular insulin receptor-β levels and tyrosine phosphorylation in IRS-1 were significantly reduced, while serine phosphorylation in IRS-1 was significantly increased in these cells, when compared to the insulin-stimulated control. Reversal to near normal levels was achieved using the NO scavenger, 2-(4-carboxyphenyl-4, 4, 5, 5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO. Conclusion These data suggest that NO is a potent modulator of insulin-mediated signal transduction and may play a significant role in the pathogenesis of type 2 diabetes mellitus.

  9. Histopathological changes in rat pancreas and skeletal muscle associated with high fat diet induced insulin resistance.

    Science.gov (United States)

    Ickin Gulen, M; Guven Bagla, A; Yavuz, O; Hismiogullari, A A

    2015-01-01

    The effects of a high fat diet on the development of diabetes mellitus, insulin resistance and secretion have been widely investigated. We investigated the effects of a high fat diet on the pancreas and skeletal muscle of normal rats to explore diet-induced insulin resistance mechanisms. Forty-four male Wistar rats were divided into six groups: a control group fed standard chow, a group fed a 45% fat diet and a group fed a 60% fat diet for 3 weeks to measure acute effects; an additional three groups were fed the same diet regimens for 8 weeks to measure chronic effects. The morphological effects of the two high fat diets were examined by light microscopy. Insulin in pancreatic islets was detected using immunohistochemistry. The homeostasis model assessment of insulin resistance index and insulin staining intensity in islets increased significantly with acute administration of high fat diets, whereas staining intensity decreased with chronic administration of the 45% fat diet. Islet areas increased significantly with chronic administration. High fat diet administration led to islet degeneration, interlobular adipocyte accumulation and vacuolization in the pancreatic tissue, as well as degeneration and lipid droplet accumulation in the skeletal muscle tissue. Vacuolization in the pancreas and lipid droplets in skeletal muscle tissue increased significantly with chronic high fat diet administration. We suggest that the glucolipotoxic effects of high fat diet administration depend on the ratio of saturated to unsaturated fatty acid content in the diet and to the total fat content of the diet.

  10. The effect of high-fat--high-fructose diet on skeletal muscle mitochondrial energetics in adult rats.

    Science.gov (United States)

    Crescenzo, Raffaella; Bianco, Francesca; Coppola, Paola; Mazzoli, Arianna; Cigliano, Luisa; Liverini, Giovanna; Iossa, Susanna

    2015-03-01

    To study the effect of isoenergetic administration to adult rats of high-fat or high-fat--high-fructose diet for 2 weeks on skeletal muscle mitochondrial energetic. Body and skeletal muscle composition, energy balance, plasma lipid profile and glucose tolerance were measured, together with mitochondrial functionality, oxidative stress and antioxidant defense. Rats fed high-fat--high-fructose diet exhibited significantly higher plasma triglycerides and non-esterified fatty acids, together with significantly higher plasma glucose and insulin response to glucose load. Skeletal muscle triglycerides and ceramide were significantly higher in rats fed high-fat--high-fructose diet. Skeletal muscle mitochondrial energetic efficiency and uncoupling protein 3 content were significantly higher, while adenine nucleotide translocase content was significantly lower, in rats fed high-fat or high-fat--high-fructose diet. The results suggest that a high-fat--high-fructose diet even without hyperphagia is able to increase lipid flow to skeletal muscle and mitochondrial energetic efficiency, with two detrimental effects: (a) energy sparing that contributes to the early onset of obesity and (b) reduced oxidation of fatty acids and lipid accumulation in skeletal muscle, which could generate insulin resistance.

  11. Carnosine content in skeletal muscle is dependent on vitamin B6 status in rats

    Directory of Open Access Journals (Sweden)

    Sofya eSuidasari

    2016-01-01

    Full Text Available Carnosine, a histidine-containing dipeptide, is well known to be associated with skeletal muscle performance. However, there is limited information on the effect of dietary micronutrients on muscle carnosine level. Pyridoxal 5′-phosphate (PLP, the active form of vitamin B6, is involved in amino acid metabolisms in the body as a co-factor. We hypothesized that enzymes involved in β-alanine biosynthesis, the rate-limiting precursor of carnosine, may also be PLP-dependent. Thus, we examined the effects of dietary vitamin B6 on the muscle carnosine content of rats. Male and female rats were fed a diet containing 1, 7, or 35 mg pyridoxine HCl/kg for 6 weeks. Carnosine in skeletal muscles was quantified by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS. In the gastrocnemius muscle of male rats, carnosine concentration was significantly higher in the 7 and 35 mg groups (+70% and +61%, respectively than in the 1 mg pyridoxine HCl/kg group, whereas that in the soleus muscle of male rats was significantly higher only in the 7 mg group (+43% than in the 1 mg pyridoxine HCl/kg group (P<0.05. In both muscles of female rats, carnosine concentration was significantly higher in the 7 and 35 mg groups (+32% ~ +226% than in the 1 mg pyridoxine HCl/kg group (P<0.05. We also found that compared to the 1 mg group, β-alanine concentrations in the 7 and 35 mg groups were markedly elevated in gastrocnemius muscles of male (+153% and +148%, respectively, P<0.05 and female (+381% and +437%, respectively, P<0.05 rats. Noteworthy, the concentrations of ornithine in the 7 and 35 mg groups were decreased in gastrocnemius muscles of male rats (−46% and −54%, respectively, P<0.05, which strongly inversely correlated with β-alanine concentration (r=−0.84, P<0.01. In humans, 19% lower muscle carnosine content was found in soleus muscle of women of the lower plasma PLP tertile, but this was not observed in gastrocnemius muscle

  12. Dietary fat influences the expression of contractile and metabolic genes in rat skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Wataru Mizunoya

    Full Text Available Dietary fat plays a major role in obesity, lipid metabolism, and cardiovascular diseases. To determine whether the intake of different types of dietary fats affect the muscle fiber types that govern the metabolic and contractile properties of the skeletal muscle, we fed male Wistar rats with a 15% fat diet derived from different fat sources. Diets composed of soybean oil (n-6 polyunsaturated fatty acids (PUFA-rich, fish oil (n-3 PUFA-rich, or lard (low in PUFAs were administered to the rats for 4 weeks. Myosin heavy chain (MyHC isoforms were used as biomarkers to delineate the skeletal muscle fiber types. Compared with soybean oil intake, fish oil intake showed significantly lower levels of the fast-type MyHC2B and higher levels of the intermediate-type MyHC2X composition in the extensor digitorum longus (EDL muscle, which is a fast-type dominant muscle. Concomitantly, MyHC2X mRNA levels in fish oil-fed rats were significantly higher than those observed in the soybean oil-fed rats. The MyHC isoform composition in the lard-fed rats was an intermediate between that of the fish oil and soybean oil-fed rats. Mitochondrial uncoupling protein 3, pyruvate dehydrogenase kinase 4, and porin mRNA showed significantly upregulated levels in the EDL of fish oil-fed rats compared to those observed in soybean oil-fed and lard-fed rats, implying an activation of oxidative metabolism. In contrast, no changes in the composition of MyHC isoforms was observed in the soleus muscle, which is a slow-type dominant muscle. Fatty acid composition in the serum and the muscle was significantly influenced by the type of dietary fat consumed. In conclusion, dietary fat affects the expression of genes related to the contractile and metabolic properties in the fast-type dominant skeletal muscle, where the activation of oxidative metabolism is more pronounced after fish oil intake than that after soybean oil intake.

  13. SPRINT-INTERVAL TRAINING INDUCES HEAT SHOCK PROTEIN 72 IN RAT SKELETAL MUSCLES

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    Yuji Ogura

    2006-06-01

    Full Text Available Previous studies have demonstrated that endurance exercise training increases the level of heat shock proteins (HSPs in skeletal muscles. However, little attention has been drawn to the effects of high intensity-short duration exercise, or sprint- interval training (SIT on HSP72 level in rat skeletal muscles. This study performed to test the hypothesis that the SIT would induce the HSP72 in fast and slow skeletal muscles of rats. Young male Wistar rats (8 weeks old were randomly assigned to a control (CON or a SIT group (n = 8/group. Animals in the SIT group were trained (1 min/sprint, 6~10 sets/day and 5~6 days/week on a treadmill for 9 weeks. After the training period, HSP72 levels in the plantaris (fast and soleus (slow muscles were analyzed by Western blotting method. Enzyme activities (hexokinase, phosphofructokinase and citrate synthase and histochemical properties (muscle fiber type compositions and cross sectional area in both muscles were also determined. The SIT resulted in significantly (p < 0.05 higher levels of HSP72 in both the plantaris and soleus muscles compared to the CON group, with the plantaris producing a greater HSP72 increase than the soleus (plantaris; 550 ± 116%, soleus; 26 ± 8%, p < 0.05. Further, there were bioenergetic improvements, fast-to-slow shift of muscle fiber composition and hypertrophy in the type IIA fiber only in the plantaris muscle. These findings indicate that the SIT program increases HSP72 level of the rat hindlimb muscles, and the SIT-induced accumulation of HSP72 differs between fast and slow muscles

  14. Motor Unit Changes Seen With Skeletal Muscle Sarcopenia in Oldest Old Rats

    Science.gov (United States)

    Kung, Theodore A.; van der Meulen, Jack H.; Urbanchek, Melanie G.; Kuzon, William M.; Faulkner, John A.

    2014-01-01

    Sarcopenia leads to many changes in skeletal muscle that contribute to atrophy, force deficits, and subsequent frailty. The purpose of this study was to characterize motor unit remodeling related to sarcopenia seen in extreme old age. Whole extensor digitorum longus muscle and motor unit contractile properties were measured in 19 adult (11–13 months) and 12 oldest old (36–37 months) Brown-Norway rats. Compared with adults, oldest old rats had significantly fewer motor units per muscle, smaller muscle cross-sectional area, and lower muscle specific force. However, mean motor unit force generation was similar between the two groups due to an increase in innervation ratio by the oldest old rats. These findings suggest that even in extreme old age both fast- and slow-twitch motor units maintain the ability to undergo motor unit remodeling that offsets some effects of sarcopenia. PMID:24077596

  15. [Energy reactions in the skeletal muscles of rats after a flight on the Kosmos-1129 biosatellite].

    Science.gov (United States)

    Mailian, E S; Buravkova, L B; Kokoreva, L V

    1983-01-01

    The polarographic analysis of biological oxidation in rat skeletal muscles after the 18.5-day flight revealed changes specific for the flight animals: oxidative phosphorylation uncoupling, distinct inertness of energy accumulation 10 hrs after recovery. Tissue respiration inhibition occurred in both flight and synchronous rats suggesting the effect of other than weightlessness factors. In the flight animals the parameters of energy metabolism returned to the prelaunch level within a longer (29 days) time than in the synchronous rats (6 days). Muscles of different function (predominance of fast or slow fibers) showed similar responses of energy metabolism to weightlessness, i. e. inhibition of the intensity and decrease of the energy efficiency of oxidative processes.

  16. [Contractile properties of skeletal muscles of rats after flight on "Kosmos-1887"].

    Science.gov (United States)

    Oganov, V S; Skuratova, S A; Murashko, L M

    1991-01-01

    Contractile properties of skeletal muscles of rats were investigated using glycerinated muscle preparations that were obtained from Cosmos-1887 animals flown for 13 days (plus 2 days on the ground) and from rats that remained hypokinetic for 13 days on the ground. In the flow rats, the absolute mass of postural muscles remained unchanged while their relative mass increased; this may be attributed to their enhanced hydration which developed during the first 2 days after landing. Strength losses of the postural muscles were less significant than after previous flights. Comparison of the Cosmos-1887 and hypokinesia control data has shown that even 2-day exposure to 1 G after 13-day flight can modify drastically flight-induced changes.

  17. Microtransplantation of acetylcholine receptors from normal or denervated rat skeletal muscles to frog oocytes

    Science.gov (United States)

    Bernareggi, Annalisa; Reyes-Ruiz, Jorge Mauricio; Lorenzon, Paola; Ruzzier, Fabio; Miledi, Ricardo

    2011-01-01

    Cell membranes, carrying neurotransmitter receptors and ion channels, can be ‘microtransplanted’ into frog oocytes. This technique allows a direct functional characterization of the original membrane proteins, together with any associated molecules they may have, still embedded in their natural lipid environment. This approach has been previously demonstrated to be very useful to study neurotransmitter receptors and ion channels contained in cell membranes isolated from human brains. Here, we examined the possibility of using the microtransplantation method to study acetylcholine receptors from normal and denervated rat skeletal muscles. We found that the muscle membranes, carrying their fetal or adult acetylcholine receptor isoforms, could be efficiently microtransplanted to the oocyte membrane, making the oocytes become sensitive to acetylcholine. These results show that oocytes injected with skeletal muscle membranes efficiently incorporate functional acetylcholine receptors, thus making the microtransplantation approach a valuable tool to further investigate receptors and ion channels of human muscle diseases. PMID:21224230

  18. Nitric oxide and Na,K-ATPase activity in rat skeletal muscle

    DEFF Research Database (Denmark)

    Juel, Carsten

    2016-01-01

    Aim: It has been suggested that nitric oxide (NO) stimulates the Na,K-ATPase in cardiac myocytes. Therefore, the aims of this study were to investigate whether NO increases Na,K-ATPase activity in skeletal muscle and, if that is the case, to identify the underlying mechanism. Method: The study used...... activity was depressed by oxidized glutathione. Conclusion: NO and cGMP stimulate the Na,K-ATPase in glycolytic skeletal muscle. Direct S-nitrosylation and interference with S-glutathionylation seem to be excluded. In addition, phosphorylation of phospholemman at serine 68 is not involved. Most likely...... isolated rat muscle, muscle homogenates and purified membranes as model systems. Na,K-ATPase activity was quantified from phosphate release due to ATP hydrolysis. Results: Exposure to the NO donor spermine NONOate (10 μm) increased the maximal Na,K-ATPase activity by 27% in isolated glycolytic muscles...

  19. Age-associated disruption of molecular clock expression in skeletal muscle of the spontaneously hypertensive rat.

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    Mitsunori Miyazaki

    Full Text Available It is well known that spontaneously hypertensive rats (SHR develop muscle pathologies with hypertension and heart failure, though the mechanism remains poorly understood. Woon et al. (2007 linked the circadian clock gene Bmal1 to hypertension and metabolic dysfunction in the SHR. Building on these findings, we compared the expression pattern of several core-clock genes in the gastrocnemius muscle of aged SHR (80 weeks; overt heart failure compared to aged-matched control WKY strain. Heart failure was associated with marked effects on the expression of Bmal1, Clock and Rora in addition to several non-circadian genes important in regulating skeletal muscle phenotype including Mck, Ttn and Mef2c. We next performed circadian time-course collections at a young age (8 weeks; pre-hypertensive and adult age (22 weeks; hypertensive to determine if clock gene expression was disrupted in gastrocnemius, heart and liver tissues prior to or after the rats became hypertensive. We found that hypertensive/hypertrophic SHR showed a dampening of peak Bmal1 and Rev-erb expression in the liver, and the clock-controlled gene Pgc1α in the gastrocnemius. In addition, the core-clock gene Clock and the muscle-specific, clock-controlled gene Myod1, no longer maintained a circadian pattern of expression in gastrocnemius from the hypertensive SHR. These findings provide a framework to suggest a mechanism whereby chronic heart failure leads to skeletal muscle pathologies; prolonged dysregulation of the molecular clock in skeletal muscle results in altered Clock, Pgc1α and Myod1 expression which in turn leads to the mis-regulation of target genes important for mechanical and metabolic function of skeletal muscle.

  20. Age-associated disruption of molecular clock expression in skeletal muscle of the spontaneously hypertensive rat.

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    Miyazaki, Mitsunori; Schroder, Elizabeth; Edelmann, Stephanie E; Hughes, Michael E; Kornacker, Karl; Balke, C William; Esser, Karyn A

    2011-01-01

    It is well known that spontaneously hypertensive rats (SHR) develop muscle pathologies with hypertension and heart failure, though the mechanism remains poorly understood. Woon et al. (2007) linked the circadian clock gene Bmal1 to hypertension and metabolic dysfunction in the SHR. Building on these findings, we compared the expression pattern of several core-clock genes in the gastrocnemius muscle of aged SHR (80 weeks; overt heart failure) compared to aged-matched control WKY strain. Heart failure was associated with marked effects on the expression of Bmal1, Clock and Rora in addition to several non-circadian genes important in regulating skeletal muscle phenotype including Mck, Ttn and Mef2c. We next performed circadian time-course collections at a young age (8 weeks; pre-hypertensive) and adult age (22 weeks; hypertensive) to determine if clock gene expression was disrupted in gastrocnemius, heart and liver tissues prior to or after the rats became hypertensive. We found that hypertensive/hypertrophic SHR showed a dampening of peak Bmal1 and Rev-erb expression in the liver, and the clock-controlled gene Pgc1α in the gastrocnemius. In addition, the core-clock gene Clock and the muscle-specific, clock-controlled gene Myod1, no longer maintained a circadian pattern of expression in gastrocnemius from the hypertensive SHR. These findings provide a framework to suggest a mechanism whereby chronic heart failure leads to skeletal muscle pathologies; prolonged dysregulation of the molecular clock in skeletal muscle results in altered Clock, Pgc1α and Myod1 expression which in turn leads to the mis-regulation of target genes important for mechanical and metabolic function of skeletal muscle.

  1. Regenerative Potential of D-δ-Tocotrienol Rich Fraction on Crushed Skeletal Muscle of Diabetic Rats

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    Bijo Elsy

    2017-06-01

    Full Text Available Background: Delayed muscle growth and regeneration of skeletal muscle in diabetics is believed to be due to diabetic myopathy because of alteration in the skeletal muscle homeostatis. Since vitamin E is a natural antioxidant and is also important for the integrity of sarcolemma, the present study was designed to explore the muscle regenerative potency of d-δ-tocotrienol-rich fraction (d-δ-TRF on crushed skeletal muscle in healthy and diabetic rats. Materials and Methods: Diabetes was induced through single subcutaneous injection of alloxan (100 mg/kg. Twenty-four albino rats were divided into four groups; healthy control, diabetic control, healthy treated, and diabetic treated. Treated groups received injections orally, daily (200 mg/kg for 3 weeks. A horizontal skin incision was made on the shaved right mid-thigh region, by splitting the fascia between gluteus maximus and tensor fascia lata, and gluteus maximus was crushed with Kocher’s forceps. Skin wound was closed with an absorbable suture. The crushed muscle changes were studied by assessing the histopathological features, histomorphological measurements, and biochemical analyses on 3rd week following induction of injury. One-way “ANOVA” followed by Tukey’s test and Student t-test were used for statistical analysis of data. Results: Results obtained through various methods indicate that the d-δ-TRF treated groups have controlled glycemic status, improved antioxidant capacity, faster revascularization, re-innervation, regeneration of myofibers, and connective tissue remodeling. Conclusion: It is, therefore, concluded that the d-δ-TRF is a beneficial nutritional adjuvant for skeletal muscles’ structural and functional recovery after crushed injury in both healthy and diabetics. [J Interdiscipl Histopathol 2017; 5(2.000: 36-42

  2. Maternal bisphenol A exposure alters rat offspring hepatic and skeletal muscle insulin signaling protein abundance.

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    Galyon, Kristina D; Farshidi, Farnoosh; Han, Guang; Ross, Michael G; Desai, Mina; Jellyman, Juanita K

    2017-03-01

    The obesogenic and diabetogenic effects of the environmental toxin bisphenol A during critical windows of development are well recognized. Liver and skeletal muscle play a central role in the control of glucose production, utilization, and storage. We hypothesized that maternal bisphenol A exposure disrupts insulin signaling in rat offspring liver and skeletal muscle. We determined the protein expression of hepatic and skeletal muscle insulin signaling molecules including insulin receptor beta, its downstream target insulin receptor substrate 1 and glucose transporters (glucose transporter 2, glucose transporter 4), and hepatic glucose-regulating enzymes phosphoenolpyruvate carboxykinase and glucokinase. Rat dams had ad libitum access to filtered drinking water (control) or drinking water with bisphenol A from 2 weeks prior to mating and through pregnancy and lactation. Offspring litters were standardized to 4 males and 4 females and nursed by the same dam. At weaning, bisphenol A exposure was removed from all offspring. Glucose tolerance was tested at 6 weeks and 6 months. Liver and skeletal muscle was collected from 3 week old and 10 month old offspring for protein expression (Western blot) of insulin receptor beta, insulin receptor substrate 1, glucose transporter 2, glucose transporter 4, phosphoenolpyruvate carboxykinase, and glucokinase. Male, but not female, bisphenol A offspring had impaired glucose tolerance at 6 weeks and 6 months. Both male and female adult offspring had higher glucose-stimulated insulin secretion as well as the ratio of stimulated insulin to glucose. Male bisphenol A offspring had higher liver protein abundance of the 200 kDa insulin receptor beta precursor (2-fold), and insulin receptor substrate 1 (1.5-fold), whereas glucose transporter 2 was 0.5-fold of the control at 3 weeks of age. In adult male bisphenol A offspring, the abundance of insulin receptor beta was higher (2-fold) and glucose transporter 4 was 0.8-fold of the control in

  3. Cardiolipin linoleic acid content and mitochondrial cytochrome c oxidase activity are associated in rat skeletal muscle.

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    Fajardo, Val Andrew; McMeekin, Lauren; Saint, Caitlin; LeBlanc, Paul J

    2015-04-01

    Cardiolipin (CL) is an inner-mitochondrial membrane phospholipid that is important for optimal mitochondrial function. Specifically, CL and CL linoleic (18:2ω6) content are known to be positively associated with cytochrome c oxidase (COX) activity. However, this association has not been examined in skeletal muscle. In this study, rats were fed high-fat diets with a naturally occurring gradient in linoleic acid (coconut oil [CO], 5.8%; flaxseed oil [FO], 13.2%; safflower oil [SO], 75.1%) in an attempt to alter both mitochondrial CL fatty acyl composition and COX activity in rat mixed hind-limb muscle. In general, mitochondrial membrane lipid composition was fairly resistant to dietary treatments as only modest changes in fatty acyl composition were detected in CL and other major mitochondrial phospholipids such as phosphatidylcholine (PC) and phosphatidylethanolamine (PE). As a result of this resistance, CL 18:2ω6 content was not different between the dietary groups. Consistent with the lack of changes in CL 18:2ω6 content, mitochondrial COX activity was also not different between the dietary groups. However, correlational analysis using data obtained from rats across the dietary groups showed a significant relationship (p = 0.009, R(2) = 0.21). Specifically, our results suggest that CL 18:2ω6 content may positively influence mitochondrial COX activity thereby making this lipid molecule a potential factor related to mitochondrial health and function in skeletal muscle.

  4. The change in thyroid hormone signaling by altered training intensity in male rat skeletal muscle.

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    Lesmana, Ronny; Iwasaki, Toshiharu; Iizuka, Yuki; Amano, Izuki; Shimokawa, Noriaki; Koibuchi, Noriyuki

    2016-08-31

    Aerobic (sub lactate threshold; sub-LT) exercise training facilitates oxidative phosphorylation and glycolysis of skeletal muscle. Thyroid hormone (TH) also facilitates such metabolic events. Thus, we studied whether TH signaling pathway is activated by treadmill training. Male adult rats received 30 min/day treadmill training with different exercise intensity for 12 days. Then plasma lactate and thyrotropin (TSH) levels were measured. By lactate levels, rats were divided into stationary control (SC, 0 m/min), sub-LT (15 m/min) and supra lactate threshold (supra-LT; 25 m/min) training groups. Immediately after the last training, the soleus muscles were dissected out to measure TH receptor (TR) mRNA and protein expressions. Other rats received intraperitoneal injection of T3, 24 h after the last training and sacrificed 6 h after the injection to measure TH target gene expression. TSH level was suppressed in both sub-LT and supra-LT groups during the exercise. TRβ1 mRNA and protein levels were increased in sub-LT group. Sensitivity to T3 was altered in several TH-target genes by training. Particularly, induction of Na(+)/K(+)-ATPase β1 expression by T3 was significantly augmented in sub-LT group. These results indicate that sub-LT training alters TH signaling at least in part by increasing TRβ1 expression. Such TH signaling alteration may contribute metabolic adaptation in skeletal muscle during physical training.

  5. Sildenafil citrate protects skeletal muscle of ischemia-reperfusion injury: immunohistochemical study in rat model

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    Dinani Matoso Fialho de Oliveira Armstrong

    2013-04-01

    Full Text Available PURPOSE: To investigate the effect of sildenafil citrate (SC on skeletal muscle ischemia-reperfusion (IR injury in rats. METHODS: Adult male Wistar rats were randomized into three groups: vehicle-treated control (CTG, sildenafil citrate-treated (SCG, and sham group (SG. CTG and SCG had femoral artery occluded for 6 hours. Saline or 1 mg/kg of SC was given 5.5 hours after occlusion. SG had a similar procedure without artery occlusion. Soleus muscle samples were acquired 4 or 24h after the reperfusion. Immunohistochemistry caspase-3 analysis was used to estimate apoptosis using the apoptotic ratio (computed as positive/negative cells. Wilcoxon rank-sum or Kruskal-Wallis tests were used to assess differences among groups. RESULTS: Eighteen animals were included in the 4h reperfusion groups and 21 animals in the 24h reperfusion groups. The mean apoptotic ratio was 0.18±0.1 for the total cohort; 0.14±0.06 for the 4h reperfusion groups and 0.19±0.08 for the 24h groups (p<0.05. The SCG had lower caspase-3 ratio compared to the control groups at the 24h reperfusion time point (p<0.05. CONCLUSION: Sildenafil citrate administration after the onset of the ischemic injury reduces IR-induced cellular damage in skeletal muscle in this rat hindlimb ischemia model.

  6. Cholinergic neurons regulate secretion of glial cell line-derived neurotrophic factor by skeletal muscle cells in culture.

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    Vianney, John-Mary; Spitsbergen, John M

    2011-05-16

    Glial cell line-derived neurotrophic factor (GDNF) has been identified as a potent survival factor for both central and peripheral neurons. GDNF has been shown to be a potent survival factor for motor neurons during programmed cell death and continuous treatment with GDNF maintains hyperinnervation of skeletal muscle in adulthood. However, little is known about factors regulating normal production of endogenous GDNF in skeletal muscle. This study aimed to examine the role that motor neurons play in regulating GDNF secretion by skeletal muscle. A co-culture of skeletal muscle cells (C2C12) and cholinergic neurons, glioma×neuroblastoma hybrid cells (NG108-15) were used to create nerve-muscle interactions in vitro. Acetylcholine receptors (AChRs) on nerve-myotube co-cultures were blocked with alpha-bungarotoxin (α-BTX). GDNF protein content in cells and in culture medium was analyzed by enzyme-linked immunosorbant assay (ELISA) and western blotting. GDNF localization was examined by immunocytochemistry. The nerve-muscle co-culture study indicated that the addition of motor neurons to skeletal muscle cells reduced the secretion of GDNF by skeletal muscle. The results also showed that blocking AChRs with α-BTX reversed the action of neural cells on GDNF secretion by skeletal muscle. Although ELISA results showed no GDNF in differentiated NG108-15 cells grown alone, immunocytochemical analysis showed that GDNF was localized in NG108-15 cells co-cultured with C2C12 myotubes. These results suggest that motor neurons may be regulating their own supply of GDNF secreted by skeletal muscle and that activation of AChRs may be involved in this process. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Chronic alcohol ingestion exacerbates skeletal muscle myopathy in HIV-1 transgenic rats

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    Bratina Margaux A

    2011-08-01

    Full Text Available Abstract Background Separately, chronic alcohol ingestion and HIV-1 infection are associated with severe skeletal muscle derangements, including atrophy and wasting, weakness, and fatigue. One prospective cohort study reported that 41% of HIV-infected patients met the criteria for alcoholism, however; few reports exist on the co-morbid effects of these two disease processes on skeletal muscle homeostasis. Thus, we analyzed the atrophic effects of chronic alcohol ingestion in HIV-1 transgenic rats and identified alterations to several catabolic and anabolic factors. Findings Relative plantaris mass, total protein content, and fiber cross-sectional area were reduced in each experimental group compared to healthy, control-fed rats. Alcohol abuse further reduced plantaris fiber area in HIV-1 transgenic rats. Consistent with previous reports, gene levels of myostatin and its receptor activin IIB were not increased in HIV-1 transgenic rat muscle. However, myostatin and activin IIB were induced in healthy and HIV-1 transgenic rats fed alcohol for 12 weeks. Catabolic signaling factors such as TGFβ1, TNFα, and phospho-p38/total-p38 were increased in all groups compared to controls. There was no effect on IL-6, leukemia inhibitory factor (LIF, cardiotrophin-1 (CT-1, or ciliary neurotrophic factor (CNTF in control-fed, transgenic rats. However, the co-morbidity of chronic alcohol abuse and HIV-1-related protein expression decreased expression of the two anabolic factors, CT-1 and CNTF. Conclusions Consistent with previous reports, alcohol abuse accentuated skeletal muscle atrophy in an animal model of HIV/AIDS. While some catabolic pathways known to drive alcoholic or HIV-1-associated myopathies were also elevated in this co-morbid model (e.g., TGFβ1, consistent expression patterns were not apparent. Thus, specific alterations to signaling mechanisms such as the induction of the myostatin/activin IIB system or reductions in growth factor signaling via

  8. Effect of diuretics and lithium on /sup 3/H-ouabain binding site concentration and Na,K-content in rat skeletal muscle

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    Noergaard, Aa.; Kjeldsen, K.

    1986-01-01

    Previous studies have shown an increase in /sup 3/H-ouabain binding sites or Na,K-pumps in vitro in cultured cells in response to incubation in low K, diuretics or lithium. However, in the present study the administration in vivo of various diuretics or lithium combined with supplementary K was not associated with any significant changes in Na,K-content or /sup 3/H-ouabain binding site concentration in rat skeletal muscle. When the diuretics were administered in combination with only the basal K requirement a decrease in both K-content and /sup 3/H-ouabain binding site concentration was seen. This indicates that the decrease in /sup 3/H-ouabain binding site concentration is not caused by these drugs per se but is secondary to the associated K-depletion. The discrepancy between the results obtained using isolated cells and rat skeletal muscles could be related to the fact that cultured cells are not subjected to the normal growth control of the intact organism. It should be emphasized that results obtained using cultured cells do not necessarily reflect processes taking place in the intact organism.

  9. Niacin in pharmacological doses alters microRNA expression in skeletal muscle of obese Zucker rats.

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    Couturier, Aline; Keller, Janine; Most, Erika; Ringseis, Robert; Eder, Klaus

    2014-01-01

    Administration of pharmacological niacin doses was recently reported to have pronounced effects on skeletal muscle gene expression and phenotype in obese Zucker rats, with the molecular mechanisms underlying the alteration of gene expression being completely unknown. Since miRNAs have been shown to play a critical role for gene expression through inducing miRNA-mRNA interactions which results in the degradation of specific mRNAs or the repression of protein translation, we herein aimed to investigate the influence of niacin at pharmacological doses on the miRNA expression profile in skeletal muscle of obese Zucker rats fed either a control diet with 30 mg supplemented niacin/kg diet or a high-niacin diet with 780 mg supplemented niacin/kg diet for 4 wk. miRNA microarray analysis revealed that 42 out of a total of 259 miRNAs were differentially expressed (adjusted P-value niacin group and the control group. Using a biostatistics approach, we could demonstrate that the most strongly up-regulated (log2 ratio ≥0.5) and down-regulated (log2 ratio ≤-0.5) miRNAs target approximately 1,800 mRNAs. Gene-term enrichment analysis showed that many of the predicted target mRNAs from the most strongly regulated miRNAs were involved in molecular processes dealing with gene transcription such as DNA binding, transcription regulator activity, transcription factor binding and in important regulatory pathways such as Wnt signaling and MAPK signaling. In conclusion, the present study shows for the first time that pharmacological niacin doses alter the expression of miRNAs in skeletal muscle of obese Zucker rats and that the niacin-regulated miRNAs target a large set of genes and pathways which are involved in gene regulatory activity indicating that at least some of the recently reported effects of niacin on skeletal muscle gene expression and phenotype in obese Zucker rats are mediated through miRNA-mRNA interactions.

  10. Niacin in pharmacological doses alters microRNA expression in skeletal muscle of obese Zucker rats.

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    Aline Couturier

    Full Text Available Administration of pharmacological niacin doses was recently reported to have pronounced effects on skeletal muscle gene expression and phenotype in obese Zucker rats, with the molecular mechanisms underlying the alteration of gene expression being completely unknown. Since miRNAs have been shown to play a critical role for gene expression through inducing miRNA-mRNA interactions which results in the degradation of specific mRNAs or the repression of protein translation, we herein aimed to investigate the influence of niacin at pharmacological doses on the miRNA expression profile in skeletal muscle of obese Zucker rats fed either a control diet with 30 mg supplemented niacin/kg diet or a high-niacin diet with 780 mg supplemented niacin/kg diet for 4 wk. miRNA microarray analysis revealed that 42 out of a total of 259 miRNAs were differentially expressed (adjusted P-value <0.05, 20 being down-regulated and 22 being up-regulated, between the niacin group and the control group. Using a biostatistics approach, we could demonstrate that the most strongly up-regulated (log2 ratio ≥0.5 and down-regulated (log2 ratio ≤-0.5 miRNAs target approximately 1,800 mRNAs. Gene-term enrichment analysis showed that many of the predicted target mRNAs from the most strongly regulated miRNAs were involved in molecular processes dealing with gene transcription such as DNA binding, transcription regulator activity, transcription factor binding and in important regulatory pathways such as Wnt signaling and MAPK signaling. In conclusion, the present study shows for the first time that pharmacological niacin doses alter the expression of miRNAs in skeletal muscle of obese Zucker rats and that the niacin-regulated miRNAs target a large set of genes and pathways which are involved in gene regulatory activity indicating that at least some of the recently reported effects of niacin on skeletal muscle gene expression and phenotype in obese Zucker rats are mediated through

  11. Effect of HIV-1-related protein expression on cardiac and skeletal muscles from transgenic rats

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    Guidot David M

    2008-04-01

    Full Text Available Abstract Background Human immunodeficiency virus type 1 (HIV-1 infection and the consequent acquired immunodeficiency syndrome (AIDS has protean manifestations, including muscle wasting and cardiomyopathy, which contribute to its high morbidity. The pathogenesis of these myopathies remains partially understood, and may include nutritional deficiencies, biochemical abnormalities, inflammation, and other mechanisms due to viral infection and replication. Growing evidence has suggested that HIV-1-related proteins expressed by the host in response to viral infection, including Tat and gp120, may also be involved in the pathophysiology of AIDS, particularly in cells or tissues that are not directly infected with HIV-1. To explore the potentially independent effects of HIV-1-related proteins on heart and skeletal muscles, we used a transgenic rat model that expresses several HIV-1-related proteins (e.g., Tat, gp120, and Nef. Outcome measures included basic heart and skeletal muscle morphology, glutathione metabolism and oxidative stress, and gene expressions of atrogin-1, muscle ring finger protein-1 (MuRF-1 and Transforming Growth Factor-β1 (TGFβ1, three factors associated with muscle catabolism. Results Consistent with HIV-1 associated myopathies in humans, HIV-1 transgenic rats had increased relative heart masses, decreased relative masses of soleus, plantaris and gastrocnemius muscles, and decreased total and myosin heavy chain type-specific plantaris muscle fiber areas. In both tissues, the levels of cystine (Cyss, the oxidized form of the anti-oxidant cysteine (Cys, and Cyss:Cys ratios were significantly elevated, and cardiac tissue from HIV-1 transgenic rats had altered glutathione metabolism, all reflective of significant oxidative stress. In HIV-1 transgenic rat hearts, MuRF-1 gene expression was increased. Further, HIV-1-related protein expression also increased atrogin-1 (~14- and ~3-fold and TGFβ1 (~5-fold and ~3-fold in heart and

  12. [Energy reactions in the skeletal muscles of rats following space flight on the Kosmos-936 biosatellite].

    Science.gov (United States)

    Mailian, E S; Bruavkova, L B; Kokoreva, L V

    1982-01-01

    The respiration of mitochondria isolated from mixed skeletal muscles of hindlimbs of rats flown for 18.5 days on Cosmos-936 was investigated polarographically. At R + 10 hours the rate of mitochondrial respiration in different metabolic states during the oxidation of succinic acid and NAD-dependent substrates declined. The enzyme activity of mitochondrial cytochrome oxidase and cytosol lactate dehydrogenase diminished. At R + 25 days both aerobic and anaerobic oxidative processes increased, thus leading to the recovery of the parameters (sometimes they not only returned to the norm but exceeded it).

  13. Muscle biopsy and cell cultures: potential diagnostic tools in hereditary skeletal muscle channelopathies

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    G Meola

    2009-06-01

    Full Text Available Hereditary muscle channelopathies are caused by dominant mutations in the genes encoding for subunits of muscle voltage- gated ion channels. Point mutations on the human skeletal muscle Na+ channel (Nav1.4 give rise to hyperkalemic periodic paralysis, potassium aggravated myotonia, paramyotonia congenita and hypokalemic periodic paralysis type 2. Point mutations on the human skeletal muscle Ca2+ channel give rise to hypokalemic periodic paralysis and malignant hyperthermia. Point mutations in the human skeletal chloride channel ClC-1 give rise to myotonia congenita. Point mutations in the inwardly rectifying K+ channel Kir2.1 give rise to a syndrome characterized by periodic paralysis, severe cardiac arrhythmias and skeletal alterations (Andersen’s syndrome. Involvement of the same ion channel can thus give rise to different phenotypes. In addition, the same mutation can lead to different phenotypes or similar phenotypes can be caused by different mutations on the same or on different channel subtypes. Bearing in mind, the complexity of this field, the growing number of potential channelopathies (such as the myotonic dystrophies, and the time and cost of the genetic procedures, before a biomolecular approach is addressed, it is mandatory to apply strict diagnostic protocols to screen the patients. In this study we propose a protocol to be applied in the diagnosis of the hereditary muscle channelopathies and we demonstrate that muscle biopsy studies and muscle cell cultures may significantly contribute towards the correct diagnosis of the channel involved. DNAbased diagnosis is now a reality for many of the channelopathies. This has obvious genetic counselling, prognostic and therapeutic implications.

  14. Differential Expression of NADPH Oxidases Depends on Skeletal Muscle Fiber Type in Rats

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    Loureiro, Adriano César Carneiro; do Rêgo-Monteiro, Igor Coutinho; Louzada, Ruy A.; Ortenzi, Victor Hugo; de Aguiar, Angélica Ponte; de Abreu, Ewerton Sousa; Cavalcanti-de-Albuquerque, João Paulo Albuquerque; Hecht, Fabio; de Oliveira, Ariclécio Cunha; Ceccatto, Vânia Marilande; Fortunato, Rodrigo S.

    2016-01-01

    NADPH oxidases (NOX) are important sources of reactive oxygen species (ROS) in skeletal muscle, being involved in excitation-contraction coupling. Thus, we aimed to investigate if NOX activity and expression in skeletal muscle are fiber type specific and the possible contribution of this difference to cellular oxidative stress. Oxygen consumption rate, NOX activity and mRNA levels, and the activity of catalase (CAT), glutathione peroxidase (GPX), and superoxide dismutase (SOD), as well as the reactive protein thiol levels, were measured in the soleus (SOL), red gastrocnemius (RG), and white gastrocnemius (WG) muscles of rats. RG showed higher oxygen consumption flow than SOL and WG, while SOL had higher oxygen consumption than WG. SOL showed higher NOX activity, as well as NOX2 and NOX4 mRNA levels, antioxidant enzymatic activities, and reactive protein thiol contents when compared to WG and RG. NOX activity and NOX4 mRNA levels as well as antioxidant enzymatic activities were higher in RG than in WG. Physical exercise increased NOX activity in SOL and RG, specifically NOX2 mRNA levels in RG and NOX4 mRNA levels in SOL. In conclusion, we demonstrated that NOX activity and expression differ according to the skeletal muscle fiber type, as well as antioxidant defense. PMID:27847553

  15. Nonproliferative and Proliferative Lesions of the Rat and Mouse Skeletal Tissues (Bones, Joints, and Teeth)

    Science.gov (United States)

    Fossey, Stacey; Vahle, John; Long, Philip; Schelling, Scott; Ernst, Heinrich; Boyce, Rogely Waite; Jolette, Jacquelin; Bolon, Brad; Bendele, Alison; Rinke, Matthias; Healy, Laura; High, Wanda; Roth, Daniel Robert; Boyle, Michael; Leininger, Joel

    2016-01-01

    The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is an initiative of the Societies of Toxicological Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in the skeletal tissues and teeth of laboratory rats and mice, with color photomicrographs illustrating examples of many common lesions. The standardized nomenclature presented in this document is also available on the internet (http://www.goreni.org/). Sources of material were databases from government, academic and industrial laboratories throughout the world. PMID:27621538

  16. Increases in skeletal muscle ATGL and its inhibitor G0S2 following 8 weeks of endurance training in metabolically different rat skeletal muscles.

    Science.gov (United States)

    Turnbull, Patrick C; Longo, Amanda B; Ramos, Sofhia V; Roy, Brian D; Ward, Wendy E; Peters, Sandra J

    2016-01-15

    Adipose triglyceride lipase (ATGL) catalyzes the rate-limiting removal of the first fatty acid from a triglyceride. ATGL is activated by comparative gene identification-58 and inhibited by G(0)/G(1) switch gene-2 protein (G0S2). Research in other tissues and cell culture indicates that inhibition is dependent on relative G0S2-to-ATGL protein content. G0S2 may also have several roles within mitochondria; however, this has yet to be observed in skeletal muscle. The purpose of this study was to determine if muscle G0S2 relative to ATGL content would decrease to facilitate intramuscular lipolysis following endurance training. Male Sprague-Dawley rats (n = 10; age 51-53 days old) were progressively treadmill trained at a 10% incline for 8 wk ending with 25 m/min for 1 h compared with control. Sciatic nerve stimulation for hind-limb muscle contraction (and lipolysis) was administered for 30 min to one leg, leaving the opposing leg as a resting control. Soleus (SOL), red gastrocnemius (RG), and white gastrocnemius were excised from both legs following stimulation or control. ATGL protein increased in all trained muscles. Unexpectedly, G0S2 protein was greater in the trained SOL and RG. In RG-isolated mitochondria, G0S2 also increased with training, yet mitochondrial G0S2 content was unaltered with acute contraction; therefore, any role of G0S2 in the mitochondria does not appear to be acutely mediated by content alone. In summary, G0S2 increased with training in oxidative muscles and mitochondria but not following acute contraction, suggesting that inhibition is not through relative G0S2-to-ATGL content but through more complicated intracellular mechanisms. Copyright © 2016 the American Physiological Society.

  17. Induction of amino acid transporters expression by endurance exercise in rat skeletal muscle

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    Murakami, Taro, E-mail: tamuraka@sgk.ac.jp; Yoshinaga, Mariko

    2013-10-04

    Highlights: •Regulation of amino acid transporter expression in working muscle remains unclear. •Expression of amino acid transporters for leucine were induced by a bout of exercise. •Requirement of leucine in muscle cells might regulate expression of its transporters. •This information is beneficial for understanding the muscle remodeling by exercise. -- Abstract: We here investigated whether an acute bout of endurance exercise would induce the expression of amino acid transporters that regulate leucine transport across plasma and lysosomal membranes in rat skeletal muscle. Rats ran on a motor-driven treadmill at a speed of 28 m/min for 90 min. Immediately after the exercise, we observed that expression of mRNAs encoding L-type amino acid transporter 1 (LAT1) and CD98 was induced in the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles. Sodium-coupled neutral amino acid transporter 2 (SNAT2) mRNA was also induced by the exercise in those three muscles. Expression of proton-assisted amino acid transporter 1 (PAT1) mRNA was slightly but not significantly induced by a single bout of exercise in soleus and EDL muscles. Exercise-induced mRNA expression of these amino acid transporters appeared to be attenuated by repeated bouts of the exercise. These results suggested that the expression of amino acid transporters for leucine may be induced in response to an increase in the requirement for this amino acid in the cells of working skeletal muscles.

  18. Dissociation between PGC-1alpha and GLUT-4 expression in skeletal muscle of rats fed a high-fat diet.

    Science.gov (United States)

    Higashida, Kazuhiko; Higuchi, Mitsuru; Terada, Shin

    2009-12-01

    It has recently been reported that a 4-wk high-fat diet gradually increases skeletal muscle peroxisome proliferator activated receptor (PPAR) gamma coactivator-1alpha (PGC-1alpha) protein content, which has been suggested to regulate GLUT-4 gene transcription. However, it has not been reported that a high-fat diet enhances GLUT-4 mRNA expression and protein content in skeletal muscle, suggesting that an increase in PGC-1alpha protein content is not sufficient to induce muscle GLUT-4 biogenesis in a high-fat fed animal. Therefore, we first evaluated the relationship between PGC-1alpha and GLUT-4 expression in skeletal muscle of rats fed a high-fat diet for 4 wk. The PGC-1alpha protein content in rat epitrochlearis muscle significantly increased by twofold after the 4-wk high-fat diet feeding. However, the high-fat diet had no effect on GLUT-4 protein content and induced a 30% decrease in GLUT-4 mRNA expression in rat skeletal muscle (p<0.05). To clarify the mechanism by which a high-fat diet downregulates GLUT-4 mRNA expression, we next examined the effect of PPARdelta activation, which is known to occur in response to a high-fat diet, on GLUT-4 mRNA expression in L6 myotubes. Incubation with 500 nM GW501516 (PPARdelta activator) for 24 h significantly decreased GLUT-4 mRNA in L6 myotubes. Taken together, these findings suggest that a high-fat diet downregulates GLUT-4 mRNA, possibly through the activation of PPARdelta, despite an increase in PGC-1alpha protein content in rat skeletal muscle, and that a posttranscriptional regulatory mechanism maintains GLUT-4 protein content in skeletal muscle of rats fed a high-fat diet.

  19. Addition of Mesenchymal Stem Cells Enhances the Therapeutic Effects of Skeletal Myoblast Cell-Sheet Transplantation in a Rat Ischemic Cardiomyopathy Model

    Science.gov (United States)

    Shudo, Yasuhiro; Miyagawa, Shigeru; Ohkura, Hanayuki; Fukushima, Satsuki; Saito, Atsuhiro; Shiozaki, Motoko; Kawaguchi, Naomasa; Matsuura, Nariaki; Shimizu, Tatsuya; Okano, Teruo; Matsuyama, Akifumi

    2014-01-01

    Introduction: Functional skeletal myoblasts (SMBs) are transplanted into the heart effectively and safely as cell sheets, which induce functional recovery in myocardial infarction (MI) patients without lethal arrhythmia. However, their therapeutic effect is limited by ischemia. Mesenchymal stem cells (MSCs) have prosurvival/proliferation and antiapoptotic effects on co-cultured cells in vitro. We hypothesized that adding MSCs to the SMB cell sheets might enhance SMB survival post-transplantation and improve their therapeutic effects. Methods and Results: Cell sheets of primary SMBs of male Lewis rats (r-SMBs), primary MSCs of human female fat tissues (h-MSCs), and their co-cultures were generated using temperature-responsive dishes. The levels of candidate paracrine factors, rat hepatocyte growth factor and vascular endothelial growth factor, in vitro were significantly greater in the h-MSC/r-SMB co-cultures than in those containing r-SMBs only, by real-time PCR and enzyme-linked immunosorbent assay (ELISA). MI was generated by left-coronary artery occlusion in female athymic nude rats. Two weeks later, co-cultured r-SMB or h-MSC cell sheets were implanted or no treatment was performed (n=10 each). Eight weeks later, systolic and diastolic function parameters were improved in all three treatment groups compared to no treatment, with the greatest improvement in the co-cultured cell sheet transplantation group. Consistent results were found for capillary density, collagen accumulation, myocyte hypertrophy, Akt-signaling, STAT3 signaling, and survival of transplanted cells of rat origin, and were related to poly (ADP-ribose) polymerase-dependent signal transduction. Conclusions: Adding MSCs to SMB cell sheets enhanced the sheets' angiogenesis-related paracrine mechanics and, consequently, functional recovery in a rat MI model, suggesting a possible strategy for clinical applications. PMID:24164292

  20. Heat stress attenuates skeletal muscle atrophy of extensor digitorum longus in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Nonaka, K; Une, S; Akiyama, J

    2015-09-01

    To investigate whether heat stress attenuates skeletal muscle atrophy of the extensor digitorum longus (EDL) muscle in streptozotocin-induced diabetic rats, 12-week-old male Wistar rats were randomly assigned to four groups (n = 6 per group): control (Con), heat stress (HS), diabetes mellitus (DM), and diabetes mellitus/heat stress (DM + HS). Diabetes was induced by intraperitoneal injection of streptozotocin (50 mg/kg). Heat stress was induced in the HS and DM + HS groups by immersion of the lower half of the body in hot water at 42 °C for 30 min; it was initiated 7 days after injection of streptozotocin, and was performed once a day, five times a week for 3 weeks. The muscle fiber cross-sectional area of EDL muscles from diabetic and non-diabetic rats was determined; heat stress protein (HSP) 72 and HSP25 expression levels were also analyzed by western blotting. Diabetes-induced muscle fiber atrophy was attenuated upon heat stress treatment in diabetic rats. HSP72 and HSP25 expression was upregulated in the DM + HS group compared with the DM group. Our findings suggest that heat stress attenuates atrophy of the EDL muscle by upregulating HSP72 and HSP25 expression.

  1. Effects of yam and diosgenin on calpain systems in skeletal muscle of ovariectomized rats.

    Science.gov (United States)

    Hsu, Kung-Hao; Chang, Chi-Chen; Tsai, Horng-Der; Tsai, Fuu-Jen; Hsieh, Yao-Yuan

    2008-06-01

    Yam or diosgenin (extracted from the root of wild yam) is traditionally used for hormone replacement in menopausal women. Calpains are crucially related to the degradation of myofibrillar proteins in skeletal muscle. This study aimed to investigate the effects of yam and diosgenin on the calpain isoform expression in ovariectomized rats, a model of menopausal status. Female rats were divided into: (1) controls; (2) ovariectomized rats; (3) ovariectomized rats receiving yam (250, 750, 1,500 mg/kg/day); (4) ovariectomized rats receiving diosgenin (10, 50, 100 mg/kg/day). Yam and diosgenin were administered for 8 weeks. The expression of mu- and m-calpain in skeletal muscles was determined by reverse transcriptase-polymerase chain reaction. The mu-calpain/beta-actin and m-calpain/beta-actin ratios in the control group (0.9 and 1.09, respectively) were significantly higher than those in the ovariectomized group (0.58 and 0.72, respectively). In the yam group, the expression of mu- and m-calpain was lowest in the ovariectomized group receiving no supplementation and lower in the 250 mg group compared with the 750 and 1,500 mg groups (for 0, 250, 750 and 1,500 mg dosage groups, mu-calpain, 0.58, 0.88, 1.24 and 1.13, respectively; m-calpain, 0.72, 1.02, 1.38 and 1.47, respectively). In contrast, there were no significant differences in the expression of mu- and m-calpain mRNAs among the different diosgenin dosage groups (for 0, 10, 50 and 100 mg of diosgenin, mu-calpain, 0.58, 0.56, 0.62 and 0.58, respectively; m-calpain, 0.72, 0.58, 0.71 and 0.54, respectively). Decreased expression of mu- or m-calpain was observed in the ovariectomized group compared with the normal controls. Yam, but not its extract (diosgenin), is associated with the regulation of calpain isoforms in ovariectomized rats. Adequate yam supplements might improve the muscular calpain-related physiopathology associated with menopausal status.

  2. Creatine prevents the imbalance of redox homeostasis caused by homocysteine in skeletal muscle of rats.

    Science.gov (United States)

    Kolling, Janaína; Scherer, Emilene B S; Siebert, Cassiana; Marques, Eduardo Peil; Dos Santos, Tiago Marcom; Wyse, Angela T S

    2014-07-15

    Homocystinuria is a neurometabolic disease caused by severe deficiency of cystathionine beta-synthase activity, resulting in severe hyperhomocysteinemia. Affected patients present several symptoms including a variable degree of motor dysfunction, being that the pathomechanism is not fully understood. In the present study we investigated the effect of chronic hyperhomocysteinemia on some parameters of oxidative stress, namely 2'7'dichlorofluorescein (DCFH) oxidation, levels of thiobarbituric acid-reactive substances (TBARS), antioxidant enzyme activities (SOD, CAT and GPx), reduced glutathione (GSH), total sulfhydryl and carbonyl content, as well as nitrite levels in soleus skeletal muscle of young rats subjected to model of severe hyperhomocysteinemia. We also evaluated the effect of creatine on biochemical alterations elicited by hyperhomocysteinemia. Wistar rats received daily subcutaneous injection of homocysteine (0.3-0.6 μmol/g body weight), and/or creatine (50mg/kg body weight) from their 6th to the 28th days age. Controls and treated rats were decapitated at 12h after the last injection. Chronic homocysteine administration increased 2'7'dichlorofluorescein (DCFH) oxidation, an index of production of reactive species and TBARS levels, an index of lipoperoxidation. Antioxidant enzyme activities, such as SOD and CAT were also increased, but GPx activity was not altered. The content of GSH, sulfhydril and carbonyl were decreased, as well as levels of nitrite. Creatine concurrent administration prevented some homocysteine effects probably by its antioxidant properties. Our data suggest that the oxidative insult elicited by chronic hyperhomocystenemia may provide insights into the mechanisms by which homocysteine exerts its effects on skeletal muscle function. Creatine prevents some alterations caused by homocysteine.

  3. Rat fetal ventral mesencephalon grown as solid tissue cultures

    DEFF Research Database (Denmark)

    Höglinger, G U; Sautter, J; Meyer, Morten;

    1998-01-01

    Free-floating roller tube (FFRT) cultures of fetal rat and human nigral tissue are a means for tissue storage prior to grafting in experimental Parkinson's disease. In the present study, FFRT cultures prepared from embryonic-day-14 rat ventral mesencephalon were maintained for 4, 8, 12, or 16 days...

  4. Total-body creatine pool size and skeletal muscle mass determination by creatine-(methyl-d3) dilution in rats

    National Research Council Canada - National Science Library

    Stephen A. Stimpson; Scott M. Turner; Lisa G. Clifton; James C. Poole; Hussein A. Mohammed; Todd W. Shearer; Greg M. Waitt; Laura L. Hagerty; Katja S. Remlinger; Marc K. Hellerstein; William J. Evans

    2012-01-01

    .... We tested in rats the hypothesis that the enrichment of creatinine-(methyl-d3) (D3-creatinine) in urine after a defined oral tracer dose of D3-creatine can be used to determine creatine pool size and skeletal muscle mass...

  5. Increased cellular proliferation in rat skeletal muscle and tendon in response to exercise: use of FLT and PET/CT

    DEFF Research Database (Denmark)

    Skovgaard, Dorthe Charlotte; Bayer, Monika L; Mackey, Abigail L

    2010-01-01

    The purpose of this study is to investigate exercise-induced cellular proliferation in rat skeletal muscle/tendon with the use of 3'-[F-18]fluoro-3'deoxythymidine (FLT) and to quantitatively study concomitant changes in the proliferation-associated factor, Ki67....

  6. In utero glucocorticoid exposure reduced fetal skeletal muscle mass in rats independent of effects on maternal nutrition

    Science.gov (United States)

    Maternal stress and undernutrition can occur together and expose the fetus to high glucocorticoid (GLC) levels during this vulnerable period. To determine the consequences of GLC exposure on fetal skeletal muscle independently of maternal food intake, groups of timed-pregnant Sprague-Dawley rats (n ...

  7. Properties of 5'-deiodinase of 3,3',5'-triiodothyronine in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, Fujiko; Nomoto, Teruko; Maeda, Michiko

    1989-01-01

    To characterize rT/sub 3/ 5'-deiodinase (5'D) in rat skeletal muscle, the effects of altered thyroid status and PTU on rT/sub 3/ f'D were studied. rT/sub 3/ 5'D activity was measured by incubating homogenates of rat skeletal muscle with (/sup 125/)rT/sub 3/, iodine labelled in the outer ring, in the presence of 20 mmol/l DL-dithiothreitol. This activity was observed to increase significantly 24 h after a single sc injection of T/sub 3/ (75..mu..g/kg). The increase following the daily administration of this drug (15 or 75 ..mu../kg) for 3 and 14 days was dependent on the dose and number of previous days of injection. A significant decrease in activity was observed 2 weeks after thyroidectomy. The addition of 0.1 mmol/l 6-n-propyl-2-thiouracil (PTU) to the incubation medium in vitro caused a marked reduction in the activity in homogenates of skeletal muscle from hypothyroid, euthyroid and hyperthyroid rats. PTU, pressent at 0.05% in the drinking water for 2 weeks virtually abolished it. The properties of rT/sub 3/ 5'D in rat skeletal muscle thus appear to be essentially the same as those of type I enzyme with respect to response toward altered thyroid status and PTU.

  8. Subsarcolemmal and intermyofibrillar mitochondrial responses to short-term high-fat feeding in rat skeletal muscle.

    Science.gov (United States)

    Crescenzo, Raffaella; Bianco, Francesca; Coppola, Paola; Mazzoli, Arianna; Liverini, Giovanna; Iossa, Susanna

    2014-01-01

    We assessed the alterations in mitochondrial function in skeletal muscle that were elicited by short-term high-fat feeding in sedentary rats. Two groups of rats were pair-fed for 1 wk and received a low-fat or high-fat diet. Body composition, energy balance, and glucose homeostasis were measured. Mitochondrial mass, oxidative capacity, and energetic efficiency as well as parameters of oxidative stress and antioxidant defense were evaluated in subsarcolemmal and intermyofibrillar mitochondria from the skeletal muscle. Body energy, lipid content, and metabolic efficiency were significantly higher and energy expenditure was significantly decreased among rats that were fed a high-fat diet, as compared with controls. Skeletal muscle mitochondrial energetic efficiency, oxidative capacity for lipid substrates, and antioxidant defense were significantly increased in rats that were fed a high-fat diet as compared with controls. Acute isocaloric high-fat feeding is able to induce increased phosphorylation efficiency in skeletal muscle subsarcolemmal and intermyofibrillar mitochondria. This modification implies a reduced oxidation of energy substrates that may contribute to the early onset of obesity. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Lactate/H+ transport kinetics in rat skeletal muscle related to fibre type and changes in transport capacity

    DEFF Research Database (Denmark)

    Juel; Pilegaard

    1998-01-01

    Lactate/H+ transport kinetics were determined by means of the pH-sensitive probe BCECF in sarcolemmal giant vesicles, obtained from rat skeletal muscle, and related to variations in lactate/H+ transport capacity. Vesicle preparations were made from red and white muscles, mixed muscles, denervated...

  10. Long-chain n-3 DHA reduces the extent of skeletal muscle fatigue in the rat in vivo hindlimb model.

    Science.gov (United States)

    Peoples, Gregory E; McLennan, Peter L

    2014-03-28

    Dietary fish oil modifies skeletal muscle membrane fatty acid composition and oxygen efficiency similar to changes in the myocardium. Oxygen efficiency is a key determinant of sustained force in mammalian skeletal muscle. Therefore, in the present study, we tested the effects of a fish-oil diet on skeletal muscle fatigue under the stress of contraction using the rat in vivo autologous perfused hindlimb model. For 8 weeks, male Wistar rats were fed a diet rich in saturated fat (SF), a diet rich in n-6 PUFA or a diet rich in long-chain (LC) n-3 PUFA DHA derived from fish oil. In anaesthetised, mechanically ventilated rats, with their hindlimbs perfused with arterial blood at a constant flow, the gastrocnemius-plantaris-soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6-12 V, 0·05 ms) to contract repetitively for 30 min. Rats fed the n-3 PUFA diet developed higher maximum twitch tension than those fed the SF and n-6 PUFA diets (PDHA into skeletal muscle membranes increases the efficiency of oxygen use over a range of contractile force and this is expressed as a higher sustained force and prolonged time to fatigue.

  11. Angiotensin receptor blockers improve insulin signaling and prevent microvascular rarefaction in the skeletal muscle of spontaneously hypertensive rats.

    Science.gov (United States)

    Rizzoni, Damiano; Pasini, Evasio; Flati, Vincenzo; Rodella, Luigi F; Paiardi, Silvia; Assanelli, Deodato; De Ciuceis, Carolina; Porteri, Enzo; Boari, Gianluca Em; Rezzani, Rita; Speca, Silvia; Favero, Gaia; Martinotti, Stefano; Toniato, Elena; Platto, Caterina; Agabiti-Rosei, Enrico

    2008-08-01

    Spontaneously hypertensive rats are an example of an animal model of genetic hypertension with insulin resistance. The aim of this study was to investigate insulin signaling in the heart and in the skeletal muscle of spontaneously hypertensive rats, as well as to evaluate the effects of renin-angiotensin system blockade. We investigated eight untreated spontaneously hypertensive rats of 12 weeks of age and eight age-matched normotensive Wistar-Kyoto controls. In addition, eight spontaneously hypertensive rats were treated for 8 weeks with the angiotensin receptor blocker olmesartan, and eight spontaneously hypertensive rats with the angiotensin-converting enzyme inhibitor enalapril. The heart and a skeletal muscle (quadriceps femoris) were promptly dissected and frozen. Insulin signaling was evaluated by Western blot analysis of involved proteins; in addition, microvessel density was indirectly evaluated by immunohistochemistry. Blood pressure values were normalized by both olmesartan and enalapril. In the heart, no statistically significant difference in the expression of proteins involved in insulin signaling was observed between untreated spontaneously hypertensive rats and Wistar-Kyoto controls. On the contrary, in the skeletal muscle of untreated spontaneously hypertensive rats, we noted a significant reduction of insulin receptors, of insulin-receptor substrate-1, and of phosphorylated-mammalian target of rapamycin. The treatment with olmesartan normalized insulin signaling, including expression of glucose transporter-4, whereas the treatment with enalapril was ineffective for the insulin receptor and less effective than olmesartan on the insulin-receptor substrate-1, phosphorylated-mammalian target of rapamycin and glucose transporter-4. There was a significant reduction in microvessel density in the skeletal muscle of spontaneously hypertensive rats compared with Wistar-Kyoto controls, and this was completely prevented by both olmesartan and enalapril

  12. Culture of skeletal myoblasts from human donors aged over 40 years: dynamics of cell growth and expression of differentiation markers

    Directory of Open Access Journals (Sweden)

    Cherubino Paolo

    2005-05-01

    Full Text Available Abstract Background Local myogenesis, neoangiogenesis and homing of progenitor cells from the bone marrow appear to contribute to repair of the infarcted myocardium. Implantation into heart tissues of autologous skeletal myoblasts has been associated with improved contractile function in animal models and in humans with acute myocardial ischemia. Since heart infarction is most prevalent in individuals of over 40 years of age, we tested whether culture methods available in our laboratory were adequate to obtain sufficient numbers of differentiated skeletal myoblasts from muscle biopsy specimens obtained from patients aged 41 to 91. Methods and results No matter of donor age, differentiated skeletal muscle cells could be produced in vitro in amounts adequate for cellular therapy (≥300 millions. Using desmin as a cytoplasmic marker, about 50% cultured cells were differentiated along myogenic lineages and expressed proteins proper of skeletal muscle (myosin type I and II, actin, actinin, spectrin and dystrophin. Cytogenetic alterations were not detected in cultured muscle cells that had undergone at least 10 population doublings. Molecular methods employed for the screening of persistent viral infections evidenced that HCV failed to replicate in muscle cells cultured from one patient with chronic HCV infection. Conclusion The proposed culture methods appear to hold promise for aged patients not only in the field of cardiovascular medicine, but also in the urologic and orthopedic fields.

  13. A model for the study of skeletal anomalies in rat fetuses

    Directory of Open Access Journals (Sweden)

    Cristiane Effting

    2004-03-01

    Full Text Available The aim of this study was to validate a model of skeletal anomalies in rat fetuses by the administration of ketoconazole (80 mg/kg to pregnant rats during organogenesis. Bones of the head, trunk and anterior and posterior limbs were examined for detection of anomalies. Statistical differences regarding the number of fetuses and postimplantation resorptions, and fetal and placental weight were significant. The frequency of skeletal anomalies in the head, trunk, and anterior and posterior limbs in the ketoconazole-treated group were also significant when compared to the control group. It could be concluded that the model suggested was valid for study of skeletal anomalies and abnormal bones development in rat fetuse, in spite of the loss of fetuses due to resorptions.O cetoconazol, uma droga que inibe a esteroidogênese, provoca teratogênese em fetos de ratos quando administrado em altas doses durante a organogênese. Entretanto, o mecanismo das malformações esqueléticas induzidas pelo cetoconazol não é claro e não existe nenhum método descrito na literatura que permita estudar os mecanismos envolvidos nas malformações esqueléticas induzidas pelo cetoconazol. O objetivo deste estudo é validar um modelo de malformações esqueléticas em fetos de ratos através da administração de cetoconazol 80 mg/kg durante a organogênses a ratas prenhes. Os ossos da cabeça, do tronco e dos membros anteriores e posteriores foram examinados para a detecção de anomalias. Foram encontradas diferenças estatísticas no número de fetos, de reabsorções pós-implantação e nos pesos dos fetos e das placentas. As freqüências de anormalidades esqueléticas na cabeça, no tronco e nos membros anteriores e posteriores no grupo tratado com cetoconazol também foram significantes quando comparadas às do grupo controle. Concluímos que o método sugerido é válido para o estudo de malformações esqueléticas e desenvolvimento anormal dos ossos em

  14. Rat whisker movement after facial nerve lesion: evidence for autonomic contraction of skeletal muscle.

    Science.gov (United States)

    Heaton, James T; Sheu, Shu Hsien; Hohman, Marc H; Knox, Christopher J; Weinberg, Julie S; Kleiss, Ingrid J; Hadlock, Tessa A

    2014-04-18

    Vibrissal whisking is often employed to track facial nerve regeneration in rats; however, we have observed similar degrees of whisking recovery after facial nerve transection with or without repair. We hypothesized that the source of non-facial nerve-mediated whisker movement after chronic denervation was from autonomic, cholinergic axons traveling within the infraorbital branch of the trigeminal nerve (ION). Rats underwent unilateral facial nerve transection with repair (N=7) or resection without repair (N=11). Post-operative whisking amplitude was measured weekly across 10weeks, and during intraoperative stimulation of the ION and facial nerves at ⩾18weeks. Whisking was also measured after subsequent ION transection (N=6) or pharmacologic blocking of the autonomic ganglia using hexamethonium (N=3), and after snout cooling intended to elicit a vasodilation reflex (N=3). Whisking recovered more quickly and with greater amplitude in rats that underwent facial nerve repair compared to resection (Pwhisker movements decreased in all rats during the initial recovery period (indicative of reinnervation), but re-appeared in the resected rats after undergoing ION transection (indicative of motor denervation). Cholinergic, parasympathetic axons traveling within the ION innervate whisker pad vasculature, and immunohistochemistry for vasoactive intestinal peptide revealed these axons branching extensively over whisker pad muscles and contacting neuromuscular junctions after facial nerve resection. This study provides the first behavioral and anatomical evidence of spontaneous autonomic innervation of skeletal muscle after motor nerve lesion, which not only has implications for interpreting facial nerve reinnervation results, but also calls into question whether autonomic-mediated innervation of striated muscle occurs naturally in other forms of neuropathy. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  15. Effects of strenuous maternal exercise on fetal organ weights and skeletal muscle development in rats.

    Science.gov (United States)

    Mottola, M F; Bagnall, K M; Belcastro, A N

    1989-02-01

    The purpose of the present study was to observe the effects of strenuous maternal aerobic exercise throughout gestation on fetal outcome in the rat. The strenuous exercise intensity consisted of a treadmill speed of 30 m.min-1 on a 10 degrees incline, for 120 min.day-1, 5 days.week-1. The rats were conditioned to run on a motor-driven treadmill by following a progressive two-week exercise program, so that by the end of the two weeks the rats were capable of running comfortably at this strenuous intensity in the non-pregnant state. Following the two-week running programme, the rats were paired by weight and randomly assigned to either a pregnant group that continued the running program throughout gestation (pregnant runner), or a pregnant group that did not continue the running program throughout pregnancy (pregnant control). At birth the neonates born to the pregnant running group did not differ in average neonatal body weight values, number per litter or total litter weight values when compared to controls, nor were superficial gross abnormalities observed in neonates born to the pregnant control or pregnant running groups. The strenuous maternal exercise intensity did not alter neonatal organ weight values (brain, heart, liver, lung, kidney), nor neonatal skeletal muscle (gastrocnemius, sternomastoid, diaphragm) when compared to control values. It is suggested that maternal exercise of this intensity throughout gestation does not affect fetal outcome in the rat, and may be due to the animals accustomization to the strenuous exercise protocol prior to pregnancy.

  16. Effect of training and detraining on skeletal muscle glucose transporter (GLUT4) content in rats.

    Science.gov (United States)

    Neufer, P D; Shinebarger, M H; Dohm, G L

    1992-09-01

    The aim of the present study was to examine the effects of treadmill exercise training and detraining on the skeletal muscle fiber type specific expression of the insulin-regulated glucose transporter protein (GLUT4) in rats. GLUT4 protein content was determined by Western and dot-blot analysis, using a polyclonal antibody raised against the carboxy-terminal peptide. Rats were sacrificed 24 h after the last training session. There were no significant changes in muscle GLUT4 after 1 day or 1 week of training. Six weeks of training increased GLUT4 protein content 1.4- to 1.7-fold (p < 0.05) over controls in the soleus and red vastus lateralis, whereas no significant change was evident in the white vastus lateralis muscle. GLUT4 protein content in both soleus and red vastus lateralis muscle returned to near control values after 7 days of detraining. Similar to GLUT4, citrate synthase activity showed no change after 1 day or 1 week of training, increased 1.8-fold over controls after 6 weeks of training, but returned to control values after 7 days detraining. These findings demonstrate that muscle GLUT4 protein is increased in rats with as little as 6 weeks of treadmill exercise training but that the adaptation is lost within 1 week of detraining. It is suggested that expression of the GLUT4 protein is coordinated with the well-documented adaptations in oxidative enzyme activity with endurance training and detraining.

  17. Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats.

    Science.gov (United States)

    Voces, J; Cabral de Oliveira, A C; Prieto, J G; Vila, L; Perez, A C; Duarte, I D G; Alvarez, A I

    2004-12-01

    Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white) and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg) was administered orally for three months to male Wistar rats weighing 200 +/- 50 g before exercise and to non-exercised rats (N = 8/group). The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05) after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05) by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type.

  18. Nuclear phenotype evaluation in skeletal muscle from Wistar rats exposed to low-level lasers

    Science.gov (United States)

    Almeida, L. G.; Sergio, L. P. S.; Vicentini, S. C.; Mencalha, A. L.; Paoli, F.; Fonseca, A. S.

    2017-03-01

    Low-level laser therapy includes devices emitting red and near-infrared radiation with output power below 100 mW. These devices are successfully used for the treatment of injuries and to improve exercise performance based on their biomodulatory effect. Despite the wide use of clinical protocols based on these lasers, the laser-induced effects on DNA are still disputed. Thus, the objective of this study was to investigate chromatin organization, ploidy degrees, and DNA fragmentation in skeletal muscle tissue from Wistar rats exposed to low-level red and infrared lasers. Wistar rats were exposed to low-level red and infrared lasers (25, 50, and 100 J cm-2, 100 mW, continuous-wave emission mode) and, after 24h, samples of this tissue were withdrawn for the analysis of chromatin organization, ploidy degrees, and DNA fragmentation by Feulgen reaction detection of micronucleus, and apoptosis by TUNEL assay. Data obtained show that low-level red and infrared lasers alter geometric and densitometric parameters as well ploidy degree in muscle nuclei from Wistar rats, but do not induce DNA fragmentation, chromatin loss, and apoptosis at fluences taken out from clinical protocols.

  19. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Ploug, T.; Stallknecht, B.M.; Pedersen, O.; Kahn, B.B.; Ohkuwa, T.; Vinten, J.; Galbo, H. (Panum Institute, Copenhagen (Denmark))

    1990-12-01

    The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers and an increase of approximately 33% for contraction-stimulated transport in slow-twitch red fibers compared with nonexercised sedentary muscle. A fully additive effect of insulin and contractions was observed both in trained and untrained muscle. Compared with transport in control rats subjected to an almost exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training session. Half-times for reversal of contraction-induced glucose transport were similar in trained and untrained muscles. The concentrations of mRNA for GLUT-1 (the erythrocyte-brain-Hep G2 glucose transporter) and GLUT-4 (the adipocyte-muscle glucose transporter) were increased approximately twofold by training in fast-twitch red muscle fibers. In parallel to this, Western blot demonstrated a approximately 47% increase in GLUT-1 protein and a approximately 31% increase in GLUT-4 protein. This indicates that the increases in maximum velocity for 3-MG transport in trained muscle is due to an increased number of glucose transporters.

  20. The Influence of Electromagnetic Radiation Generated by a Mobile Phone on the Skeletal System of Rats

    Directory of Open Access Journals (Sweden)

    Karolina Sieroń-Stołtny

    2015-01-01

    Full Text Available The study was focused on the influence of electromagnetic field generated by mobile phone on the skeletal system of rats, assessed by measuring the macrometric parameters of bones, mechanical properties of long bones, calcium and phosphorus content in bones, and the concentration of osteogenesis (osteocalcin and bone resorption (NTX, pyridinoline markers in blood serum. The study was carried out on male rats divided into two groups: experimental group subjected to 28-day cycle of exposures in electromagnetic field of 900 MHz frequency generated by mobile phone and a control, sham-exposed one. The mobile phone-generated electromagnetic field did not influence the macrometric parameters of long bones and L4 vertebra, it altered mechanical properties of bones (stress and energy at maximum bending force, stress at fracture, it decreased the content of calcium in long bones and L4 vertebra, and it altered the concentration of osteogenesis and bone resorption markers in rats. On the basis of obtained results, it was concluded that electromagnetic field generated by 900 MHz mobile phone does not have a direct impact on macrometric parameters of bones; however, it alters the processes of bone mineralization and the intensity of bone turnover processes and thus influences the mechanical strength of bones.

  1. Skeletal unloading and dietary copper depletion are detrimental to bone quality of mature rats

    Science.gov (United States)

    Smith, Brenda J.; King, Jarrod B.; Lucas, Edralin A.; Akhter, Mohammed P.; Arjmandi, Bahram H.; Stoecker, Barbara J.

    2002-01-01

    This study was designed to examine the skeletal response to copper depletion and mechanical unloading in mature animals. In a 2 x 2 experimental design, 5.5-mo-old male Sprague-Dawley rats (n = 36) consumed either the control (AIN-93M) or Cu-depletion ((-)Cu) diet beginning 21 d before suspension and throughout the remainder of the study. Half of the rats in each dietary treatment group were either tail-suspended (TS) or kept ambulatory (AMB) for 28 d. Lower bone mineral densities (BMD) of 5th lumbar vertebra (L5) (P bone resorption, was significantly greater in TS rats, but unaltered by (-)Cu. No changes in serum or bone alkaline phosphatase activity, an indicator of bone formation, were observed. Our findings suggest that TS and (-)Cu decreased BMD in unloaded femur and vertebra but had no effect on normally loaded humerus. Bone loss with TS appeared to be related to accelerated bone resorption. Alterations in bone metabolism and bone mechanical properties in the mature skeleton resulting from (-)Cu warrant further investigation.

  2. The influence of electromagnetic radiation generated by a mobile phone on the skeletal system of rats.

    Science.gov (United States)

    Sieroń-Stołtny, Karolina; Teister, Łukasz; Cieślar, Grzegorz; Sieroń, Dominik; Śliwinski, Zbigniew; Kucharzewski, Marek; Sieroń, Aleksander

    2015-01-01

    The study was focused on the influence of electromagnetic field generated by mobile phone on the skeletal system of rats, assessed by measuring the macrometric parameters of bones, mechanical properties of long bones, calcium and phosphorus content in bones, and the concentration of osteogenesis (osteocalcin) and bone resorption (NTX, pyridinoline) markers in blood serum. The study was carried out on male rats divided into two groups: experimental group subjected to 28-day cycle of exposures in electromagnetic field of 900 MHz frequency generated by mobile phone and a control, sham-exposed one. The mobile phone-generated electromagnetic field did not influence the macrometric parameters of long bones and L4 vertebra, it altered mechanical properties of bones (stress and energy at maximum bending force, stress at fracture), it decreased the content of calcium in long bones and L4 vertebra, and it altered the concentration of osteogenesis and bone resorption markers in rats. On the basis of obtained results, it was concluded that electromagnetic field generated by 900 MHz mobile phone does not have a direct impact on macrometric parameters of bones; however, it alters the processes of bone mineralization and the intensity of bone turnover processes and thus influences the mechanical strength of bones.

  3. Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats

    Directory of Open Access Journals (Sweden)

    J. Voces

    2004-12-01

    Full Text Available Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg was administered orally for three months to male Wistar rats weighing 200 ± 50 g before exercise and to non-exercised rats (N = 8/group. The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05 after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05 by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type.

  4. Skeletal muscle atrogene expression and insulin resistance in a rat model of polytrauma.

    Science.gov (United States)

    Akscyn, Robert M; Franklin, John L; Gavrikova, Tatyana A; Messina, Joseph L

    2016-02-01

    Polytrauma is a combination of injuries to more than one body part or organ system. Polytrauma is common in warfare, and in automobile and industrial accidents. The combination of injuries can include burn, fracture, hemorrhage, and trauma to the extremities or specific organ systems. Resistance to anabolic hormones, loss of muscle mass, and metabolic dysfunction can occur following injury. To investigate the effects of combined injuries, we have developed a highly reproducible rodent model of polytrauma. This model combines burn injury, soft tissue trauma, and penetrating injury to the gastrointestinal (GI) tract. Adult, male Sprague-Dawley rats were anesthetized with pentobarbital and subjected to a 15-20% total body surface area scald burn, or laparotomy and a single puncture of the cecum with a G30 needle, or the combination of both injuries (polytrauma). In the current studies, the inflammatory response to polytrauma was examined in skeletal muscle. Changes in skeletal muscle mRNA levels of the proinflammatory cytokines TNF-α, IL-1β, and IL-6 were observed following single injuries and polytrauma. Increased expression of the E3 ubiquitin ligases Atrogin-1/FBX032 and TRIM63/MuRF-1 were measured following injury, as was skeletal muscle insulin resistance, as evidenced by decreased insulin-inducible insulin receptor (IR) and AKT/PKB (Protein Kinase B) phosphorylation. Changes in the abundance of IR and insulin receptor substrate-1 (IRS-1) were observed at the protein and mRNA levels. Additionally, increased TRIB3 mRNA levels were observed 24 h following polytrauma, the same time when insulin resistance was observed. This may suggest a role for TRIB3 in the development of acute insulin resistance following injury.

  5. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P muscles. IGF-I infusion resulted in significant increases in the total protein and DNA content of TA muscles (P hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  6. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  7. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P protein and DNA content of TA muscles (P DNA-to-protein ratio of the hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  8. Effect of ethyl pyruvate on skeletal muscle metabolism in rats fed on a high fat diet.

    Science.gov (United States)

    Olek, Robert A; Ziolkowski, Wieslaw; Wierzba, Tomasz H; Kaczor, Jan J

    2013-07-01

    Impaired mitochondrial capacity may be implicated in the pathology of chronic metabolic diseases. To elucidate the effect of ethyl pyruvate supplementation on skeletal muscles metabolism we examined changes in activities of mitochondrial and antioxidant enzymes, as well as sulfhydryl groups oxidation (an indirect marker of oxidative stress) during the development of obesity. After 6 weeks feeding of control or high fat diet, Wistar rats were divided into four groups: control diet, control diet and ethyl pyruvate, high fat diet, and high fat diet and ethyl pyruvate. Ethyl pyruvate was administered as 0.3% solution in drinking water, for the following 6 weeks. High fat diet feeding induced the increase of activities 3-hydroxyacylCoA dehydrogenase, citrate synthase, and fumarase. Moreover, higher catalase and superoxide dismutase activities, as well as sulfhydryl groups oxidation, were noted. Ethyl pyruvate supplementation did not affect the mitochondrial enzymes' activities, but induced superoxide dismutase activity and sulfhydryl groups oxidation. All of the changes were observed in soleus muscle, but not in extensor digitorum longus muscle. Additionally, positive correlations between fasting blood insulin concentration and activities of catalase (p = 0.04), and superoxide dismutase (p = 0.01) in soleus muscle were noticed. Prolonged ethyl pyruvate consumption elevated insulin concentration, which may cause modifications in oxidative type skeletal muscles.

  9. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    Science.gov (United States)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P muscles. IGF-I infusion resulted in significant increases in the total protein and DNA content of TA muscles (P hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  10. [Modulation of the effects of dexamethasone in rat skeletal muscle by testosterone].

    Science.gov (United States)

    Trush, V V; Soboliev, V I

    2013-01-01

    In experiments on young females white rats by means of methods of electromyography and ergography we investigated the efficiency of a testosterone-propionate for smoothing of negative effects of dexamethasone on skeletal muscle. It has been established that the chronic injection of dexamethasone causes the decreasing of amplitude of contraction of forward tibial muscle on 29.7-59.3% (after 5-25 injections) and the lengthening of the latent period of muscle's excitation on 18.5-16.5% (after 15-25 injections), whereas the complex application of testosterone and dexamethasone prevents the changing of these parameters. At the same time testosterone didn't provide the smoothing of negative influence of dexamethasone on muscle's resistance to fatigue development.

  11. Partial Restoration Of Skeletal Strength In Ovariectomized Rats By Treatment With Strontium Salts

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Andersen, Pernille/Høegh; Christgau, Stephan

    AIM Ovariectomy of female rats induces significant bone-loss by depriving endogenous estrogen production. We assessed whether administration of strontium salts had a therapeutic benefit in this animal model of postmenopausal osteoporosis. INTRODUCTION In most women after menopause, the rate of bone...... loss exceeds the rate of bone formation, resulting in a net decrease in bone mass and ultimately in development of osteoporosis and elevated risk of sustaining fragility fracture. Most approved osteoporosis treatments work by decreasing the rate of bone resorption, however, these treatments also...... decrease new bone formation over time due to the coupling between these two processes. Elemental non-radioactive Strontium has been demonstrated to have both an anti resorptive as well as an anabolic effect on skeletal metabolism. This has been demonstrated in animal experiments after chromic...

  12. The superoxide dismutase mimetic tempol does not alleviate glucocorticoid-mediated rarefaction of rat skeletal muscle capillaries.

    Science.gov (United States)

    Mandel, Erin R; Dunford, Emily C; Abdifarkosh, Ghoncheh; Turnbull, Patrick C; Perry, Christopher G R; Riddell, Michael C; Haas, Tara L

    2017-05-01

    Sustained elevations in circulating glucocorticoids elicit reductions in skeletal muscle microvascular content, but little is known of the underlying mechanisms. We hypothesized that glucocorticoid-induced oxidative stress contributes to this phenomenon. In rats that were implanted with corticosterone (CORT) or control pellets, CORT caused a significant decrease in muscle glutathione levels and a corresponding increase in protein carbonylation, an irreversible oxidative modification of proteins. Decreased endothelial nitric oxide synthase and increased endothelin-1 mRNA levels were detected after 9 days of CORT, and blood flow to glycolytic muscles was diminished. Control and CORT rats were treated concurrently with drinking water containing the superoxide dismutase mimetic tempol (172 mg/L) or the α-1 adrenergic receptor antagonist prazosin (50 mg/L) for 6 or 16 days. Both tempol and prazosin alleviated skeletal muscle protein carbonylation. Tempol failed to prevent CORT-mediated capillary rarefaction and was ineffective in restoring skeletal muscle blood flow. In contrast, prazosin blocked capillary rarefaction and restored skeletal muscle blood flow to control levels. The failure of tempol to prevent CORT-induced skeletal muscle microvascular rarefaction does not support a dominant role of superoxide-induced oxidative stress in this process. Although a decrease in protein carbonylation was observed with prazosin treatment, our data suggest that the maintenance of skeletal muscle microvascular content is related more closely with counteracting the CORT-mediated influence on skeletal muscle vascular tone. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  13. Homocysteine induces energy imbalance in rat skeletal muscle: is creatine a protector?

    Science.gov (United States)

    Kolling, Janaína; Scherer, Emilene B S; Siebert, Cassiana; Hansen, Fernanda; Torres, Felipe V; Scaini, Giselli; Ferreira, Gabriela; de Andrade, Rodrigo B; Gonçalves, Carlos A S; Streck, Emílio L; Wannmacher, Clovis M D; Wyse, Angela T S

    2013-10-01

    Homocystinuria is a neurometabolic disease caused by a severe deficiency of cystathionine beta-synthase activity, resulting in severe hyperhomocysteinemia. Affected patients present several symptoms including a variable degree of motor dysfunction. In this study, we investigated the effect of chronic hyperhomocysteinemia on the cell viability of the mitochondrion, as well as on some parameters of energy metabolism, such as glucose oxidation and activities of pyruvate kinase, citrate synthase, isocitrate dehydrogenase, malate dehydrogenase, respiratory chain complexes and creatine kinase in gastrocnemius rat skeletal muscle. We also evaluated the effect of creatine on biochemical alterations elicited by hyperhomocysteinemia. Wistar rats received daily subcutaneous injections of homocysteine (0.3-0.6 µmol/g body weight) and/or creatine (50 mg/kg body weight) from the 6th to the 28th days of age. The animals were decapitated 12 h after the last injection. Homocysteine decreased the cell viability of the mitochondrion and the activities of pyruvate kinase and creatine kinase. Succinate dehydrogenase was increased other evaluated parameters were not changed by this amino acid. Creatine, when combined with homocysteine, prevented or caused a synergistic effect on some changes provoked by this amino acid. Creatine per se or creatine plus homocysteine altered glucose oxidation. These findings provide insights into the mechanisms by which homocysteine exerts its effects on skeletal muscle function, more studies are needed to elucidate them. Although creatine prevents some alterations caused by homocysteine, it should be used with caution, mainly in healthy individuals because it could change the homeostasis of normal physiological functions.

  14. The effect of growth-mimicking continuous strain on the early stages of skeletal development in micromass culture.

    Science.gov (United States)

    Klumpers, Darinka D; Smit, Theo H; Mooney, David J

    2015-01-01

    Embryonic skeletogenesis involves proliferation, condensation and subsequent chondrogenic differentiation of mesenchymal precursor cells, and the strains and stresses inherent to these processes have been hypothesized to influence skeletal development. The aim of this study was to determine the effect of growth-mimicking strain on the process of early skeletal development in vitro. To this end, we applied continuous uniaxial strain to embryonic skeletal precursor cells in micromass culture. Strain was applied at different times of culture to specifically address the effect of mechanical loading on the sequential stages of cellular proliferation, condensation and differentiation. We found that growth-mimicking strain at all three times did not affect proliferation or chondrogenic differentiation under the tested conditions. However, the timing of the applied strain did play a role in the density of mesenchymal condensations. This finding suggests that a mechanically dynamic environment, and specifically strain, can influence skeletal patterning. The growth-mimicking micromass model presented here may be a useful tool for further studies into the role of mechanical loading in early skeletal development.

  15. Interval and Continuous Exercise Training Produce Similar Increases in Skeletal Muscle and Left Ventricle Microvascular Density in Rats

    Directory of Open Access Journals (Sweden)

    Flávio Pereira

    2013-01-01

    Full Text Available Interval training (IT, consisting of alternated periods of high and low intensity exercise, has been proposed as a strategy to induce more marked biological adaptations than continuous exercise training (CT. The purpose of this study was to assess the effects of IT and CT with equivalent total energy expenditure on capillary skeletal and cardiac muscles in rats. Wistar rats ran on a treadmill for 30 min per day with no slope (0%, 4 times/week for 13 weeks. CT has constant load of 70% max; IT has cycles of 90% max for 1 min followed by 1 min at 50% max. CT and IT increased endurance and muscle oxidative capacity and attenuated body weight gain to a similar extent (P>0.05. In addition, CT and IT similarly increased functional capillary density of skeletal muscle (CT: 30.6±11.7%; IT: 28.7±11.9% and the capillary-to-fiber ratio in skeletal muscle (CT: 28.7±14.4%; IT: 40.1±17.2% and in the left ventricle (CT: 57.3±53.1%; IT: 54.3±40.5%. In conclusion, at equivalent total work volumes, interval exercise training induced similar functional and structural alterations in the microcirculation of skeletal muscle and myocardium in healthy rats compared to continuous exercise training.

  16. Effects of hypokalemia on the properties and expression of the (Na+,K+)-ATPase of rat skeletal muscle.

    Science.gov (United States)

    Hsu, Y M; Guidotti, G

    1991-01-05

    Rats maintained on a low potassium diet develop hypokalemia, which is associated with an approximately 80% decrease in the number of (Na+,K+)-ATPase molecules in skeletal muscle sarcolemma (Norgaard, A., Kjeldsen, K., and Clausen, T. (1981) Nature 293, 739-741); the skeletal muscles of the hypokalemic rats become paralyzed after exposure to insulin in low [K+] media (Otsuka, M., and Ohtsuki, I. (1970) Am. J. Physiol. 219, 1178-1182). We have been interested in the interactions between the insulin receptor and the alpha 2 isoform of the (Na+,K+)-ATPase as a mechanism for the insulin activation of (Na+,K+)-pumping and decided to use the hypokalemic rats to obtain additional information on this question. We show here that the amount of the alpha 2 isoform in the skeletal muscles of hypokalemic rats is greatly decreased as determined by immunoblotting and (Na+,K+)-ATPase activity; the effect of hypokalemia on the amount of the alpha 1 isoform is small. The mechanism of the decrease in the alpha 2 isoform is not known, but it is not due to transcriptional regulation of the alpha 2 gene because the amounts of the transcripts for this polypeptide are increased in the rats on the low potassium diet. The (Na+,K+)-pump that remains in the skeletal muscles of rats on a low potassium diet for a period of 2 weeks is still activated by insulin; under these conditions, however, insulin does not bring about a decrease in the intracellular [Na+] in contrast to the situation with normal muscle.

  17. Adaptation in properties of skeletal muscle to coronary artery occlusion/reperfusion in rats

    Energy Technology Data Exchange (ETDEWEB)

    Ogoh, Shigehiko [Univ. of North Texas, Fort Worth, TX (United States). Health Science Center; Hirai, Taku [Kyoto Univ. (Japan). Graduate School of Medicine; Nohara, Ryuuji [Kitano Hospital, Osaka (Japan); Taguchi, Sadayoshi [Kyoto Univ. (Japan). Graduate School of Human and Environmental Studies

    2002-10-01

    The present study was designed to determine if changes in function and metabolism of heart muscle induce alterations in characteristics of skeletal muscle. We investigated the histochemical and biochemical properties of soleus (SOL) and extensor digitorum longus (EDL) muscles in Wistar rats at the chronic phase after coronary artery occlusion/reperfusion. The size of myocardial infarct region was evaluated using a high resolution pinhole single photo emission computed tomography (SPECT) system. 4wk after left coronary artery occlusion/reperfusion, the SOL and EDL of hindlimb were dissected out and immersed in isopentane cooled with liquid nitrogen for subsequent histochemical and biochemical analysis. From SPECT imaging, the blood circulation was recovered, but the recovery of fatty acid metabolism was not observed in infarct region of heart. Citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD) activities in infarct region of heart were lower in the myocardial infarction (MI, n=6) group compared with that of age-matched sham-operated (Sham, n=6) group. In addition, heart muscle hypertrophy caused by the dysfunction in MI group was observed. In skeletal muscle, the atrophy and transition of fiber type distribution in MI group, reported in previous studies of heart failure, were not observed. However, the succinate dehydrogenase (SDH) activity in the slow twitch oxidative (SO) from SOL of MI group decreased by 9.8% and in the fast twitch oxidative glycolytic fibers (FOG), 8.0% as compared with sham group. Capillary density of the SO fibers from SOL of MI group also reduced by 18.5% and in the FOG fibers, 18.2% as compared with Sham group. Decreased capillary density in this study related significantly to decreased SDH activity of single muscle fibers in chronic phase of perfusion after surgical infarction. Our results make it clear that there is a difference in the reaction of skeletal muscle to coronary artery occlusion/reperfusion compared with chronic

  18. Neuromuscular electrical stimulation improves GLUT-4 and morphological characteristics of skeletal muscle in rats with heart failure.

    Science.gov (United States)

    de Leon, E B; Bortoluzzi, A; Rucatti, A; Nunes, R B; Saur, L; Rodrigues, M; Oliveira, U; Alves-Wagner, A B; Xavier, L L; Machado, U F; Schaan, B D; Dall'Ago, P

    2011-02-01

    Changes in skeletal muscle morphology and metabolism are associated with limited functional capacity in heart failure, which can be attenuated by neuromuscular electrical stimulation (ES). The purpose of the present study was to analyse the effects of ES upon GLUT-4 protein content, fibre structure and vessel density of the skeletal muscle in a rat model of HF subsequent to myocardial infarction. Forty-four male Wistar rats were assigned to one of four groups: sham (S), sham submitted to ES (S+ES), heart failure (HF) and heart failure submitted to ES (HF+ES). The rats in the ES groups were submitted to ES of the left leg during 20 days (2.5 kHz, once a day, 30 min, duty cycle 50%- 15 s contraction/15 s rest). After this period, the left tibialis anterior muscle was collected from all the rats for analysis. HF+ES rats showed lower values of lung congestion when compared with HF rats (P = 0.0001). Although muscle weight was lower in HF rats than in the S group, thus indicating hypotrophy, 20 days of ES led to their recovery (P muscle vessel density (P muscle. © 2010 The Authors. Acta Physiologica © 2010 Scandinavian Physiological Society.

  19. Ketoconazole- and fluconazole-induced embryotoxicity and skeletal anomalies in wistar rats: a comparative study

    Directory of Open Access Journals (Sweden)

    Vanessa Cristiane de Santana Amaral

    2008-12-01

    Full Text Available Ketoconazole and fluconazole are two broad-spectrum azole antifungals used for the treatment of superficial and systemic mycoses. Embryotoxicity and teratogenicity have been reported in some studies when those drugs are administered at high doses to pregnant rats. The aim of this study was to present a comparative study of embryotoxic effects as well as the skeletal anomalies in fetuses of Wistar rats which received ketoconazole and fluconazole at teratogenic doses on gestational days (GD 6 through 15 (organogenesis period. On gestational day (GD 21, the dams were euthanized and examined for standard parameters of reproductive outcome. Fetuses were stained with alizarin red and the bones of the head, trunk, forelimb and hindlimb were examined for detection of skeletal anomalies. The frequency of skeletal anomalies in the ketoconazole-treated group was significant when compared to the fluconazole and the control group.O cetoconazol e o fluconazol são dois antifúngicos azólicos, de amplo espectro, utilizados no tratamento de micoses superficiais e sistêmicas. Alguns estudos relatam a embriotoxicidade e teratogenicidade induzidas por estes fármacos quando os mesmos são administrados em altas doses a ratas prenhes. O objetivo deste trabalho foi apresentar um estudo comparativo dos efeitos embriotóxicos e das anomalias esqueléticas em fetos de ratas Wistar que receberam cetoconazol e fluconazol em doses teratogênicas do 6º ao 15º dia gestacional (GD (período da organogênese. No 21º GD as ratas foram eutanaziadas e examinadas quanto aos parâmetros padrões de performance reprodutiva. Os fetos foram corados com vermelho de alizarina e os ossos da cabeça, do tronco e dos membros anteriores e posteriores foram examinados para a verificação de anomalias esqueléticas. A freqüência de anomalias esqueléticas no grupo tratado com cetoconazol foi significante quando comparada à dos grupos fluconazol e controle.

  20. Effect of static magnetic field and/or cadmium in the antioxidant enzymes activity in rat heart and skeletal muscle.

    Science.gov (United States)

    Amara, Salem; Garrel, Catherine; Favier, Alain; Ben Rhouma, Khémais; Sakly, Mohsen; Abdelmelek, Hafedh

    2009-12-01

    Currently, environmental and industrial pollution along with increase and causes multiple stress conditions, the combined exposure to magnetic field and other toxic agents is recognised as an important research area, with a view to better protecting human health against their probable unfavourable effects. In the present study, we investigated the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the antioxidant enzymes activity and the malondialdehyde (MDA) concentration in rat skeletal and cardiac muscles. The exposure of rats to SMF (128 mT, 1 h/day during 30 consecutive days) decreased the activities of glutathione peroxidase (GPx) and the superoxide dismutase (CuZn-SOD) in heart muscle. Sub-chronic exposure to SMF increased the MDA concentration in rat cardiac muscle. Cd treatment (CdCl2, 40 mg/l, per os) during 4 weeks decreased the activities of catalase (CAT) in skeletal muscle and the CuZn-SOD in the heart. Moreover, Cd administration increased MDA concentration in the both structures. The combined effect of SMF (128 mT, 1 h/day during 30 consecutive days) and Cd (40 mg/l, per os) disrupt the antioxidant enzymes activity in rat skeletal and cardiac muscles. Moreover, we noted a huge increase in MDA concentration in the heart and skeletal muscle compared to control group. Thus it is possible that the SMF- and/or Cd-induced depletion of antioxidant enzymes activity in muscle tissues might, like the enhanced lipid peroxidation, importantly contribute to oxidative damage. The combined effect of SMF and Cd altered significantly the antioxidant enzymatic capacity and induced lipid peroxidation in both skeletal and cardiac muscle.

  1. Overload-induced skeletal muscle hypertrophy is not impaired in STZ-diabetic rats

    Science.gov (United States)

    Fortes, Marco Aurélio S; Pinheiro, Carlos Hermano J; Guimarães-Ferreira, Lucas; Vitzel, Kaio F; Vasconcelos, Diogo A A; Curi, Rui

    2015-01-01

    The aim of this study was to evaluate the effect of overload-induced hypertrophy on extensor digitorum longus (EDL) and soleus muscles of streptozotocin-induced diabetic rats. The overload-induced hypertrophy and absolute tetanic and twitch forces increases in EDL and soleus muscles were not different between diabetic and control rats. Phospho-Akt and rpS6 contents were increased in EDL muscle after 7 days of overload and returned to the pre-overload values after 30 days. In the soleus muscle, the contents of total and phospho-Akt and total rpS6 were increased in both groups after 7 days. The contents of total Akt in controls and total rpS6 and phospho-Akt in the diabetic rats remained increased after 30 days. mRNA expression after 7 days of overload in the EDL muscle of control and diabetic animals showed an increase in MGF and follistatin and a decrease in myostatin and Axin2. The expression of FAK was increased and of MuRF-1 and atrogin-1 decreased only in the control group, whereas Ankrd2 expression was enhanced only in diabetic rats. In the soleus muscle caused similar changes in both groups: increase in FAK and MGF and decrease in Wnt7a, MuRF-1, atrogin-1, and myostatin. Differences between groups were observed only in the increased expression of follistatin in diabetic animals and decreased Ankrd2 expression in the control group. So, insulin deficiency does not impair the overload-induced hypertrophic response in soleus and EDL muscles. However, different mechanisms seem to be involved in the comparable hypertrophic responses of skeletal muscle in control and diabetic animals. PMID:26197932

  2. Effects of exercise training on circulating and skeletal muscle renin-angiotensin system in chronic heart failure rats.

    Directory of Open Access Journals (Sweden)

    Igor Lucas Gomes-Santos

    Full Text Available BACKGROUND: Accumulated evidence shows that the ACE-AngII-AT1 axis of the renin-angiotensin system (RAS is markedly activated in chronic heart failure (CHF. Recent studies provide information that Angiotensin (Ang-(1-7, a metabolite of AngII, counteracts the effects of AngII. However, this balance between AngII and Ang-(1-7 is still little understood in CHF. We investigated the effects of exercise training on circulating and skeletal muscle RAS in the ischemic model of CHF. METHODS/MAIN RESULTS: Male Wistar rats underwent left coronary artery ligation or a Sham operation. They were divided into four groups: 1 Sedentary Sham (Sham-S, 2 exercise-trained Sham (Sham-Ex, sedentary CHF (CHF-S, and exercise-trained CHF (CHF-Ex. Angiotensin concentrations and ACE and ACE2 activity in the circulation and skeletal muscle (soleus and plantaris were quantified. Skeletal muscle ACE and ACE2 protein expression, and AT1, AT2, and Mas receptor gene expression were also evaluated. CHF reduced ACE2 serum activity. Exercise training restored ACE2 and reduced ACE activity in CHF. Exercise training reduced plasma AngII concentration in both Sham and CHF rats and increased the Ang-(1-7/AngII ratio in CHF rats. CHF and exercise training did not change skeletal muscle ACE and ACE2 activity and protein expression. CHF increased AngII levels in both soleus and plantaris muscle, and exercise training normalized them. Exercise training increased Ang-(1-7 in the plantaris muscle of CHF rats. The AT1 receptor was only increased in the soleus muscle of CHF rats, and exercise training normalized it. Exercise training increased the expression of the Mas receptor in the soleus muscle of both exercise-trained groups, and normalized it in plantaris muscle. CONCLUSIONS: Exercise training causes a shift in RAS towards the Ang-(1-7-Mas axis in skeletal muscle, which can be influenced by skeletal muscle metabolic characteristics. The changes in RAS circulation do not necessarily

  3. Glucose metabolism and metabolic flexibility in cultured skeletal muscle cells is related to exercise status in young male subjects

    DEFF Research Database (Denmark)

    Lund, Jenny; S Tangen, Daniel; Wiig, Håvard

    2017-01-01

    We hypothesised that skeletal muscles of healthy young people have a large variation in oxidative capacity and fibre-type composition, and aimed therefore to investigate glucose metabolism in biopsies and myotubes isolated from musculus vastus lateralis from healthy males with varying degrees...... deoxyglucose accumulation and fractional glucose oxidation (glucose oxidation relative to glucose uptake), and were also more sensitive to the suppressive action of acutely added oleic acid to the cells. Despite lack of correlation of fibre types between skeletal muscle biopsies and cultured cells, myotubes...

  4. Temporal profile of rat skeletal muscle capillary haemodynamics during recovery from contractions

    Science.gov (United States)

    Ferreira, Leonardo F; Padilla, Danielle J; Musch, Timothy I; Poole, David C

    2006-01-01

    In skeletal muscle capillaries, red blood cell (RBC) flux (FRBC), velocity (VRBC) and haematocrit (HctCAP) are key determinants of microvascular O2 exchange. However, the mechanisms leading to the changes in FRBC, VRBC and HctCAP during muscle contractions and recovery thereafter are not fully understood. To address this issue we used intravital microscopy to investigate the temporal profile of the rat spinotrapezius muscle (n = 5) capillary haemodynamics during recovery from 3 min of twitch muscle contractions (1 Hz, 4–6 V). Specifically, we hypothesized that (1) during early recovery FRBC and VRBC would decrease rapidly and FRBC would display a biphasic response (consistent with a muscle pump effect on capillary haemodynamics), and (2) there would be a dynamic relationship between changes (Δ) in VRBC and HctCAP. The values at rest (R) and end-recovery (ER) were significantly lower (P 0.05). Based on the early decrease in FRBC(within 5 s), overall dynamic profile of FRBC and the ∼20 s ‘delay’ to the decrease in VRBC we conclude that the muscle pump does not appear to contribute substantially to the steady-state capillary haemodynamics in the contracting rat spinotrapezius muscle. Moreover, our findings suggest that alterations in VRBC do not obligate proportional changes in HctCAP within individual capillaries following muscle contractions. PMID:16581868

  5. Proteomic identification of age-dependent protein nitration in rat skeletal muscle.

    Science.gov (United States)

    Kanski, Jaroslaw; Alterman, Michail A; Schöneich, Christian

    2003-11-15

    Age-related protein nitration was studied in skeletal muscle of Fisher 344 and Fisher 344/Brown Norway (BN) F1 rats by a proteomic approach. Proteins from young (4 months) and old (24 months) Fisher 344 rats and young (6 months) and old (34 months) Fisher 344/BN F1 animals were separated by 2-D gel electrophoresis. Western blot showed an age-related increase in the nitration of a few specific proteins, which were identified by MALDI-TOF MS and ESI-MS/MS. We identified age-dependent apparent nitration of beta-enolase, alpha-fructose aldolase, and creatine kinase, which perform important functions in muscle energy metabolism, suggesting that the nitration of such key proteins can be, in part, responsible for the decline of muscle motor function of the muscle. Furthermore, we have identified the apparent nitration of succinate dehydrogenase, rab GDP dissociation inhibitor beta (GdI-2), triosephosphate isomerase, troponin I, alpha-crystallin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

  6. Central injection of GALR1 agonist M617 attenuates diabetic rat skeletal muscle insulin resistance through the Akt/AS160/GLUT4 pathway.

    Science.gov (United States)

    Fang, Penghua; Yu, Mei; He, Biao; Guo, Lili; Huang, Xiaoli; Kong, Guimei; Shi, Mingyi; Zhu, Yan; Bo, Ping; Zhang, Zhenwen

    2017-03-01

    Insulin resistance of skeletal muscle plays an important role in the pathogenesis of type 2 diabetes. Galanin, a 29/30-amino-acid neuropeptide, plays multiple biological actions, including anti-diabetic effects. Although recent results of our study showed that administration of galanin could mitigate insulin resistance by promoting glucose transporter 4 (GLUT4) expression and translocation in skeletal muscle of rats, there is no literature available regarding to the effect of type 1 of galanin receptors (GALR1) on insulin resistance in skeletal muscle of type 2 diabetic rats. Herein, we intended to survey the central effect of GALR1 agonist M617 on insulin resistance in skeletal muscle and its underlying mechanisms. We found that the intracerebroventricular injection of M617 increased glucose infusion rates in hyperinsulinemic euglycemic clamp tests, but attenuated the plasma insulin and glucose concentrations of diabetic rats. Furthermore, administration of M617 markedly increased GLUT4 mRNA expression and GLUT4 translocation in skeletal muscle of diabetic rats. Last, perfusion of M617 increased phosphorylated Akt and phosphorylated AS160 levels in the skeletal muscle of diabetic rats. In conclusion, central injection of M617 mitigated insulin resistance of skeletal muscle by enhancing GLUT4 translocation from intracellular pools to plasma membranes via the activation of the Akt/AS160/GLUT4 signaling pathway.

  7. A combination of nutriments improves mitochondrial biogenesis and function in skeletal muscle of type 2 diabetic Goto-Kakizaki rats.

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    Weili Shen

    Full Text Available BACKGROUND: Recent evidence indicates that insulin resistance in skeletal muscle may be related to reduce mitochondrial number and oxidation capacity. However, it is not known whether increasing mitochondrial number and function improves insulin resistance. In the present study, we investigated the effects of a combination of nutrients on insulin resistance and mitochondrial biogenesis/function in skeletal muscle of type 2 diabetic Goto-Kakizaki rats. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated that defect of glucose and lipid metabolism is associated with low mitochondrial content and reduced mitochondrial enzyme activity in skeletal muscle of the diabetic Goto-Kakizaki rats. The treatment of combination of R-alpha-lipoic acid, acetyl-L-carnitine, nicotinamide, and biotin effectively improved glucose tolerance, decreased the basal insulin secretion and the level of circulating free fatty acid (FFA, and prevented the reduction of mitochondrial biogenesis in skeletal muscle. The nutrients treatment also significantly increased mRNA levels of genes involved in lipid metabolism, including peroxisome proliferator-activated receptor-alpha (Ppar alpha, peroxisome proliferator-activated receptor-delta (Ppar delta, and carnitine palmitoyl transferase-1 (Mcpt-1 and activity of mitochondrial complex I and II in skeletal muscle. All of these effects of mitochondrial nutrients are comparable to that of the antidiabetic drug, pioglitazone. In addition, the treatment with nutrients, unlike pioglitazone, did not cause body weight gain. CONCLUSIONS/SIGNIFICANCE: These data suggest that a combination of mitochondrial targeting nutrients may improve skeletal mitochondrial dysfunction and exert hypoglycemic effects, without causing weight gain.

  8. Effects of cadmium on the renal and skeletal muscle microcirculation in rats

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Chong.

    1990-01-01

    The effects of cadmium on the arteriolar diameters of the kidney and skeletal muscle were quantified, because of the hypertensive effect of cacmium. The effect of cacmium on the constrictor response of the renal arterioles to angiotensin II (Ang II) were also assessed. In vivo preparations of the rat hydronephrotic kidney and cremaster muscle were used for direct visualization of the microvessels with intravital television microscopy. Hydronephrosis was induced in twenty-seven male Wistar-Kyoto rats (150-180 g) by unilateral ureter ligation. The hydronephrotic kidney, with intact cortical circulation and innervation, was exteriorized in a specially designed bath for microcirculation observation 6-8 weeks following the ureter ligation. The cremaster muscle experiments were conducted in another thirty-seven male WKY rats (120-180 g). Disparate effects of cadmium were observed in these two microcirculation beds. Topical cadmium (1.35 [mu]M-0.45 mM) increased the diameters of the pre- and postglomerular vessels in the hydronephrotic kidney maximally by 15-26%. Cadmium (0.27 mM) inhibited the Ang II response of the arterioles non-competitively. However, intraperitoneally injected cadmium (2 mg/kg), which significantly increased the mean arterial pressure, did not dilate the arterioles nor alter the Ang II response. On the other hand, cadmium (13.5 [mu]M-0.72 mM) constricted the larger arterioles in the cremaster muscle (60-160 [mu]m) concentration-dependently, but not small arterioles (15-30 [mu]m). In summary, topical cadmium dilates renal arterioles and decreases their reactivity to Ang II, but constricts the larger cremaster arterioles. The disparate effects of cadmium suggest different Ca[sup 2+] utilization mechanisms in different vascular beds. The construction of the cremaster arterioles may contribute to cadmium-induced hypertension by increasing peripheral resistance.

  9. Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure.

    Directory of Open Access Journals (Sweden)

    Morten Munkvik

    Full Text Available During isometric contractions, slow twitch soleus muscles (SOL from rats with chronic heart failure (chf are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf if left ventricle end diastolic pressure was >15 mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off at 30 Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (F(max and the concentrations of ATP and CrP were not different in the two groups. During stimulation, F(max and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue.

  10. Protective effect of quercetin on skeletal and neural tube teratogenicity induced by cyclophosphamide in rat fetuses

    Science.gov (United States)

    Khaksary Mahabady, Mahmood; Gholami, Mohammad Reza; Najafzadeh Varzi, Hossein; Zendedel, Abolfazl; Doostizadeh, Mona

    2016-01-01

    Cyclophosphamide (CP) is a drug commonly used to treat neoplastic disease and some autoimmune diseases. It is also a well-known and well-studied teratogen causing a variety of birth defects in fetuses of pregnant women treated with the drug. There are many reports that show the adverse effects of CP can be decreased by use of antioxidant drugs. It appears that, quercetin has antioxidant effect. The aim of this study was prevention or decrease of teratogenicity of CP in fetuses of rats by quercetin. This study was performed on 35 pregnant rats divided into six groups. Control group was received normal saline (5 mL kg-1, intraperitoneally) and 2-6 groups received a single dose of CP (15 mg kg-1), a single dose of quercetin (75 or 200 mg kg-1), CP plus quercetin (75 or 200 mg kg-1) intraperitoneally at 9th day of gestation, respectively. Fetuses were collected at 20th day of gestation and after determination of weight and crown rump length were stained by alizarin red – alcian blue method and skeletal system were examined by stereomicroscope. The results showed that the cleft palate, exencephaly, spina bifida and omphalocele incidence were 55.56%, 27.77%, 33.34% and 11.11%, in fetuses of rat that received only CP, respectively. However, it decreased to 16.00%, 16.00%, 16.00% and 8.00% by quercetin (75 mg kg-1) and so to 12.90%, 12.90%, 6.45% and 3.28% by quercetin (200 mg kg-1), respectively. On the basis of results, quercetin significantly can decrease teratogenicity induced by CP. PMID:27482358

  11. Morphological differences in skeletal muscle atrophy of rats with motor nerve and/or sensory nerve injury

    Institute of Scientific and Technical Information of China (English)

    Lei Zhao; Guangming Lv; Shengyang Jiang; Zhiqiang Yan; Junming Sun; Ling Wang; Donglin Jiang

    2012-01-01

    Skeletal muscle atrophy occurs after denervation. The present study dissected the rat left ventral root and dorsal root at L4-6 or the sciatic nerve to establish a model of simple motor nerve injury, sensory nerve injury or mixed nerve injury. Results showed that with prolonged denervation time, rats with simple motor nerve injury, sensory nerve injury or mixed nerve injury exhibited abnormal behavior, reduced wet weight of the left gastrocnemius muscle, decreased diameter and cross-sectional area and altered ultrastructure of muscle cells, as well as decreased cross-sectional area and increased gray scale of the gastrocnemius muscle motor end plate. Moreover, at the same time point, the pathological changes were most severe in mixed nerve injury, followed by simple motor nerve injury, and the changes in simple sensory nerve injury were the mildest. These findings indicate that normal skeletal muscle morphology is maintained by intact innervation. Motor nerve injury resulted in larger damage to skeletal muscle and more severe atrophy than sensory nerve injury. Thus, reconstruction of motor nerves should be considered first in the clinical treatment of skeletal muscle atrophy caused by denervation.

  12. Effects of recombinant retroviral vector mediated human insulin like growth factor-1 gene transfection on skeletal muscle growth in rat

    Institute of Scientific and Technical Information of China (English)

    RONG Shu-Ling; LU Yong-Xin; LIAO Yu-Hua; WANG Xiao-Lin; GUO He-Ping; CHANG Chao; GAO Yan-Zhang; MI Shao-Hua; Wan Jian-Ping

    2006-01-01

    Background This study transferred a recombinant gene encoding human insulin like growth factor-1 (hIGF-1)into modified primary skeletal myoblasts with a retroviral vector (pLgXSN) and determined whether the hIGF-1 promoted growth of skeletal muscle in rat.Methods hIGF-lcDNA was amplified in vitro from normal human liver cells by using RT-PCR and cloned into plasmid vector pLgXSN. The recombinant vector pLghIGF-1SN and control vector pLgGFPSN were transfected into packaging cell PT67 and G418 was used to select positive colony. Myoblasts were infected with a high titre viral supernatant and transduction efficiency was evaluated as GFP expression. The expression of hIGF-1 mRNA in myoblasts was investigated by immunocytochemistry and RT-PCR. MTT assays detected the growth of myoblasts in vitro. Myoblasts transduced with pLghIGF-1SN were injected into hind limb muscles of 10-12 week male SD rats. Formed tissues were harvested 4 weeks later. Myocyte diameter, mean weight of hind limb and body were measured to evaluate the skeletal muscle growth.Results Recombinant retroviral plasmid vector pLghIGF-1SN was constructed successfully. The titre of the packaged recombinant retrovirus was 1 × 106 cfu/ml. The transfection rate of PT67 cells reached 100% after G418 screening. hIGF-1 expression was positive in myoblast-IGF-1. The proliferation rate of myoblast-IGF-1 in vitro was higher than GFP-myoblast or myoblast (P< 0.05). The mean weights of hind limb and body of rats injected myoblast-IGF-1 were higher than those of the rats injected with myoblast-GFP or myoblast (P< 0.05). Myocyte diameter had a significant increase in IGF-1 group compared to GFP group and myoblast group (P< 0.05).Conclusions The transfection of the human IGF- 1 gene mediated by a retroviral vector can promote the growth of skeletal muscle in rats. Genetically modified primary skeletal myoblasts provide a possibly effective approach to treat some skeletal muscle diseases.

  13. Effects of nitrate supplementation via beetroot juice on contracting rat skeletal muscle microvascular oxygen pressure dynamics

    Science.gov (United States)

    Ferguson, Scott K.; Hirai, Daniel M.; Copp, Steven W.; Holdsworth, Clark T.; Allen, Jason D.; Jones, Andrew M.; Musch, Timothy I.; Poole, David C.

    2013-01-01

    NO3− supplementation via beetroot juice (BR) augments exercising skeletal muscle blood flow subsequent to its reduction to NO2− then NO. We tested the hypothesis that enhanced vascular control following BR would elevate the skeletal muscle O2 delivery/O2 utilization ratio (microvascular PO2, PmvO2) and raise the PmvO2 during the rest-contractions transition. Rats were administered BR (~0.8 mmol/kg/day, n=10) or water (control, n=10) for 5 days. PmvO2 was measured during 180 s of electrically-induced (1 Hz) twitch spinotrapezius muscle contractions. There were no changes in resting or contracting steady-state PmvO2. However, BR slowed the PmvO2 fall following contractions onset such that time to reach 63% of the initial PmvO2 fall increased (MRT1; control: 16.8±1.9, BR: 24.4±2.7 s, p<0.05) and there was a slower relative rate of PmvO2 fall (Δ1PmvO2/τ1; control: 1.9±0.3, BR: 1.2±0.2 mmHg/s, p<0.05). Despite no significant changes in contracting steady state PmvO2, BR supplementation elevated the O2 driving pressure during the crucial rest-contractions transients thereby providing a potential mechanism by which BR supplementation may improve metabolic control. PMID:23584049

  14. Enhancement of Skeletal Muscle in Aged Rats Following High-Intensity Stretch-Shortening Contraction Training.

    Science.gov (United States)

    Rader, Erik P; Naimo, Marshall A; Layner, Kayla N; Triscuit, Alyssa M; Chetlin, Robert D; Ensey, James; Baker, Brent A

    2016-08-03

    Exercise is the most accessible, efficacious, and multifactorial intervention to improve health and treat chronic disease. High-intensity resistance exercise, in particular, also maximizes skeletal muscle size and strength-outcomes crucial at advanced age. However, such training is capable of inducing muscle maladaptation when misapplied at old age. Therefore, characterization of parameters (e.g., mode and frequency) that foster adaptation is an active research area. To address this issue, we utilized a rodent model that allowed training at maximal intensity in terms of muscle activation and tested the hypothesis that muscles of old rats adapt to stretch-shortening contraction (SSC) training, provided the training frequency is sufficiently low. At termination of training, normalized muscle mass (i.e., muscle mass divided by tibia length) and muscle quality (isometric force divided by normalized muscle mass) were determined. For young rats, normalized muscle mass increased by ∼20% regardless of training frequency. No difference was observed for muscle quality values after 2 days versus 3 days per week training (0.65 ± 0.09 N/mg/mm vs. 0.59 ± 0.05 N/mg/mm, respectively). For old rats following 3 days per week training, normalized muscle mass was unaltered and muscle quality was 30% lower than young levels. Following 2 days per week training at old age, normalized muscle mass increased by 17% and muscle quality was restored to young levels. To investigate this enhanced response, oxidative stress was assessed by lipid peroxidation quantification. For young rats, lipid peroxidation levels were unaltered by training. With aging, baseline levels of lipid peroxidation increased by 1.5-fold. For old rats, only 2 days per week training decreased lipid peroxidation to levels indistinguishable from young values. These results imply that, appropriately scheduled high-intensity SSC training at old age is capable of restoring muscle to a younger phenotype in terms

  15. Glycogen stability and glycogen phosphorylase activities in isolated skeletal muscles from rat and toad.

    Science.gov (United States)

    Goodman, C A; Stephenson, G M

    2000-01-01

    There is increasing evidence that endogenous glycogen depletion may affect excitation-contraction (E-C) coupling events in vertebrate skeletal muscle. One approach employed in physiological investigations of E-C coupling involves the use of mechanically skinned, single fibre preparations obtained from tissues stored under paraffin oil, at room temperature (RT: 20-24 degrees C) and 4 degrees C for several hours. In the present study, we examined the effect of these storage conditions on the glycogen content in three muscles frequently used in research on E-C coupling: rat extensor digitorum longus (EDL) and soleus (SOL) and toad iliofibularis (IF). Glycogen content was determined fluorometrically in homogenates prepared from whole muscles, stored under paraffin oil for up to 6 h at RT or 4 degrees C. Control muscles and muscles stored for 0.5 and 6 h were also analysed for total phosphorylase (Phos(total)) and phosphorylase a (Phos a) activities. No significant change was observed in the glycogen content of EDL and SOL muscles stored at RT for 0.5 h. In rat muscles stored at RT for longer than 0.5 h, the glycogen content decreased to 67.6% (EDL) and 78.7% (SOL) of controls after 3 h and 25.3% (EDL) and 37.4% (SOL) after 6 h. Rat muscles stored at 4 degrees C retained 79.0% (EDL) and 92.5% (SOL) of glycogen after 3 h and 75.2% (EDL) and 61.1% (SOL) after 6 h. The glycogen content of IF muscles stored at RT or 4 degrees C for 6 h was not significantly different from controls. Phos(total) was unchanged in all muscles over the 6 h period, at both temperatures. Phos a was also unchanged in the toad IF muscles, but in rat muscles it decreased rapidly, particularly in EDL (4.1-fold after 0.5 h at RT). Taken together these results indicate that storage under paraffin oil for up to 6 h at RT or 4 degrees C is accompanied by minimal glycogen loss in toad IF muscles and by a time- and temperature-dependent glycogen loss in EDL and SOL muscles of the rat.

  16. Bradykinin does not acutely sensitize the reflex pressor response during hindlimb skeletal muscle stretch in decerebrate rats.

    Science.gov (United States)

    Rollins, Korynne S; Smith, Joshua R; Esau, Peter J; Kempf, Evan A; Hopkins, Tyler D; Copp, Steven W

    2017-10-01

    Hindlimb skeletal muscle stretch (i.e., selective activation of the muscle mechanoreflex) in decerebrate rats evokes reflex increases in blood pressure and sympathetic nerve activity. Bradykinin has been found to sensitize mechanogated channels through a bradykinin B2 receptor-dependent mechanism. Moreover, bradykinin B2 receptor expression on sensory neurons is increased following chronic femoral artery ligation in the rat (a model of simulated peripheral artery disease). We tested the hypothesis that injection of bradykinin into the arterial supply of a hindlimb in decerebrate, unanesthetized rats would acutely augment (i.e., sensitize) the increase in blood pressure and renal sympathetic nerve activity during hindlimb muscle stretch to a greater extent in rats with a ligated femoral artery than in rats with a freely perfused femoral artery. The pressor response during static hindlimb muscle stretch was compared before and after hindlimb arterial injection of 0.5 µg of bradykinin. Injection of bradykinin increased blood pressure to a greater extent in "ligated" (n = 10) than "freely perfused" (n = 10) rats. The increase in blood pressure during hindlimb muscle stretch, however, was not different before vs. after bradykinin injection in freely perfused (14 ± 2 and 15 ± 2 mmHg for pre- and post-bradykinin, respectively, P = 0.62) or ligated (15 ± 3 and 14 ± 2 mmHg for pre- and post-bradykinin, respectively, P = 0.80) rats. Likewise, the increase in renal sympathetic nerve activity during stretch was not different before vs. after bradykinin injection in either group of rats. We conclude that bradykinin did not acutely sensitize the pressor response during hindlimb skeletal muscle stretch in freely perfused or ligated decerebrate rats. Copyright © 2017 the American Physiological Society.

  17. Peripheral nerve injury causes transient expression of MHC class I antigens in rat motor neurons and skeletal muscles

    DEFF Research Database (Denmark)

    Maehlen, J; Nennesmo, I; Olsson, A B

    1989-01-01

    After a peripheral nerve lesion (rat facial and sciatic) an induction of major histocompatibility complex (MHC) antigens class I was detected immunohistochemically in skeletal muscle fibers and motor neurons. This MHC expression was transient after a nerve crush, when regeneration occurred......, but persisted after a nerve cut, when regeneration was prevented. Since the time course of MHC class I expression correlates to that of regeneration a role for this cell surface molecule in regeneration may be considered....

  18. [Lactate dehydrogenase isoenzymatic makeup of the skeletal muscles of rats after a flight on the Kosmos-690 biosatellite].

    Science.gov (United States)

    Petrova, N V

    1978-01-01

    The isoenzyme composition of lactate dehydrogenase in the soleus and plantaris muscles of rats which had flown for 20.5 days onboard the biosatellite Cosmos-690 equipped with a radiation source was studied. Difference in the isoenzyme composition of lactate dehydrogenase in flight and synchronous rats disappeared 27 days after the experiments; however, some changes persisted as compared with vivarium controls. The data obtained give evidence that irradiation-induced effects in skeletal muscles manifested themselves at a far later stage than weightlessness-induced changes.

  19. Differential regulation of oxytocin receptor in various adipose tissue depots and skeletal muscle types in obese Zucker rats.

    Science.gov (United States)

    Gajdosechova, L; Krskova, K; Olszanecki, R; Zorad, S

    2015-07-01

    Multifunctional peptide oxytocin currently undergoes intensive research due to its proposed anti-obesity properties. Until now, little is known about regulation of oxytocin receptor in metabolically active tissues in obesity. The aim of the present study was to measure expression of oxytocin receptor upon obese phenotype with respect to the variety among adipose tissue and skeletal muscles with distinct anatomical localisation. Total homogenates were prepared from epididymal, retroperitoneal and inguinal adipose tissues as well as quadriceps and soleus muscle from lean and obese Zucker rats. Oxytocin receptor protein was determined by immunoblot. Interestingly, elevated oxytocin receptor was observed in epididymal adipose tissue of obese rats in contrast to its downregulation in subcutaneous and no change in retroperitoneal fat. In lean animals, oxytocin receptor protein was expressed at similar levels in all adipose depots. This uniformity was not observed in the case of skeletal muscle in which fibre type composition seems to be determinant of oxytocin receptor expression. Quadriceps muscle with the predominance of glycolytic fibres exhibits higher oxytocin receptor expression than almost exclusively oxidative soleus muscle. Oxytocin receptor protein levels were decreased in both skeletal muscles analysed upon obese phenotype. The present work demonstrates that even under identical endocrine circumstances, oxytocin receptor is differentially regulated in adipose tissue of obese rats depending on fat depot localisation. These results also imply which tissues may be preferentially targeted by oxytocin treatment in metabolic disease.

  20. Metformin selectively attenuates mitochondrial H2O2 emission without affecting respiratory capacity in skeletal muscle of obese rats.

    Science.gov (United States)

    Kane, Daniel A; Anderson, Ethan J; Price, Jesse W; Woodlief, Tracey L; Lin, Chien-Te; Bikman, Benjamin T; Cortright, Ronald N; Neufer, P Darrell

    2010-09-15

    Metformin is a widely prescribed drug for treatment of type 2 diabetes, although no cellular mechanism of action has been established. To determine whether in vivo metformin treatment alters mitochondrial function in skeletal muscle, respiratory O(2) flux and H(2)O(2) emission were measured in saponin-permeabilized myofibers from lean and obese (fa/fa) Zucker rats treated for 4 weeks with metformin. Succinate- and palmitoylcarnitine-supported respiration generated greater than twofold higher rates of H(2)O(2) emission in myofibers from untreated obese versus lean rats, indicative of an obesity-associated increased mitochondrial oxidant emitting potential. In conjunction with improved glycemic control, metformin treatment reduced H(2)O(2) emission in muscle from obese rats to rates near or below those observed in lean rats during both succinate- and palmitoylcarnitine-supported respiration. Surprisingly, metformin treatment did not affect basal or maximal rates of O(2) consumption in muscle from obese or lean rats. Ex vivo dose-response experiments revealed that metformin inhibits complex I-linked H(2)O(2) emission at a concentration approximately 2 orders of magnitude lower than that required to inhibit respiratory O(2) flux. These findings suggest that therapeutic concentrations of metformin normalize mitochondrial H(2)O(2) emission by blocking reverse electron flow without affecting forward electron flow or respiratory O(2) flux in skeletal muscle. Copyright 2010 Elsevier Inc. All rights reserved.

  1. Effect of L-Carnitine on Skeletal Muscle Lipids and Oxidative Stress in Rats Fed High-Fructose Diet

    Directory of Open Access Journals (Sweden)

    Panchamoorthy Rajasekar

    2007-01-01

    Full Text Available There is evidence that high-fructose diet induces insulin resistance, alterations in lipid metabolism, and oxidative stress in rat tissues. The purpose of this study was to evaluate the effect of L-carnitine (CAR on lipid accumulation and peroxidative damage in skeletal muscle of rats fed high-fructose diet. Fructose-fed animals (60 g/100 g diet displayed decreased glucose/insulin (G/I ratio and insulin sensitivity index (ISI0,120 indicating the development of insulin resistance. Rats showed alterations in the levels of triglycerides, free fatty acids, cholesterol, and phospholipids in skeletal muscle. The condition was associated with oxidative stress as evidenced by the accumulation of lipid peroxidation products, protein carbonyls, and aldehydes along with depletion of both enzymic and nonenzymic antioxidants. Simultaneous intraperitoneal administration of CAR (300 mg/kg/day to fructose-fed rats alleviated the effects of fructose. These rats showed near-normal levels of the parameters studied. The effects of CAR in this model suggest that CAR supplementation may have some benefits in patients suffering from insulin resistance.

  2. Effects of High-Fat Feeding on Skeletal Muscle Gene Expression in Diabetic Goto-Kakizaki Rats

    Directory of Open Access Journals (Sweden)

    Jing Nie

    2017-05-01

    Full Text Available In the present report, we examined the responses of diabetic Goto-Kakizaki (GK rats and control Wistar-Kyoto (WKY rats fed either a standard chow or high-fat diet (HFD from weaning to 20 weeks of age. This comparison included gene expression profiling of skeletal muscle using Affymetrix gene array chips. The expression profiling is interpreted within the context of a wide array of physiological measurements. Genes whose expressions are different between the 2 strains regardless of diet, as well as genes that differ between strains only with HFD, were identified. In addition, genes that were regulated by diet in 1 or both strains were identified. The results suggest that both strains respond to HFD by an increased capacity to oxidize lipid fuels in the musculature but that this adaptation occurs more rapidly in WKY rats. The results also demonstrated an impaired cytokine signalling and heightened inflammatory status in the GK rats.

  3. Chromium picolinate enhances skeletal muscle cellular insulin signaling in vivo in obese, insulin-resistant JCR:LA-cp rats.

    Science.gov (United States)

    Wang, Zhong Q; Zhang, Xian H; Russell, James C; Hulver, Matthew; Cefalu, William T

    2006-02-01

    Chromium is one of the few trace minerals for which a specific cellular mechanism of action has not been identified. Recent in vitro studies suggest that chromium supplementation may improve insulin sensitivity by enhancing insulin receptor signaling, but this has not been demonstrated in vivo. We investigated the effect of chromium supplementation on insulin receptor signaling in an insulin-resistant rat model, the JCR:LA-corpulent rat. Male JCR:LA-cp rats (4 mo of age) were randomly assigned to receive chromium picolinate (CrPic) (obese n=6, lean n=5) or vehicle (obese n=5, lean n=5) for 3 mo. The CrPic was provided in the water, and based on calculated water intake, rats randomized to CrPic received 80 microg/(kg.d). At the end of the study, skeletal muscle (vastus lateralis) biopsies were obtained at baseline and at 5, 15, and 30 min postinsulin stimulation to assess insulin signaling. Obese rats treated with CrPic had significantly improved glucose disposal rates and demonstrated a significant increase in insulin-stimulated phosphorylation of insulin receptor substrate (IRS)-1 and phosphatidylinositol (PI)-3 kinase activity in skeletal muscle compared with obese controls. The increase in cellular signaling was not associated with increased protein levels of the IRS proteins, PI-3 kinase or Akt. However, protein tyrosine phosphatase 1B (PTP1B) levels were significantly lower in obese rats administered CrPic than obese controls. When corrected for protein content, PTP1B activity was also significantly lower in obese rats administered CrPic than obese controls. Our data suggest that chromium supplementation of obese, insulin-resistant rats may improve insulin action by enhancing intracellular signaling.

  4. Sodium valproate increases the brain isoform of glycogen phosphorylase: looking for a compensation mechanism in McArdle disease using a mouse primary skeletal-muscle culture in vitro

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    Noemí de Luna

    2015-05-01

    Full Text Available McArdle disease, also termed ‘glycogen storage disease type V’, is a disorder of skeletal muscle carbohydrate metabolism caused by inherited deficiency of the muscle-specific isoform of glycogen phosphorylase (GP-MM. It is an autosomic recessive disorder that is caused by mutations in the PYGM gene and typically presents with exercise intolerance, i.e. episodes of early exertional fatigue frequently accompanied by rhabdomyolysis and myoglobinuria. Muscle biopsies from affected individuals contain subsarcolemmal deposits of glycogen. Besides GP-MM, two other GP isoforms have been described: the liver (GP-LL and brain (GP-BB isoforms, which are encoded by the PYGL and PYGB genes, respectively; GP-BB is the main GP isoform found in human and rat foetal tissues, including the muscle, although its postnatal expression is dramatically reduced in the vast majority of differentiated tissues with the exception of brain and heart, where it remains as the major isoform. We developed a cell culture model from knock-in McArdle mice that mimics the glycogen accumulation and GP-MM deficiency observed in skeletal muscle from individuals with McArdle disease. We treated mouse primary skeletal muscle cultures in vitro with sodium valproate (VPA, a histone deacetylase inhibitor. After VPA treatment, myotubes expressed GP-BB and a dose-dependent decrease in glycogen accumulation was also observed. Thus, this in vitro model could be useful for high-throughput screening of new drugs to treat this disease. The immortalization of these primary skeletal muscle cultures could provide a never-ending source of cells for this experimental model. Furthermore, VPA could be considered as a gene-expression modulator, allowing compensatory expression of GP-BB and decreased glycogen accumulation in skeletal muscle of individuals with McArdle disease.

  5. Electrical pulse stimulation of cultured human skeletal muscle cells as an in vitro model of exercise.

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    Nataša Nikolić

    Full Text Available BACKGROUND AND AIMS: Physical exercise leads to substantial adaptive responses in skeletal muscles and plays a central role in a healthy life style. Since exercise induces major systemic responses, underlying cellular mechanisms are difficult to study in vivo. It was therefore desirable to develop an in vitro model that would resemble training in cultured human myotubes. METHODS: Electrical pulse stimulation (EPS was applied to adherent human myotubes. Cellular contents of ATP, phosphocreatine (PCr and lactate were determined. Glucose and oleic acid metabolism were studied using radio-labeled substrates, and gene expression was analyzed using real-time RT-PCR. Mitochondrial content and function were measured by live imaging and determination of citrate synthase activity, respectively. Protein expression was assessed by electrophoresis and immunoblotting. RESULTS: High-frequency, acute EPS increased deoxyglucose uptake and lactate production, while cell contents of both ATP and PCr decreased. Chronic, low-frequency EPS increased oxidative capacity of cultured myotubes by increasing glucose metabolism (uptake and oxidation and complete fatty acid oxidation. mRNA expression level of pyruvate dehydrogenase complex 4 (PDK4 was significantly increased in EPS-treated cells, while mRNA expressions of interleukin 6 (IL-6, cytochrome C and carnitin palmitoyl transferase b (CPT1b also tended to increase. Intensity of MitoTracker®Red FM was doubled after 48 h of chronic, low-frequency EPS. Protein expression of a slow fiber type marker (MHCI was increased in EPS-treated cells. CONCLUSIONS: Our results imply that in vitro EPS (acute, high-frequent as well as chronic, low-frequent of human myotubes may be used to study effects of exercise.

  6. EFFECTS OF THE FRUCTOOLIGOSACCHARIDES (FOS AND INULIN ON BONE METABOLISM OF THE SKELETALLY MATURE FEMALE RATS

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    Claudia Cardoso NETTO

    2012-12-01

    Full Text Available The aim of this study was establish if the fructooligosaccharides (FOS and inulin alone or together attenuate age related bone loss in skeletally mature female rats. Forty 10-month old female rats were randomly assigned to four diet groups for 2 months: control, FOS, inulin and FOS + inulin. Bone mineral density (BMD using dualenergy X-ray absorptiometry (DXA, femur quality using morphometry and biomechanic properties, biochemical assays by the determination of serum parathyroid hormone (PTH, alkaline phosphatase activity (ALP, degradation products of C-terminal peptides of type I collagen (CTX-I, osteocalcin (OC, osteoprotegerin (OPG and nuclear factor κappa B ligand (RANk-L. The FOS increased hip axis BMD (0.255 ± 0.005 g/cm2 and femur neck width (2.19 ± 0.01 mm and reduced PTH (4.0 x 10-3 ± 0.0006 µg/L, FOS + inulin increased the femur proportional limit (87.2 ± 1.0 N and reduced PTH (2.5 x 10-3 ± 0.0006 µg/L and ALP (23.2 ± 5.1 U/L, all the prebiotics reduced OPG (FOS = 1.1 ± 0.3, inulin = 1.1 ± 0.3, FOS + inulin = 1.4 ± 0.4 µg/L and RANk-L (FOS = 1.65 x 10-2 ± 0.003, inulin = 1.78 x 10-2 ± 0.003, FOS + inulin = 2.83 x 10-2 ± 0.006 µg/L , no prebiotics changed OC and CTX-I. The results suggested that the consumption of FOS or FOS + inulin may reduce the bone turnover, however, further studies about prebiotics and their synergistic effect on age related bone loss are required.

  7. The monoacylglycerol lipase inhibitor JZL184 decreases inflammatory response in skeletal muscle contusion in rats.

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    Jiang, Shu-Kun; Zhang, Miao; Tian, Zhi-Ling; Wang, Meng; Zhao, Rui; Wang, Lin-Lin; Li, Shan-Shan; Liu, Min; Li, Jiao-Yong; Zhang, Meng-Zhou; Guan, Da-Wei

    2015-08-15

    Muscle wound healing process is a typical inflammation-evoked event. The monoacylglycerol lipase (MAGL) inhibitor (4-nitrophenyl)4-[bis(1,3-benzodioxol -5-yl)-hydroxymethyl]piperidine-1-carboxylate (JZL184) has been previously reported to reduce inflammation in colitis and acute lung injury in mice, which provide a new strategy for primary care of skeletal muscle injury. We investigated the effect of JZL184 on inflammation in rat muscle contusion model, and found decreased neutrophil and macrophage infiltration and pro-inflammatory cytokine expression. With extension of post-traumatic interval, myofiber regeneration was significantly hindered with increased collagen types I and ІІІ mRNAfibroblast infiltration as well as promoted fibrosis. Furthermore, 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-morpholin-4-ylpyrazole-3-carboxamide (AM281, a selective cannabinoid CB1 receptor antagonist) and [6-iodo-2-methyl-1-(2-morpholin-4-ylethyl)indol-3-yl]-(4-methoxyphenyl)methanone (AM630, a selective cannabinoid CB2 receptor antagonist) treatment alleviated the anti-inflammatory effect of JZL184. Our findings demonstrate that JZL184 is able to inhibit the inflammatory response and interfere with contused muscle healing, in which the anti-inflammatory action may be mediated through cannabinoid CB1 and CB2 receptors.

  8. The effect of acute denervation on the microcirculation of skeletal muscle: rat cremaster model.

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    Chen, L E; Seaber, A V; Bossen, E; Urbaniak, J R

    1991-03-01

    Although tissue is denervated during replantation of a severed part, tissue transfer, or muscle transplantation, there are few studies concerning the effects of acute denervation on muscle microcirculation. We have described a surgical procedure that totally denervates the rat cremaster muscle. Histological examination of the denervated tissue has given convincing evidence of nerve degeneration and skeletal muscle atrophy, accompanied by electrophysiological evidence of total denervation. The diameters of each component of the microcirculation were measured before and after denervation. Arterioles and arteries ranging in size from 10 to 70 microns in diameter were found to increase significantly in size immediately after acute denervation. Larger arteries and veins did not undergo significant diametrical increases. These findings suggest that total acute denervation significantly increases the diameter of small arteries and arterioles, thereby decreasing the resistance in the arterial bed and increasing blood flow. Since this phenomenon is of limited duration (20 min), it would appear to be ineffective in enhancing reperfusion and oxygenation at the time of reattachment of amputated parts or during vascularized tissue transfers, until methods of prolonging it for several hours or more are found.

  9. Amylin evokes protein p20 phosphorylation and insulin resistance in rat skeletal muscle extensor digitorum longus

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In the present study, we investigate effect of amylin on the insulin sensitivity of rat skeletal muscle extensor digitorum longus (EDL) using in vitro intact muscle incubation in combination with metabolic radioactive labeling. The molecular basis of the amylin action was further examined using proteomic analysis. In particular, proteins of interest were characterized using an integrated microcharacterization procedure that involved in-gel trypsin digestion, organic solvent extraction, high performance liquid chromatography separation, microsequencing and microsequence analysis. We found that amylin significantly decreased the insulin-stimulated glucose incorporation into glycogen (p < 0.01) and produced a protein spot of approximately 20 ku in size. This amylin responsive protein (hereby designated as amylin responsive protein 1, APR1) was identified to be protein p20. Moreover, ARP1 spots on gels were found to consistently produce a corresponding radioactive spot on X-ray films in 32Pi but not in 35S-methionine labeling experiments. In conclusion, our results showed that in vitro amylin concomitantly evoked the production of ARP1 and caused insulin resistance in EDL muscle. It is suggested that protein p20 may be involved in amylin signal transduction and the appearance of ARP1 may be a step in a molecular pathway leading to the development of insulin resistance. ARP1 might therefore be a useful molecular marker for amylin action, insulin resistance and Type 2 diabetes.

  10. Hsp25 and Hsp72 content in rat skeletal muscle following controlled shortening and lengthening contractions.

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    Holwerda, Andrew M; Locke, Marius

    2014-12-01

    The cytoprotective proteins, Hsp25 and Hsp72, are increased in skeletal muscle after nondamaging, shortening contractions, but the temporal pattern of expression and stimulatory mechanisms remain unclear. Thus, we sought to define the in vivo temporal patterns of expression for Hsp25 and Hsp72 after 2 opposing contractions types. To do this, male Sprague-Dawley rats had 1 tibialis anterior (TA) muscle electrically stimulated (5 sets of 20 repetitions) while being either forcibly lengthened (LC) or shortened (SC). At 2, 8, 24, 48, 72, or 168 h after the contractions both the stimulated and the nonstimulated (contra-lateral control) TA muscles were removed and processed to examine muscle damage (hemotoxylin and eosin staining) and Hsp content (Western blot analyses). Cross-sections from TA muscles subjected to LCs showed muscle fibre damage at 8 h and thereafter. In contrast, no muscle fibre damage was observed at any time point following SCs. When normalized to contra-lateral controls, Hsp25 and Hsp72 content were significantly (P < 0.01) increased at 24 h (3.1- and 3.8-fold, respectively) and thereafter. There were no significant increases in Hsp25 or Hsp72 content at any time point following SC. These data suggest that LCs, but not SCs, result in Hsp accumulation and that the fibre/cellular damage sustained from LCs may be the stimulus for elevating Hsp content.

  11. AMP deaminase histochemical activity and immunofluorescent isozyme localization in rat skeletal muscle

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    Thompson, J. L.; Sabina, R. L.; Ogasawara, N.; Riley, D. A.

    1992-01-01

    The cellular distribution of AMP deaminase (AMPda) isozymes was documented for rat soleus and plantaris muscles, utilizing immunofluorescence microscopy and immunoprecipitation methods. AMPda is a ubiquitous enzyme existing as three distinct isozymes, A, B and C, which were initially purified from skeletal muscle, liver (and kidney), and heart, respectively. AMPda-A is primarily concentrated subsarcolemmally and intermyofibrillarly within muscle cells, while isozymes B and C are concentrated within non-myofiber elements of muscle tissue. AMPda-B is principally associated with connective tissues surrounding neural elements and the muscle spindle capsule, and AMPda-C is predominantly associated with circulatory elements, such as arterial and venous walls, capillary endothelium, and red blood cells. These specific localizations, combined with documented differences in kinetic properties, suggest multiple functional roles for the AMPda isozymes or temporal segregation of similar AMPda functions. Linkage of the AMPda substrate with adenosine production pathways at the AMP level and the localization of isozyme-C in vascular tissue suggest a regulatory role in the microcirculation.

  12. Effect of Salvia leriifolia Benth. root extracts on ischemia-reperfusion in rat skeletal muscle

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    Nassiri-Asl Marjan

    2007-07-01

    Full Text Available Abstract Background Salvia leriifolia have been shown to decrease ischemia-reperfusion (I/R injury in brain tissues. In this study, the effects of S. leriifolia aqueous and ethanolic extracts were evaluated on an animal model of I/R injury in the rat hind limb. Methods Ischemia was induced using free-flap surgery in skeletal muscle. The aqueous and ethanolic extracts of S. leriifolia (100, 200 and 400 mg/kg root and normal saline (10 ml/kg were administered intraperitoneally 1 h prior reperfusion. During preischemia, ischemia and reperfusion conditions the electromyographic (EMG potentials in the muscles were recorded. The markers of oxidative stress including thiobarbituric acid reactive substances (TBARS, total sulfhydryl (SH groups and antioxidant capacity of muscle (using FRAP assay were measured. Results In peripheral ischemia, the average peak-to-peak amplitude during ischemic-reperfusion was found to be significantly larger in extracts groups in comparison with control group. Following extracts administration, the total SH contents and antioxidant capacity were elevated in muscle flap. The MDA level was also declined significantly in test groups. Conclusion It is concluded that S. leriifolia root extracts have some protective effects on different markers of oxidative damage in muscle tissue injury caused by lower limb ischemia-reperfusion.

  13. Lesions of rat skeletal muscle after local block of acetylcholinesterase and neuromuscular stimulation.

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    Mense, S; Simons, D G; Hoheisel, U; Quenzer, B

    2003-06-01

    In skeletal muscle, a local increase of acetylcholine (ACh) in a few end plates has been hypothesized to cause the formation of contraction knots that can be found in myofascial trigger points. To test this hypothesis in rats, small amounts of an acetylcholinesterase inhibitor [diisopropylfluorophosphate (DFP)] were injected into the proximal half of the gastrocnemius muscle, and the muscle nerve was electrically stimulated for 30-60 min for induction of muscle twitches. The distal half of the muscle, which performed the same contractions, served as a control to assess the effects of the twitches without DFP. Sections of the muscle were evaluated for morphological changes in relation to the location of blocked end plates. Compared with the distal half of the muscle, the DFP-injected proximal half exhibited significantly higher numbers of abnormally contracted fibers (local contractures), torn fibers, and longitudinal stripes. DFP-injected animals in which the muscle nerve was not stimulated and that were allowed to survive for 24 h exhibited the same lesions but in smaller numbers. The data indicate that an increased concentration of ACh in a few end plates causes damage to muscle fibers. The results support the assumption that a dysfunctional end plate exhibiting increased release of ACh may be the starting point for regional abnormal contractions, which are thought to be essential for the formation of myofascial trigger points.

  14. Effect of ammodytin L from Vipera ammodytes on L-6 cells from rat skeletal muscle.

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    Incerpi, S; de Vito, P; Luly, P; Rufini, S

    1995-08-31

    Ammodytin L (AMDL) is a myotoxic phospholipase-like protein from the venom of Vipera ammodytes with a serine in position 49 instead of an aspartate, therefore this toxin is devoid of phospholipase activity, and the membrane-damaging effect does not involve any step of phospholipase activity. The aim of the present study was to analyze the effect of AMDL on L-6 cells from rat skeletal muscle to investigate its mechanism of action and the role of calcium ions in its muscle-damaging activity. Our data indicate that the effect of ammodytin L is strongly dependent on the degree of cell differentiation. Low doses of myotoxin gave rise to a marked release of creatine kinase in myotubes differentiated from L-6 myoblasts and the presence of calcium ions plays a role in the cytotoxic effect. The presence of EGTA in the incubation buffer reduced by 50% the release of creatine kinase. No membrane damage was observed in myoblasts, but there was a significant increase of intracellular calcium concentration measured with Fura-2. A non-specific membrane effect of AMDL was ruled out using platelets as reference cells: no platelet aggregation pattern and no increase in intracellular calcium were observed.

  15. Glutamine supplementation stimulates protein-synthetic and inhibits protein-degradative signaling pathways in skeletal muscle of diabetic rats.

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    Adriana C Lambertucci

    Full Text Available In this study, we investigated the effect of glutamine (Gln supplementation on the signaling pathways regulating protein synthesis and protein degradation in the skeletal muscle of rats with streptozotocin (STZ-induced diabetes. The expression levels of key regulatory proteins in the synthetic pathways (Akt, mTOR, GSK3 and 4E-BP1 and the degradation pathways (MuRF-1 and MAFbx were determined using real-time PCR and Western blotting in four groups of male Wistar rats; 1 control, non-supplemented with glutamine; 2 control, supplemented with glutamine; 3 diabetic, non-supplemented with glutamine; and 4 diabetic, supplemented with glutamine. Diabetes was induced by the intravenous injection of 65 mg/kg bw STZ in citrate buffer (pH 4.2; the non-diabetic controls received only citrate buffer. After 48 hours, diabetes was confirmed in the STZ-treated animals by the determination of blood glucose levels above 200 mg/dL. Starting on that day, a solution of 1 g/kg bw Gln in phosphate buffered saline (PBS was administered daily via gavage for 15 days to groups 2 and 4. Groups 1 and 3 received only PBS for the same duration. The rats were euthanized, and the soleus muscles were removed and homogenized in extraction buffer for the subsequent measurement of protein and mRNA levels. The results demonstrated a significant decrease in the muscle Gln content in the diabetic rats, and this level increased toward the control value in the diabetic rats receiving Gln. In addition, the diabetic rats exhibited a reduced mRNA expression of regulatory proteins in the protein synthesis pathway and increased expression of those associated with protein degradation. A reduction in the skeletal muscle mass in the diabetic rats was observed and was alleviated partially with Gln supplementation. The data suggest that glutamine supplementation is potentially useful for slowing the progression of muscle atrophy in patients with diabetes.

  16. Oral Rg1 supplementation strengthens antioxidant defense system against exercise-induced oxidative stress in rat skeletal muscles

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    Yu Szu-Hsien

    2012-05-01

    Full Text Available Abstract Background Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1 on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress. Methods Forty weight-matched rats were evenly divided into control (N = 20 and Rg1 (N = 20 groups. Rg1 was orally administered at the dose of 0.1 mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA muscles were surgically collected immediately after exercise along with non-exercise rats. Results Exhaustive exercise significantly (p Conclusions This study provide compelling evidences that Rg1 supplementation can strengthen antioxidant defense system in skeletal muscle and completely attenuate the membrane lipid peroxidation induced by exhaustive exercise. Our findings suggest that Rg1 can use as a nutraceutical supplement to buffer the exhaustive exercise-induced oxidative stress.

  17. Effect of resistance exercise training on expression of Hsp70 and inflammatory cytokines in skeletal muscle and adipose tissue of STZ-induced diabetic rats.

    Science.gov (United States)

    Molanouri Shamsi, M; Mahdavi, M; Quinn, L S; Gharakhanlou, R; Isanegad, A

    2016-09-01

    Impairment of adipose tissue and skeletal muscles accrued following type 1 diabetes is associated with protein misfolding and loss of adipose mass and skeletal muscle atrophy. Resistance training can maintain muscle mass by changing both inflammatory cytokines and stress factors in adipose tissue and skeletal muscle. The purpose of this study was to determine the effects of a 5-week ladder climbing resistance training program on the expression of Hsp70 and inflammatory cytokines in adipose tissue and fast-twitch flexor hallucis longus (FHL) and slow-twitch soleus muscles in healthy and streptozotocin-induced diabetic rats. Induction of diabetes reduced body mass, while resistance training preserved FHL muscle weight in diabetic rats without any changes in body mass. Diabetes increased Hsp70 protein content in skeletal muscles, adipose tissue, and serum. Hsp70 protein levels were decreased in normal and diabetic rats by resistance training in the FHL, but not soleus muscle. Furthermore, resistance training decreased inflammatory cytokines in FHL skeletal muscle. On the other hand, Hsp70 and inflammatory cytokine protein levels were increased by training in adipose tissue. Also, significant positive correlations between inflammatory cytokines in adipose tissue and skeletal muscles with Hsp70 protein levels were observed. In conclusion, we found that in diabetic rats, resistance training decreased inflammatory cytokines and Hsp70 protein levels in fast skeletal muscle, increased adipose tissue inflammatory cytokines and Hsp70, and preserved FHL muscle mass. These results suggest that resistance training can maintain skeletal muscle mass in diabetes by changing inflammatory cytokines and stress factors such as Hsp70 in skeletal muscle and adipose tissue.

  18. Effect of ascorbic acid on fatigue of skeletal muscle fibres in long-term cold exposed Sprague Dawley rats.

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    Rashid, Aneeqa; Khan, Umar Ali; Ayub, Muhammad

    2011-01-01

    On exposure to prolonged cold temperature, the body responds for effective heat production both by shivering and non-shivering thermogenesis. Cold exposure increases the production of reactive oxygen species which influence the sarcoplasmic reticulum Ca++ release from the skeletal muscles and affect their contractile properties. The role of ascorbic acid supplementation on force of contraction during fatigue of cold exposed skeletal muscles was evaluated in this study. Ninety healthy, male Sprague Dawley rats were randomly divided into three groups of control (I), cold exposed (II), and cold exposed with ascorbic acid 500 mg/L supplementation mixed in drinking water (III). Group II and III were given cold exposure by keeping their cages in ice-filled tubs for 1 hr/day for one month. After one month, the extensor digitorum longus muscle was dissected out and force of contraction during fatigue in the skeletal muscle fibres was analysed on a computerised data acquisition system. The cold exposed group showed a significant delay in the force of contraction during fatigue of skeletal muscle fibres compared to control group. Group III showed easy fatigability and a better force of contraction than the cold exposed group. Ascorbic acid increases the force of contraction and decreases resistance to fatigue in the muscles exposed to chronic cold.

  19. Effects of alprostadil and iloprost on renal, lung, and skeletal muscle injury following hindlimb ischemia-reperfusion injury in rats.

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    Erer, Dilek; Özer, Abdullah; Demirtaş, Hüseyin; Gönül, İpek Işık; Kara, Halil; Arpacı, Hande; Çomu, Faruk Metin; Oktar, Gürsel Levent; Arslan, Mustafa; Küçük, Ayşegül

    2016-01-01

    To evaluate the effects of alprostadil (prostaglandin [PGE1] analog) and iloprost (prostacyclin [PGI2] analog) on renal, lung, and skeletal muscle tissues after ischemia reperfusion (I/R) injury in an experimental rat model. Wistar albino rats underwent 2 hours of ischemia via infrarenal aorta clamping with subsequent 2 hours of reperfusion. Alprostadil and iloprost were given starting simultaneously with the reperfusion period. Effects of agents on renal, lung, and skeletal muscle (gastrocnemius) tissue specimens were examined. Renal medullary congestion, cytoplasmic swelling, and mean tubular dilatation scores were significantly lower in the alprostadil-treated group than those found in the I/R-only group (Piloprost-treated groups (P=0.017 and P=0.001; Piloprost-treated group than the scores found in the nontreated I/R group (Piloprost significantly reduce lung tissue I/R injury. Alprostadil has more prominent protective effects against renal I/R injury, while iloprost is superior in terms of protecting the skeletal muscle tissue against I/R injury.

  20. Effects of alprostadil and iloprost on renal, lung, and skeletal muscle injury following hindlimb ischemia–reperfusion injury in rats

    Science.gov (United States)

    Erer, Dilek; Özer, Abdullah; Demirtaş, Hüseyin; Gönül, İpek Işık; Kara, Halil; Arpacı, Hande; Çomu, Faruk Metin; Oktar, Gürsel Levent; Arslan, Mustafa; Küçük, Ayşegül

    2016-01-01

    Objectives To evaluate the effects of alprostadil (prostaglandin [PGE1] analog) and iloprost (prostacyclin [PGI2] analog) on renal, lung, and skeletal muscle tissues after ischemia reperfusion (I/R) injury in an experimental rat model. Materials and methods Wistar albino rats underwent 2 hours of ischemia via infrarenal aorta clamping with subsequent 2 hours of reperfusion. Alprostadil and iloprost were given starting simultaneously with the reperfusion period. Effects of agents on renal, lung, and skeletal muscle (gastrocnemius) tissue specimens were examined. Results Renal medullary congestion, cytoplasmic swelling, and mean tubular dilatation scores were significantly lower in the alprostadil-treated group than those found in the I/R-only group (Palprostadil- and iloprost-treated groups (P=0.017 and P=0.001; PAlprostadil and iloprost significantly reduce lung tissue I/R injury. Alprostadil has more prominent protective effects against renal I/R injury, while iloprost is superior in terms of protecting the skeletal muscle tissue against I/R injury. PMID:27601882

  1. Production of compartmented cultures of rat sympathetic neurons.

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    Campenot, Robert B; Lund, Karen; Mok, Sue-Ann

    2009-01-01

    The compartmented culture, in which primary neurons plated in a proximal compartment send their axons under silicone grease barriers and into left and right distal compartments, has enhanced the experimental capabilities of neuronal cultures. Treatments can be applied separately to cell bodies/proximal axons or distal axons, and cell bodies/proximal axons and distal axons can be separately harvested and analyzed. Distal axons can be axotomized, and the neurons can be studied while their axons regenerate. Construction of the culture dishes requires 3 h for 48 cultures, and preparing the neurons also requires 3 h. Compartmented cultures provide enough cellular material for biochemical analyses such as immunoblotting. The uses of compartmented cultures have included studies of neurotrophic factor retrograde signaling, axonal transport, and axonal protein and lipid biosynthesis. Here we focus on sympathetic neurons cultured from neonatal rats and provide protocols for the production and some of the uses of compartmented cultures.

  2. Time course of training-induced microcirculatory changes and of vegf expression in skeletal muscles of spontaneously hypertensive female rats

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    S.L. Amaral

    2008-05-01

    Full Text Available Exercise-induced vessel changes modulate arterial pressure (AP in male spontaneously hypertensive rats (SHR. Vascular endothelial growth factor (VEGF is important for angiogenesis of skeletal muscle. The present study evaluated the time course of VEGF and angiogenesis after short- and long-term exercise training of female SHR and Wistar Kyoto (WKY rats, 8-9 weeks (200-250 g. Rats were allocated to daily training or remained sedentary for 3 days (N = 23 or 13 weeks (N = 23. After training, the carotid artery was catheterized for AP measurements. Locomotor (tibialis anterior and gracilis and non-locomotor skeletal muscles (temporalis were harvested and prepared for histologic and protein expression analyses. Training increased treadmill performance by all groups (SHR = 28%, WKY = 64%, 3 days and (SHR = 141%, WKY = 122%, 13 weeks. SHR had higher values of AP than WKY (174 ± 4 vs 111 ± 2 mmHg that were not altered by training. Three days of running increased VEGF expression (SHR = 28%, WKY = 36% simultaneously with an increase in capillary-to-fiber ratio in gracilis muscle (SHR = 19%, WKY = 15%. In contrast, 13 weeks of training increased gracilis capillary-to-fiber ratio (SHR = 18%, WKY = 19%, without simultaneous changes in VEGF expression. Training did not change VEGF expression and capillarity of temporalis muscle. We conclude that training stimulates time- and tissue-dependent VEGF protein expression, independent of pressure levels. VEGF triggers angiogenesis in locomotor skeletal muscle shortly after the exercise starts, but is not involved in the maintenance of capillarity after long-term exercise in female rats.

  3. Effect of beta-ADrenergic Agonist on Cyclic AMP Synthesis in Chicken Skeletal Muscle Cells in Culture

    Science.gov (United States)

    Young, R. B.; Bridge, K. Y.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Several beta-adrenergic receptor (bAR) agonists are known to cause hypertrophy of skeletal muscle tissue. Because it seems logical that these agonists exert their action on muscle through stimulation of cAMP synthesis, five bAR agonists encompassing a range in activity from strong to weak were evaluated for their ability to stimulate cAMP accumulation in embryonic chicken skeletal muscle cells in culture. Two strong agonists (epinephrine and isoproterenol), one moderate agonist (albuterol), and two weak agonists known to cause hypertrophy in animals (clenbuterol and cimaterol) were studied. Dose response curves were determined over six orders of magnitude in concentration for each agonist, and values were determined for their maximum stimulation of cAMP synthesis rate (Bmax) and the agonist concentration at which 50% stimulation of cAMP synthesis (EC50) occurred. Bmax values decreased in the following order: isoproterenol, epinephrine, albuterol, cimaterol, clenbuterol. Cimaterol and clenbuterol at their Bmax levels were approximately 15-fold weaker than isoproterenol in stimulating the rate of cAMP synthesis. In addition, the EC50 values for isoproterenol, cimaterol, clenbuterol, epinephrine, and albuterol were 360 nM, 630 nM, 900 nM, 2,470 nM, and 3,650 nM, respectively. Finally, dose response curves show that the concentrations of cimaterol and clenbuterol in culture media at concentrations known to cause significant muscle hypertrophy in animals had no detectable effect on stimulation of CAMP accumulation in chicken skeletal muscle cells.

  4. Iron deficiency causes a shift in AMP-activated protein kinase (AMPK subunit composition in rat skeletal muscle

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    Merrill John F

    2012-11-01

    Full Text Available Abstract Background As a cellular energy sensor, the 5’AMP-activated protein kinase (AMPK is activated in response to energy stresses such as hypoxia and muscle contraction. To determine effects of iron deficiency on AMPK activation and signaling, as well as the AMPK subunit composition in skeletal muscle, rats were fed a control (C=50-58 mg/kg Fe or iron deficient (ID=2-6 mg/kg Fe diet for 6–8 wks. Results Their respective hematocrits were 47.5% ± 1.0 and 16.5% ± 0.6. Iron deficiency resulted in 28.3% greater muscle fatigue (p Conclusions This study indicates that chronic iron deficiency causes a shift in the expression of AMPKα, β, and γ subunit composition. Iron deficiency also causes chronic activation of AMPK as well as an increase in AMPKα1 activity in exercised skeletal muscle.

  5. AMP-activated protein kinase activates transcription of the UCP3 and HKII genes in rat skeletal muscle.

    Science.gov (United States)

    Stoppani, James; Hildebrandt, Audrey L; Sakamoto, Kei; Cameron-Smith, David; Goodyear, Laurie J; Neufer, P Darrell

    2002-12-01

    AMP-activated protein kinase (AMPK) has recently emerged as a key signaling protein in skeletal muscle, coordinating the activation of both glucose and fatty acid metabolism in response to increased cellular energy demand. To determine whether AMPK signaling may also regulate gene transcription in muscle, rats were given a single subcutaneous injection (1 mg/g) of the AMP analog 5-aminoimidazole-4-carboxamide-1-beta-d-ribonucleoside (AICAR). AICAR injection activated (P < 0.05) AMPK-alpha 2 ( approximately 2.5-fold) and transcription of the uncoupling protein-3 (UCP3, approximately 4-fold) and hexokinase II (HKII, approximately 10-fold) genes in both red and white skeletal muscle. However, AICAR injection also elicited (P < 0.05) an acute drop (60%) in blood glucose and a sustained (2-h) increase in blood lactate, prompting concern regarding the specificity of AICAR on transcription. To maximize AMPK activation in muscle while minimizing potential systemic counterregulatory responses, a single-leg arterial infusion technique was employed in fully conscious rats. Relative to saline-infused controls, single-leg arterial infusion of AICAR (0.125, 0.5, and 2.5 micro g. g(-1). min(-1) for 60 min) induced a dose-dependent increase (2- to 4-fold, P < 0.05) in UCP3 and HKII transcription in both red and white skeletal muscle. Importantly, AICAR infusion activated transcription only in muscle from the infused leg and had no effect on blood glucose or lactate levels. These data provide evidence that AMPK signaling is linked to the transcriptional regulation of select metabolic genes in skeletal muscle.

  6. Imaging of human sodium-iodide symporter gene expression mediated by recombinant adenovirus in skeletal muscle of living rats

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hyun Suk; Park, Seong-Wook [Department of Internal Medicine (Cardiology), Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, 138-736, Seoul (Korea); Lee, Heuiran; Kim, Sung Jin [Department of Microbiology, University of Ulsan College of Medicine, Seoul (Korea); Lee, Won Woo [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seongnam (Korea); Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea); Yang, You-Jung; Moon, Dae Hyuk [Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea)

    2004-09-01

    We evaluated the feasibility of non-invasive imaging of recombinant adenovirus-mediated human sodium-iodide symporter (hNIS) gene expression by {sup 99m}TcO{sub 4}{sup -} scintigraphy in skeletal muscle of rats. Replication-defective recombinant adenovirus encoding hNIS gene [Rad-CMV-hNIS 5 x 10{sup 7}, 2 x 10{sup 8} or 1 x 10{sup 9} plaque forming units (pfu)] or {beta}-galactosidase gene (Rad-CMV-LacZ 1 x 10{sup 9} pfu) was injected into the right biceps femoris muscle of rats (n=5-6 for each group). Three days after gene transfer, scintigraphy was performed using a gamma camera 30 min after injection of {sup 99m}TcO{sub 4}{sup -} (1.85 MBq). An additional two rats injected with 1 x 10{sup 9} pfu of Rad-CMV-hNIS underwent {sup 99m}TcO{sub 4}{sup -} scintigraphy with sodium perchlorate. After the imaging studies, rats were sacrificed for assessment of the biodistribution of {sup 99m}TcO{sub 4}{sup -} and measurement of hNIS mRNA expression. In all the rats injected with 1 x 10{sup 9} pfu of Rad-CMV-hNIS, hNIS expression was successfully imaged by {sup 99m}TcO{sub 4}{sup -} scintigraphy, while rats injected with Rad-CMV-LacZ or lower doses of Rad-CMV-hNIS failed to show uptake. The biodistribution studies indicated that a significantly different amount of {sup 99m}TcO{sub 4}{sup -} was retained in the liver (p<0.001) and the right muscle (p<0.05), with the highest uptake in rats injected with 1 x 10{sup 9} pfu of Rad-CMV-hNIS. The muscular hNIS mRNA level quantified by real-time reverse transcription-polymerase chain reaction was significantly higher in rats injected with 1 x 10{sup 9} pfu of Rad-CMV-hNIS (p<0.05), with a positive correlation with the imaging counts (r=0.810, p<0.05) and the biodistribution (r=0.847, p<0.001). Hot spots in rats injected with 1 x 10{sup 9} pfu of Rad-CMV-hNIS were specifically inhibited by sodium perchlorate. This study illustrated that {sup 99m}TcO{sub 4}{sup -} scintigraphy can monitor Rad-CMV-hNIS-mediated gene expression in

  7. Modified methods for culturing myoblasts of rats: Combination of multi-enzymatic digestion and double purification

    Institute of Scientific and Technical Information of China (English)

    Li Zhang; Wei Wang; Ming Fan; Xiaoping Chen; Shuhong Liu; Liang Sun

    2007-01-01

    BACKGROUND: With developments of tissue engineering and genetic engineering, we aim to culture myoblasts, which are characterized by high purity, high quality and high production, for wide application in neural regeneration researches.OBJECTIVE: To modify traditional dissociation method in order to obtain myoblasts, which are characterized by high purity, high quality and high production, and explore the biological properties under in vitro culture.DESIGN: Observational study.SETTING: Basic Institute of Academy of Military Medical Sciences of Chinese PLA.MATERIALS: Four neonatal Wistar rats of 5 days old, both genders and mean body mass of 10 g were selected in this study. The main reagents and devices were detailed as follows: DMEM medium (Gibco Company), fetus bovine serum (FBS, Hycolne Company), collagenase Ⅱ (Sigma Company), trypsin (Sigma Company), dispase Ⅱ (Sigma Company), desmin antibody (Fuzhou Maixin Company), antibody Ⅱ and ABC kit (Wuhan Boster Biotechnology Company), desk centrifuge (KUBATO, Japan), and inverted phase contrast microscope (LEICA DMIRB, Germany).METHODS: The experiment was carried out in the Basic Institute of Academy of Military Medical Sciences of Chinese PLA from June to October 2006. Neonatal rats were sacrificed under sterile condition to obtain skeletal muscles of limbs, which were washed with cold PBS (containing benzylpenicillin and estreptomicina), and muscular tissue was sheared into pieces. Then, those muscular pieces were added with mixed digestive enzyme (containing 2 g/L collagenase Ⅱ + 5 g/L dispase Ⅱ + 0.28 g/L CaCl2) as twice volume as pieces, dealt with mechanical pipetting for 5 minutes and cultured in CO2 incubator for 10 minutes.The operation was done for three times and the muscular pieces were digested for 45 minutes in total.Moreover, cells were suspended again in order to obtain myoblasts from skeletal muscle of neonatal rats. In addition, myoblasts were purified with differential attachment technique

  8. Effects of different fatty acid chain lengths on fatty acid oxidation-related protein expression levels in rat skeletal muscles.

    Science.gov (United States)

    Ishizawa, Rie; Masuda, Kazumi; Sakata, Susumu; Nakatani, Akira

    2015-01-01

    Skeletal muscles can adapt to dietary interventions that affect energy metabolism. Dietary intake of medium-chain fatty acids (MCFAs) enhances mitochondrial oxidation of fatty acids (FAO) in type IIa skeletal muscle fibers. However, the effect of MCFAs diet on mitochondrial or cytoplasmic FAO-related protein expression levels in different types of muscle fibers remains unclear. This study aims to examine the effects of a high-fat diet, containing MCFAs, on mitochondrial enzyme activities and heart-type fatty acid-binding protein (H-FABP) levels in different types of skeletal muscle fibers. Five-week-old male Wistar rats were assigned to one of the following three dietary conditions: standard chow (SC, 12% of calories from fat), high-fat MCFA, or high-fat long-chain fatty acids (LCFAs) diet (60% of calories from fat for both). The animals were provided food and water ad libitum for 4 weeks, following which citrate synthase (CS) activity and H-FABP concentration were analyzed. The epididymal fat pads (EFP) were significantly smaller in the MCFA group than in the LCFA group (p increase in CS activity compared with that observed in SC-fed controls in all types of skeletal muscle fibers (triceps, surface portion of gastrocnemius (gasS), deep portion of gastrocnemius (gasD), and soleus; p increase the expression of the mitochondrial enzyme CS, but not that of H-FABP, in both fast- and slow-twitch muscle fibers, suggesting that H-FABP expression is dependent on the chain length of fatty acids in the cytoplasm of skeletal muscles cells.

  9. Production of superoxide/H2O2 by dihydroorotate dehydrogenase in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Hey-Mogensen, Martin; Goncalves, Renata L S; Orr, Adam L; Brand, Martin D

    2014-07-01

    Dehydrogenases that use ubiquinone as an electron acceptor, including complex I of the respiratory chain, complex II, and glycerol-3-phosphate dehydrogenase, are known to be direct generators of superoxide and/or H2O2. Dihydroorotate dehydrogenase oxidizes dihydroorotate to orotate and reduces ubiquinone to ubiquinol during pyrimidine metabolism, but it is unclear whether it produces superoxide and/or H2O2 directly or does so only indirectly from other sites in the electron transport chain. Using mitochondria isolated from rat skeletal muscle we establish that dihydroorotate oxidation leads to superoxide/H2O2 production at a fairly high rate of about 300pmol H2O2·min(-1)·mg protein(-1) when oxidation of ubiquinol is prevented and complex II is uninhibited. This H2O2 production is abolished by brequinar or leflunomide, known inhibitors of dihydroorotate dehydrogenase. Eighty percent of this rate is indirect, originating from site IIF of complex II, because it can be prevented by malonate or atpenin A5, inhibitors of complex II. In the presence of inhibitors of all known sites of superoxide/H2O2 production (rotenone to inhibit sites in complex I (site IQ and, indirectly, site IF), myxothiazol to inhibit site IIIQo in complex III, and malonate plus atpenin A5 to inhibit site IIF in complex II), dihydroorotate dehydrogenase generates superoxide/H2O2, at a small but significant rate (23pmol H2O2·min(-1)·mg protein(-1)), from the ubiquinone-binding site. We conclude that dihydroorotate dehydrogenase can generate superoxide and/or H2O2 directly at low rates and is also capable of indirect production at higher rates from other sites through its ability to reduce the ubiquinone pool.

  10. PGC-1α mediates a rapid, exercise-induced downregulation of glycogenolysis in rat skeletal muscle.

    Science.gov (United States)

    Kim, Sang Hyun; Koh, Jin Ho; Higashida, Kazuhiko; Jung, Su Ryun; Holloszy, John O; Han, Dong-Ho

    2015-02-01

    Long-term endurance exercise training results in a reduction in the rates of muscle glycogen depletion and lactic acid accumulation during submaximal exercise; this adaptation is mediated by an increase in muscle mitochondria. There is evidence suggesting that short-term training induces adaptations that downregulate glycogenolysis before there is an increase in functional mitochondria. We discovered that a single long bout of exercise induces decreases in expression of glycogenolytic and glycolytic enzymes in rat skeletal muscle; this adaptation results in slower rates of glycogenolysis and lactic acid accumulation in muscle during contractile activity. Two additional days of training amplified the adaptive response, which appears to be mediated by PGC-1α; this adaptation is biologically significant, because glycogen depletion and lactic acid accumulation are major causes of muscle fatigue. Endurance exercise training can increase the ability to perform prolonged strenuous exercise. The major adaptation responsible for this increase in endurance is an increase in muscle mitochondria. This adaptation occurs too slowly to provide a survival advantage when there is a sudden change in environment that necessitates prolonged exercise. In the present study, we discovered another, more rapid adaptation, a downregulation of expression of the glycogenolytic and glycolytic enzymes in muscle that mediates a slowing of muscle glycogen depletion and lactic acid accumulation. This adaptation, which appears to be mediated by PGC-1α, occurs in response to a single exercise bout and is further enhanced by two additional daily exercise bouts. It is biologically significant, because glycogen depletion and lactic acid accumulation are two of the major causes of muscle fatigue and exhaustion. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

  11. Multiple causes of fatigue during shortening contractions in rat slow twitch skeletal muscle.

    Science.gov (United States)

    Hortemo, Kristin Halvorsen; Munkvik, Morten; Lunde, Per Kristian; Sejersted, Ole M

    2013-01-01

    Fatigue in muscles that shorten might have other causes than fatigue during isometric contractions, since both cross-bridge cycling and energy demand are different in the two exercise modes. While isometric contractions are extensively studied, the causes of fatigue in shortening contractions are poorly mapped. Here, we investigate fatigue mechanisms during shortening contractions in slow twitch skeletal muscle in near physiological conditions. Fatigue was induced in rat soleus muscles with maintained blood supply by in situ shortening contractions at 37°C. Muscles were stimulated repeatedly (1 s on/off at 30 Hz) for 15 min against a constant load, allowing the muscle to shorten and perform work. Fatigue and subsequent recovery was examined at 20 s, 100 s and 15 min exercise. The effects of prior exercise were investigated in a second exercise bout. Fatigue developed in three distinct phases. During the first 20 s the regulatory protein Myosin Light Chain-2 (slow isoform, MLC-2s) was rapidly dephosphorylated in parallel with reduced rate of force development and reduced shortening. In the second phase there was degradation of high-energy phosphates and accumulation of lactate, and these changes were related to slowing of muscle relengthening and relaxation, culminating at 100 s exercise. Slowing of relaxation was also associated with increased leak of calcium from the SR. During the third phase of exercise there was restoration of high-energy phosphates and elimination of lactate, and the slowing of relaxation disappeared, whereas dephosphorylation of MLC-2s and reduced shortening prevailed. Prior exercise improved relaxation parameters in a subsequent exercise bout, and we propose that this effect is a result of less accumulation of lactate due to more rapid onset of oxidative metabolism. The correlation between dephosphorylation of MLC-2s and reduced shortening was confirmed in various experimental settings, and we suggest MLC-2s as an important regulator of

  12. Multiple causes of fatigue during shortening contractions in rat slow twitch skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Kristin Halvorsen Hortemo

    Full Text Available Fatigue in muscles that shorten might have other causes than fatigue during isometric contractions, since both cross-bridge cycling and energy demand are different in the two exercise modes. While isometric contractions are extensively studied, the causes of fatigue in shortening contractions are poorly mapped. Here, we investigate fatigue mechanisms during shortening contractions in slow twitch skeletal muscle in near physiological conditions. Fatigue was induced in rat soleus muscles with maintained blood supply by in situ shortening contractions at 37°C. Muscles were stimulated repeatedly (1 s on/off at 30 Hz for 15 min against a constant load, allowing the muscle to shorten and perform work. Fatigue and subsequent recovery was examined at 20 s, 100 s and 15 min exercise. The effects of prior exercise were investigated in a second exercise bout. Fatigue developed in three distinct phases. During the first 20 s the regulatory protein Myosin Light Chain-2 (slow isoform, MLC-2s was rapidly dephosphorylated in parallel with reduced rate of force development and reduced shortening. In the second phase there was degradation of high-energy phosphates and accumulation of lactate, and these changes were related to slowing of muscle relengthening and relaxation, culminating at 100 s exercise. Slowing of relaxation was also associated with increased leak of calcium from the SR. During the third phase of exercise there was restoration of high-energy phosphates and elimination of lactate, and the slowing of relaxation disappeared, whereas dephosphorylation of MLC-2s and reduced shortening prevailed. Prior exercise improved relaxation parameters in a subsequent exercise bout, and we propose that this effect is a result of less accumulation of lactate due to more rapid onset of oxidative metabolism. The correlation between dephosphorylation of MLC-2s and reduced shortening was confirmed in various experimental settings, and we suggest MLC-2s as an

  13. Putative PPAR target genes express highly in skeletal muscle of insulin-resistant MetS model SHR/NDmc-cp rats.

    Science.gov (United States)

    Hariya, Natsuyo; Miyake, Kunio; Kubota, Takeo; Goda, Toshinao; Mochizuki, Kazuki

    2015-01-01

    It is known that insulin resistance in skeletal muscle induces subsequent metabolic diseases such as metabolic syndrome (MetS). However, which genes are altered in the skeletal muscle by development of insulin resistance in animal models has not been examined. In this study, we performed microarray and subsequent real-time RT-PCR analyses using total RNA extracted from the gastrocnemius muscle of the MetS model, spontaneously hypertensive corpulent congenic (SHR/NDmc-cp) rats, and control Wistar Kyoto (WKY) rats. SHR/NDmc-cp rats displayed overt insulin resistance relative to WKY rats. The expression of many genes related to fatty acid oxidation was higher in SHR/NDmc-cp rats than in WKY rats. Among 18 upregulated genes, putative peroxisome proliferator responsive elements were found in the upstream region of 15 genes. The protein expression of ACOX2, an upregulated gene, and peroxisome proliferator-activated receptor (PPAR) G1, but not of PPARG2, PPARA or PPARD, was higher in the gastrocnemius muscle of SHR/NDmc-cp rats than that in WKY rats. These results suggest that insulin resistance in the MetS model, SHR/NDmc-cp rats, is positively associated with the expression of fatty acid oxidation-related genes, which are presumably PPARs’ targets, in skeletal muscle.

  14. Contractile Properties of Esophageal Striated Muscle: Comparison with Cardiac and Skeletal Muscles in Rats

    Directory of Open Access Journals (Sweden)

    Takahiko Shiina

    2010-01-01

    Full Text Available The external muscle layer of the mammalian esophagus consists of striated muscles. We investigated the contractile properties of esophageal striated muscle by comparison with those of skeletal and cardiac muscles. Electrical field stimulation with single pulses evoked twitch-like contractile responses in esophageal muscle, similar to those in skeletal muscle in duration and similar to those in cardiac muscle in amplitude. The contractions of esophageal muscle were not affected by an inhibitor of gap junctions. Contractile responses induced by high potassium or caffeine in esophageal muscle were analogous to those in skeletal muscle. High-frequency stimulation induced a transient summation of contractions followed by sustained contractions with amplitudes similar to those of twitch-like contractions, although a large summation was observed in skeletal muscle. The results demonstrate that esophageal muscle has properties similar but not identical to those of skeletal muscle and that some specific properties may be beneficial for esophageal peristalsis.

  15. Effect of saponin treatment on the sarcoplasmic reticulum of rat, cane toad and crustacean (yabby) skeletal muscle.

    Science.gov (United States)

    Launikonis, B S; Stephenson, D G

    1997-10-15

    1. Mechanically skinned fibres from skeletal muscles of the rat, toad and yabby were used to investigate the effect of saponin treatment on sarcoplasmic reticulum (SR) Ca2+ loading properties. The SR was loaded submaximally under control conditions before and after treatment with saponin and SR Ca2+ was released with caffeine. 2. Treatment with 10 micrograms ml-1 saponin greatly reduced the SR Ca2+ loading ability of skinned fibres from the extensor digitorum longus muscle of the rat with a rate constant of 0.24 min-1. Saponin concentrations up to 150 micrograms ml-1 and increased exposure time up to 30 min did not further reduce the SR Ca2+ loading ability of the SR, which indicates that the inhibitory action of 10-150 micrograms ml-1 saponin is not dose dependent. The effect of saponin was also not dependent on the state of polarization of the transverse-tubular system. 3. Treatment with saponin at concentrations up to 100 micrograms ml-1 for 30 min did not affect the Ca2+ loading ability of SR in skinned skeletal muscle fibres from the twitch portion of the toad iliofibularis muscle but SR Ca2+ loading ability decreased markedly with a time constant of 0.22 min-1 in the presence of 150 micrograms ml-1 saponin. 4. The saponin dependent increase in permeability could be reversed in both rat and toad fibres by short treatment with 6 microM Ruthenium Red, a potent SR Ca2+ channel blocker, suggesting that saponin does affect the SR Ca2+ channel properties in mammalian and anuran skeletal muscle. 5. Treatment of skinned fibres of long sarcomere length (> 6 microns) from the claw muscle of the yabby (a freshwater decapod crustacean) with 10 micrograms ml-1 saponin for 30 min abolished the ability of the SR to load Ca2+, indicating that saponin affects differently the SR from skeletal muscles of mammals, anurans and crustaceans. 6. It is concluded that at relatively low concentrations, saponin causes inhibition of the skeletal SR Ca2+ loading ability in a species

  16. Effects of alprostadil and iloprost on renal, lung, and skeletal muscle injury following hindlimb ischemia–reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Erer D

    2016-08-01

    Full Text Available Dilek Erer,1,* Abdullah Özer,1,* Hüseyin Demirtaş,1 İpek Işık Gönül,2 Halil Kara,3 Hande Arpacı,4 Faruk Metin Çomu,5 Gürsel Levent Oktar,1 Mustafa Arslan,6 Ayşegül Küçük7 1Department of Cardiovascular Surgery, 2Department of Pathology, Gazi University Medical Faculty, 3Department of Pharmacology, Yıldırım Beyazıt University Medical Faculty, 4Department of Oral and Maxillofacial Surgery, Ankara University Faculty of Dentistry, Besevler, Ankara, 5Department of Physiology, Kırıkkale University Medical Faculty, Kırıkkale, 6Department of Anesthesiology and Reanimation, Gazi University Medical Faculty, Ankara, 7Department of Physiology, Dumlupınar University Medical Faculty, Kütahya, Turkey *These authors contributed equally to this work Objectives: To evaluate the effects of alprostadil (prostaglandin [PGE1] analog and iloprost (prostacyclin [PGI2] analog on renal, lung, and skeletal muscle tissues after ischemia reperfusion (I/R injury in an experimental rat model.Materials and methods: Wistar albino rats underwent 2 hours of ischemia via infrarenal aorta clamping with subsequent 2 hours of reperfusion. Alprostadil and iloprost were given starting simultaneously with the reperfusion period. Effects of agents on renal, lung, and skeletal muscle (gastrocnemius tissue specimens were examined.Results: Renal medullary congestion, cytoplasmic swelling, and mean tubular dilatation scores were significantly lower in the alprostadil-treated group than those found in the I/R-only group (P<0.0001, P=0.015, and P<0.01, respectively. Polymorphonuclear leukocyte infiltration, pulmonary partial destruction, consolidation, alveolar edema, and hemorrhage scores were significantly lower in alprostadil- and iloprost-treated groups (P=0.017 and P=0.001; P<0.01 and P<0.0001. Polymorphonuclear leukocyte infiltration scores in skeletal muscle tissue were significantly lower in the iloprost-treated group than the scores found in the nontreated I

  17. Diet- or warfarin-induced vitamin K insufficiency elevates circulating undercarboxylated osteocalcin without altering skeletal status in growing female rats.

    Science.gov (United States)

    Haffa, A; Krueger, D; Bruner, J; Engelke, J; Gundberg, C; Akhter, M; Binkley, N

    2000-05-01

    To further characterize the skeletal role of vitamin K (K), markers of bone turnover, density, and strength were evaluated in rats with diet- or warfarin (W)-induced K insufficiency. One hundred two, 7-week-old, female rats were randomly assigned to low K (phylloquinone [K1], 20 microg/kg diet), control K (K1, 1300 microg/kg diet), low-dose W (W, 1.5 mg/kg control diet), or high-dose W plus K (W/K1, 10/100 mg/kg diet). Femur bone mineral content (BMC) and bone mineral density (BMD), plasma prothrombin time (PT) and prothrombin concentration (PC), and serum total alkaline phosphatase (ALP) and skeletal alkaline phosphatase (sALP) were measured at baseline and days 20, 40, 60, and 80. Serum total osteocalcin (OC) and undercarboxylated osteocalcin (ucOC) and femur length (FL) were measured at baseline and day 80. Left femur OC was measured and biomechanical testing of the right femur and third lumbar vertebral body was performed at day 80. Low dietary K elevated circulating ucOC (17% higher than control; p diet manipulation. This does not hinder peak bone mass attainment in female rats; however, W causes less newly synthesized OC to be deposited in bone.

  18. Postinjury Exercise and Platelet-Rich Plasma Therapies Improve Skeletal Muscle Healing in Rats But Are Not Synergistic When Combined.

    Science.gov (United States)

    Contreras-Muñoz, Paola; Torrella, Joan Ramon; Serres, Xavier; Rizo-Roca, David; De la Varga, Meritxell; Viscor, Ginés; Martínez-Ibáñez, Vicente; Peiró, José Luis; Järvinen, Tero A H; Rodas, Gil; Marotta, Mario

    2017-07-01

    Skeletal muscle injuries are the most common sports-related injury and a major concern in sports medicine. The effect of platelet-rich plasma (PRP) injections on muscle healing is still poorly understood, and current data are inconclusive. To evaluate the effects of an ultrasound-guided intramuscular PRP injection, administered 24 hours after injury, and/or posttraumatic daily exercise training for 2 weeks on skeletal muscle healing in a recently established rat model of skeletal muscle injury that highly mimics the muscle trauma seen in human athletes. Controlled laboratory study. A total of 40 rats were assigned to 5 groups. Injured rats (medial gastrocnemius injury) received a single PRP injection (PRP group), daily exercise training (Exer group), or a combination of a single PRP injection and daily exercise training (PRP-Exer group). Untreated and intramuscular saline-injected animals were used as controls. Muscle force was determined 2 weeks after muscle injury, and muscles were harvested and evaluated by means of histological assessment and immunofluorescence microscopy. Both PRP (exhibiting 4.8-fold higher platelet concentration than whole blood) and exercise training improved muscle strength (maximum tetanus force, TetF) in approximately 18%, 20%, and 30% of rats in the PRP, PRP-Exer, and Exer groups, respectively. Specific markers of muscle regeneration (developmental myosin heavy chain, dMHC) and scar formation (collagen I) demonstrated the beneficial effect of the tested therapies in accelerating the muscle healing process in rats. PRP and exercise treatments stimulated the growth of newly formed regenerating muscle fibers (1.5-, 2-, and 2.5-fold increase in myofiber cross-sectional area in PRP, PRP-Exer, and Exer groups, respectively) and reduced scar formation in injured skeletal muscle (20%, 34%, and 41% of reduction in PRP, PRP-Exer, and Exer groups, respectively). Exercise-treated muscles (PRP-Exer and Exer groups) had significantly reduced

  19. Effects of ethanol on voltage-sensitive Na-channels in cultured skeletal muscle: Up-regulation as a result of chronic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Brodie, C.; Sampson, S.R. (Bar-Ilan Univ., Ramat-Gan (Israel))

    1990-12-01

    The effects of acute and chronic treatment with ethanol were studied on the number and activity of tetrodotoxin-sensitive Na-channels in cultured rat skeletal muscle. The number of channels was determined by measurements of specific binding of (3H) saxitoxin (STX) in whole cell preparations. Measurements were also made of the frequency and rate of rise of spontaneously occurring action potentials, which are the physiologic expression of Na-channel density. Acute ethanol (37.5-150 mM), while causing depolarization of membrane potential and blockade of electrical activity, was without effect on specific STX binding. Neither methanol, acetaldehyde nor ethylene glycol had significant effects on these properties when given acutely in the same concentrations as ethanol. Chronic ethanol caused dose-related increases in STX binding and action potential properties with maximal levels being attained after 3 days of treatment at a concentration of 150 mM. On removal of ethanol from the culture medium all properties returned to control levels after 48 hr. Both increased external K+ and tetrodotoxin, which up-regulate Na-channels by reducing cytosolic Ca++, potentiated the ethanol-induced increase in Na-channel density. The increase in STX binding was not associated with changes in affinity of the binding sites for the ligand but was completely prevented by treatment with cycloheximide and actinomycin D. The results demonstrate that ethanol interacts with the cell membrane to induce synthesis of STX-binding sites.

  20. Skeletal site-specific response to ovariectomy in a rat model: change in bone density and microarchitecture.

    Science.gov (United States)

    Liu, Xi Ling; Li, Chun Lei; Lu, Weijia William; Cai, Wei Xin; Zheng, Li Wu

    2015-04-01

    Ovariectomized (OVX) rat model has been widely used in osteoporosis-related studies. However, the discrepancies in age and skeletal sites being investigated make it difficult to compare the results from different studies. The purpose of this study was to provide information of systemic skeletal site-specific changes in a stable OVX rat model. Thirty-three 6-month Spraque-Dawley female rats were used. Fifteen rats underwent ovariectomy, and fifteen received sham surgery. Three animals without any surgery were sacrificed at week 0 to serve as baseline. Three animals in the OVX and sham group, respectively, were euthanized at week 2, 4, 12, 24 and 36 post-surgery. Ten bone sites, including parietal bone, interparietal bone, maxilla, mandible, humerus, ulna, femur, tibia, lumber vertebra, and ilium, were subjected to micro-CT. Overall, long bones, lumber vertebra, and ilium showed similar trend of bone loss post-OVX, with tibia and femur suffered the most bone loss and spine the least (decreased by 75.0%, 70.4% and 36.6% in bone mineral density BMD at week 36 from base line, respectively). Upon OVX, jaw bones and cranial bones only showed a minor reduction in BMD (decreased by 1~3% from baseline) at week 36. Significant deterioration of trabecular structure was detected in long bones, lumber vertebra, and ilium post-OVX, while jaw bones remained relatively stable. This study for the first time assessed the systemic site-specific bone loss and microarchitecture changes in OVX rat model. It provided valuable information for selecting bone site and observation time in osteoporosis-related study. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Coptidis Rhizoma Water Extract Stimulates 5'-AMP-Activated Protein Kinase in Rat Skeletal Muscle%Coptidis Rhizoma Water Extract Stimulates5'-AMP-Activated Protein Kinase in Rat Skeletal Muscle

    Institute of Scientific and Technical Information of China (English)

    Xiao Ma; Tatsuro Egawa; Rieko Oshima; Eriko Kurogi; Hiroko Tanabe; Satoshi Tsuda; Tatsuya Hayashi

    2011-01-01

    AIM: Coptidis Rhizoma (CR), the dried rhizomes of Asian herbs (including Coptis chinensis French), has been used to treat diabetes mellitus for thousands of years. We explored the possibility that CR acts directly on skeletal muscle, the major organ responsible for glucose homeostasis, and activates 5'-AMP-activated protein kinase (AMPK), a signaling intermediary leading to metabolic enhancement of skeletal muscle. METHODS: Isolated rat epitrochlearis and soleus muscles were incubated in a buffer containing a CR water extract (CE), and activation of AMPK and related events were examined. RESULTS: In response to CE treatment, phosphorylation of Thr172 at the catalytic α subunit of AMPK, an essential step for full kinase activation, increased in both muscles. Phosphorylation of Ser79 of acetyl CoA carboxylase (ACC), an endogenous substrate of AMPK, increased concotnitantly. Analysis of isoform-specific AMPK activity revealed that CE activated both the α1 and α2 isoforms of the catalytic subunit. Importantly, the maximal effect of CE on AMPK phosphorylation was significantly greater than that of berberine (BBR), indicating that the action of CE is not totally ascribed to BBR. CONCLUSION: We propose that CE is an acute activator of AMPK in both fast- and slow-twitch skeletal muscles.

  2. Effect of voluntary exercise on the expression of IGF-I and androgen receptor in three rat skeletal muscles and on serum IGF-I and testosterone levels.

    Science.gov (United States)

    Matsakas, A; Nikolaidis, M G; Kokalas, N; Mougios, V; Diel, P

    2004-10-01

    The effects of anabolic agents and training on skeletal muscle are believed to be mediated by a variety of growth and transcription factors. Among these regulatory proteins, insulin-like growth factor-I (IGF-I) and androgen receptor (AR) play a crucial role. The purpose of this study was to investigate the effects of wheel running on IGF-I and AR mRNA expression in three distinct rat skeletal muscles (i.e., gastrocnemius, vastus lateralis, and soleus), as well as on the serum levels of IGF-I and testosterone. Twenty male Wistar rats were housed in cages with free access to running wheels for 12 weeks, while nine rats served as controls. Analysis of the mRNA expression of IGF-I and AR using real time RT-PCR revealed no significant differences between the trained and untrained rats in any of the muscles studied. Enzyme immunoassay showed significantly lower serum levels of IGF-I and testosterone in the trained compared to the untrained animals. These results suggest that chronic exercise in wheels does not affect IGF-I and AR mRNA levels in rat skeletal muscle, while decreasing the circulating levels of two anabolic factors, i.e., IGF-I and testosterone. It is concluded that IGF-I, AR and testosterone seem to play a marginal role during the adaptation process of rat skeletal muscle to long-term wheel running.

  3. Expression profiles of muscle disease-associated genes and their isoforms during differentiation of cultured human skeletal muscle cells

    Directory of Open Access Journals (Sweden)

    Abdul-Hussein Saba

    2012-12-01

    Full Text Available Abstract Background The formation of contractile myofibrils requires the stepwise onset of expression of muscle specific proteins. It is likely that elucidation of the expression patterns of muscle-specific sarcomeric proteins is important to understand muscle disorders originating from defects in contractile sarcomeric proteins. Methods We investigated the expression profile of a panel of sarcomeric components with a focus on proteins associated with a group of congenital disorders. The analyses were performed in cultured human skeletal muscle cells during myoblast proliferation and myotube development. Results Our culture technique resulted in the development of striated myotubes and the expression of adult isoforms of the sarcomeric proteins, such as fast TnI, fast TnT, adult fast and slow MyHC isoforms and predominantly skeletal muscle rather than cardiac actin. Many proteins involved in muscle diseases, such as beta tropomyosin, slow TnI, slow MyBPC and cardiac TnI were readily detected in the initial stages of muscle cell differentiation, suggesting the possibility of an early role for these proteins as constituent of the developing contractile apparatus during myofibrillogenesis. This suggests that in disease conditions the mechanisms of pathogenesis for each of the mutated sarcomeric proteins might be reflected by altered expression patterns, and disturbed assembly of cytoskeletal, myofibrillar structures and muscle development. Conclusions In conclusion, we here confirm that cell cultures of human skeletal muscle are an appropriate tool to study developmental stages of myofibrillogenesis. The expression of several disease-associated proteins indicates that they might be a useful model system for studying the pathogenesis of muscle diseases caused by defects in specific sarcomeric constituents.

  4. A new take on an old story: chick limb organ culture for skeletal niche development and regenerative medicine evaluation

    Directory of Open Access Journals (Sweden)

    EL Smith

    2013-09-01

    Full Text Available Scientific research and progress, particularly in the drug discovery and regenerative medicine fields, is typically dependent on suitable animal models to develop new and improved clinical therapies for injuries and diseases. In vivo model systems are frequently utilised, but these models are expensive, highly complex and pose a number of ethical considerations leading to the development and use of a number of alternative ex vivo model systems. The ex vivo embryonic chick long bone and limb bud models have been utilised in the scientific research field as a model to understand skeletal development for over eighty years. The rapid development of avian skeletal tissues, coupled with the ease of experimental manipulation, availability of genome sequence and the presence of multiple cell and tissue types has seen such model systems gain significant research interest in the last few years in the tissue engineering field. The models have been explored both as systems for understanding the developmental bone niche and as potential testing tools for tissue engineering strategies for bone repair and regeneration. This review details the evolution of the chick limb organ culture system and presents recent innovative developments and emerging techniques and technologies applied to these models that are aiding our understanding of skeletal developmental and regenerative medicine research and application.

  5. Effect of myeloperoxidase and anoxia/reoxygenation on mitochondrial respiratory function of cultured primary equine skeletal myoblasts.

    Science.gov (United States)

    Ceusters, Justine D; Mouithys-Mickalad, Ange A; Franck, Thierry J; Derochette, Sandrine; Vanderplasschen, Alain; Deby-Dupont, Ginette P; Serteyn, Didier A

    2013-09-01

    Horses are particularly sensitive to excessive inflammatory reaction where myeloperoxidase, a marker of inflammation, may contribute to mitochondrial dysfunctions. This study investigated the interaction between myeloperoxidase and cultured primary equine skeletal myoblasts, particularly its effect on mitochondrial respiration combined or not with anoxia followed by reoxygenation (AR). We showed that active myeloperoxidase entered into the cells, interacted with mitochondria and decreased routine and maximal respirations. When combined with AR, myeloperoxidase caused a further decrease of these respiratory parameters while the leak increased. Our results indicate that myeloperoxidase amplifies the mitochondrial damages initiated by AR phenomenon and alters the mitochondrial function.

  6. Myosin heavy chain expression and atrophy in rat skeletal muscle during transition from cardiac hypertrophy to heart failure.

    Science.gov (United States)

    Carvalho, Robson Francisco; Cicogna, Antonio Carlos; Campos, Gerson Eduardo Rocha; De Assis, Jeane Marlene Fogaça; Padovani, Carlos Roberto; Okoshi, Marina Politi; Pai-Silva, Maeli Dal

    2003-08-01

    The purpose of this investigation was to determine whether changes in myosin heavy chain (MHC) expression and atrophy in rat skeletal muscle are observed during transition from cardiac hypertrophy to chronic heart failure (CHF) induced by aortic stenosis (AS). AS and control animals were studied 12 and 18 weeks after surgery and when overt CHF had developed in AS animals, 28 weeks after the surgery. The following parameters were studied in the soleus muscle: muscle atrophy index (soleus weight/body weight), muscle fibre diameter and frequency and MHC expression. AS animals presented decreases in both MHC1 and type I fibres and increases in both MHC2a and type IIa fibres during late cardiac hypertrophy and CHF. Type IIa fibre atrophy occurred during CHF. In conclusion, our data demonstrate that skeletal muscle phenotype changes occur in both late cardiac hypertrophy and heart failure; this suggests that attention should be given to the fact that skeletal muscle phenotype changes occur prior to overt heart failure symptoms.

  7. Effects of shakuyakukanzoto and its absorbed components on twitch contractions induced by physiological Ca2+ release in rat skeletal muscle.

    Science.gov (United States)

    Kaifuchi, Noriko; Omiya, Yuji; Kushida, Hirotaka; Fukutake, Miwako; Nishimura, Hiroaki; Kase, Yoshio

    2015-07-01

    Shakuyakukanzoto (SKT) is a kampo medicine composed of equal proportions of Glycyrrhizae radix (G. radix) and Paeoniae radix (P. radix). A double-blind study reported that SKT significantly ameliorated painful muscle cramp in cirrhosis patients without the typical severe side effects of muscle weakness and central nervous system (CNS) depression. Previous basic studies reported that SKT and its active components induced relaxation by a direct action on skeletal muscle and that SKT did not depress CNS functions; however, why SKT has a lower incidence of muscle weakness remains unknown. In the present study, we investigated which components are absorbed into the blood of rats after a single oral administration of SKT to identify the active components of SKT. We also investigated the effects of SKT and its components on the twitch contraction induced by physiological Ca(2+) release. Our study demonstrated that SKT and five G. radix isolates, which are responsible for the antispasmodic effect of SKT, did not inhibit the twitch contraction in contrast to dantrolene sodium, a direct-acting peripheral muscle relaxant, indicating that the mechanisms of muscle contraction of SKT and dantrolene in skeletal muscle differ. These findings suggest that SKT does not reduce the contractile force in skeletal muscle under physiological conditions, i.e., SKT may have a low risk of causing muscle weakness in clinical use. Considering that most muscle relaxants and anticonvulsants cause various harmful side effects such as weakness and CNS depression, SKT appears to have a benign safety profile.

  8. Glycogen content regulates peroxisome proliferator activated receptor-∂ (PPAR-∂) activity in rat skeletal muscle.

    Science.gov (United States)

    Philp, Andrew; MacKenzie, Matthew G; Belew, Micah Y; Towler, Mhairi C; Corstorphine, Alan; Papalamprou, Angela; Hardie, D Grahame; Baar, Keith

    2013-01-01

    Performing exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR) coactivator-1α (PGC-1α) and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4): control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]). Gastrocnemius (GTN) muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP) assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E) finished with higher AMPK-α2 activity (147%, pexercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal muscle in response to exercise.

  9. Imaging mass spectrometry reveals fiber-specific distribution of acetylcarnitine and contraction-induced carnitine dynamics in rat skeletal muscles.

    Science.gov (United States)

    Furuichi, Yasuro; Goto-Inoue, Naoko; Manabe, Yasuko; Setou, Mitsutoshi; Masuda, Kazumi; Fujii, Nobuharu L

    2014-10-01

    Carnitine is well recognized as a key regulator of long-chain fatty acyl group translocation into the mitochondria. In addition, carnitine, as acetylcarnitine, acts as an acceptor of excess acetyl-CoA, a potent inhibitor of pyruvate dehydrogenase. Here, we provide a new methodology for accurate quantification of acetylcarnitine content and determination of its localization in skeletal muscles. We used matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) to visualize acetylcarnitine distribution in rat skeletal muscles. MALDI-IMS and immunohistochemistry of serial cross-sections showed that acetylcarnitine was enriched in the slow-type muscle fibers. The concentration of ATP was lower in muscle regions with abundant acetylcarnitine, suggesting a relationship between acetylcarnitine and metabolic activity. Using our novel method, we detected an increase in acetylcarnitine content after muscle contraction. Importantly, this increase was not detected using traditional biochemical assays of homogenized muscles. We also demonstrated that acetylation of carnitine during muscle contraction was concomitant with glycogen depletion. Our methodology would be useful for the quantification of acetylcarnitine and its contraction-induced kinetics in skeletal muscles.

  10. Effect of insulin in combination with selenium on blood glucose and GLUT4 expression in skeletal muscle of streptozotocin-induced diabetic rats

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To evaluate the effect of low-dose insulin [1 U/(kg·d)] in combination with selenium [180 g/(kg·d)] on general physiological parameters and glucose transporter (GLUT4) level in skeletal muscle of streptozotocin (STZ)-induced diabetic rats. Methods Diabetic rats were treated with insulin,selenium,and insulin and selenium in combination for four weeks. The level of blood glucose was determined using One Touch SureStep Blood Glucose meter and the level of GLUT4 in skeletal muscle was examined by immu...

  11. Exhaustive Training Increases Uncoupling Protein 2 Expression and Decreases Bcl-2/Bax Ratio in Rat Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    W. Y. Liu

    2013-01-01

    Full Text Available This work investigates the effects of oxidative stress due to exhaustive training on uncoupling protein 2 (UCP2 and Bcl-2/Bax in rat skeletal muscles. A total of 18 Sprague-Dawley female rats were randomly divided into three groups: the control group (CON, the trained control group (TC, and the exhaustive trained group (ET. Malondialdehyde (MDA, superoxide dismutase (SOD, xanthine oxidase (XOD, ATPase, UCP2, and Bcl-2/Bax ratio in red gastrocnemius muscles were measured. Exhaustive training induced ROS increase in red gastrocnemius muscles, which led to a decrease in the cell antiapoptotic ability (Bcl-2/Bax ratio. An increase in UCP2 expression can reduce ROS production and affect mitochondrial energy production. Thus, oxidative stress plays a significant role in overtraining.

  12. Rat embryonic palatal shelves respond to TCDD in organ culture

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, B.D.; Birnbaum, L.S. (National Institute of Environmental Health Sciences, Research Triangle Park, NC (USA))

    1990-05-01

    TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), a highly toxic environmental contaminant, is teratogenic in mice, inducing cleft palate (CP) and hydronephrosis at doses which are not overtly maternally or embryo toxic. Palatal shelves of embryonic mice respond to TCDD, both in vivo and in organ culture, with altered differentiation of medial epithelial cells. By contrast, in the rat TCDD produces substantial maternal, embryonic, and fetal toxicity, including fetal lethality, with few malformations. In this study the possible effects of maternal toxicity on induction of cleft palate were eliminated by exposure of embryonic rat palatal shelves in organ culture. The shelves were examined for specific TCDD-induced alterations in differentiation of the medial cells. On Gestation Day (GD) 14 or 15 palatal shelves from embryonic F344 rats were placed in organ culture for 2 to 3 days (IMEM:F12 medium, 5% FBS, 0.1% DMSO) containing 0, 1 x 10(-8), 1 x 10(-9), 1 x 10(-10), or 5 x 10(-11) M TCDD. The medial epithelial peridermal cells degenerated on shelves exposed to control media or 5 x 10(-11) M TCDD. Exposure to 10(-10), 10(-9), and 10(-8) M TCDD inhibited this degeneration in 20, 36, and 60% of the shelves, respectively, and was statistically significant at the two highest doses. A normally occurring decrease in (3H)TdR incorporation was inhibited in some GD 15 shelves cultured with 10(-10) and 10(-9) M TCDD. The medial cells of TCDD-exposed shelves continued to express high levels of immunohistochemically detected EGF receptors. The altered differentiation of rat medial epithelium is similar to that reported for TCDD-exposed mouse medial cells in vivo and in vitro. However, in order to obtain these responses, the cultured rat shelves require much higher concentrations of TCDD than the mouse shelves.

  13. Acetaminophen metabolism, cytotoxicity, and genotoxicity in rat primary hepatocyte cultures

    Energy Technology Data Exchange (ETDEWEB)

    Milam, K.M.; Byard, J.L.

    1985-06-30

    Acetaminophen (APAP) metabolism, cytotoxicity, and genotoxicity were measured in primary cultures of rat hepatocytes. Although 3 mM APAP caused a slight increase in cellular release of lactate dehydrogenase into the culture medium, cellular glutathione concentration (an index of APAP metabolism) was reduced by 50%. APAP at 7 mM was significantly more toxic to these hepatocytes and had a similar but more marked effect on glutathione concentrations. In spite of its cytotoxicity, neither dose of APAP stimulated DNA repair synthesis when monitored by the rate of incorporation of (/sup 3/H)thymidine into DNA following exposure to APAP. Thus, although APAP has been shown to be both hepato- and nephrotoxic in several in vivo and in vitro systems, the reactive toxic metabolite of APAP is not genotoxic in rat primary hepatocyte cultures.

  14. Long-term organ culture of adult rat colon

    DEFF Research Database (Denmark)

    1978-01-01

    . The effect of in vivo carcinogen pretreatment was also studied. The explant culture from control untreated animals showed good epithelial differentiation with crypts until 6 weeks. In contrast, the explants from animals pretreated with 4 weekly doses of azoxymethane consistently showed epithelial......Colon explants from adult rats were maintained in culture for over 3 months in our laboratories with good epithelial preservation and cellular differentiation. The light and transmission electron microscopic features of rat colon mucosa during the culture period are described. In all the explants...... that remained viable, there was an initial phase of degeneration of the surface and crypt cells, later these areas were repopulated in one week, showing well-formed crypts, goblet cells, and ultrastructural features such as extensive lateral interdigitations, microvilli and glycocalyx--typical of colon...

  15. Age-associated tyrosine nitration of rat skeletal muscle glycogen phosphorylase b: characterization by HPLC-nanoelectrospray-tandem mass spectrometry.

    Science.gov (United States)

    Sharov, Victor S; Galeva, Nadezhda A; Kanski, Jaroslaw; Williams, Todd D; Schöneich, Christian

    2006-04-01

    We identified age-dependent post-translational modifications of skeletal muscle glycogen phosphorylase b (Ph-b), isolated from F1 hybrids of Fisher 344 x Brown Norway rats. Ph-b isolated from 34 months old rats showed a statistically significant decrease in specific activity compared to 6 months old animals: 13.8+/-0.7 vs. 20.6+/-0.8 U mg(-1) protein, respectively. Western blot analysis of the purified Ph-b with anti-3-NT antibodies revealed an age-dependent accumulation of 3-nitrotyrosine (3-NT), quantified by reverse-phase HPLC-UV analysis to increase from 0.05+/-0.03 to 0.34+/-0.11 (mol 3-NT/mol Ph-b) for 6 vs. 34 months old rats, respectively. HPLC-nanoelectrospray ionization-tandem mass spectrometry revealed the accumulation of 3-NT on Tyr113, Tyr161 and Tyr573. While nitration of Tyr113 was detected for both young and old rats, 3-NT at positions 161 and 573 was identified only for Ph-b isolated from 34 months old rats. The sequence of the rat muscle Ph-b was corrected based on our protein sequence mapping and a custom rat PHS2 sequence containing 17 differently located amino acid residues was used instead of the database sequence. The in vitro reaction of peroxynitrite with Ph-b resulted in the nitration of multiple Tyr residues at positions 51, 52, 113, 155, 185, 203, 262, 280, 404, 473, 731, and 732. Thus, the in vitro nitration conditions only mimic the nitration of a single Tyr residue observed in vivo suggesting alternative pathways controlling the accumulation of 3-NT in vivo. Our data show a correlation of age-dependent 3-NT accumulation with Ph-b inactivation.

  16. The anti-convulsants lacosamide, lamotrigine, and rufinamide reduce myotonia in isolated human and rat skeletal muscle.

    Science.gov (United States)

    Skov, Martin; de Paoli, Frank V; Nielsen, Ole B; Pedersen, Thomas H

    2017-07-01

    In myotonia congenita, loss of ClC-1 Cl(-) channel function results in skeletal muscle hyperexcitability and myotonia. Anti-myotonic treatment has typically targeted the voltage-gated sodium channel in skeletal muscle (Nav1.4). In this study we explored whether 3 sodium channel-modulating anti-epileptics can reduce myotonia in isolated rat and human muscle. Dissected muscles were rendered myotonic by ClC-1 channel inhibition. The ability of the drugs to suppress myotonia was then assessed from subclinical to maximal clinical concentrations. Drug synergy was determined using isobole plots. All drugs were capable of abolishing myotonia in both rat and human muscles. Lamotrigine and rufinamide completely suppressed myotonia at submaximal clinical concentrations, whereas lacosamide had to be raised above the maximal clinical concentration to suppress myotonia completely. A synergistic effect of lamotrigine and rufinamide was observed. These findings suggest that lamotrigine and rufinamide could be considered for anti-myotonic treatment in myotonia congenita. Muscle Nerve 56: 136-142, 2017. © 2016 Wiley Periodicals, Inc.

  17. Effect of low-level laser therapy (808 nm on skeletal muscle after endurance exercise training in rats

    Directory of Open Access Journals (Sweden)

    Livia Assis

    2015-12-01

    Full Text Available BACKGROUND: Low-level laser therapy (LLLT has been demonstrated to be effective in optimizing skeletal muscle performance in animal experiments and in clinical trials. However, little is known about the effects of LLLT on muscle recovery after endurance training. OBJECTIVE: This study evaluates the effects of low-level laser therapy (LLLT applied after an endurance training protocol on biochemical markers and morphology of skeletal muscle in rats. METHOD: Wistar rats were divided into control group (CG, trained group (TG, and trained and laser irradiated group (TLG. The endurance training was performed on a treadmill, 1 h/day, 5 days/wk, for 8 wk at 60% of the maximal speed reached during the maximal effort test (Tmax and laser irradiation was applied after training. RESULTS: Both trained groups showed significant increase in speed compared to the CG. The TLG demonstrated a significantly reduced lactate level, increased tibialis anterior (TA fiber cross-section area, and decreased TA fiber density. Myogenin expression was higher in soleus and TA muscles in both trained groups. In addition, LLLT produced myogenin downregulation in the TA muscle of trained animals. CONCLUSION: These results suggest that LLLT could be an effective therapeutic approach for stimulating recovery during an endurance exercise protocol.

  18. Fiber type effects on contraction-stimulated glucose uptake and GLUT4 abundance in single fibers from rat skeletal muscle.

    Science.gov (United States)

    Castorena, Carlos M; Arias, Edward B; Sharma, Naveen; Bogan, Jonathan S; Cartee, Gregory D

    2015-02-01

    To fully understand skeletal muscle at the cellular level, it is essential to evaluate single muscle fibers. Accordingly, the major goals of this study were to determine if there are fiber type-related differences in single fibers from rat skeletal muscle for: 1) contraction-stimulated glucose uptake and/or 2) the abundance of GLUT4 and other metabolically relevant proteins. Paired epitrochlearis muscles isolated from Wistar rats were either electrically stimulated to contract (E-Stim) or remained resting (No E-Stim). Single fibers isolated from muscles incubated with 2-deoxy-d-[(3)H]glucose (2-DG) were used to determine fiber type [myosin heavy chain (MHC) isoform protein expression], 2-DG uptake, and abundance of metabolically relevant proteins, including the GLUT4 glucose transporter. E-Stim, relative to No E-Stim, fibers had greater (P GLUT4, tethering protein containing a UBX domain for GLUT4 (TUG), cytochrome c oxidase IV (COX IV), and filamin C protein levels were significantly greater (P GLUT4 levels for MHC-IIax fibers exceeded MHC-IIxb fibers. GLUT4, COX IV, filamin C, and TUG abundance in single fibers was significantly (P GLUT4 abundance among the fiber types were not accompanied by significant differences in contraction-stimulated glucose uptake.

  19. Isolation and Primary Culture of Rat Hepatocytes Using Kiwifruit Actinidin

    Directory of Open Access Journals (Sweden)

    Z. Shirvani Farsani

    2007-07-01

    Full Text Available Introduction & Objective: Isolation of cells from different tissues rely on proteolytic enzymes mainly collagenases that selectively digest collagen fibers of extra-cellular matrix. It is important to find new and proper collagenases from plant sources. In the present research actinidin, a cysteine protease abundant in Kiwifruit, was used to isolate and culture of rat hepatocytes. Materials & Methods: Different concentrations of actinidin was used to isolate rat hepatocytes by one or two-step perfusion method. The viability of the separated cells was examined by the trypan blue test. The isolated rat hepatocytes were cultured on collagen coated plates in William´s E medium. The morphology of hepatocytes was examined microscopically after staining with the Papanicolaou method.Results: Actinidin in the concentration of 0.4 mg/ml in two-step perfusion method properly isolated hepatocytes from rat liver. The viability of isolated hepatocytes that successfully cultured in collagen coated plates was 90-95 percent.Conclusion: These results showed that actinidin is a proper protease for isolation of hepatocytes. In addition, purification of this enzyme is simpler than the collagenases.

  20. Electromyographic studies regarding denervation potentials in skeletal muscles at sites near and distant from the burn in rats.

    Science.gov (United States)

    Sajadi, Simin; Mansoori, Korosh; Forogh, Bijan; Fatemi, Mohammad Javad; Ahadi, Tannaz; Chahardoli Razji, Mahnaz

    2016-04-01

    Changes in membrane AChRs in skeletal muscles located near or distant from burn injury similar to denervated muscles may make electrodiagnostic features indistinguishable from true neuropathic changes. The aim of this study was to examine electrodiagnostic changes of muscles at sites local and distant from the burn after thermal injuries due to neuromuscular junction dysfunction. A total of 40 adult male rats were randomly allocated to four groups. Rats in group 1 received thermal burn injury over gastrocnemius muscle of one leg and sham burn on the other leg. A 20-25% and 30-35% surface body area burn and also 30-35% surface body area sham burn were produced at distant site from gastrocnemius muscle in group 2, 3 and 4, respectively. To explore any fibrillation potential, the rats underwent serial electromyographic studies of bilateral gastrocnemius muscles over 5 weeks after burn injury. There were no denervation potentials either in muscles at sites distant from 20-25% and 30-35% of total body surface area burns or in muscles beneath the burn. In the present study on rats, thermal burn injury could not make fibrillation potentials in the electrodiagnostic study of muscles located near and distant from the burn site.

  1. The Role of Lumbar Sympathetic Nerves in Regulation of Blood Flow to Skeletal Muscle during Anaphylactic Hypotension in Anesthetized Rats.

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    Jie Song

    Full Text Available During hypovolemic shock, skeletal muscle blood flow could be redistributed to vital organs via vasoconstriction in part evoked by activation of the innervating sympathetic nerve activity. However, it is not well known whether this mechanism operates during anaphylactic shock. We determined the femoral artery blood flow (FBF and lumbar sympathetic nerve activity (LSNA mainly regulating the hindquater muscle blood flow during anaphylactic hypotension in anesthetized rats. Anesthetized Sprague-Dawley rats were randomly allocated to the following groups (n = 7/group: (1 non-sensitized, (2 anaphylaxis, (3 anaphylaxis-lumbar sympathectomy (LS and (4 anaphylaxis-sinoaortic denervation (SAD groups. Anaphylaxis was induced by an intravenous injection of the ovalbumin antigen to the sensitized rats. The systemic arterial pressure (SAP, heart rate (HR, central venous pressure (CVP, FBF and LSNA were continuously measured. In the anaphylaxis group, LSNA and HR increased, while SAP and FBF decreased after antigen injection. In the anaphylaxis-SAD group, LSNA did not significantly change during the early phase, but the responses of SAP and FBF were similar to those in the anaphylaxis group. In the anaphylaxis-LS group, both FBF and SAP decreased similarly to the anaphylaxis group during anaphylactic hypotension. These results indicated that LSNA increased via baroreceptor reflex, but this sympathoexcitation or LS did not affect antigen-induced decreases in FBF or SAP. Lumbar sympathetic nerves are not involved in regulation of the blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats.

  2. Ex Vivo Gene Therapy Using Human Mesenchymal Stem Cells to Deliver Growth Factors in the Skeletal Muscle of a Familial ALS Rat Model.

    Science.gov (United States)

    Suzuki, Masatoshi; Svendsen, Clive N

    2016-01-01

    Therapeutic protein and molecule delivery to target sites by transplanted human stem cells holds great promise for ex vivo gene therapy. Our group has demonstrated the therapeutic benefits of ex vivo gene therapy targeting the skeletal muscles in a transgenic rat model of familial amyotrophic lateral sclerosis (ALS). We used human mesenchymal stem cells (hMSCs) and genetically modified them to release neuroprotective growth factors such as glial cell line-derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF). Intramuscular growth factor delivery via hMSCs can enhance neuromuscular innervation and motor neuron survival in a rat model of ALS (SOD1(G93A) transgenic rats). Here, we describe the protocol of ex vivo delivery of growth factors via lentiviral vector-mediated genetic modification of hMSCs and hMSC transplantation into the skeletal muscle of a familial ALS rat model.

  3. Leucine-rich diet alters the eukaryotic translation initiation factors expression in skeletal muscle of tumour-bearing rats

    Directory of Open Access Journals (Sweden)

    Mello Maria

    2007-03-01

    Full Text Available Abstract Background Cancer-cachexia induces a variety of metabolic disorders on protein turnorver, decreasing protein synthesis and increasing protein degradation. Controversly, insulin, other hormones, and branched-chain amino acids, especially leucine, stimulate protein synthesis and modulate the activity of translation initiation factors involved in protein synthesis. Since the tumour effects are more pronounced when associated with pregnancy, ehancing muscle-wasting proteolysis, in this study, the influence of a leucine-rich diet on the protein synthesis caused by cancer were investigated. Methods Pregnant rats with or without Walker 256 tumour were distributed into six groups. During 20 days of experiment, three groups were fed with a control diet: C – pregnant control, W – tumour-bearing, and P – pair-fed, which received the same amount of food as ingested by the W group; three other groups of pregnant rats were fed a leucine-rich diet: L – pregnant leucine, WL – tumour-bearing, and PL – pair-fed, which received the same amount of food as ingested by the WL group. Results The gastrocnemius muscle of WL rats showed increased incorporation of leucine in protein compared to W rats; the leucine-rich diet also prevented the decrease in plasma insulin normally seen in W. The expression of translation initiation factors increased when tumour-bearing rats fed leucine-rich diet, with increase of ~35% for eIF2α and eIF5, ~17% for eIF4E and 20% for eIF4G; the expression of protein kinase S6K1 and protein kinase C was also highly enhanced. Conclusion The results suggest that a leucine-rich diet increased the protein synthesis in skeletal muscle in tumour-bearing rats possibly through the activation of eIF factors and/or the S6kinase pathway.

  4. The Effect of Pueraria Lobata/Rehmannia Glutinosa and Exercise on Fatty Acid Transporters Expression in Ovariectomized Rats Skeletal Muscles

    Science.gov (United States)

    Kim, Hye Jin; Yoon, Hae Min; Kwon, Oran; Lee, Won Jun

    2016-01-01

    [Purpose] Pueraria lobata/rehmannia glutinosa (PR) and exercise have been receiving a lot of attention from postmenopausal women, as a result of the side effects of estrogen replacement therapy. However, the effects of PR and exercise on fatty acid transporters (FATPs), which play essential role in fatty acid transport, have not been studied. In this study, we evaluated the effects of PR and aerobic exercise on FATP1, FABPpm and FAT/CD36 expression in ovariectomized rat skeletal muscles. [Methods] Sixty rats were randomly divided into 6 groups: (1)HSV; high fat diet (HFD)+sedentary+vehicle, (2)HSP; HFD+sedentary+PR, (3)HSH; HFD+sedentary+17β-estradiol, (4)HEV; HFD+exercise+vehicle, (5) HEP; HFD+exercise+PR, (6)HEH; HFD+exercise+17β-estradiol. Exercise consisted of treadmill exercise (1-4th week: 15 m/min for 30 min, 5-8th week: 18 m/min for 40 min, 5 times/week). [Results] Exercise does not alter FATP1 and FAT/CD36 gene levels in soleus and plantaris muscles. In contrast, exercise had main effect on up-regulation of FABPpm mRNA expression in both muscles. However, FABPpm level was not increased by exercise combined with treatments, indicative of no additive effects of PR or hormone on FABPpm gene expression. On the other hand, immunohistochemistry result showed that translocation of FATPs proteins to plasma membrane were higher in PR, exercise groups, and exercise combined with PR groups in both muscles. [Conclusion] These result showed that aerobic exercise and PR may help increase fat-oxidation through the induction of FABPpm, a muscle specific transporter, in OVX rat skeletal muscles. In addition, FABPpm expression is possibly regulated post-transcriptionally in exercise, or pre-translationally in PR. PMID:27757385

  5. Effect of insulin in combination with selenium on blood glucose and GLUT4 expression in skeletal muscle of streptozotocin-induced diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Tian-jiao Xu; Bing-xiang Yuan; Ya-min Zou

    2009-01-01

    Objective To evaluate the effect of low-dose insulin [1 U/(kg · d)] in combination with selenium [180 g/(kg · d)] on general physiological parameters and glucose transporter (GLUT4) level in skeletal mnscle of streptozotocin (STZ)-induced diabetic rats. Methods Diabetic rats were treated with insulin, selenium, and insulin and selenium in combination for four weeks. The level of blood glucose was determined using One Tonch SnreStep Blood Glucose meter and the level of GLUT4 in skeletal muscle was examined by immunobiotting and immnnohistochemistry. Results Our data showed that insulin in combination with selenium could significantly lower blood glucose level and restore the disturbance in GLUT4 level in skeletal muscle. Treatment with insulin was only partially effective in restoring diabetic alterations. Conclusion It can be concluded that there is a synergistic action between insulin and selenium, and that treatment of diabetic rats with combined doses of insulin and selenium is effective in the normalization of blood glucose level and correction of altered GLUT4 distribution in skeletal mnscle of diabetic rats.

  6. Compatibility of hyaluronic acid hydrogel and skeletal muscle myoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wei; Zhang Li; Sun Liang; Wang Chengyue [Jinzhou Central Hospital, Jinzhou 121000 (China); Fan Ming; Liu Shuhong, E-mail: Weiwang_Ly@yahoo.com.c [Institute of Basic Medical Sciences, Academy of Military Medical Science, Beijing 100850 (China)

    2009-04-15

    Compatibility of hyaluronic acid hydrogel (HAH) and skeletal muscle myoblasts has been investigated for the first time in the present paper. Skeletal muscle myoblasts were separated from skeletons of rats and incubated with a HAH-containing culture medium. Cell morphology, hydrophilicity and cell adhesion of the HAH scaffold were investigated using optical microscopy, scanning electron microscopy, Hoechest33258 fluorescent staining, the immunocytochemistry method and water adsorption rate measurement. It was found that at a proper concentration (around 0.5%) of hyaluronic acid, the hydrogel possessed good compatibility with skeletal muscle myoblasts. The hydrogel can create a three-dimensional structure for the growth of skeletal muscle myoblasts and benefit cell attachment to provide a novel scaffold material for the tissue engineering of skeletal muscle.

  7. Triptolide upregulates NGF synthesis in rat astrocyte cultures.

    Science.gov (United States)

    Xue, Bing; Jiao, Jian; Zhang, Lei; Li, Kai-Rong; Gong, Yun-Tao; Xie, Jun-Xia; Wang, Xiao-Min

    2007-07-01

    Triptolide (T10), an extract from the traditional Chinese herb, Tripterygium wilfordii Hook F (TWHF), has been shown to attenuate the rotational behavior induced by D: -amphetamine and prevent the loss of dopaminergic neurons in the substantia nigra in rat models of Parkinson's disease. To examine if the neuroprotective effect is mediated by its stimulation of production of neurotrophic factors from astrocytes, we investigated the effect of T10 on synthesis and release of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in rat astrocyte cultures. T10 did not affect the synthesis and release of either BDNF or GDNF. However, it significantly increased NGF mRNA expression. It also increased both intracellular NGF and NGF level in culture medium. These results indicate that the neuroprotective effect of T10 might be mediated, at least in part, via a stimulation of the production and release of NGF in astrocytes.

  8. Proteomic analysis of indium embryotoxicity in cultured postimplantation rat embryos.

    Science.gov (United States)

    Usami, Makoto; Nakajima, Mikio; Mitsunaga, Katsuyoshi; Miyajima, Atsuko; Sunouchi, Momoko; Doi, Osamu

    2009-12-01

    Indium embryotoxicity was investigated by proteomic analysis with two-dimensional electrophoresis of rat embryos cultured from day 10.5 of gestation for 24h in the presence of 50 microM indium trichloride. In the embryo proper, indium increased quantity of several protein spots including those identified as serum albumin, phosphorylated cofilin 1, phosphorylated destrin and tyrosyl-tRNA synthetase. The increased serum albumin, derived from the culture medium composed of rat serum, may decrease the toxicity of indium. The increase of phosphorylated cofilin 1 might be involved in dysmorphogenicity of indium through perturbation of actin functions. In the yolk sac membrane, indium induced quantitative and qualitative changes in the protein spots. Proteins from appeared spots included stress proteins, and those from decreased or disappeared spots included serum proteins, glycolytic pathway enzymes and cytoskeletal proteins, indicating yolk sac dysfunction. Thus, several candidate proteins that might be involved in indium embryotoxicity were identified.

  9. In utero glucocorticoid (GLC) exposure reduces fetal skeletal muscle growth in rats

    Science.gov (United States)

    Maternal undernutrition and stress expose the fetus to above normal levels of GLC and predispose to intrauterine growth restriction. The aim of this study was to determine if fetal GLC exposure impairs skeletal muscle growth independently of maternal undernutrition. Three groups (n=7/group) of timed...

  10. Precocious glucocorticoid exposure reduces skeletal muscle satellite cells in the fetal rat

    Science.gov (United States)

    Perinatal skeletal muscle growth rates are a function of protein and myonuclear accretion. Precocious exposure of the fetus to glucocorticoids (GLC) in utero impairs muscle growth. Reduced muscle protein synthesis rates contribute to this response, but the consequences for myonuclear hyperplasia are...

  11. Pressure-time cell death threshold for albino rat skeletal muscles as related to pressure sore biomechanics.

    Science.gov (United States)

    Linder-Ganz, Eran; Engelberg, Santiego; Scheinowitz, Mickey; Gefen, Amit

    2006-01-01

    Deep pressure sores (DPS) are associated with inadequate soft tissue perfusion and excessive tissue deformation over critical time durations, as well as with ischemia-reperfusion cycles and deficiency of the lymphatic system. Muscle tissue shows the lowest tolerance to pressure injuries, compared with more superficial tissues. In this communication, we present new histopathology data for muscle tissue of albino (Sprague-Dawley) rats exposed to pressures for 15 or 30 min. These data are superimposed with an extensive literature review of all previous histopathology reported for albino rat skeletal muscles subjected to pressure. The pooled data enabled a new mathematical characterization of the pressure-time threshold for cell death in striated muscle of rats, in the form of a sigmoid pressure-time relation, which extends the previous pressure-time relation to the shorter exposure periods. We found that for pressure exposures shorter than 1 h, the magnitude of pressure is the important factor for causing cell death and the exposure time has little or no effect: even relatively short exposures (15 min - 1 h) to pressures greater than 32 kPa (240 mmHg) cause cell death in rat muscle tissue. For exposures of 2 h or over, again the magnitude of pressure is the important factor for causing cell death: pressures greater than 9 kPa (67 mmHg) applied for over 2 h consistently cause muscle cell death. For the intermediate exposures (between 1 and 2 h), the magnitude of cell-death-causing pressure strongly depends on the time of exposure, i.e., critical pressure levels drop from 32 to 9 kPa. The present sigmoidal pressure-time cell death threshold is useful for design of studies in albino rat models of DPS, and may also be helpful in numerical simulations of DPS development, where there is often a need to extrapolate from tissue pressures to biological damage.

  12. THE EFFECTS OF AEROBIC EXERCISE ON SKELETAL MUSCLE METABOLISM, MORPHOLOGY AND IN SITU ENDURANCE IN DIABETIC RATS

    Directory of Open Access Journals (Sweden)

    Nilay Ergen

    2005-12-01

    Full Text Available The effects of aerobic exercise training on skeletal muscle endurance capacity were examined in diabetic rats in situ. Moderate diabetes was induced by iv injection of streptozotocin and an exercise training program on a treadmill was carried out for 8 weeks. The animals randomly assigned to one of the four experimental groups: control-sedentary (CS, control-exercise (CE, diabetic-sedentary (DS or diabetic-exercise (DE. The changes in the muscle endurance capacity were evaluated through the square wave impulses (supramaximal of 0.2-ms duration at 1 Hz in the in situ gastrocnemius-soleus muscle complex. Muscle was stimulated continuously until tension development reduced to the half of this maximal value. Time interval between the beginning and the end of stimulation period is defined as contraction duration. Following the training period, blood glucose level reduced significantly in the DE group compared to DS group (p < 0.05. The soles muscle citrate synthase activity was increased significantly in both of the trained groups compared to sedentary animals (p < 0.05. Fatigued muscle lactate values were not significantly different from each other. Ultrastractural abnormality of the skeletal muscle in DS group disappeared with training. Presence of increased lipid droplets, mitochondria clusters and glycogen accumulation was observed in the skeletal muscle of DE group. The contraction duration was longer in the DE group than others (p < 0.001. Fatigue resistance of exercised diabetic animals may be explained by increased intramyocellular lipid droplets, high blood glucose level and muscle citrate synthase activity

  13. Effects of eccentric exercise on branched-chain amino acid profiles in rat serum and skeletal muscle.

    Science.gov (United States)

    Qun, Z; Xinkai, Y; Jing, W

    2014-04-01

    Supplementation of branched-chain amino acid (BCAA) is often used to attenuate exercise-induced skeletal muscle damage and promote adaptation, but no definitive conclusion on the benefits of BCAA on muscle recovery after injurious exercise can be drawn. Exploration of the systematic BCAA alteration in muscular injury-repair stage per se without any BCAA supplement should provide some useful information in favour of BCAA application in muscle regeneration after injury. One bout of 90-min downhill-running exercise was performed to cause rat skeletal muscle injury. After exercise, myofibrillar BCAA concentrations showed minor changes compared with exercise before, while serum concentrations of BCAA were lower after exercise. Especially, serum leucine, isoleucine and total BCAA concentrations 2 weeks post-run were significantly lower than normal values of exercise before (p = 0.008, p = 0.041, p = 0.015). The data demonstrate that a single eccentric exercise can significantly decrease the serum BCAA concentrations, which mean high utilization of BCAA for myogenesis after injurious exercise.

  14. Identification of a skeletal muscle-specific regulatory domain in the rat GLUT4/muscle-fat gene.

    Science.gov (United States)

    Richardson, J M; Pessin, J E

    1993-10-05

    To identify sequences responsible for the muscle-specific expression of the rat GLUT4/muscle-fat gene, we examined the transcriptional regulation of this gene in the differentiating murine C2C12 skeletal muscle cell line. Differentiated myofibers displayed a 4-5-fold increase in GLUT4 mRNA compared with undifferentiated myoblasts which paralleled the conversion from non-muscle beta-actin mRNA to muscle-specific alpha-actin mRNA expression. Transient transfection of progressive 5' and 3' deletions of the GLUT4 5'-flanking DNA identified a 281-base pair region located between -517 and -237 relative to the transcription start site which conferred myotube-specific expression. This region increased reporter activity in the context of the GLUT4 minimal promoter in an orientation-independent manner and, in addition, onto the heterologous thymidine kinase promoter. Myotube-specific expression of both GLUT4 reporter constructs and the endogenous mouse GLUT4 mRNA was also observed to be thyroid hormone-dependent. Further, cotransfection of reporter constructs containing the 281-base pair GLUT4 differentiation-specific enhancer with the thyroid hormone receptor specifically increased luciferase activity in myotubes approximately 12-fold. Thus, these data demonstrate the presence of a proximal skeletal muscle-specific activation domain that is necessary for both myotube-specific GLUT4 expression and thyroid hormone responsiveness.

  15. Protein nonenzymatic modifications and proteasome activity in skeletal muscle from the short-lived rat and long-lived pigeon.

    Science.gov (United States)

    Portero-Otín, Manel; Requena, Jesús R; Bellmunt, Maria Josep; Ayala, Victoria; Pamplona, Reinald

    2004-10-01

    What are the mechanisms determining the rate of animal aging? Of the two major classes of endothermic animals, bird species are strikingly long-lived compared to similar size mammalian counterparts. Since oxidative stress is causally related to the basic aging process, markers of different kinds of oxidative damage to proteins (glutamic semialdehyde, aminoadipic semialdehyde, N(epsilon)-(carboxyethyl)lysine; N(epsilon)-(carboxymethyl)lysine, N(epsilon)-(malondialdehyde)lysine and dinitrophenylhydrazyne-reactive protein carbonyls, peptidase activities of the proteasome, and amino acid and membrane fatty acyl composition were identified and measured in skeletal muscle from the short-lived rat (maximum life span, 4 years) and compared with the long-lived pigeon (maximum life span, 35 years). Skeletal muscle from pigeon showed significantly higher levels of glutamic semialdehyde, protein carbonyls (by western blot), N(epsilon)-(carboxyethyl)lysine and N(epsilon)-(carboxymethyl)lysine. No differences were observed for aminoadipic semialdehyde, whereas the lipoxidation marker N(epsilon)-(malondialdehyde)lysine displayed a significant low steady-state level, probably related with their significantly lower membrane unsaturation. The amino acid compositional analysis revealed that arginine, serine, threonine and methionine showed significantly lower levels in pigeon. Finally, pigeon samples showed also significantly lower levels of the peptidase activities of the proteasome. These results reinforces the role of structural components such as membrane unsaturation and protein composition in determining the longer maximum life span showed by birds compared with mammals of similar body size.

  16. β-Hydroxy-β-methylbutyrate (HMβ supplementation stimulates skeletal muscle hypertrophy in rats via the mTOR pathway

    Directory of Open Access Journals (Sweden)

    Pimentel Gustavo D

    2011-02-01

    Full Text Available Abstract β-Hydroxy-β-methylbutyrate (HMβ supplementation is used to treat cancer, sepsis and exercise-induced muscle damage. However, its effects on animal and human health and the consequences of this treatment in other tissues (e.g., fat and liver have not been examined. The purpose of this study was to evaluate the effects of HMβ supplementation on skeletal muscle hypertrophy and the expression of proteins involved in insulin signalling. Rats were treated with HMβ (320 mg/kg body weight or saline for one month. The skeletal muscle hypertrophy and insulin signalling were evaluated by western blotting, and hormonal concentrations were evaluated using ELISAs. HMβ supplementation induced muscle hypertrophy in the extensor digitorum longus (EDL and soleus muscles and increased serum insulin levels, the expression of the mammalian target of rapamycin (mTOR and phosphorylation of p70S6K in the EDL muscle. Expression of the insulin receptor was increased only in liver. Thus, our results suggest that HMβ supplementation can be used to increase muscle mass without adverse health effects.

  17. Preliminary investigation of sequence-independent DNA binding proteins in rat skeletal muscle sarcoplasmic reticulum and their function

    Institute of Scientific and Technical Information of China (English)

    赵文; 姜志胜; 倪菊华; 陈光慧; 刘乃奎; 汤健; 贾弘褆; 唐朝枢

    2000-01-01

    To observe the binding of plasmid DNA to non-nuclear DNA binding proteins in sar-coplasmic reticulum (SR) and the effects of this binding on SR function, sarcoplasmic reticulum proteins in rat skeletal muscle were isolated by differential centrifuge and sucrose density-gradient centrifuge. The results showed that there are two sequence-independent DNA binding proteins in SR proteins, the molecular weights of which are 83 and 58 ku, respectively. Ca2+ uptake and release of SR were remarkably promoted by the binding of plasmid DNA to DNA binding proteins in SR, the mechanism is probably through increasing of Ca2+-ATPase activity in SR and changing of character of Ca2+ release channel ryanodine receptors induced by the binding. These results suggest that there exist DNA binding proteins in SR and its binding to DNA may affect Ca2+ transport of SR.

  18. Preliminary investigation of sequence-independent DNA binding proteins in rat skeletal muscle sarcoplasmic reticulum and their function

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To observe the binding of plasmid DNA to non-nuclear DNA binding proteins in sarcoplasmic reticulum (SR) and the effects of this binding on SR function, sarcoplasmic reticulum proteins in rat skeletal muscle were isolated by differential centrifuge and sucrose density-gradient centrifuge. The results showed that there are two sequence-independent DNA binding proteins in SR proteins, the molecular weights of which are 83 and 58 ku, respectively. Ca2+ uptake and release of SR were remarkably promoted by the binding of plasmid DNA to DNA binding proteins in SR, the mechanism is probably through increasing of Ca2+-ATPase activity in SR and changing of character of Ca2+ release channel ryanodine receptors induced by the binding. These results suggest that there exist DNA binding proteins in SR and its binding to DNA may affect Ca2+ transport of SR.

  19. Exercise-induced regulation of phospholemman (FXYD1) in rat skeletal muscle: implications for Na+/K+-ATPase activity

    DEFF Research Database (Denmark)

    Rasmussen, M K; Kristensen, M; Juel, C

    2008-01-01

    BACKGROUND: Na(+)/K(+)-ATPase activity is upregulated during muscle exercise to maintain ionic homeostasis. One mechanism may involve movement of alpha-subunits to the outer membrane (translocation). AIM: We investigated the existence of exercise-induced translocation and phosphorylation...... of phospholemman (PLM, FXYD1) protein in rat skeletal muscle and exercise-induced changes in V(max) and K(m) for Na(+) of the Na(+)/K(+)-ATPase. METHODS: Two membrane fractionation methods and immunoprecipitation were used. Results: Both fractionation methods revealed a 200-350% increase in PLM in the sarcolemma...... after 30 min of treadmill running, while the phosphorylation of Ser-68 of PLM appeared to be unchanged. Exercise did not change V(max) or K(m) for Na(+) of the Na(+)/K(+)-ATPase in muscle homogenate, but induced a 67% increase in V(max) in the sarcolemmal giant vesicle preparation; K(m) for Na...

  20. Noradrenaline-induced increases in calcium and tension in skeletal muscle conductance and resistance arteries from rats with post-infarction heart failure

    DEFF Research Database (Denmark)

    Trautner, Simon; Amtorp, Ole; Boesgaard, Soren

    2006-01-01

    We tested the hypothesis that arterial reactivity to noradrenaline is augmented in congestive heart failure (CHF), which could contribute to the deleterious changes in peripheral vascular resistance and compliance in this condition. From male Wistar rats with post-infarction CHF and sham-operated......, endothelial dysfunction nor changes in baseline vascular tone could be demonstrated in the skeletal muscle vascular bed of this animal model of heart failure.......We tested the hypothesis that arterial reactivity to noradrenaline is augmented in congestive heart failure (CHF), which could contribute to the deleterious changes in peripheral vascular resistance and compliance in this condition. From male Wistar rats with post-infarction CHF and sham......-operated rats, skeletal muscle conductance and resistance arteries (mean lumen diameters: 514 and 186 microm) were isolated and mounted on wire myographs, and wall tension was recorded in response to cumulative application of acetylcholine and noradrenaline to the vessel segments. In a subset of experiments...

  1. Effect of helium/neon laser irradiation on nerve growth factor synthesis and secretion in skeletal muscle cultures.

    Science.gov (United States)

    Schwartz, Fidi; Brodie, Chaya; Appel, Elana; Kazimirsky, Gila; Shainberg, Asher

    2002-04-01

    Low energy laser irradiation therapy in medicine is widespread but the mechanisms are not fully understood. The aim of the present study was to elucidate the mechanism by which the light might induce therapeutic effects. Skeletal muscle cultures were chosen as a target for light irradiation and nerve growth factor (NGF) was the biochemical marker for analysis. It was found that there is a transient elevation of intracellular calcium in the myotubes immediately after irradiation (Phelium/neon irradiation (633 nm) with an energy of 3 J/cm(2). In addition, helium/neon irradiation augmented the level of NGF mRNA fivefold and increased NGF release to the medium of the myotubes. Thus, it is speculated that transient changes in calcium caused by light can modulate NGF release from the myotubes and also affect the nerves innervating the muscle. The NGF is probably responsible for the beneficial effects of low-level light.

  2. Fatiguing stimulation of one skeletal muscle triggers heat shock protein activation in several rat organs: the role of muscle innervation.

    Science.gov (United States)

    Jammes, Yves; Steinberg, Jean Guillaume; By, Youlet; Brerro-Saby, Christelle; Condo, Jocelyne; Olivier, Marine; Guieu, Regis; Delliaux, Stephane

    2012-11-15

    We hypothesised that activation of muscle afferents by fatigue triggers a widespread activation of heat shock proteins (HSPs) in resting muscles and different organs. In anaesthetised rats, HSP25 and HSP70 levels were determined in both tibialis anterior (TA) and extensor digitorum longus (EDL) muscles and in the diaphragm, kidney and brain by ELISA, which mostly identifies phosphorylated HSP, and western blotting. One TA muscle was electrically stimulated and tissues were sampled 10 or 60 min after the stimulation had ended. The nerve supply to the stimulated TA or its counterpart in the contralateral limb was left intact or suppressed. In control rats, no muscle stimulation was performed and tissues were sampled at the same time points (10 or 60 min). After TA stimulation, ELISA showed an increased HSP25 content in the contralateral TA, EDL and diaphragm at 10 min but not at 60 min, and HSP70 increased in all sampled tissues at 60 min. Western blotting did not show any changes in HSP25 and HSP70 at 10 min, while at 60 min HSP25 increased in all sampled tissues except the brain and HSP70 was elevated in all tissues. Denervation of the contralateral non-stimulated limb suppressed HSP changes in TA and after denervation of the stimulated TA the widespread activation of HSPs in other organs was absent. Our data suggest that fatigue-induced activation of skeletal muscle afferents triggers an early increase in phosphorylated HSP25 in muscles and a delayed elevation of non-phosphorylated HSP25 and HSP70 in skeletal and respiratory muscles, kidney and brain.

  3. Single fiber analyses of glycogen-related proteins reveal their differential association with glycogen in rat skeletal muscle.

    Science.gov (United States)

    Murphy, Robyn M; Xu, Hongyang; Latchman, Heidy; Larkins, Noni T; Gooley, Paul R; Stapleton, David I

    2012-12-01

    To understand how glycogen affects skeletal muscle physiology, we examined enzymes essential for muscle glycogen synthesis and degradation using single fibers from quiescent and stimulated rat skeletal muscle. Presenting a shift in paradigm, we show these proteins are differentially associated with glycogen granules. Protein diffusibility and/or abundance of glycogenin, glycogen branching enzyme (GBE), debranching enzyme (GDE), phosphorylase (GP), and synthase (GS) were examined in fibers isolated from rat fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus (SOL) muscle. GDE and GP proteins were more abundant (~10- to 100-fold) in fibers from EDL compared with SOL muscle. GS and glycogenin proteins were similar between muscles while GBE had an approximately fourfold greater abundance in SOL muscle. Mechanically skinned fibers exposed to physiological buffer for 10 min showed ~70% total pools of GBE and GP were diffusible (nonbound), whereas GDE and GS were considerably less diffusible. Intense in vitro stimulation, sufficient to elicit a ~50% decrease in intracellular glycogen, increased diffusibility of GDE, GP, and GS (~15-60%) and decreased GBE diffusibility (~20%). Amylase treatment, which breaks α-1,4 linkages of glycogen, indicated differential diffusibilities and hence glycogen associations of GDE and GS. Membrane solubilization (1% Triton-X-100) allowed a small additional amount of GDE and GS to diffuse from fibers, suggesting the majority of nonglycogen-associated GDE/GS is associated with myofibrillar/contractile network of muscle rather than membranes. Given differences in enzymes required for glycogen metabolism, the current findings suggest glycogen particles have fiber-type-dependent structures. The greater catabolic potential of glycogen breakdown in fast-twitch fibers may account for different contraction induced rates of glycogen utilization.

  4. Gestational Undernourishment Modifies the Composition of Skeletal Muscle Transverse Tubule Membranes and the Mechanical Properties of Muscles in Newborn Rats

    Directory of Open Access Journals (Sweden)

    Ricardo Tonathiu Ramírez-Oseguera

    2013-10-01

    Full Text Available Backgroud/Aims: Skeletal muscle (SM constitutes more than 40% of the body weight in adulthood. Transports dietary glucose mainly through the insulin-dependent glucose transporter (Glut-4 located in the Transverse tubule membrane system (TT. The TT development ends shortly after birth. The TT membrane hosts the proteins involved in excitation-contraction coupling and glucose uptake. Glycaemic regulation through movement is a key function of fully developed skeletal muscle. In this study, we aimed to characterize the effect of gestational undernourishment (GUN in rats GLUT-4 expression and on the protein/lipid content of the TT membranes. We also examined the effect of GUN on the mechanical properties of muscles as an indication of the metabolic condition of the SM at birth. Methods: Isolated TT membrane from SM of GUN rats were used to study lipid/protein content and protein stability by differential scanning calorimetry. The effect of GUN on the SM mechanical properties was determined in isolated Extensor Digitorum Longus (EDL muscle. Results: We demonstrate that compared to control, GUN in the new-born produces; i decreases body weight; ii diminution in SM mass; iii decreases the formation of TT membranes; iv expresses TT membrane proteins with higher thermal stability. The TT membrane expression of GLUT-4 in GUN offspring was twice that of controls. The isolated EDL of GUN offspring was 20% stronger as measured by contractile force and more resistant to fatigue relative to controls. Conclusion; These results provide the first evidence of adaptive changes of the SM in new-borns exposed to severe gestational food restriction. The effects of GUN on muscle at birth are the first step toward detrimental SM metabolic function, contributing to the physiopathology of metabolic diseases in adulthood.

  5. D-TRP(8-γMSH Prevents the Effects of Endotoxin in Rat Skeletal Muscle Cells through TNFα/NF-KB Signalling Pathway.

    Directory of Open Access Journals (Sweden)

    Ana Belén Gómez-SanMiguel

    Full Text Available Sepsis induces anorexia and muscle wasting secondary to an increase in muscle proteolysis. Melanocyte stimulating hormones (MSH is a family of peptides that have potent anti-inflammatory effects. Melanocortin receptor-3 (MC3-R has been reported as the predominant anti-inflammatory receptor for melanocortins. The aim of this work was to analyse whether activation of MC3-R, by administration of its agonist D-Trp(8-γMSH, is able to modify the response of skeletal muscle to inflammation induced by lipopolysaccharide endotoxin (LPS or TNFα. Adult male rats were injected with 250 μg/kg LPS and/or 500 μg/kg D-Trp(8-γMSH 17:00 h and at 8:00 h the following day, and euthanized 4 hours afterwards. D-Trp(8-γMSH decreased LPS-induced anorexia and prevented the stimulatory effect of LPS on hypothalamic IL-1β, COX-2 and CRH as well as on serum ACTH and corticosterone. Serum IGF-I and its expression in liver and gastrocnemius were decreased in rats injected with LPS, but not in those that also received D-Trp(8-γMSH. However, D-Trp(8-γMSH was unable to modify the effect of LPS on IGFBP-3. In the gastrocnemius D-Trp(8-γMSH blocked LPS-induced decrease in pAkt, pmTOR, MHC I and MCH II, as well as the increase in pNF-κB(p65, FoxO1, FoxO3, LC3b, Bnip-3, Gabarap1, atrogin-1, MuRF1 and in LC3a/b lipidation. In L6 myotube cultures, D-Trp(8-γMSH was able to prevent TNFα-induced increase of NF-κB(p65 phosphorylation and decrease of Akt phosphorylation as well as of IGF-I and MHC I expression. These data suggest that MC3-R activation prevents the effect of endotoxin on skeletal wasting by modifying inflammation, corticosterone and IGF-I responses and also by directly acting on muscle cells through the TNFα/NF-κB(p65 pathway.

  6. Trimethyltin (TMT) neurotoxicity in organotypic rat hippocampal slice cultures

    DEFF Research Database (Denmark)

    Noraberg, J; Gramsbergen, J B; Fonnum, F

    1998-01-01

    The neurotoxic effects of trimethyltin (TMT) on the hippocampus have been extensively studied in vivo. In this study, we examined whether the toxicity of TMT to hippocampal neurons could be reproduced in organotypic brain slice cultures in order to test the potential of this model for neurotoxico......The neurotoxic effects of trimethyltin (TMT) on the hippocampus have been extensively studied in vivo. In this study, we examined whether the toxicity of TMT to hippocampal neurons could be reproduced in organotypic brain slice cultures in order to test the potential of this model...... for neurotoxicological studies, including further studies of neurotoxic mechanisms of TMT. Four-week-old cultures, derived from 7-day-old donor rats and grown in serum-free medium, were exposed to TMT (0.5-100 microM) for 24 h followed by 24 h in normal medium. TMT-induced neurodegeneration was then monitored by (a...... of TMT neurotoxicity....

  7. [Effects of rutaecarpine on inflammatory cytokines in insulin resistant primary skeletal muscle cells].

    Science.gov (United States)

    Yang, Jian-Wen; Nie, Xu-Qiang; Shi, Hai-Xia; Zhang, Yu-Jin; Zhang, Jian-Yong; Yuan, Ye; Bian, Ka

    2014-08-01

    It is now well established that inflammation plays an important role in the development of numerous chronic metabolic diseases including insulin resistance (IR) and type 2 diabetes (T2DM). Skeletal muscle is responsible for 75% of total insulin-dependent glucose uptake; consequently, skeletal muscle IR is considered to be the primary defect of systemic IR development. Our pre- vious study has shown that rutaecarpine (Rut) can benefit blood lipid profile, mitigate inflammation, and improve kidney, liver, pan- creas pathology status of T2DM rats. However, the effects of Rut on inflammatory cytokines in the development of IR-skeletal muscle cells have not been studied. Thus, our objective was to investigate effects of Rut on inflammatory cytokines interleukiri (IL)-1, IL-6 and tumor necrosis factor (TNF)-α in insulin resistant primary skeletal muscle cells (IR-PSMC). Primary cultures of skeletal muscle cells were prepared from 5 neonate SD rats, and the primary rat skeletal muscle cells were identified by cell morphology, effect of ru- taecarpine on cell proliferation by MTT assay. IR-PSMC cells were induced by palmitic acid (PA), the glucose concentration was measured by glucose oxidase and peroxidase (GOD-POD) method. The effects of Rut on inflammatory cytokines IL-1, IL-6 and TNF-α in IR-PSMC cells were tested by enzyme-linked immunosorbent assay (ELISA) kit. The results show that the primary skeletal muscle cells from neonatal rat cultured for 2-4 days, parallel alignment regularly, and cultured for 7 days, cells fused and myotube formed. It was shown that Rut in concentration 0-180. 0 μmol x L(-1) possessed no cytotoxic effect towards cultured primary skeletal muscle cells. However, after 24 h exposure to 0.6 mmol x L(-1) PA, primary skeletal muscle cells were able to induce a state of insulin resistance. The results obtained indicated significant decrease (P inflammatory cytokines in the IR-PSMC cells.

  8. Transformation of adult rat cardiac myocytes in primary culture.

    Science.gov (United States)

    Banyasz, Tamas; Lozinskiy, Ilya; Payne, Charles E; Edelmann, Stephanie; Norton, Byron; Chen, Biyi; Chen-Izu, Ye; Izu, Leighton T; Balke, C William

    2008-03-01

    We characterized the morphological, electrical and mechanical alterations of cardiomyocytes in long-term cell culture. Morphometric parameters, sarcomere length, T-tubule density, cell capacitance, L-type calcium current (I(Ca,L)), inward rectifier potassium current (I(K1)), cytosolic calcium transients, action potential and contractile parameters of adult rat ventricular myocytes were determined on each day of 5 days in culture. We also analysed the health of the myocytes using an apoptotic/necrotic viability assay. The data show that myocytes undergo profound morphological and functional changes during culture. We observed a progressive reduction in the cell area (from 2502 +/- 70 microm(2) on day 0 to 1432 +/- 50 microm(2) on day 5), T-tubule density, systolic shortening (from 0.11 +/- 0.02 to 0.05 +/- 0.01 microm) and amplitude of calcium transients (from 1.54 +/- 0.19 to 0.67 +/- 0.19) over 5 days of culture. The negative force-frequency relationship, characteristic of rat myocardium, was maintained during the first 2 days but diminished thereafter. Cell capacitance (from 156 +/- 8 to 105 +/- 11 pF) and membrane currents were also reduced (I(Ca,L), from 3.98 +/- 0.39 to 2.12 +/- 0.37 pA pF; and I(K1), from 34.34p +/- 2.31 to 18.00 +/- 5.97 pA pF(-1)). We observed progressive depolarization of the resting membrane potential during culture (from 77.3 +/- 2.5 to 34.2 +/- 5.9 mV) and, consequently, action potential morphology was profoundly altered as well. The results of the viability assays indicate that these alterations could not be attributed to either apoptosis or necrosis but are rather an adaptation to the culture conditions over time.

  9. Glycogen content regulates peroxisome proliferator activated receptor-∂ (PPAR-∂ activity in rat skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Andrew Philp

    Full Text Available Performing exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR coactivator-1α (PGC-1α and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4: control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]. Gastrocnemius (GTN muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E finished with higher AMPK-α2 activity (147%, p<0.05, nuclear AMPK-α2 and PGC-1α, but no difference in AMPK-α1 activity compared to CON. In addition, PPAR-∂ binding to the CPT1 promoter was significantly increased only in the LG-E group. Finally, cell reporter studies in contracting C2C12 myotubes indicated that PPAR-∂ activity following contraction is sensitive to glucose availability, providing mechanistic insight into the association between PPAR-∂ and glycogen content/substrate availability. The present study is the first to examine PPAR-∂ activity in skeletal muscle in response to an acute bout of endurance exercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal

  10. Cholesterol induces fetal rat enterocyte death in culture

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    Gazzola J.

    2004-01-01

    Full Text Available The effect of cholesterol on fetal rat enterocytes and IEC-6 cells (line originated from normal rat small intestine was examined. Both cells were cultured in the presence of 20 to 80 µM cholesterol for up to 72 h. Apoptosis was determined by flow cytometric analysis and fluorescence microscopy. The expression of HMG-CoA reductase and peroxisome proliferator-activated receptor gamma (PPARgamma was measured by RT-PCR. The addition of 20 µM cholesterol reduced enterocyte proliferation as early as 6 h of culture. Reduction of enterocyte proliferation by 28 and 41% was observed after 24 h of culture in the presence and absence of 10% fetal calf serum, respectively, with the effect lasting up to 72 h. Treatment of IEC-6 cells with cholesterol for 24 h raised the proportion of cells with fragmented DNA by 9.7% at 40 µM and by 20.8% at 80 µM. When the culture period was extended to 48 h, the effect of cholesterol was still more pronounced, with the percent of cells with fragmented DNA reaching 53.5% for 40 µM and 84.3% for 80 µM. Chromatin condensation of IEC-6 cells was observed after treatment with cholesterol even at 20 µM. Cholesterol did not affect HMG-CoA reductase expression. A dose-dependent increase in PPARgamma expression in fetal rat enterocytes was observed. The expression of PPAR-gamma was raised by 7- and 40-fold, in the presence and absence of fetal calf serum, respectively, with cholesterol at 80 mM. The apoptotic effect of cholesterol on enterocytes was possibly due to an increase in PPARgamma expression.

  11. Isolating highly pure rat spermatogonial stem cells in culture.

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    Hamra, F Kent; Chapman, Karen M; Wu, Zhuoru; Garbers, David L

    2008-01-01

    Methods are detailed for isolating highly pure populations of spermatogonial stem cells from primary cultures of testis cells prepared from 22- to 24-day-old rats. The procedure is based on the principle that testicular somatic cells bind tightly to plastic and collagen matrices when cultured in serum-containing medium, whereas spermatogonia and spermatocytes do not bind to plastic or collagen when cultured in serum-containing medium. The collagen-non-binding testis cells obtained using these procedures are thus approx. 97% pure spermatogenic cells. Stem spermatogonia are then easily isolated from the purified spermatogenic population during a short incubation step in culture on laminin matrix. The spermatogenic cells that bind to laminin are more than 90% undifferentiated, type A spermatogonia and are greatly enriched in genetically modifiable stem cells that can develop into functional spermatozoa. This method does not require flow cytometry and can also be applied to obtain enriched cultures of mouse spermatogonial stem cells. The isolated spermatogonia provide a highly potent and effective source of stem cells that have been used to initiate in vitro and in vivo culture studies on spermatogenesis.

  12. Effect of Exercise Training on Skeletal Muscle SIRT1 and PGC-1α Expression Levels in Rats of Different Age.

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    Huang, Chi-Chang; Wang, Ting; Tung, Yu-Tang; Lin, Wan-Teng

    2016-01-01

    The protein deacetylase sirtuin 1 (SIRT1) and activate peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) pathway drives the muscular fiber-type switching, and can directly regulate the biophysiological functions of skeletal muscle. To investigate whether 12-week swimming exercise training modulates the SIRT1/PGC-1α pathway associated proteins expression in rats of different age. Male 3-month-old (3M), 12-month-old (12M) and 18-month-old (18M) Sprague-Dawley rats were used and assigned to sedentary control (C) or 12-week swimming exercise training (E) and divided into six groups: 3MC (n = 8), 12MC (n = 6), 18MC (n = 8), 3ME (n = 8), 12ME (n = 5) and 18ME (n = 6). Body weight, muscle weight, epididymal fat mass and muscle morphology were performed at the end of the experiment. The protein levels of SIRT1, PGC-1α, AMPK and FOXO3a in the gastrocnemius and soleus muscles were examined. The SIRT1, PGC-1α and AMPK levels in the gastrocnemius and soleus muscles were up-regulated in the three exercise training groups than three control groups. The FOXO3a level in the 12ME group significantly increased in the gastrocnemius muscles than 12MC group, but significantly decreased in the soleus muscles. In 3-, 12- and 18-month-old rats with and without exercise, there was a significant main effect of exercise on PGC-1α, AMPK and FOXO3a in the gastrocnemius muscles, and SIRT1, PGC-1α and AMPK in the soleus muscles. Our result suggests that swimming training can regulate the SIRT1/PGC-1α, AMPK and FOXO3a proteins expression of the soleus muscles in aged rats.

  13. Basal and insulin-stimulated skeletal muscle sugar transport in endotoxic and bacteremic rats

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    Westfall, M.V.; Sayeed, M.M.

    1988-04-01

    Membrane glucose transport with and without insulin was studied in soleus muscle from 5-h endotoxic rats (40 mg/kg Salmonella enteritidis lipopolysaccharide), and in soleus and epitrochlearis muscles from 12-h bacteremic (Escherichia coli, 4 X 10(10) CFU/kg) rats. Glucose transport was measured in muscles by evaluating the fractional efflux of /sup 14/C-labeled 3-O-methylglucose (/sup 14/C-3-MG) after loading muscles with /sup 14/C-3-MG. Basal 3-MG transport was elevated in soleus muscles from endotoxic as well as in soleus and epitrochlearis muscles from bacteremic rats compared with time-matched controls. Low insulin concentrations stimulated /sup 14/C-3-MG transport more in bacteremic and endotoxic rat muscles than in controls. However, sugar transport in the presence of high insulin dose was attenuated in soleus and epitrochlearis muscles from bacteremic rats and soleus muscles from endotoxic rats compared with controls. Analysis of the dose-response relationship with ALLFIT revealed that the maximal transport response to insulin was significantly decreased in both models of septic shock. Sensitivity to insulin (EC50) was increased in endotoxic rat muscles, and a somewhat similar tendency was observed in bacteremic rat soleus muscles. Neural and humoral influences and/or changes in cellular metabolic energy may contribute to the increase in basal transport. Shifts in insulin-mediated transport may be due to alterations in insulin-receptor-effector coupling and/or the number of available glucose transporters.

  14. Culturing Schwann Cells from Neonatal Rats by Improved Enzyme Digestion Combined with Explants-culture Method.

    Science.gov (United States)

    Liu, Di; Liang, Xiao-Chun; Zhang, Hong

    2016-08-01

    Objective To develop an improved method for culturing Schwann cells(SCs) by using both enzyme digestion and explants-culture approaches and compared with traditional explants-culture method and general hemi-explants-culture method. Methods Bilaterally sciatic nerves and brachial plexus nerves were dissected from 3 to 5-day-old neonatal SD rats and explants-culture method,general hemi-explants-culture method,and improved enzyme digestion combined with explants-culture method were adopted to culture SCs,respectively. SCs were digested and passaged after 7 days in culture and counted under the microscope. The purity of SCs was identified by S-100 immunofluorescence staining. Results The SCs of improved method group grew fastest and the total number of cells obtained was(1.85±0.13)×10(6);the SCs of the hemi-explants-culture method group grew slower than the improved method group and the total number of cells obtained was (1.10±0.10)×10(6);the SCs of the explants-culture method group grew slowest and the total number of cells obtained was (0.77±0.03)×10(6).The total number of cells obtained showed significant difference among the three groups(Pculture method group,and (74.50±4.23)% in the explants-culture method group(Pculture method can obtain sufficient amount of high-purity SCs in a short time and thus may be applied in further research on peripheral nerve regeneration.

  15. Mycelial culture of Phellinus linteus protects primary cultured rat hepatocytes against hepatotoxins.

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    Kim, S H; Lee, H S; Lee, S; Cho, J; Ze, K; Sung, J; Kim, Y C

    2004-12-01

    Hepatoprotective activity of Phellinus linteus was studied using H(2)O(2)- or galactosamine-injured primary cultures of rat hepatocytes as screening systems. The methanolic extract of the mycelial culture of Phellinus linteus significantly protected against hepatotoxins-induced toxicity in primary cultured rat hepatocytes as seen from the decreased level of glutamic pyruvic transaminase released from the injured hepatocytes. The methanolic extract of the mycelial culture of Phellinus linteus was subsequently fractionated with n-hexane, ethyl acetate, n-butanol and water. Among these fractions, 100 microg/mL of the ethyl acetate fraction was the most active one. The relative protections were 68.9 +/- 5.3% in H(2)O(2)-injured hepatocytes and 46.8 +/- 3.9% in galactosamine-injured hepatocytes, respectively. The ethyl acetate fraction appeared to maintain the glutathione level which was decreased by the treatment of H(2)O(2) or galactosamine and restored the level of RNA synthesis more than two times compared to galactosamine-injured hepatocytes. These results suggest that the ethyl acetate fraction of the mycelial culture of Phellinus linteus protects hepatocytes from H(2)O(2)- or galactosamine-induced injury by maintaining hepatic glutathione level and RNA synthesis as well.

  16. A Modified Technique for Culturing Primary Fetal Rat Cortical Neurons

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    Sui-Yi Xu

    2012-01-01

    Full Text Available The study explored a modified primary culture system for fetal rat cortical neurons. Day E18 embryos from pregnant Sprague Dawley rats were microdissected under a stereoscope. To minimize enzymatic damage to the cultured neurons, we applied a sequential digestion protocol using papain and Dnase I. The resulting sifted cell suspension was seeded at a density of 50,000 cells per cm2 onto 0.1 mg/mL L-PLL-covered vessels. After a four-hour incubation in high-glucose Dulbecco’s Modified Eagle’s Medium (HG-DMEM to allow the neurons to adhere, the media was changed to neurobasal medium that was refreshed by changing half of the volume after three days followed by a complete medium change every week. The cells displayed progressively robust neurite extension, and nonneuronal-like cells could barely be detected by five days in vitro (DIV; cell growth was still substantial at 14 DIV. Neurons were identified by β-tubulin III immunofluorescence, and neuronal purity within the cultures was assessed at over 95% by both flow cytometry and by dark-field counting of β-tubulin III-positive cells. These results suggest that the protocol was successful and that the high purity of neurons in this system could be used as the basis for generating various cell models of neurological disease.

  17. Whey protein hydrolysate enhances HSP90 but does not alter HSP60 and HSP25 in skeletal muscle of rats.

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    Carolina Soares Moura

    Full Text Available Whey protein hydrolysate (WPH intake has shown to increase HSP70 expression. The aim of the present study was to investigate whether WPH intake would also influences HSP90, HSP60 and HSP25 expression, as well as associated parameters. Forty-eight male Wistar rats were divided into sedentary (unstressed and exercised (stressed groups, and were fed with three different sources of protein: whey protein (WP, whey protein hydrolysate (WPH and casein (CAS as a control, based on the AIN93G diet for 3 weeks. WPH intake increased HSP90 expression in both sedentary and exercised animals compared to WP or CAS, however no alteration was found from exercise or diet to HSP60 or HSP25. Co-chaperone Aha1 and p-HSF1 were also increased in the exercised animals fed with WPH in comparison with WP or CAS, consistent with enhanced HSP90 expression. VEGF and p-AKT were increased in the WPH exercised group. No alteration was found in BCKDH, PI3-Kinase (p85, GFAT, OGT or PGC for diet or exercise. The antioxidant system GPx, catalase and SOD showed different responses to diet and exercise. The data indicate that WPH intake enhanced factors related to cell survival, such as HSP90 and VEGF, but does not alter HSP60 or HSP25 in rat skeletal muscle.

  18. Endurance exercise induces REDD1 expression and transiently decreases mTORC1 signaling in rat skeletal muscle

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    Hayasaka, Miki; Tsunekawa, Haruka; Yoshinaga, Mariko; Murakami, Taro

    2014-01-01

    Abstract Working muscle conserves adenosine triphosphate (ATP) for muscle contraction by attenuating protein synthesis through several different pathways. Regulated in development and DNA damage response 1 (REDD1) is one candidate protein that can itself attenuate muscle protein synthesis during muscle contraction. In this study, we investigated whether endurance exercise induces REDD1 expression in association with decreased mammalian target of rapamycin (mTOR) complex I (mTORC1) signaling and global protein synthesis in rat skeletal muscle. After overnight fasting, rats ran on a treadmill at a speed of 28 m/min for 60 min, and were killed before and immediately, 1, 3, 6, 12, and 24 h after exercise. REDD1 mRNA and corresponding protein levels increased rapidly immediately after exercise, and gradually decreased back to the basal level over a period of 6 h in the gastrocnemius muscle. Phosphorylation of mTOR Ser2448 and S6K1 Thr389 increased with the exercise, but diminished in 1–3 h into the recovery period after cessation of exercise. The rate of protein synthesis, as determined by the surface sensing of translation (SUnSET) method, was not altered by exercise in fasted muscle. These results suggest that REDD1 attenuates exercise‐induced mTORC1 signaling. This may be one mechanism responsible for blunting muscle protein synthesis during exercise and in the early postexercise recovery period. PMID:25539833

  19. The effect of exercises on the content and reception of the steroid hormones in rat skeletal muscles.

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    Tchaikovsky, V S; Astratenkova, J V; Basharina, O B

    1986-01-01

    Two peaks of hormone concentration in blood and skeletal muscles (SM) were found, immediately after intensive physical exercises (PE) and the late period of rest. Immediately after PE testosterone (T) and estradiol (E2) concentration in SM increased on 36 and 430%, returning to the initial level in 2 h. E2 and androstenedione content in SM increased from 33 +/- 7 to 89 +/- 3 and from 563 +/- 58 to 767 +/- 38 pg/g tissue accordingly in 48 h, returning to the initial level in 72 h. T content increased in blood 3.7-fold in SM 2.2-fold in 72 h after PE. Androgen receptor (AR) contents in SM cytosol increased (on 28%) in 2 h, then returned to the control level and increased again in 72 h (from 0.6 +/- 0.4 to 1.2 +/- 0.2 fmol/mg protein) after PE. Kd did not change significantly and were 0.33 +/- 0.03 nM. The experiments on female rats showed the same tendency, but T increasing was more marked compared to male rats. The obtained results showed that the hormonal regulation of metabolic processes in SM has a cyclic character and is connected with the changing of hormonal content and hormonal SM receptors.

  20. Effect of Electrical Stimulation and Vibration Therapy on Skeletal Muscle Trophism in Rats with Complete Spinal Cord Injury.

    Science.gov (United States)

    Butezloff, Mariana M; Zamarioli, Ariane; Maranho, Daniel A; Shimano, Antonio C

    2015-11-01

    The goals of this work were to analyze the skeletal muscle changes after complete spinal cord injury (SCI) in rats and to compare the effects of electrical stimulation and whole-body vibration on prevention of muscle hypotrophy in these animals. Seven-week-old male Wistar rats were divided into four groups: (1) sham operation (sham, n = 12), (2) SCI (n = 10), (3) SCI + electrical stimulation (n = 9), and (4) SCI + whole-body vibration (n = 9). Complete SCI was generated by surgical transection of the cord at the T10 level. Therapies were initiated 3 days after the surgery and continued for 30 days at a frequency of 3 days per week, 20 mins per day. The animals were killed on day 33 after injury for subsequent analyses. SCI caused a significant decrease in muscle mass and fibers, perimeter measurements, and mechanical resistance to traction as well as an increase in fibrotic tissue. Electrical stimulation, but not whole-body vibration, resulted in significant partial muscle hypotrophy prevention. Electrical stimulation may be a potentially beneficial therapeutic modality to prevent muscle hypotrophy after SCI.

  1. Influence of rat substrain and growth conditions on the characteristics of primary cultures of adult rat spinal cord astrocytes.

    Science.gov (United States)

    Codeluppi, Simone; Gregory, Ebba Norsted; Kjell, Jacob; Wigerblad, Gustaf; Olson, Lars; Svensson, Camilla I

    2011-04-15

    Primary astrocyte cell cultures have become a valuable tool for studies of signaling pathways that regulate astrocyte physiology, reactivity, and function; however, differences in culture preparation affect data reproducibility. The aim of this work was to define optimal conditions for obtaining primary astrocytes from adult rat spinal cord with an expression profile most similar to adult human spinal cord astrocytes. Hence, we examined whether different Sprague-Dawley substrains and culture conditions affect astrocyte culture quality. Medium supplemented with fetal bovine serum from three sources (Sigma, Gibco, Hyclone) or a medium with defined composition (AM medium) was used to culture astrocytes isolated from spinal cords of adult Harlan and Charles River Spraque-Dawley rats. Purity was significantly different between cultures established in media with different sera. No microglia were detected in AM or Hyclone cultures. Gene expression was also affected, with AM cultures expressing the highest level of glutamine synthetase, connexin-43, and glutamate transporter-1. Interestingly, cell response to starvation was substrain dependent. Charles River-derived cultures responded the least, while astrocytes derived from Harlan rats showed a greater decrease in Gfap and glutamine synthetase, suggesting a more quiescent phenotype. Human and Harlan astrocytes cultured in AM media responded similarly to starvation. Taken together, this study shows that rat substrain and growth medium composition affect purity, expression profile and response to starvation of primary astrocytes suggesting that cultures of Harlan rats in AM media have optimal astrocyte characteristics, purity, and similarity to human astrocytes.

  2. Alternate-Day High-Fat Diet Induces an Increase in Mitochondrial Enzyme Activities and Protein Content in Rat Skeletal Muscle.

    Science.gov (United States)

    Li, Xi; Higashida, Kazuhiko; Kawamura, Takuji; Higuchi, Mitsuru

    2016-04-06

    Long-term high-fat diet increases muscle mitochondrial enzyme activity and endurance performance. However, excessive calorie intake causes intra-abdominal fat accumulation and metabolic syndrome. The purpose of this study was to investigate the effect of an alternating day high-fat diet on muscle mitochondrial enzyme activities, protein content, and intra-abdominal fat mass in rats. Male Wistar rats were given a standard chow diet (CON), high-fat diet (HFD), or alternate-day high-fat diet (ALT) for 4 weeks. Rats in the ALT group were fed a high-fat diet and standard chow every other day for 4 weeks. After the dietary intervention, mitochondrial enzyme activities and protein content in skeletal muscle were measured. Although body weight did not differ among groups, the epididymal fat mass in the HFD group was higher than those of the CON and ALT groups. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities in the plantaris muscle of rats in HFD and ALT were significantly higher than that in CON rats, whereas there was no difference between HFD and ALT groups. No significant difference was observed in muscle glycogen concentration or glucose transporter-4 protein content among the three groups. These results suggest that an alternate-day high-fat diet induces increases in mitochondrial enzyme activities and protein content in rat skeletal muscle without intra-abdominal fat accumulation.

  3. Alternate-Day High-Fat Diet Induces an Increase in Mitochondrial Enzyme Activities and Protein Content in Rat Skeletal Muscle

    Science.gov (United States)

    Li, Xi; Higashida, Kazuhiko; Kawamura, Takuji; Higuchi, Mitsuru

    2016-01-01

    Long-term high-fat diet increases muscle mitochondrial enzyme activity and endurance performance. However, excessive calorie intake causes intra-abdominal fat accumulation and metabolic syndrome. The purpose of this study was to investigate the effect of an alternating day high-fat diet on muscle mitochondrial enzyme activities, protein content, and intra-abdominal fat mass in rats. Male Wistar rats were given a standard chow diet (CON), high-fat diet (HFD), or alternate-day high-fat diet (ALT) for 4 weeks. Rats in the ALT group were fed a high-fat diet and standard chow every other day for 4 weeks. After the dietary intervention, mitochondrial enzyme activities and protein content in skeletal muscle were measured. Although body weight did not differ among groups, the epididymal fat mass in the HFD group was higher than those of the CON and ALT groups. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities in the plantaris muscle of rats in HFD and ALT were significantly higher than that in CON rats, whereas there was no difference between HFD and ALT groups. No significant difference was observed in muscle glycogen concentration or glucose transporter-4 protein content among the three groups. These results suggest that an alternate-day high-fat diet induces increases in mitochondrial enzyme activities and protein content in rat skeletal muscle without intra-abdominal fat accumulation. PMID:27058555

  4. Role of carnitine palmitoyltransferase I in the control of ketogenesis in primary cultures of rat astrocytes.

    Science.gov (United States)

    Blázquez, C; Sánchez, C; Velasco, G; Guzmán, M

    1998-10-01

    The role of carnitine palmitoyltransferase I (CPT-I) in the control of ketogenesis was studied in primary cultures of rat astrocytes. Ketone bodies were the major product of [14C]palmitate oxidation by cultured astrocytes, whereas CO2 made a minor contribution to the total oxidation products. Using tetradecylglycidate as a specific, cell-permeable inhibitor of CPT-I, a flux control coefficient of 0.77 +/- 0.07 was calculated for CPT-I over the flux of [14C]palmitate to ketone bodies. CPT-I from astrocytes was sensitive to malonyl-CoA (IC50 = 3.4 +/- 0.8 microM) and cross-reacted on western blots with an antibody raised against liver CPT-I. On the other hand, astrocytes expressed significant acetyl-CoA carboxylase (ACC) activity, and consequently they contained considerable amounts of malonyl-CoA. Western blot analysis of ACC isoforms showed that ACC in astrocytes--like in neurons, liver, and white adipose tissue--mostly comprised the 265-kDa isoform, whereas the 280-kDa isoform--which was highly expressed in skeletal muscle--showed much lower abundance. Forskolin was used as a tool to study the modulation of the ketogenic pathway in astrocytes. Thus, forskolin decreased in parallel ACC activity and intracellular malonyl-CoA levels, whereas it stimulated CPT-I activity and [14C]palmitate oxidation to both ketone bodies and CO2. Results show that in cultured astrocytes (a) CPT-I exerts a very high degree of control over ketogenesis from palmitate, (b) the ACC/malonyl-CoA/CPT-I system is similar to that of liver, and (c) the ACC/malonyl-CoA/CPT-I system is subject to regulation by cyclic AMP.

  5. Assessment of reactive oxygen species production in cultured equine skeletal myoblasts in response to conditions of anoxia followed by reoxygenation with or without exposure to peroxidases.

    Science.gov (United States)

    Ceusters, Justine D; Mouithys-Mickalad, Ange A; de la Rebière de Pouyade, Geoffroy; Franck, Thierry J; Votion, Dominique M; Deby-Dupont, Ginette P; Serteyn, Didier A

    2012-03-01

    To culture equine myoblasts from muscle microbiopsy specimens, examine myoblast production of reactive oxygen species (ROS) in conditions of anoxia followed by reoxygenation, and assess the effects of horseradish peroxidase (HRP) and myeloperoxidase (MPO) on ROS production. 5 healthy horses (5 to 15 years old). Equine skeletal myoblast cultures were derived from 1 or 2 microbiopsy specimens obtained from a triceps brachii muscle of each horse. Cultured myoblasts were exposed to conditions of anoxia followed by reoxygenation or to conditions of normoxia (control cells). Cell production of ROS in the presence or absence of HRP or MPO was assessed by use of a gas chromatography method, after which cells were treated with a 3,3'-diaminobenzidine chromogen solution to detect peroxidase binding. Equine skeletal myoblasts were successfully cultured from microbiopsy specimens. In response to anoxia and reoxygenation, ROS production of myoblasts increased by 71%, compared with that of control cells. When experiments were performed in the presence of HRP or MPO, ROS production in myoblasts exposed to anoxia and reoxygenation was increased by 228% and 183%, respectively, compared with findings for control cells. Chromogen reaction revealed a close adherence of peroxidases to cells, even after several washes. Results indicated that equine skeletal myoblast cultures can be generated from muscle microbiopsy specimens. Anoxia-reoxygenation-treated myoblasts produced ROS, and production was enhanced in the presence of peroxidases. This experimental model could be used to study the damaging effect of exercise on muscles in athletic horses.

  6. Skeletal muscle regeneration via engineered tissue culture over electrospun nanofibrous chitosan/PVA scaffold.

    Science.gov (United States)

    Kheradmandi, Mahsa; Vasheghani-Farahani, Ebrahim; Ghiaseddin, Ali; Ganji, Fariba

    2016-07-01

    Skeletal muscle tissue shows a remarkable potential in regeneration of injured tissue. However, in some of chronic and volumetric muscle damages, the native tissue is incapable to repair and remodeling the trauma. In the same condition, stem-cell therapy increased regeneration in situations of deficient muscle repair, but the major problem seems to be the lack of ability to attachment and survive of injected cells on the exact location. In this study, chitosan/poly(vinyl alcohol) nanofibrous scaffold was studied to promote cell attachment and provide mechanical support during regeneration. Scaffold was characterized using scanning electron microscope, X-ray diffraction, and tensile test. Degradation and swelling behavior of scaffold were studied for 20 days. The cell-scaffold interaction was characterized by MTT assay for 10 days and in vivo biocompatibility of scaffold in a rabbit model was evaluated. Results showed that cells had a good viability, adhesion, growth, and spread on the scaffold, which make this mat a desirable engineered muscular graft. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1720-1727, 2016.

  7. Decreased in vivo glucose uptake but normal expression of GLUT1 and GLUT4 in skeletal muscle of diabetic rats.

    Science.gov (United States)

    Kahn, B B; Rossetti, L; Lodish, H F; Charron, M J

    1991-01-01

    This study was designed to determine whether altered glucose transporter expression is essential for the in vivo insulin-resistant glucose uptake characteristic of streptozocin-induced diabetes. Immunofluorescence in rat skeletal muscle colocalizes GLUT4 with dystrophin, both intrinsic to muscle fibers. In contrast, GLUT1 is extrinsic to muscle fibers, probably in perineurial sheath. Immunoblotting shows that levels of GLUT1 and GLUT4 protein per DNA in hindlimb muscle are unaltered from control levels at 7 d of diabetes but decrease to approximately 20% of control at 14 d of diabetes. This decrease is prevented by insulin treatment. In adipose cells of 7 d diabetic rats, GLUT4 levels are depressed. Thus, GLUT4 undergoes tissue-specific regulation in response to diabetes. GLUT4 and GLUT1 mRNA levels in muscle are decreased 62-70% at both 7 and 14 d of diabetes and are restored by insulin treatment. At 7 d of diabetes, when GLUT4 protein levels in muscle are unaltered, in vivo insulin-stimulated glucose uptake measured by euglycemic clamp is 54% of control. This reflects impairment in both glycogen synthesis and glycolysis and the substrate common to these two pathways, glucose-6-phosphate, is decreased approximately 30% in muscle of diabetic rats. These findings suggest a defect early in the pathway of glucose utilization, probably at the step of glucose transport. Because GLUT1 and GLUT4 levels are unaltered at 7 d of diabetes, reduced glucose uptake in muscle probably reflects impaired glucose transporter translocation or intrinsic activity. Later, at 14 d of diabetes, GLUT1 and GLUT4 protein levels are reduced, suggesting that sequential defects may contribute to the insulin-resistant glucose transport characteristic of diabetes. Images PMID:2040701

  8. Recovery of skeletal muscle after 3 mo of hindlimb immobilization in rats

    Science.gov (United States)

    Booth, F. W.; Seider, M. J.

    1979-01-01

    During immobilization, skeletal muscle undergoes decreases in size and strength with concomitant atrophic and degenerative changes in slow-twitch muscle fibers. Currently there are no objective data in slow-twitch muscle demonstrating recovery of biochemical or physiological indices following termination of immobilization. The purpose of this study was to determine whether the soleus, a slow-twitch muscle, could recover normal biochemical or physiological levels following termination of immobilization. Adenosine triphosphate, glycogen, and protein concentration (mg/g wet wt) all significantly decreased following 90 days of hindlimb immobilization, but these three values returned to control levels by the 60th recovery day. Similarly, soleus muscle wet weight and protein content (mg protein/muscle) returned to control levels by the 14th recovery day. In contrast, maximal isometric tension did not return to normal until the 120th day. These results indicate that following muscular atrophy, which was achieved through 90 days of hindlimb immobilization, several biochemical and physiological values in skeletal muscle are recovered at various times after the end of immobilization.

  9. Maternal High Fat Diet Alters Skeletal Muscle Mitochondrial Catalytic Activity in Adult Male Rat Offspring

    Science.gov (United States)

    Pileggi, Chantal A.; Hedges, Christopher P.; Segovia, Stephanie A.; Markworth, James F.; Durainayagam, Brenan R.; Gray, Clint; Zhang, Xiaoyuan D.; Barnett, Matthew P. G.; Vickers, Mark H.; Hickey, Anthony J. R.; Reynolds, Clare M.; Cameron-Smith, David

    2016-01-01

    A maternal high-fat (HF) diet during pregnancy can lead to metabolic compromise, such as insulin resistance in adult offspring. Skeletal muscle mitochondrial dysfunction is one mechanism contributing to metabolic impairments in insulin resistant states. Therefore, the present study aimed to investigate whether mitochondrial dysfunction is evident in metabolically compromised offspring born to HF-fed dams. Sprague-Dawley dams were randomly assigned to receive a purified control diet (CD; 10% kcal from fat) or a high fat diet (HFD; 45% kcal from fat) for 10 days prior to mating, throughout pregnancy and during lactation. From weaning, all male offspring received a standard chow diet and soleus muscle was collected at day 150. Expression of the mitochondrial transcription factors nuclear respiratory factor-1 (NRF1) and mitochondrial transcription factor A (mtTFA) were downregulated in HF offspring. Furthermore, genes encoding the mitochondrial electron transport system (ETS) respiratory complex subunits were suppressed in HF offspring. Moreover, protein expression of the complex I subunit, NDUFB8, was downregulated in HF offspring (36%), which was paralleled by decreased maximal catalytic linked activity of complex I and III (40%). Together, these results indicate that exposure to a maternal HF diet during development may elicit lifelong mitochondrial alterations in offspring skeletal muscle. PMID:27917127

  10. Histomorphometric analysis of the response of rat skeletal muscle to swimming, immobilization and rehabilitation

    Directory of Open Access Journals (Sweden)

    C.C.F. Nascimento

    2008-09-01

    Full Text Available The objective of the present study was to determine to what extent, if any, swimming training applied before immobilization in a cast interferes with the rehabilitation process in rat muscles. Female Wistar rats, mean weight 260.52 ± 16.26 g, were divided into 4 groups of 6 rats each: control, 6 weeks under baseline conditions; trained, swimming training for 6 weeks; trained-immobilized, swimming training for 6 weeks and then immobilized for 1 week; trained-immobilized-rehabilitated, swimming training for 6 weeks, immobilized for 1 week and then remobilized with swimming for 2 weeks. The animals were then sacrificed and the soleus and tibialis anterior muscles were dissected, frozen in liquid nitrogen and processed histochemically (H&E and mATPase. Data were analyzed statistically by the mixed effects linear model (P < 0.05. Cytoarchitectural changes such as degenerative characteristics in the immobilized group and regenerative characteristics such as centralized nucleus, fiber size variation and cell fragmentation in the groups submitted to swimming were more significant in the soleus muscle. The diameters of the lesser soleus type 1 and type 2A fibers were significantly reduced in the trained-immobilized group compared to the trained group (P < 0.001. In the tibialis anterior, there was an increase in the number of type 2B fibers and a reduction in type 2A fibers when trained-immobilized rats were compared to trained rats (P < 0.001. In trained-immobilized-rehabilitated rats, there was a reduction in type 2B fibers and an increase in type 2A fibers compared to trained-immobilized rats (P < 0.009. We concluded that swimming training did not minimize the deleterious effects of immobilization on the muscles studied and that remobilization did not favor tissue re-adaptation.

  11. Cadmium accelerates bone loss in ovariectomized mice and fetal rat limb bones in culture

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, M.H.; Whelton, B.D.; Stern, P.H.; Peterson, D.P. (Argonne National Lab., IL (USA))

    1988-11-01

    Loss of bone mineral after ovariectomy was studied in mice exposed to dietary cadmium at 0.25, 5, or 50 ppm. Results show that dietary cadmium at 50 ppm increased bone mineral loss to a significantly greater extent in ovariectomized mice than in sham-operated controls. These results were obtained from two studies, one in which skeletal calcium content was determined 6 months after ovariectomy and a second in which {sup 45}Ca release from {sup 45}Ca-prelabeled bones was measured immediately after the start of dietary cadmium exposure. Furthermore, experiments with {sup 45}Ca-prelabeled fetal rat limb bones in culture demonstrated that Cd at 10 nM in the medium, a concentration estimated to be in the plasma of mice exposed to 50 ppm dietary Cd, strikingly increased bone resorption. These in vitro results indicate that cadmium may enhance bone mineral loss by a direct action on bone. Results of the in vivo studies are consistent with a significant role of cadmium in the etiology of Itai-Itai disease among postmenopausal women in Japan and may in part explain the increased risk of postmenopausal osteoporosis among women who smoke.

  12. High-intensity interval training increases intrinsic rates of mitochondrial fatty acid oxidation in rat red and white skeletal muscle.

    Science.gov (United States)

    Hoshino, Daisuke; Yoshida, Yuko; Kitaoka, Yu; Hatta, Hideo; Bonen, Arend

    2013-03-01

    High-intensity interval training (HIIT) can increase mitochondrial volume in skeletal muscle. However, it is unclear whether HIIT alters the intrinsic capacity of mitochondrial fatty acid oxidation, or whether such changes are associated with changes in mitochondrial FAT/CD36, a regulator of fatty acid oxidation, or with reciprocal changes in the nuclear receptor coactivator (peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α)) and the corepressor (receptor-interacting protein 140 (RIP140)). We examined whether HIIT alters fatty acid oxidation rates in the isolated subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria of red and white skeletal muscle and (or) induces changes in muscle PGC-1α and RIP140 proteins and mitochondrial FAT/CD36 protein content. Rats were divided into untrained or HIIT-trained groups. HIIT animals performed 10 bouts of 1-min high-intensity treadmill running (30-55 m·min(-1)), separated by 2 min of rest, for 5 days a week for 4 weeks. As expected, after the training period, HIIT increased mitochondrial enzymes (citrate synthase, COXIV, and β-hydroxyacyl CoA dehydrogenase) in red and white muscle, indicating that muscle mitochondrial volume had increased. HIIT also increased the rates of palmitate oxidation in mitochondria of red (37% for SS and 19% for IMF) and white (36% for SS and 12% for IMF) muscle. No changes occurred in SS and IMF mitochondrial FAT/CD36 proteins, despite increasing FAT/CD36 at the whole-muscle level (27% for red and 22% for white). Concurrently, muscle PGC-1α protein was increased in red (22%) and white (16%) muscle, but RIP140 was not altered. These results indicate that increases in SS and IMF mitochondrial fatty acid oxidation induced by HIIT are accompanied by an increase in PGC-1α, but not RIP140 or FAT/CD36.

  13. High-fat diet induces skeletal muscle oxidative stress in a fiber type-dependent manner in rats.

    Science.gov (United States)

    Pinho, Ricardo A; Sepa-Kishi, Diane M; Bikopoulos, George; Wu, Michelle V; Uthayakumar, Abinas; Mohasses, Arta; Hughes, Meghan C; Perry, Christopher G R; Ceddia, Rolando B

    2017-09-01

    This study investigated the effects of high-fat (HF) diet on parameters of oxidative stress among muscles with distinct fiber type composition and oxidative capacities. To accomplish that, male Wistar rats were fed either a low-fat standard chow (SC) or a HF diet for 8 weeks. Soleus, extensor digitorum longus (EDL), and epitrochlearis muscles were collected and mitochondrial H2O2 (mtH2O2) emission, palmitate oxidation, and gene expression and antioxidant system were measured. Chronic HF feeding enhanced fat oxidation in oxidative and glycolytic muscles. It also caused a significant reduction in mtH2O2 emission in the EDL muscle, although a tendency towards a reduction was also found in the soleus and epitrochlearis muscles. In the epitrochlearis, HF diet increased mRNA expression of the NADPH oxidase complex; however, this muscle also showed an increase in the expression of antioxidant proteins, suggesting a higher capacity to generate and buffer ROS. The soleus muscle, despite being highly oxidative, elicited H2O2 emission rates equivalent to only 20% and 35% of the values obtained for EDL and epitrochlearis muscles, respectively. Furthermore, the Epi muscle with the lowest oxidative capacity was the second highest in H2O2 emission. In conclusion, it appears that intrinsic differences related to the distribution of type I and type II fibers, rather than oxidative capacity, drove the activity of the anti- and pro-oxidant systems and determine ROS production in different skeletal muscles. This also suggests that the impact of potentially deleterious effects of ROS production on skeletal muscle metabolism/function under lipotoxic conditions is fiber type-specific. Copyright © 2017. Published by Elsevier Inc.

  14. Implications of combined ovariectomy/multi-deficiency diet on rat bone with age-related variation in bone parameters and bone loss at multiple skeletal sites by DEXA.

    Science.gov (United States)

    Govindarajan, Parameswari; Schlewitz, Gudrun; Schliefke, Nathalie; Weisweiler, David; Alt, Volker; Thormann, Ulrich; Lips, Katrin Susanne; Wenisch, Sabine; Langheinrich, Alexander C; Zahner, Daniel; Hemdan, Nasr Y; Böcker, Wolfgang; Schnettler, Reinhard; Heiss, Christian

    2013-02-28

    Osteoporosis is a multi-factorial, chronic, skeletal disease highly prevalent in post-menopausal women and is influenced by hormonal and dietary factors. Because animal models are imperative for disease diagnostics, the present study establishes and evaluates enhanced osteoporosis obtained through combined ovariectomy and deficient diet by DEXA (dual-energy X-ray absorptiometry) for a prolonged time period. Sprague-Dawley rats were randomly divided into sham (laparotomized) and OVX-diet (ovariectomized and fed with deficient diet) groups. Different skeletal sites were scanned by DEXA at the following time points: M0 (baseline), M12 (12 months post-surgery), and M14 (14 months post-surgery). Parameters analyzed included BMD (bone mineral density), BMC (bone mineral content), bone area, and fat (%). Regression analysis was performed to determine the interrelationships between BMC, BMD, and bone area from M0 to M14. BMD and BMC were significantly lower in OVX-diet rats at M12 and M14 compared to sham rats. The Z-scores were below -5 in OVX-diet rats at M12, but still decreased at M14 in OVX-diet rats. Bone area and percent fat were significantly lower in OVX-diet rats at M14 compared to sham rats. The regression coefficients for BMD vs. bone area, BMC vs. bone area, and BMC vs. BMD of OVX-diet rats increased with time. This is explained by differential percent change in BMD, BMC, and bone area with respect to time and disease progression. Combined ovariectomy and deficient diet in rats caused significant reduction of BMD, BMC, and bone area, with nearly 40% bone loss after 14 months, indicating the development of severe osteoporosis. An increasing regression coefficient of BMD vs. bone area with disease progression emphasizes bone area as an important parameter, along with BMD and BMC, for prediction of fracture risk.

  15. Rhynchophylline Protects Cultured Rat Neurons against Methamphetamine Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Dan Dan Xu

    2012-01-01

    Full Text Available Rhynchophylline (Rhy is an active component isolated from species of the genus Uncaria which has been used for the treatment of ailments to the central nervous system in traditional Chinese medicine. Besides acting as a calcium channel blocker, Rhy was also reported to be able to protect against glutamate-induced neuronal death. We thus hypothesize that Rhy may have neuroprotective activity against methamphetamine (MA. The primary neurons were cultured directly from the cerebral cortex of neonatal rats, acting as in vitro model in the present study. The neurotoxicity of MA and the protective effect of Rhy were evaluated by MTT assay. The effects of MA, Rhy or their combination on intracellular free calcium concentration ([Ca2+]i were determined in individual neocortical neurons by the Fluo-3/AM tracing method. The MTT assay demonstrated that MA has a dose-dependent neurotoxicity in neuronal cultures. The addition of Rhy prior to the exposure to MA prevented neuronal death. Time course studies with the Fluo-3/AM probe showed that Rhy significantly decreased neuronal [Ca2+]i which was elevated by the exposure to MA. Our results suggested that Rhy can protect the neuronal cultures against MA exposure and promptly attenuate intracellular calcium overload triggered by MA challenge. This is the first report demonstrating an inhibitory effect of Rhy against MA impairment in cultured neurons in vitro.

  16. [Metabolic characterization of rat sertoli cell in vitro culture].

    Science.gov (United States)

    Shi, Bingyang; Zhang, Shuxiang; Guo, Meijin; Wang, Yonghong; Zhang, Siliang; Shi, Xiaolin

    2009-05-01

    Sertoli cell (SC) is intrinsic to the testis and provides an appropriate growth environment for the germ cells. It was separated from rat's testis and identified by hematoxylin and eosin staining(HE) and immunocytochemical reaction, then cultivated in vitro. Culture conditions such as pH, osmotic pressure and metabolic parameters that include consumption rates of glucose, glutamine, amino acids and formation rates of lactic acid, ammonium ion were investigated. It was showed that adhesion process of SCs was accomplished within 2-4 hours after inoculation. It was also observed that the SCs entered into the decline phase when the concentration of ammonium ion and lactic acid were above 2.3 mmol/L and 14 mmol/L, respectively, which caused osmotic pressure above 326 mosm/kg and pH below 6.8 in the medium. As the changes of amino acids during culture were concerned, Glu and Ala accumulated rapidly, while Val, Leu, Ile reduced slightly and at the same time Ser, Arg, and Gly were stable. The restrict factors for SCs grown in static culture might be high osmotic pressure and low pH, which were generated when glutamine and glucose were metabolized into lactic acid. The findings could be fundamental in the process optimization of large scale Sertoli cells in vitro culture.

  17. Characterization of glucose uptake by cultured rat podocytes.

    Science.gov (United States)

    Lewko, Barbara; Bryl, Ewa; Witkowski, Jacek M; Latawiec, Elzbieta; Gołos, Magdalena; Endlich, Nicole; Hähnel, Brunhilde; Koksch, Claudia; Angielski, Stefan; Kriz, Wilhelm; Stepinski, Jan

    2005-01-01

    The nonmetabolizable glucose analogue [(3)H]-2-deoxy-D-glucose ((3)H-2DG) was used to study glucose transport in cultured rat podocytes. Intracellular accumulation of (3)H-2DG was linear up to 20 min and was inhibited by cytochalasin B (80% inhibition) and by phlorizin (20% inhibition). Pretreatment with insulin stimulated the (3)H-2DG uptake 1.5-fold. A Hill analysis of the rate of glucose transport yielded a V(max) value of approximately 10 mM and S(0.5)of 7.8 mM. The value h = 1.0 for a Hill coefficient confirmed that glucose uptake exhibited a Michaelis-Menten kinetics. Transporters GLUT2 and GLUT4 were expressed in over 90% podocytes. Of the GLUT2- and GLUT4-expressing cells, approximately one-fourth expressed the membrane-bound fraction. We conclude that cultured rat podocytes possess a differentiated glucose transport system consisting chiefly of facilitative GLUT2 and GLUT4 transporters. It seems likely that a sodium-dependent glucose cotransporter may also be present in these cells.

  18. [Skeletal muscle mixed fiber tissue metabolism in rats after a flight on the Kosmos-690 biosatellite].

    Science.gov (United States)

    Gaevskaia, M S; Belitskaia, R A; Kolganova, N S; Kolchina, E V; Kurkina, L M

    1979-01-01

    On the R+O day the quadriceps muscle of rats showed a decrease in the content of T protein and an inhibition of LDH activity of sacroplasmatic proteins. These changes resulted from the combined affect of space flight factors and gamma-irradiation, and may be considered as a decline of compensatory synthetic processes responsible for the recovery of muscle proteins in weightlessness. Inhibition of the age-associated shift of the M:H ratio of LDH found on the R+25 day can be attributed to the inhibitory effect of gamma-irradiation. No change in the content of glycogen in the gastrocnemius muscle of flight rats was noted.

  19. Activation of GPR30 improves exercise capacity and skeletal muscle strength in senescent female Fischer344 × Brown Norway rats.

    Science.gov (United States)

    Wang, Hao; Alencar, Allan; Lin, Marina; Sun, Xuming; Sudo, Roberto T; Zapata-Sudo, Gisele; Lowe, Dawn A; Groban, Leanne

    2016-06-17

    The molecular mechanisms of muscle weakness and sarcopenia in postmenopausal women are largely unknown. To determine the effect of a new estrogen receptor, GPR30, in the maintenance of exercise capacity and skeletal muscle function in females, the selective GPR30 agonist, G1 (100 μg/kg/day), or vehicle (V, soybean oil) was administered subcutaneously daily (n = 7 per group) to ovariectomized (OVX) 27-month-old Fischer 344 × Brown Norway (F344BN) female rats. Following 8 weeks of treatment, the exercise capacity (treadmill walk time to exhaustion) was reduced in OVX vs. sham rats (5.1 ± 1.4 vs. 11.0 ± 0.9 min, P exercise capacity (12.9 ± 1.2 min; P effects of estrogen loss on exercise capacity and skeletal muscle contractile function in old F344BN rats. The protective effects of GPR30 might be through its upregulation of heat shock proteins in skeletal muscle. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Metabolic effects of the iodothyronine functional analogue TRC150094 on the liver and skeletal muscle of high-fat diet fed overweight rats: an integrated proteomic study.

    Science.gov (United States)

    Silvestri, Elena; Glinni, Daniela; Cioffi, Federica; Moreno, Maria; Lombardi, Assunta; de Lange, Pieter; Senese, Rosalba; Ceccarelli, Michele; Salzano, Anna Maria; Scaloni, Andrea; Lanni, Antonia; Goglia, Fernando

    2012-07-06

    A novel functional iodothyronine analogue, TRC150094, which has a much lower potency toward thyroid hormone receptor (α1/β1) activation than triiodothyronine, has been shown to be effective at reducing adiposity in rats simultaneously receiving a high-fat diet (HFD). Here, by combining metabolic, functional and proteomic analysis, we studied how the hepatic and skeletal muscle phenotypes might respond to TRC150094 treatment in HFD-fed overweight rats. Drug treatment increased both the liver and skeletal muscle mitochondrial oxidative capacities without altering mitochondrial efficiency. Coherently, in terms of individual respiratory in-gel activity, blue-native analysis revealed an increased activity of complex V in the liver and of complexes II and V in tibialis muscle in TCR150094-treated animals. Subsequently, the identification of differentially expressed proteins and the analysis of their interrelations gave an integrated view of the phenotypic/metabolic adaptations occurring in the liver and muscle proteomes during drug treatment. TRC150094 significantly altered the expression of several proteins involved in key liver metabolic pathways, including amino acid and nitrogen metabolism, and fructose and mannose metabolism. The canonical pathways most strongly influenced by TRC150094 in tibialis muscle included glycolysis and gluconeogenesis, amino acid, fructose and mannose metabolism, and cell signaling. The phenotypic/metabolic influence of TRC150094 on the liver and skeletal muscle of HFD-fed overweight rats suggests the potential clinical application of this iodothyronine analogue in ameliorating metabolic risk parameters altered by diet regimens.

  1. Metformin ameliorates insulin resistance in L6 rat skeletal muscle cells through upregulation of SIRT3

    Institute of Scientific and Technical Information of China (English)

    Song Yuping; Shi Jingli; Wu Ying; Han Chong; Zou Junjie; Shi Yongquan; Liu Zhimin

    2014-01-01

    Background SIRT3 is an important regulator in cell metabolism,and recent studies have shown that it may be involved in the pharmacological effects of mefformin.However,the molecular mechanisms underlying this process are unclear.Methods The effects of SIRT3 on the regulation of oxidative stress and insulin resistance in skeletal muscle were evaluated in vitro.Differentiated L6 skeletal muscle cells were treated with 750 μmol/L palmitic acid to induce insulin resistance.SIRT3 was knocked down and overexpressed in L6 cells.SIRT3,nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65,c-Jun N-terminal kinase 1 (JNK1),and superoxide dismutase 2 (SOD2) were evaluated by Western blotting.Results Over expression of SIRT3 increased glucose uptake and decreased ROS production in L6-IR cells as well as in L6 cells.Knock-down of SIRT3 induced increased production of ROS while decreased glucose uptake in both L6 and L6-IR cells,and these effects were reversed by N-acetyl-L-cysteine (NAC).Metformin increased the expression of SIRT3 (1.5-fold) and SOD2 (2-fold) while down regulating NF-κB p65 (1.5-fold) and JNK1 (1.5-fold).Knockdown of SIRT3 (P<0.05)reversed the metformin-induced decreases in NF-κB p65 and JNK1 and the mefformin-induced increase in SOD2 (P<0.05).Conclusions Upregulated SIRT3 is involved in the pharmacological mechanism by which mefformin promotes glucose uptake.Additionally,SIRT3 may function as an important regulator of oxidative stress and a new alternative approach for targeting insulin resistance-related diseases.

  2. Differential effect of long-term leucine supplementation on skeletal muscle and adipose tissue in old rats: an insulin signaling pathway approach.

    Science.gov (United States)

    Zeanandin, Gilbert; Balage, Michèle; Schneider, Stéphane M; Dupont, Joëlle; Hébuterne, Xavier; Mothe-Satney, Isabelle; Dardevet, Dominique

    2012-04-01

    Leucine acts as a signal nutrient in promoting protein synthesis in skeletal muscle and adipose tissue via mTOR pathway activation, and may be of interest in age-related sarcopenia. However, hyper-activation of mTOR/S6K1 has been suggested to inhibit the first steps of insulin signaling and finally promote insulin resistance. The impact of long-term dietary leucine supplementation on insulin signaling and sensitivity was investigated in old rats (18 months old) fed a 15% protein diet supplemented (LEU group) or not (C group) with 4.5% leucine for 6 months. The resulting effects on muscle and fat were examined. mTOR/S6K1 signaling pathway was not significantly altered in muscle from old rats subjected to long-term dietary leucine excess, whereas it was increased in adipose tissue. Overall glucose tolerance was not changed but insulin-stimulated glucose transport was improved in muscles from leucine-supplemented rats related to improvement in Akt expression and phosphorylation in response to food intake. No change in skeletal muscle mass was observed, whereas perirenal adipose tissue mass accumulated (+45%) in leucine-supplemented rats. A prolonged leucine supplementation in old rats differently modulates mTOR/S6K pathways in muscle and adipose tissue. It does not increase muscle mass but seems to promote hypertrophy and hyperplasia of adipose tissue that did not result in insulin resistance.

  3. Rat whisker movement after facial nerve lesion: Evidence for autonomic contraction of skeletal muscle.

    NARCIS (Netherlands)

    Heaton, J.T.; Sheu, S.H.; Hohman, M.H.; Knox, C.J.; Weinberg, J.S.; Kleiss, I.J.; Hadlock, T.A.

    2014-01-01

    Vibrissal whisking is often employed to track facial nerve regeneration in rats; however, we have observed similar degrees of whisking recovery after facial nerve transection with or without repair. We hypothesized that the source of non-facial nerve-mediated whisker movement after chronic denervati

  4. Histopathological nerve and skeletal muscle changes in rats subjected to persistent insulin-induced hypoglycemia

    DEFF Research Database (Denmark)

    Jensen, Vivi Flou Hjorth; Mølck, Anne-Marie; Heydenreich, Annette;

    2016-01-01

    -study-comparator and thereby reduce the number of animals used during development. Thus, the aims of the present study were i) to develop a preclinical animal model of persistent hypoglycemia in rats using human insulin infusion for four weeks and ii) to investigate histopathological changes in sciatic nerves and quadriceps...

  5. Fractal dimension analysis of weight-bearing bones of rats during skeletal unloading

    Science.gov (United States)

    Pornprasertsuk, S.; Ludlow, J. B.; Webber, R. L.; Tyndall, D. A.; Sanhueza, A. I.; Yamauchi, M.

    2001-01-01

    Fractal analysis was used to quantify changes in trabecular bone induced through the use of a rat tail-suspension model to simulate microgravity-induced osteopenia. Fractal dimensions were estimated from digitized radiographs obtained from tail-suspended and ambulatory rats. Fifty 4-month-old male Sprague-Dawley rats were divided into groups of 24 ambulatory (control) and 26 suspended (test) animals. Rats of both groups were killed after periods of 1, 4, and 8 weeks. Femurs and tibiae were removed and radiographed with standard intraoral films and digitized using a flatbed scanner. Square regions of interest were cropped at proximal, middle, and distal areas of each bone. Fractal dimensions were estimated from slopes of regression lines fitted to circularly averaged plots of log power vs. log spatial frequency. The results showed that the computed fractal dimensions were significantly greater for images of trabecular bones from tail-suspended groups than for ambulatory groups (p fractal dimensions than other regions (p fractal analysis could be a useful technique to evaluate the structural changes of bone.

  6. Effects of Yam and Diosgenin on Calpain Systems in Skeletal Muscle of Ovariectomized Rats

    Directory of Open Access Journals (Sweden)

    Kung-Hao Hsu

    2008-06-01

    Conclusion: Yam, but not its extract (diosgenin, is associated with the regulation of calpain isoforms in ovariectomized rats. Adequate yam supplements might improve the muscular calpain-related physiopathology associated with menopausal status. [Taiwan J Obstet Cynecol 2008;47(2:1 80-186

  7. Transcriptional profiling of rat skeletal muscle hypertrophy under restriction of blood flow.

    Science.gov (United States)

    Xu, Shouyu; Liu, Xueyun; Chen, Zhenhuang; Li, Gaoquan; Chen, Qin; Zhou, Guoqing; Ma, Ruijie; Yao, Xinmiao; Huang, Xiao

    2016-12-15

    Blood flow restriction (BFR) under low-intensity resistance training (LIRT) can produce similar effects upon muscles to that of high-intensity resistance training (HIRT) while overcoming many of the restrictions to HIRT that occurs in a clinical setting. However, the potential molecular mechanisms of BFR induced muscle hypertrophy remain largely unknown. Here, using a BFR rat model, we aim to better elucidate the mechanisms regulating muscle hypertrophy as induced by BFR and reveal possible clinical therapeutic targets for atrophy cases. We performed genome wide screening with microarray analysis to identify unique differentially expressed genes during rat muscle hypertrophy. We then successfully separated the differentially expressed genes from BRF treated soleus samples by comparing the Affymetrix rat Genome U34 2.0 array with the control. Using qRT-PCR and immunohistochemistry (IHC) we also analyzed other related differentially expressed genes. Results suggested that muscle hypertrophy induced by BFR is essentially regulated by the rate of protein turnover. Specifically, PI3K/AKT and MAPK pathways act as positive regulators in controlling protein synthesis where ubiquitin-proteasome acts as a negative regulator. This represents the first general genome wide level investigation of the gene expression profile in the rat soleus after BFR treatment. This may aid our understanding of the molecular mechanisms regulating and controlling muscle hypertrophy and provide support to the BFR strategies aiming to prevent muscle atrophy in a clinical setting. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Ganglioside GM3 content in skeletal muscles is increased in type 2 but decreased in type 1 diabetes rat models: Implications of glycosphingolipid metabolism in pathophysiology of diabetes.

    Science.gov (United States)

    Bozic, Josko; Markotic, Anita; Cikes-Culic, Vedrana; Novak, Anela; Borovac, Josip A; Vucemilovic, Hrvoje; Trgo, Gorana; Ticinovic Kurir, Tina

    2017-05-22

    Ganglioside GM3 is found in the plasma membrane, where its accumulation attenuates insulin receptor signaling. Considering the role of skeletal muscles in insulin-stimulated glucose uptake, the aim of the present study was to determine the expression of GM3 and its precursors in skeletal muscles of rat models of type 1 and type 2 diabetes mellitus (T1DM and T2DM, respectively). Diabetes was induced in male Sprague-Dawley rats by streptozotocin injection (55 mg/kg, i.p., for T1DM induction; 35 mg/kg, i.p., for T2DM induction), followed by feeding of rats with either a normal pellet diet (T1DM) or a high-fat diet (T2DM). Rats were killed 2 weeks after diabetes induction and samples of skeletal muscle were collected. Frozen quadriceps muscle sections were stained with a primary antibody against GM3 (Neu5Ac) and visualized using a secondary antibody coupled with Texas Red. The muscle content of ganglioside GM3 and its precursors was analyzed by high-performance thin-layer chromatography (HPTLC) followed by GM3 immunostaining. Muscle GM3 content was significantly higher in T2DM compared with control rats (P < 0.001). Furthermore, levels of the GM3 precursors ceramide, glucosylceramide, and lactosylceramide were significantly higher in T2DM compared with control rats (P < 0.05), whereas ceramide content was significantly lower in T1DM rats (P < 0.05). The intensity of the GM3 band on HPTLC was significantly higher in T2DM rats (P < 0.001) and significantly lower in T1DM rats (P < 0.05) compared with control. The expression patterns of GM3 ganglioside and its precursors in diabetic rats suggest that the role of glycosphingolipid metabolism may differ between T2DM and T1DM. © 2017 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

  9. Effect of nifedipine on depolarization-induced force responses in skinned skeletal muscle fibres of rat and toad.

    Science.gov (United States)

    Posterino, G S; Lamb, G D

    1998-01-01

    The effect of the dihydropyridine, nifedipine, on excitation-contraction coupling was compared in toad and rat skeletal muscle, using the mechanically skinned fibre technique, in order to understand better the apparently disparate results of previous studies and to examine recent proposals on the importance of certain intracellular factors in determining the efficacy of dihydropyridines. In twitch fibres from the iliofibularis muscle of the toad, 10 microM nifedipine completely inhibited depolarization-induced force responses within 30 s, without interfering with direct activation of the Ca(2+)-release channels by caffeine application or reduction of myoplasmic [Mg2+]. At low concentrations of nifedipine, inhibition was considerably augmented by repeated depolarizations, with half-maximal inhibition occurring at < 0.1 microM nifedipine. In contrast, in rat extensor digitorum longus (EDL) fibres 1 microM nifedipine had virtually no effect on depolarization-induced force responses, and 10 microM nifedipine caused only approximately 25% reduction in the responses, even upon repeated depolarizations. In rat fibres, 10 microM nifedipine shifted the steady-state force inactivation curve to more negative potentials by < 11 mV, whereas in toad fibres the potent inhibitory effect of nifedipine indicated a much larger shift. The inhibitory effect of nifedipine in rat fibres was little, if at all, increased by the absence of Ca2+ in the transverse tubular (t-) system, provided that the Ca2+ was replaced with sufficient Mg2+. The presence of the reducing agents dithiothreitol (10 mM) or glutathione (10 mM) in the solution bathing a toad skinned fibre did not reduce the inhibitory effect of nifedipine, suggesting that the potency of nifedipine in toad skinned fibres was not due to the washout of intracellular reducing agents. The results are considered in terms of a model that can account for the markedly different effects of nifedipine on the two putative functions of the

  10. Effects of acute exercise on lipid content and dietary lipid uptake in liver and skeletal muscle of lean and diabetic rats.

    Science.gov (United States)

    Janssens, Sharon; Jonkers, Richard A M; Groen, Albert K; Nicolay, Klaas; van Loon, Luc J C; Prompers, Jeanine J

    2015-11-15

    Insulin resistance is associated with ectopic lipid accumulation. Physical activity improves insulin sensitivity, but the impact of exercise on lipid handling in insulin-resistant tissues remains to be elucidated. The present study characterizes the effects of acute exercise on lipid content and dietary lipid partitioning in liver and skeletal muscle of lean and diabetic rats by use of magnetic resonance spectroscopy (MRS). After baseline measurements, rats were randomized to exercise or no-exercise groups. A subset of animals was subjected to MRS directly after 1 h of treadmill running for measurement of total intrahepatocellular lipid (IHCL) and intramyocellular lipid (IMCL) content (n=7 lean and diabetic rats). The other animals were administered 13C-labeled lipids orally after treadmill visit (with or without exercise) followed by MRS measurements after 4 and 24 h to determine the 13C enrichment of IHCL and IMCL (n=8 per group). Total IHCL and IMCL content were fivefold higher in diabetic vs. lean rats (Plean and diabetic rats (Plean rats (Plean and diabetic rats, lipid uptake was 44% reduced after acute exercise (Plean and diabetic rats, and exercise differentially affects dietary lipid uptake in muscle and liver.

  11. Computational tool for morphological analysis of cultured neonatal rat cardiomyocytes.

    Science.gov (United States)

    Leite, Maria Ruth C R; Cestari, Idágene A; Cestari, Ismar N

    2015-08-01

    This study describes the development and evaluation of a semiautomatic myocyte edge-detector using digital image processing. The algorithm was developed in Matlab 6.0 using the SDC Morphology Toolbox. Its conceptual basis is the mathematical morphology theory together with the watershed and Euclidean distance transformations. The algorithm enables the user to select cells within an image for automatic detection of their borders and calculation of their surface areas; these areas are determined by adding the pixels within each myocyte's boundaries. The algorithm was applied to images of cultured ventricular myocytes from neonatal rats. The edge-detector allowed the identification and quantification of morphometric alterations in cultured isolated myocytes induced by 72 hours of exposure to a hypertrophic agent (50 μM phenylephrine). There was a significant increase in the mean surface area of the phenylephrine-treated cells compared with the control cells (p<;0.05), corresponding to cellular hypertrophy of approximately 50%. In conclusion, this edge-detector provides a rapid, repeatable and accurate measurement of cell surface areas in a standardized manner. Other possible applications include morphologic measurement of other types of cultured cells and analysis of time-related morphometric changes in adult cardiac myocytes.

  12. Gene expression profiling in skeletal muscle of Zucker diabetic fatty rats: implications for a role of stearoyl-CoA desaturase 1 in insulin resistance.

    Science.gov (United States)

    Voss, M D; Beha, A; Tennagels, N; Tschank, G; Herling, A W; Quint, M; Gerl, M; Metz-Weidmann, C; Haun, G; Korn, M

    2005-12-01

    Insulin resistance in skeletal muscle is a hallmark of type 2 diabetes. Therefore, we sought to identify and validate genes involved in the development of insulin resistance in skeletal muscle. Differentially regulated genes in skeletal muscle of male obese insulin-resistant, and lean insulin-sensitive Zucker diabetic fatty (ZDF) rats were determined using Affymetrix microarrays. Based on these data, various aspects of glucose disposal, insulin signalling and fatty acid composition were analysed in a muscle cell line overexpressing stearoyl-CoA desaturase 1 (SCD1). Gene expression profiling in insulin-resistant skeletal muscle revealed the most pronounced changes in gene expression for genes involved in lipid metabolism. Among these, Scd1 showed increased expression in insulin-resistant animals, correlating with increased amounts of palmitoleoyl-CoA. This was further investigated in a muscle cell line that overexpressed SCD1 and accumulated lipids, revealing impairments of glucose uptake and of different steps of the insulin signalling cascade. We also observed differential effects of high-glucose and fatty acid treatment on glucose uptake and long-chain fatty acyl-CoA profiles, and in particular an accumulation of palmitoleoyl-CoA in cells overexpressing SCD1. Insulin-resistant skeletal muscle of ZDF rats is characterised by a specific gene expression profile with increased levels of Scd1. An insulin-resistant phenotype similar to that obtained by treatment with palmitate and high glucose can be induced in vitro by overexpression of SCD1 in muscle cells. This supports the hypothesis that elevated SCD1 expression is a possible cause of insulin resistance and type 2 diabetes.

  13. Noradrenaline-induced increases in calcium and tension in skeletal muscle conductance and resistance arteries from rats with post-infarction heart failure.

    Science.gov (United States)

    Trautner, Simon; Amtorp, Ole; Boesgaard, Soren; Andersen, Claus B; Galbo, Henrik; Haunsoe, Stig; Sheykhzade, Majid

    2006-05-10

    We tested the hypothesis that arterial reactivity to noradrenaline is augmented in congestive heart failure (CHF), which could contribute to the deleterious changes in peripheral vascular resistance and compliance in this condition. From male Wistar rats with post-infarction CHF and sham-operated rats, skeletal muscle conductance and resistance arteries (mean lumen diameters: 514 and 186 microm) were isolated and mounted on wire myographs, and wall tension was recorded in response to cumulative application of acetylcholine and noradrenaline to the vessel segments. In a subset of experiments, wall tension and cytosolic free calcium ion concentration [Ca(2+)](i) were recorded simultaneously during noradrenaline application, using wire myography and the FURA-2 technique. No significant differences were found in the arterial baseline levels of [Ca(2+)](i) or tension between CHF and sham rats. In the resistance arteries of CHF rats, the noradrenaline-induced increases in [Ca(2+)](i) were significantly enhanced (P=0.003). Despite the augmented [Ca(2+)](i) levels, the tension responses to noradrenaline were unaltered in these arteries. In the conductance arteries, there were no significant differences in noradrenaline-induced [Ca(2+)](i) or tension responses between CHF and control rats. CHF did not alter vascular morphology or change vascular relaxations to acetylcholine in either type of artery. In conclusion, these results do not support the contention that arterial reactivity to noradrenaline is augmented in the skeletal muscle vascular bed in CHF. On the contrary, the unchanged contractile responsiveness in the resistance arteries despite the enhanced levels of [Ca(2+)](i) during noradrenaline application suggests that the contractile function of these vessels is compromised in CHF. Neither vascular remodeling, endothelial dysfunction nor changes in baseline vascular tone could be demonstrated in the skeletal muscle vascular bed of this animal model of heart failure.

  14. Effects of the Infusion of 4% or 20% Human Serum Albumin on the Skeletal Muscle Microcirculation in Endotoxemic Rats.

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    Elisa Damiani

    Full Text Available Sepsis-induced microcirculatory alterations contribute to tissue hypoxia and organ dysfunction. In addition to its plasma volume expanding activity, human serum albumin (HSA has anti-oxidant and anti-inflammatory properties and may have a protective role in the microcirculation during sepsis. The concentration of HSA infused may influence these effects. We compared the microcirculatory effects of the infusion of 4% and 20% HSA in an experimental model of sepsis.Adult male Wistar rats were equipped with arterial and venous catheters and received an intravenous infusion of lipopolysaccharide (LPS, serotype O127:B8, 10 mg/kg over 30 minutes or vehicle (SHAM, n = 6. Two hours later, endotoxemic animals were randomized to receive 10 mL/kg of either 4% HSA (LPS+4%HSA, n = 6, 20% HSA (LPS+20%HSA, n = 6 or 0.9% NaCl (LPS+0.9%NaCl, n = 6. No fluids were given to an additional 6 animals (LPS. Vessel density and perfusion were assessed in the skeletal muscle microcirculation with sidestream dark field videomicroscopy at baseline (t0, 2 hours after LPS injection (t1, after HSA infusion (t2 and 1 hour later (t3. The mean arterial pressure (MAP and heart rate were recorded. Serum endothelin-1 was measured at t2.MAP was stable over time in all groups. The microcirculatory parameters were significantly altered in endotoxemic animals at t1. The infusion of both 4% and 20% HSA similarly increased the perfused vessel density and blood flow velocity and decreased the flow heterogeneity to control values. Microvascular perfusion was preserved in the LPS+20%HSA group at t3, whereas alterations reappeared in the LPS+4%HSA group.In a rat model of normotensive endotoxemia, the infusion of 4% or 20% HSA produced a similar acute improvement in the microvascular perfusion in otherwise unresuscitated animals.

  15. Transcriptome-wide RNA sequencing analysis of rat skeletal muscle feed arteries. II. Impact of exercise training in obesity

    Science.gov (United States)

    Jenkins, Nathan T.; Thorne, Pamela K.; Martin, Jeffrey S.; Rector, R. Scott; Davis, J. Wade; Laughlin, M. Harold

    2014-01-01

    We employed next-generation RNA sequencing (RNA-Seq) technology to determine the extent to which exercise training alters global gene expression in skeletal muscle feed arteries and aortic endothelial cells of obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Transcriptional profiles of the soleus and gastrocnemius muscle feed arteries (SFA and GFA, respectively) and aortic endothelial cell-enriched samples from rats that underwent an endurance exercise training program (EndEx; n = 12) or a interval sprint training program (IST; n = 12) or remained sedentary (Sed; n = 12) were examined. In response to EndEx, there were 39 upregulated (e.g., MANF) and 20 downregulated (e.g., ALOX15) genes in SFA and 1 upregulated (i.e., Wisp2) and 1 downregulated (i.e., Crem) gene in GFA [false discovery rate (FDR) < 10%]. In response to IST, there were 305 upregulated (e.g., MANF, HSPA12B) and 324 downregulated genes in SFA and 101 upregulated and 66 downregulated genes in GFA, with an overlap of 32 genes between arteries. Furthermore, in aortic endothelial cells, there were 183 upregulated (e.g., eNOS, SOD-3) and 141 downregulated (e.g., ATF3, Clec1b, npy, leptin) genes with EndEx and 71 upregulated and 69 downregulated genes with IST, with an overlap of 35 between exercise programs. Expression of only two genes (Tubb2b and Slc9a3r2) was altered (i.e., increased) by exercise in all three arteries. The finding that both EndEx and IST produced greater transcriptional changes in the SFA compared with the GFA is intriguing when considering the fact that treadmill bouts of exercise are associated with greater relative increases in blood flow to the gastrocnemius muscle compared with the soleus muscle. PMID:24408995

  16. Skeletal muscle adaptations following spinal cord contusion injury in rat and the relationship to locomotor function: a time course study.

    Science.gov (United States)

    Hutchinson, K J; Linderman, J K; Basso, D M

    2001-10-01

    Experimental spinal cord injury (SCI) via contusion of moderate severity results in residual locomotor deficits, including a lack of coordination and trunk stability. Given that muscle contractile properties and fiber composition adapt to reduced neural input and/or weight bearing, contusion-induced locomotor deficits may reflect changes in hindlimb skeletal muscle. Therefore, we examined muscle adaptations during early (1 week), intermediate (3 week), and late (10 week) stages of motor recovery after moderate SCI. Forty-two Sprague Dawley rats underwent SCI via 1.1mm cord displacement with the OSU impact device or served as age and weight-matched or laminectomy controls. Subsets of rats had soleus (SOL) in vitro physiological testing or SOL and extensor digitorum longus (EDL) myosin heavy chain (MHC) fiber type analysis. At 1 week post-SCI during paralysis/paresis, a significant decrease in wet weight occurred in the plantaris, medial/lateral gastrocnemius (MG/LG), tibialis anterior, and SOL. Changes in contractile properties of the SOL did not accompany muscle wet weight changes. By 3 weeks, the loss of weight-bearing activity early after SCI induced significant decreases in SOL peak twitch and peak tetanic tension as well as significantly greater IIx MHC expression in the EDL. By 10 weeks post-SCI, after several weeks of weight supported stepping, muscle wet weight, contractile properties and MHC composition returned to baseline levels except for MG/LG atrophy. Thus, muscle plasticity appears to be extremely sensitive to locomotor deficits and their resolution after moderate spinal cord contusion.

  17. Prophylactic Effects of Melatonin on Sodium Valproate-Induced Neural Tube Defects and Skeletal Malformations in Rat Embryos

    Directory of Open Access Journals (Sweden)

    Omolbanin Rahgazar

    2011-01-01

    Full Text Available Problem statement: Some reports showed the teratogenic effects of sodium valproate can be prevented by application of antioxidant drugs and stimulation of the maternal immune system. Therefore, in this study, the prophylactic effect of melatonin on teratogenic effects of sodium valproate was compared. Approach: This study was performed on 31 pregnant rats that were divided into five groups. Control group received normal saline and test groups received sodium valproate (300 mg kg−1, sodium valproate (300 mg kg−1 plus melatonin (5 mg kg−1 and sodium valproate (300 mg kg−1 plus melatonin (10 mg kg−1 and melatonin (10 mg kg−1, intraperitonealy at 8-9th days of gestation, respectively. Fetuses were collected at 20th day of gestation and after determination of weight and length; they were stained by Alizarin red-Alcian blue method. Results: Cleft palate, spina bifida and exencephaly incidence were 17.70, 20 and 20% in fetuses of rats that received only sodium valproate. Cleft palate, spina bifida and exencephaly incidence were 4.16, 8.33 and 8.33% range in group which received sodium valproate plus melatonin (5 mg kg−1, respectively. However, Cleft palate, spina bifida and excencaphaly incidence were 4/76, 0 and 0% in group which received sodium valproate plus melatonin (10 mg kg−1, respectively. The mean of weight and length of animals fetuses that received melatonin were significantly greater than those received only sodium valproate. Conclusion: It is concluded that melatonin with dose of 10 mg kg−1 had significantly more prophylactic effect than melatonin with dose of 5 mg kg−1 on incidence of sodium valproate-induced skeletal malformations.

  18. Expression of heat shock protein 72 in atrophied rat skeletal muscles

    Science.gov (United States)

    Oishi, Y.; Ishihara, A.; Talmadge, R. J.; Ohira, Y.; Taniguchi, K.; Matsumoto, H.; Roy, R. R.; Edgerton, V. R.

    2001-01-01

    Changes in the expression of heat shock protein 72 (HSP72) in response to atrophic-inducing perturbations of muscle involving chronic mechanical unloading and denervation were determined. Adult male Wistar rats were assigned randomly to a sedentary cage control (CON), hind limb unloading (HU, via tail suspension), HU plus tenotomy (HU + TEN), HU plus denervation (HU + DEN), or HU + TEN + DEN group. Tenotomy and DEN involved cutting the Achilles tendon and removing a segment of the sciatic nerve, respectively. After 5 days, HSP72 levels in the soleus of the HU + DEN and HU + TEN + DEN groups were 42 (P rat plantarflexor are responsive to a chronic decrease in the levels of loading and/or activation and suggest that the neuromuscular activity level and the presence of innervation of a muscle are important factors that induce HSP72 expression.

  19. Partial Restoration Of Skeletal Strength In Ovariectomized Rats By Treatment With Strontium Salts

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Andersen, Pernille/Høegh; Christgau, Stephan

    AIM Ovariectomy of female rats induces significant bone-loss by depriving endogenous estrogen production. We assessed whether administration of strontium salts had a therapeutic benefit in this animal model of postmenopausal osteoporosis. INTRODUCTION In most women after menopause, the rate of bone....... RESULTS Strontium content at the end of the 5 week treatment period showed relatively large inter-individual variation with average levels in S-G treated animals of 76404606 ppm and 59641969 ppm. Calcium, magnesium and iron levels were not affected by the treatments (table 1). CTX decreased...... significantly compared to vehicle treatment over the five week treatment period in the S-M treated but not in the S-G treated rats. None of the treaments decreased bone formation. pQCT analysis of the distal femur revealed only a relatively modest effect of strontium treatment on BMD (693 and 703 mg/cm3 in S...

  20. [Morphohistochemical study of skeletal muscles in rats after experimental flight on "Kosmos-1887"].

    Science.gov (United States)

    Il'ina-Kakueva, E I

    1990-01-01

    Morphometric and histochemical methods were used to examine the soleus, gastrocnemius (medial portion), quadriceps femoris (central portion) and biceps brachii muscles of Wistar SPF rats two days after the 13-day flight on Cosmos-1887. It was found that significant atrophy developed only in the soleus muscle. The space flight did not change the percentage content of slow (type I) and fast (type II) fibers in fast twitch muscles. During two days at 1 g the slow soleus muscle developed substantial circulation disorders, which led to interstitial edema and necrotic changes. The gastrocnemius muscle showed small foci containing necrotic myofibers. Two days after recovery no glycogen aggregates were seen in myofibers, which were previously observed in other rats examined 4--8 hours after flight. An initial stage of muscle readaptation to 1 g occurred, when NAD.H2-dehydrogenase activity was decreased.

  1. Contraction-associated translocation of protein kinase C in rat skeletal muscle

    DEFF Research Database (Denmark)

    Richter, Erik; Cleland, P J; Rattigan, S

    1987-01-01

    Electrical stimulation of the sciatic nerve of the anaesthetized rat in vivo led to a time-dependent translocation of protein kinase C from the muscle cytosol to the particulate fraction. Maximum activity of protein kinase C in the particulate fraction occurred after 2 min of intermittent short t...... tetanic contractions of the gastrocnemius-plantaris-soleus muscle group and coincided with the loss of activity from the cytosol. Translocation of protein kinase C may imply a role for this kinase in contraction-initiated changes in muscle metabolism.......Electrical stimulation of the sciatic nerve of the anaesthetized rat in vivo led to a time-dependent translocation of protein kinase C from the muscle cytosol to the particulate fraction. Maximum activity of protein kinase C in the particulate fraction occurred after 2 min of intermittent short...

  2. Biphasic regulation of development of the high-affinity saxitoxin receptor by innervation in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, S.J.; Catterall, W.A.

    1982-11-01

    Specific binding of /sup 3/H-saxitoxin (STX) was used to quantitate the density of voltage-sensitive sodium channels in developing rat skeletal muscle. In adult triceps surae, a single class of sites with a KD . 2.9 nM and a density of 21 fmol/mg wet wt was detected. The density of these high-affinity sites increased from 2.0 fmol/mg wet wt to the adult value in linear fashion during days 2-25 after birth. Denervation of the triceps surae at day 11 or 17 reduced final saxitoxin receptor site density to 10.4 or 9.2 fmol/mg wet wt, respectively, without changing KD. Denervation of the triceps surae at day 5 did not alter the subsequent development of saxitoxin receptor sites during days 5-9 and accelerated the increase of saxitoxin receptor sites during days 9-13. After day 13, saxitoxin receptor development abruptly ceased and the density of saxitoxin receptor sites declined to 11 fmol/wg wet wt. These results show that the regulation of high-affinity saxitoxin receptor site density by innervation is biphasic. During the first phase, which is independent of continuing innervation, the saxitoxin receptor density increases to 47-57% of the adult level. After day 11, the second phase of development, which is dependent on continuing innervation, gives rise to the adult density of saxitoxin receptors.

  3. Crocus sativus L. (Saffron Extract and its Active Constituents (Crocin and Safranal on Ischemia-Reperfusion in Rat Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Hossein Hosseinzadeh

    2009-01-01

    Full Text Available Saffron and its constituents have been shown to decrease ischemia-reperfusion (I/R injury in kidney or brain tissues. In this study, the effects of saffron ethanolic extract and its constituents, crocin and safranal, were evaluated in skeletal muscle during I/R injury. Hind limb ischemia was induced using clamping the common femoral artery and vein. After 2 h ischemia, the clamp of the femoral vessels of animals was taken off and the animal underwent 1h reperfusion. Muscle injuries were evaluated by recording of the electromyographic (EMG potentials and performing some biochemical analysis including thiobarbituric acid reactive substances (TBARS, total sulfhydryl (SH groups and antioxidant capacity of muscle (using FRAP assay. The ethanolic extract of saffron (5, 20 and 80 mg kg−1, crocin (50, 200 and 400 mg kg−1, safranal (0.1, 0.25 and 0.5 ml kg−1 and normal saline (10 ml kg−1 were administered intraperitoneally 1 h prior reperfusion. The average peak-to-peak amplitude during I/R was significantly increased in extract, crocin and safranal groups in comparison with control-ischemic group. Following saffron, crocin and safranal administration, the total SH contents and antioxidant capacity were elevated in muscle flap. The MDA level was declined significantly in test groups. It is concluded that saffron extract and its constituents show a protective effect against lower limb I/R in rat.

  4. Would Interstitial Fluid Flow be Responsible for Skeletal Maintenance in Tail-Suspended Rats?

    Science.gov (United States)

    Li, Wen-Ting; Huang, Yun-Fei; Sun, Lian-Wen; Luan, Hui-Qin; Zhu, Bao-Zhang; Fan, Yu-Bo

    2016-12-01

    Despite the fast development of manned space flight, the mechanism and countermeasures of weightlessness osteoporosis in astronauts are still within research. It is accepted that unloading has been considered as primary factor, but the precise mechanism is still unclear. Since bone's interstitial fluid flow (IFF) is believed to be significant to nutrient supply and waste metabolism of bone tissue, it may influence bone quality as well. We investigated IFF's variation in different parts of body (included parietal bone, ulna, lumbar, tibia and tailbone) of rats using a tail-suspended (TS) system. Ten female Sprague-Dawley (SD) rats were divided into two groups: control (CON) and tail-suspension (TS) group. And after 21 days' experiment, the rats were injected reactive red to observe lacuna's condition under a confocal laser scanning microscope. The variations of IFF were analyzed by the number and area of lacuna. Volumetric bone mineral density (vBMD) and microarchitecture of bones were evaluated by micro-CT. The correlation coefficients between lacuna's number/area and vBMD were also analyzed. According to our experimental results, a 21 days' tail-suspension could cause a decrease of IFF in lumbar, tibia and tailbone and an increase of IFF in ulna. But in parietal bone, it showed no significant change. The vBMD and microarchitecture parameters also decreased in lumbar and tibia and increased in ulna. But in parietal bone and tailbone, it showed no significant change. And correlation analysis showed significant correlation between vBMD and lacuna's number in lumbar, tibia and ulna. Therefore, IFF decrease may be partly contribute to bone loss in tail-suspended rats, and it should be further investigated.

  5. Effects of skeletal unloading on the vasomotor properties of the rat femur principal nutrient artery

    OpenAIRE

    Prisby, Rhonda D.; Behnke, Bradley J.; Allen, Matthew R.; Delp, Michael D.

    2015-01-01

    Spaceflight and prolonged bed rest induce deconditioning of the cardiovascular system and bone loss. Previous research has shown declines in femoral bone and marrow perfusion during unloading and with subsequent reloading in hindlimb-unloaded (HU) rats, an animal model of chronic disuse. We hypothesized that the attenuated bone and marrow perfusion may result from altered vasomotor properties of the bone resistance vasculature. Therefore, the purpose of this study was to determine the effects...

  6. Effect of lipid infusion on metabolism and force of rat skeletal muscles during intense contractions

    OpenAIRE

    Silveira, LR; Hirabara, SM; Alberici, LC; Lambertucci, RH; Peres, CM; TAKAHASHI,HK; Pettri, A; Alba-Loureiro, T; Luchessi, AD; Cury-Boaventura, MF; VERCESI, AE; R. Curi

    2007-01-01

    The hypothesis that during intense muscle contraction induced by electrical stimulation, long chain fatty acids (LCFA) might reduce mitochondrial ATP/ADP ratio, raising the contribution of glycolysis for ATP production was examined. The effect of a lipid infusion (Lipovenus emulsion) on UCP-3 mRNA level, lactate, glucose-6-phosphate (G-6P) and glycogen content was investigated in rat. Blood samples for determination of free fatty acids and lactate were collected at 0, 30 and 60 min during res...

  7. Would Interstitial Fluid Flow be Responsible for Skeletal Maintenance in Tail-Suspended Rats?

    Science.gov (United States)

    Li, Wen-Ting; Huang, Yun-Fei; Sun, Lian-Wen; Luan, Hui-Qin; Zhu, Bao-Zhang; Fan, Yu-Bo

    2017-02-01

    Despite the fast development of manned space flight, the mechanism and countermeasures of weightlessness osteoporosis in astronauts are still within research. It is accepted that unloading has been considered as primary factor, but the precise mechanism is still unclear. Since bone's interstitial fluid flow (IFF) is believed to be significant to nutrient supply and waste metabolism of bone tissue, it may influence bone quality as well. We investigated IFF's variation in different parts of body (included parietal bone, ulna, lumbar, tibia and tailbone) of rats using a tail-suspended (TS) system. Ten female Sprague-Dawley (SD) rats were divided into two groups: control (CON) and tail-suspension (TS) group. And after 21 days' experiment, the rats were injected reactive red to observe lacuna's condition under a confocal laser scanning microscope. The variations of IFF were analyzed by the number and area of lacuna. Volumetric bone mineral density (vBMD) and microarchitecture of bones were evaluated by micro-CT. The correlation coefficients between lacuna's number/area and vBMD were also analyzed. According to our experimental results, a 21 days' tail-suspension could cause a decrease of IFF in lumbar, tibia and tailbone and an increase of IFF in ulna. But in parietal bone, it showed no significant change. The vBMD and microarchitecture parameters also decreased in lumbar and tibia and increased in ulna. But in parietal bone and tailbone, it showed no significant change. And correlation analysis showed significant correlation between vBMD and lacuna's number in lumbar, tibia and ulna. Therefore, IFF decrease may be partly contribute to bone loss in tail-suspended rats, and it should be further investigated.

  8. Cryotherapy reduces skeletal muscle damage after ischemia/reperfusion in rats.

    Science.gov (United States)

    Puntel, Gustavo O; Carvalho, Nélson R; Dobrachinski, Fernando; Salgueiro, Andréia C F; Puntel, Robson L; Folmer, Vanderlei; Barbosa, Nilda B V; Royes, Luiz F F; Rocha, João Batista T; Soares, Félix A A

    2013-02-01

    The aim of this study was to analyze the effects of cryotherapy on the biochemical and morphological changes in ischemic and reperfused (I/R) gastrocnemius muscle of rats. Forty male Wistar rats were divided into control and I/R groups, and divided based on whether or not the rats were submitted to cryotherapy. Following the reperfusion period, biochemical and morphological analyses were performed. Following cryotherapy, a reduction in thiobarbituric acid-reactive substances and dichlorofluorescein oxidation levels were observed in I/R muscle. Cryotherapy in I/R muscle also minimized effects such as decreased cellular viability, levels of non-protein thiols and calcium ATPase activity as well as increased catalase activity. Cryotherapy also limited mitochondrial dysfunction and decreased the presence of neutrophils in I/R muscle, an effect that was corroborated by reduced myeloperoxidase activity in I/R muscle treated with cryotherapy. The effects of cryotherapy are associated with a reduction in the intensity of the inflammatory response and also with a decrease in mitochondrial dysfunction.

  9. Detection of histidine decarboxylase in rat aorta and cultured rat aortic smooth muscle cells.

    Science.gov (United States)

    Tippens, A S; Davis, S V; Hayes, J R; Bryda, E C; Green, T L; Gruetter, C A

    2004-08-01

    Having previously demonstrated release of histamine from mast-cell-deficient rat aorta, the objective of this study was to determine and localize histamine synthesis capability in the aorta by detecting histidine decarboxylase (HDC), the enzyme that catalyzes histamine formation. Experiments were conducted with nested reverse transcription-polymerase chain reaction (nRT-PCR) to detect HDC mRNA and with immunofluorescence and western blot analysis to detect HDC protein in rat aorta, cultured rat aortic smooth muscle (RASMC) and endothelial cells (RAEC). Gel electrophoresis of nRT-PCR products indicated HDC mRNA in liver, aorta and RASMC but not in RAEC or kidney. Sequence analysis confirmed that the band observed in RASMC was the target HDC amplicon. Immunofluorescence indicated the presence of HDC protein in RASMC and not in RAEC. Western Blot analysis revealed HDC protein (55 kDa) in liver, aorta, RASMC but not in RAEC or kidney. The results of this study are the first to demonstrate the presence of HDC mRNA and protein in rat aorta and more specifically in RASMC, indicative of their capability to synthesize histamine. Copyright 2004 Birkhäuser Verlag, Basel

  10. Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise.

    Directory of Open Access Journals (Sweden)

    Francesca Magherini

    Full Text Available Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies.

  11. HAIR CELL-LIKE CELL GENERATION INDUCED BY NATURE CULTURE OF ADULT RAT AUDITORY EPITHELIUM

    Institute of Scientific and Technical Information of China (English)

    Liu Hui; Zhu Hongliang; Li Shengli; Yao Xiaobao; Wang Xiaoxia

    2006-01-01

    Objective To establish adult rat auditory epithelial cell culture and try to find precursor cells of auditory hair cells in vitro. Methods With refinement of culture media and techniques, cochlear sensory epithelial cells of adult rat were cultured. Immunocytochemistry and Bromodeoxyuridine (BrdU)labeling were used to detect properties and mitotic status of cultured cells. Results The cultured auditory epithelial cells showed a large, flat epithelial morphotype and expressed F-actin and cytokeratin, a subset of cells generated from auditory epithelium were labeled by calretinin, a specific marker of early hair cell. Conclusion Adult rat auditory epithelium can be induced to generate hair cell-like cells by nature culture, this phenomenon suggests that progenitor cells may exist in rat cochlea and they may give birth to new hair cells. Whether these progenitor cells are tissue specific stem cells is still need more study.

  12. Effects of acetylcholinesterase gene silencing on its activity in cultured human skeletal muscle.

    Science.gov (United States)

    Mis, Katarina; Mars, Tomaz; Golicnik, Marko; Jevsek, Marko; Grubic, Zoran

    2006-01-01

    In spite of several reports demonstrating that acetylcholinesterase (AChE [EC 3.1.1.7]) expression is importantly regulated at the level of its mRNA, we still know little about the relationship between AChE mRNA level and the level of mature, catalytically active enzyme in the cell. Better insight into this relationship is, however, essential for our understanding of the molecular pathways underlying AChE synthesis in living cells. We have approached this problem previously (Grubic et al., 1995; Brank et al., 1998; Mis et al., 2003; Jevsek et al., 2004); however, recently introduced small interfering RNA (siRNA) methodology, which allows blockade of gene expression at the mRNA level, opens new possibilities in approaching the AChE mRNA-AChE activity relationship. With this technique one can eliminate AChE mRNA in the cell, specifically and at selected times, and follow the effects of such treatment at the mature enzyme level. In this study we followed AChE activity in siRNA-treated cultured human myoblasts. Our aim was to find out how the temporal profile of the AChE mRNA decrease is reflected at the level of AChE activity under normal conditions and after inhibition of preexisting AChE by diisopropyl phosphorofluoridate (DFP).AChE activity was determined at selected time intervals after siRNA treatment in both myoblast homogenates and in culture medium to follow the effects of siRNA treatment at the level of intracellular AChE synthesis and at the level of AChE secreted from the cell.

  13. Effects of electrostimulation on glycogenolysis in cultured rat myotubes

    DEFF Research Database (Denmark)

    Elsner, Peter; Grunnet, Niels; Quistorff, Bjørn

    2003-01-01

    A model for electrostimulation causing contractions of primary cultures of rat myotubes was established. The kinetics of glycogen degradation was investigated for a 2-h period to elucidate the coupling between contraction and glycogenolytic flux. Electrostimulation caused contraction and increased...... glycogenolytic flux, but had no effect on glycogen phosphorylase-a activity. Forskolin increased glycogenolytic flux more than electrostimulation, and caused a fast activation of glycogen phosphorylase, while it did not elicit contraction. The effects of electrostimulation and forskolin on glycogenolytic flux...... were partly additive. The metabolism of glucose and glycogen was almost equally anaerobic and aerobic. The ATP content remained constant during glycogenolysis, but phosphocreatine decreased with the largest decrease in electrostimulated cells. The calculated ATP turnover rate increased about 3 times...

  14. A proteome map of primary cultured rat Schwann cells

    Directory of Open Access Journals (Sweden)

    Shen Mi

    2012-03-01

    Full Text Available Abstract Background Schwann cells (SCs are the principal glial cells of the peripheral nervous system with a wide range of biological functions. SCs play a key role in peripheral nerve regeneration and are involved in several hereditary peripheral neuropathies. The objective of this study was to gain new insight into the whole protein composition of SCs. Results Two-dimensional liquid chromatography coupled with tandem mass spectrometry (2D LC-MS/MS was performed to identify the protein expressions in primary cultured SCs of rats. We identified a total of 1,232 proteins, which were categorized into 20 functional classes. We also used quantitative real time RT-PCR and Western blot analysis to validate some of proteomics-identified proteins. Conclusion We showed for the first time the proteome map of SCs. Our data could serve as a reference library to provide basic information for understanding SC biology.

  15. [Kurloff's thymic inclusion : action on rat gonads in culture].

    Science.gov (United States)

    De Graeve, P; Vincent, M F; Amiel, S; Moatti, J P; Guilhem, A; Bimes, C

    1981-12-01

    Thymic and splenic extracts rich in FOA-KURLOFF (F.K.) body cells, obtained from guinea-pigs treated with oestrogen, were added to rat testis or ovaries in culture. Controls were prepared with extracts from thymus and spleen of non treated animals and from kidneys of treated or non treated animals. After five hours the level of sexual hormones and the germinal cells were studied. The F.K. substance has no effect on germinal cells and on progesterone and testosterone secretion. The F.K. substance induces a significative decrease of oestrogen secretion. In an other paper we established that F.K. bodies induced a hyperactivity of internal theca folliculi and of ovarian interstitial cells. It is a false image of activity in connection with a hypersecretion of FSH. The F.K. substance inhibits oestrogen synthesis.

  16. Effects of hyperbaric oxygen at 1.25 atmospheres absolute with normal air on macrophage number and infiltration during rat skeletal muscle regeneration.

    Science.gov (United States)

    Fujita, Naoto; Ono, Miharu; Tomioka, Tomoka; Deie, Masataka

    2014-01-01

    Use of mild hyperbaric oxygen less than 2 atmospheres absolute (2026.54 hPa) with normal air is emerging as a common complementary treatment for severe muscle injury. Although hyperbaric oxygen at over 2 atmospheres absolute with 100% O2 promotes healing of skeletal muscle injury, it is not clear whether mild hyperbaric oxygen is equally effective. The purpose of the present study was to investigate the impact of hyperbaric oxygen at 1.25 atmospheres absolute (1266.59 hPa) with normal air on muscle regeneration. The tibialis anterior muscle of male Wistar rats was injured by injection of bupivacaine hydrochloride, and rats were randomly assigned to a hyperbaric oxygen experimental group or to a non-hyperbaric oxygen control group. Immediately after the injection, rats were exposed to hyperbaric oxygen, and the treatment was continued for 28 days. The cross-sectional area of centrally nucleated muscle fibers was significantly larger in rats exposed to hyperbaric oxygen than in controls 5 and 7 days after injury. The number of CD68- or CD68- and CD206-positive cells was significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. Additionally, tumor necrosis factor-α and interleukin-10 mRNA expression levels were significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. The number of Pax7- and MyoD- or MyoD- and myogenin-positive nuclei per mm2 and the expression levels of these proteins were significantly higher in rats exposed to hyperbaric oxygen than in controls 5 days after injury. These results suggest that mild hyperbaric oxygen promotes skeletal muscle regeneration in the early phase after injury, possibly due to reduced hypoxic conditions leading to accelerated macrophage infiltration and phenotype transition. In conclusion, mild hyperbaric oxygen less than 2 atmospheres absolute with normal air is an appropriate support therapy for severe muscle injuries.

  17. Effects of Fenvalerate on Steroidogenesis in Cultured Rat Granulosa Cells

    Institute of Scientific and Technical Information of China (English)

    JIAN-FENG CHEN; GUI-DONG DAI; XIN-RU WANG; HAI-YAN CHEN; RU LIU; JUN HE; LIN SONG; QIAN BIAN; LI-CHUN XU; JIAN-WEI ZHOU; HANG XIAO

    2005-01-01

    Objective This study was designed to examine the in vitro effects of fenvalerate on steroid production and steroidogenic enzymes mRNA expression level in rat granulosa cells. Methods Using primary cultured rat granulosa cells (rGCs) as model, fenvalerate of various concentrations (0, 1, 5, 25, 125, 625 μmol/L) was added to the medium for 24 h. In some cases, optimal concentrations of 22(R)-hydroxycholesterol (25 μmol/L), Follicle stimulating hormone (FSH, 2 mg/L), or 8-Bromo-cAMP (1 mmol/L) were provided. Concentrations of 17β-estradiol(E2) and progesterone (P4) in the medium from the same culture wells were measured by RIA and the steroidogenic enzyme mRNA level was quantified by semi-quantitative RT-PCR. Results Fenvalerate decreased both P4 and E2 production in a dose-dependent manner while it could significantly stimulate rGCs proliferation. This inhibition was stronger in the presence of FSH. Furthermore, it could not be reversed by 22(R)-hydroxycholesterol or 8-Bromo-cAMP. RT-PCR revealed that fenvalerate had no significant effect on 3β-HSD, but could increase the P450scc mRNA level. In addition, 17β-HSD mRNA level was dramatically reduced with the increase of fenvalerate dose after 24 h treatment. Conclusion Fenvalerate inhibits both P4 and E2 production in rGCs. These results support the view that fenvalerate is considered as a kind of endocrine-disrupting chemicals. The mechanism of its disruption may involve the effects on steroidogenesis signaling cascades and/or steroidogenic enzyme's activity.

  18. Comparative sensitivity of human and rat neural cultures to chemical-induced inhibition of neurite outgrowth

    Energy Technology Data Exchange (ETDEWEB)

    Harrill, Joshua A.; Freudenrich, Theresa M.; Robinette, Brian L.; Mundy, William R., E-mail: mundy.william@epa.gov

    2011-11-15

    There is a need for rapid, efficient and cost-effective alternatives to traditional in vivo developmental neurotoxicity testing. In vitro cell culture models can recapitulate many of the key cellular processes of nervous system development, including neurite outgrowth, and may be used as screening tools to identify potential developmental neurotoxicants. The present study compared primary rat cortical cultures and human embryonic stem cell-derived neural cultures in terms of: 1) reproducibility of high content image analysis based neurite outgrowth measurements, 2) dynamic range of neurite outgrowth measurements and 3) sensitivity to chemicals which have been shown to inhibit neurite outgrowth. There was a large increase in neurite outgrowth between 2 and 24 h in both rat and human cultures. Image analysis data collected across multiple cultures demonstrated that neurite outgrowth measurements in rat cortical cultures were more reproducible and had higher dynamic range as compared to human neural cultures. Human neural cultures were more sensitive than rat cortical cultures to chemicals previously shown to inhibit neurite outgrowth. Parallel analysis of morphological (neurite count, neurite length) and cytotoxicity (neurons per field) measurements were used to detect selective effects on neurite outgrowth. All chemicals which inhibited neurite outgrowth in rat cortical cultures did so at concentrations which did not concurrently affect the number of neurons per field, indicating selective effects on neurite outgrowth. In contrast, more than half the chemicals which inhibited neurite outgrowth in human neural cultures did so at concentrations which concurrently decreased the number of neurons per field, indicating that effects on neurite outgrowth were secondary to cytotoxicity. Overall, these data demonstrate that the culture models performed differently in terms of reproducibility, dynamic range and sensitivity to neurite outgrowth inhibitors. While human neural

  19. Mineral and Skeletal Homeostasis Influence the Manner of Bone Loss in Metabolic Osteoporosis due to Calcium-Deprived Diet in Different Sites of Rat Vertebra and Femur

    Directory of Open Access Journals (Sweden)

    Marzia Ferretti

    2015-01-01

    Full Text Available Rats fed calcium-deprived diet develop osteoporosis due to enhanced bone resorption, secondary to parathyroid overactivity resulting from nutritional hypocalcemia. Therefore, rats provide a good experimental animal model for studying bone modelling alterations during biochemical osteoporosis. Three-month-old Sprague-Dawley male rats were divided into 4 groups: (1 baseline, (2 normal diet for 4 weeks, (3 calcium-deprived diet for 4 weeks, and (4 calcium-deprived diet for 4 weeks and concomitant administration of PTH (1-34 40 µg/Kg/day. Histomorphometrical analyses were made on cortical and trabecular bone of lumbar vertebral body as well as of mid-diaphysis and distal metaphysis of femur. In all rats fed calcium-deprived diet, despite the reduction of trabecular number (due to the maintenance of mineral homeostasis, an intense activity of bone deposition occurs on the surface of the few remaining trabeculae (in answering to mechanical stresses and, consequently, to maintain the skeletal homeostasis. Different responses were detected in different sites of cortical bone, depending on their main function in answering mineral or skeletal homeostasis. This study represents the starting point for work-in-progress researches, with the aim of defining in detail timing and manners of evolution and recovery of biochemical osteoporosis.

  20. Effect of Kaiyu Qingwei Granule (开郁清胃颗粒) on Insulin Receptor in Liver and Skeletal Muscular Cell Membrane in Diabetes Mellitus Rats

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-fang (柳红芳); TONG Xiao-lin(仝小林); WANG Qing-guo(王庆国); ZUO Ping-ping(左萍萍); GUO An-chen(郭安臣); LIU Hong-xing(刘红星)

    2003-01-01

    Objective: To investigate the effect of Kaiyu Qingwei granule (KYQWG,开郁清胃颗粒) on the insulin binding capacity of liver and skeletal muscular cell membrane and serum insulin-like growth factor-1 (IGF-1) in streptozotocin-induced diabetic rats. Methods:Rats in four experimental groups were investigated: the control group, the model group, the KYQWG group and the Metformin group. The insulin binding rate (IBR) of liver and skeletal muscular cell membrane was detected by receptor-ligand radiometric method and changes of serum levels of glucose, insulin and IGF-1 were observed before and after 4 weeks of medication. Results: The KYQWG group had a lower blood glucose level and IBR of liver and muscular cell membrane, as compared with those in the model group (P<0.01 or P<0.05), and a higher level of IGF-1 than that in the model group(P<0.01), but had no obvious changes in the serum level of insulin. Conclusion: KYQWG may increase the serum level of IGF-1 in diabetic rats, thus to decrease the insulin resistance at ante-receptor sites and improve the sugar metabolic disturbance in rats with diabetes mellitus.

  1. Mineral and Skeletal Homeostasis Influence the Manner of Bone Loss in Metabolic Osteoporosis due to Calcium-Deprived Diet in Different Sites of Rat Vertebra and Femur

    Science.gov (United States)

    Cavani, Francesco; Smargiassi, Alberto

    2015-01-01

    Rats fed calcium-deprived diet develop osteoporosis due to enhanced bone resorption, secondary to parathyroid overactivity resulting from nutritional hypocalcemia. Therefore, rats provide a good experimental animal model for studying bone modelling alterations during biochemical osteoporosis. Three-month-old Sprague-Dawley male rats were divided into 4 groups: (1) baseline, (2) normal diet for 4 weeks, (3) calcium-deprived diet for 4 weeks, and (4) calcium-deprived diet for 4 weeks and concomitant administration of PTH (1-34) 40 µg/Kg/day. Histomorphometrical analyses were made on cortical and trabecular bone of lumbar vertebral body as well as of mid-diaphysis and distal metaphysis of femur. In all rats fed calcium-deprived diet, despite the reduction of trabecular number (due to the maintenance of mineral homeostasis), an intense activity of bone deposition occurs on the surface of the few remaining trabeculae (in answering to mechanical stresses and, consequently, to maintain the skeletal homeostasis). Different responses were detected in different sites of cortical bone, depending on their main function in answering mineral or skeletal homeostasis. This study represents the starting point for work-in-progress researches, with the aim of defining in detail timing and manners of evolution and recovery of biochemical osteoporosis. PMID:26064895

  2. Development of an Assay Based on the Effects of PGBx on the Isolated Perfused Rat Heart and Rat Skeletal Muscle.

    Science.gov (United States)

    1980-09-01

    and thyrotoxic rats. Eur. J. Pharac. 2,113-118. Aronson, C. E., Hess, M. E. and Shanfeld, J. (1972) Metabolic actions of tyramine and McNeil-A-343 in...that body weight and food intake of these diabetic mice also showed dose-dependency. As the dose of PGB administered to the animals was increased,x the...hypoglycemic effect became more pronounced, but food intake and body weight showed an inverse relationship to the quantity of drug which the mice

  3. Macrophage-mediated inflammation and glial response in the skeletal muscle of a rat model of familial amyotrophic lateral sclerosis (ALS).

    Science.gov (United States)

    Van Dyke, Jonathan M; Smit-Oistad, Ivy M; Macrander, Corey; Krakora, Dan; Meyer, Michael G; Suzuki, Masatoshi

    2016-03-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive motor dysfunction and loss of large motor neurons in the spinal cord and brain stem. While much research has focused on mechanisms of motor neuron cell death in the spinal cord, degenerative processes in skeletal muscle and neuromuscular junctions (NMJs) are also observed early in disease development. Although recent studies support the potential therapeutic benefits of targeting the skeletal muscle in ALS, relatively little is known about inflammation and glial responses in skeletal muscle and near NMJs, or how these responses contribute to motor neuron survival, neuromuscular innervation, or motor dysfunction in ALS. We recently showed that human mesenchymal stem cells modified to release glial cell line-derived neurotrophic factor (hMSC-GDNF) extend survival and protect NMJs and motor neurons in SOD1(G93A) rats when delivered to limb muscles. In this study, we evaluate inflammatory and glial responses near NMJs in the limb muscle collected from a rat model of familial ALS (SOD1(G93A) transgenic rats) during disease progression and following hMSC-GDNF transplantation. Muscle samples were collected from pre-symptomatic, symptomatic, and end-stage animals. A significant increase in the expression of microglial inflammatory markers (CD11b and CD68) occurred in the skeletal muscle of symptomatic and end-stage SOD1(G93A) rats. Inflammation was confirmed by ELISA for inflammatory cytokines interleukin-1 β (IL-1β) and tumor necrosis factor-α (TNF-α) in muscle homogenates of SOD1(G93A) rats. Next, we observed active glial responses in the muscle of SOD1(G93A) rats, specifically near intramuscular axons and NMJs. Interestingly, strong expression of activated glial markers, glial fibrillary acidic protein (GFAP) and nestin, was observed in the areas adjacent to NMJs. Finally, we determined whether ex vivo trophic factor delivery influences inflammation and terminal

  4. Relationships between fetal body weight of Wistar rats at term and the extent of skeletal ossification

    Directory of Open Access Journals (Sweden)

    I. Chahoud

    2005-04-01

    Full Text Available We investigated the relationship between fetal body weight at term (pregnancy day 21 and the extent of ossification of sternum, metacarpus, metatarsus, phalanges (proximal, medial and distal of fore- and hindlimbs and cervical and coccygeal vertebrae in Wistar rats. The relationships between fetal body weight and sex, intrauterine position, uterine horn, horn size, and litter size were determined using historical control data (7594 fetuses; 769 litters of untreated rats. Relationships between body weight and degree of ossification were examined in a subset of 1484 historical control fetuses (154 litters which were subsequently cleared and stained with alizarin red S. Fetal weight was independent of horn size, uterine horn side (left or right or intrauterine position. Males were heavier than females and fetal weight decreased with increasing litter size. Evaluation of the skeleton showed that ossification of sternum, metacarpus and metatarsus was extensively complete and independent of fetal weight on pregnancy day 21. In contrast, the extent of ossification of fore- and hindlimb phalanges and of cervical and sacrococcygeal vertebrae was dependent on fetal body weight. The strongest correlation between body weight and degree of ossification was found for hindlimb, medial and proximal phalanges. Our data therefore suggest that, in full-term rat fetuses (day 21, reduced ossification of sternum, metacarpus and metatarsus results from a localized impairment of bone calcification (i.e., a malformation or variation rather than from general growth retardation and that ossification of hindlimb (medial and proximal phalanges is a good indicator of treatment-induced fetal growth retardation.

  5. Increased intrinsic mitochondrial respiratory capacity in skeletal muscle from rats with streptozotocin-induced hyperglycemia

    DEFF Research Database (Denmark)

    Larsen, Steen; Scheede-Bergdahl, Celena; Whitesell, Thomas

    2015-01-01

    expression and integrated mitochondrial respiratory function. Mitochondrial capacity for oxidative phosphorylation (OXPHOS) was found to be higher in the slow (more oxidative) soleus muscle from STZ rats when evaluating lipid and complex I linked OXPHOS capacity, whereas no difference was detected between...... the groups when evaluating the more physiol. complex I and II linked OXPHOS capacity. These findings indicate that chronic hyperglycemia results in an elevated intrinsic mitochondrial respiratory capacity in both soleus and, at varying degree, plantaris muscle, findings that are consistent with human T1DM...

  6. Expression profile of mitrogen-activated protein kinase (MAPK signaling genes in the skeletal muscle & liver of rat with type 2 diabetes: Role in disease pathology

    Directory of Open Access Journals (Sweden)

    Xiaoli Tang

    2014-01-01

    Full Text Available Background & objectives: Type 2 diabetes (T2D is characterized as hyperglycaemia caused by defects in insulin secretion, and it affects target tissues, such as skeletal muscle, liver and adipose tissue. Therefore, analyzing the changes of gene expression profiles in these tissues is important to elucidate the pathogenesis of T2D. We, therefore, measured the gene transcript alterations in liver and skeletal muscle of rat with induced T2D, to detect differentially expressed genes in liver and skeletal muscle and perform gene-annotation enrichment analysis. Methods: In the present study, skeletal muscle and liver tissue from 10 streptozotocin-induced diabetic rats and 10 control rats were analyzed using gene expression microarrays. KEGG pathways enriched by differentially expressed genes (DEGs were identified by WebGestalt Expander and GATHER software. DEGs were validated by the method of real-time PCR and western blot. Results: From the 9,929 expressed genes across the genome, 1,305 and 997 differentially expressed genes (DEGs, P<0.01 were identified in comparisons of skeletal muscle and liver, respectively. Large numbers of DEGs (200 were common in both comparisons, which was clearly more than the predicted number (131 genes, P<0.001. For further interpretation of the gene expression data, three over-representation analysis softwares (WebGestalt, Expander and GATHER were used. All the tools detected one KEGG pathway (MAPK signaling and two GO (gene ontology biological processes (response to stress and cell death, with enrichment of DEGs in both tissues. In addition, PPI (protein-protein interaction networks constructed using human homologues not only revealed the tendency of DEGs to form a highly connected module, but also suggested a "hub" role of p38-MAPK-related genes (such as MAPK14 in the pathogenesis of T2D. Interpretation & conclusions: Our results indicated the considerably aberrant MAPK signaling in both insulin-sensitive tissues of T2D

  7. Muscular hypertrophy and changes in cytokine production after eccentric training in the rat skeletal muscle.

    Science.gov (United States)

    Ochi, Eisuke; Nakazato, Koichi; Ishii, Naokata

    2011-08-01

    We investigated the time course effects of eccentric training on muscular size, strength, and growth factor/cytokine production by using an isokinetic-exercise system for rats. Male Wistar rats (n = 34) were randomly assigned into 4 groups: 5 session eccentric-training group (ECC5S, n = 10); 5 session sham-operated group (CON5S, n = 10); 10 session eccentric-training group (ECC10S, n = 7); 10 session sham-operated group (CON10S, n = 7). In each group, a session of either training or sham operation was performed every 2 days. The training consisted of 4 sets of forced dorsiflexion (5 repetitions) combined with electric stimulation of plantar flexors. The wet weight of medial gastrocnemius muscle did not increase significantly after 5 sessions of training, whereas that after 10 sessions of training significantly increased with a concomitant increase in the cross-sectional area (CSA) of muscle fibers (weight, p eccentric training for 20 days cause increases in muscular size and strength associated with increases in IL-6, follistatin, phospho-stat-3, and a decrease in myostatin. The delayed responses of IL-6, myostatin, phospho-stat-3, and follistatin would be due to the chronic effects of repeated training and possibly important for muscular hypertrophy.

  8. Effect of chronic ethanol ingestion and exercise training on skeletal muscle in rat.

    Science.gov (United States)

    Vila, L; Ferrando, A; Voces, J; Cabral de Oliveira, C; Prieto, J G; Alvarez, A I

    2001-09-01

    The aim of this study was to investigate the interactive effects of exercise training and chronic ethanol consumption on metabolism, capillarity, and myofibrillar composition in rat limb muscles. Male Wistar rats were treated in separate groups as follows: non exercised-control; ethanol (15%) in animals' drinking water for 12 weeks; exercise training in treadmill and ethanol administration plus exercise for 12 weeks. Ethanol administration decreased capillarity and increased piruvate kinase and lactate dehydrogenase activities in white gastrocnemius; in plantaris muscle, ethanol increased citrate synthase activity and decreased cross-sectional area of type I, IIa, and IIb fibres. Exercise increased capillarity in all four limb muscles and decreased type I fibre area in plantaris. The decreased capillarity effect induced by ethanol in some muscles, was ameliorated when alcohol was combined with exercise. While alcoholic myopathy affects predominantly type IIb fibres, ethanol administration and aerobic exercise in some cases can affect type I and type IIa fibre areas. The exercise can decrease some harmful effects produced by ethanol in the muscle, including the decrease in the fibre area and capillary density.

  9. Exercise training, glucose transporters, and glucose transport in rat skeletal muscles

    Science.gov (United States)

    Rodnick, K. J.; Henriksen, E. J.; James, D. E.; Holloszy, J. O.

    1992-01-01

    It was previously found that voluntary wheel running induces an increase in the insulin-sensitive glucose transporter, i.e., the GLUT4 isoform, in rat plantaris muscle (K. J. Rodnick, J. O. Holloszy, C. E. Mondon, and D. E. James. Diabetes 39: 1425-1429, 1990). The present study was undertaken to determine whether 1) the increase in muscle GLUT4 protein is associated with an increase in maximally stimulated glucose transport activity, 2) a conversion of type IIb to type IIa or type I muscle fibers plays a role in the increase in GLUT4 protein, and 3) an increase in the GLUT1 isoform is a component of the adaptation of muscle to endurance exercise. Five weeks of voluntary wheel running that resulted in a 33% increase in citrate synthase activity induced a 50% increase in GLUT4 protein in epitrochlearis muscles of female Sprague-Dawley rats. The rate of 2-deoxy-glucose transport maximally stimulated with insulin or insulin plus contractions was increased approximately 40% (P less than 0.05). There was no change in muscle fiber type composition, evaluated by myosin ATPase staining, in the epitrochlearis. There was also no change in GLUT1 protein concentration. We conclude that an increase in GLUT4, but not of GLUT1 protein, is a component of the adaptive response of muscle to endurance exercise and that the increase in GLUT4 protein is associated with an increased capacity for glucose transport.

  10. Skeletal muscle atrophy in sedentary Zucker obese rats is not caused by calpain-mediated muscle damage or lipid peroxidation induced by oxidative stress.

    Science.gov (United States)

    Pompeani, Nancy; Rybalka, Emma; Latchman, Heidy; Murphy, Robyn M; Croft, Kevin; Hayes, Alan

    2014-12-30

    Skeletal muscle undergoes significant atrophy in Type 2 diabetic patients and animal models. We aimed to determine if atrophy of Zucker rat skeletal muscle was due to the activation of intracellular damage pathways induced by excess reactive oxygen species production (specifically those associated with the peroxidation of lipid membranes) and calpain activity. 14 week old obese Zucker rats and littermate lean controls were injected with 1% Evan's Blue Dye. Animals were anaesthetised and extensor digitorum longus and soleus muscles were dissected, snap frozen and analysed for ROS-mediated F2-isoprostane production and calpain activation/autolysis. Contralateral muscles were histologically analysed for markers of muscle membrane permeability and atrophy. Muscle mass was lower in extensor digitorum longus and soleus of obese compared with lean animals, concomitant with reduced fibre area. Muscles from obese rats had a higher proportional area of Evan's Blue Dye fluorescence, albeit this was localised to the interstitium/external sarcolemma. There were no differences in F2-isoprostane production when expressed relative to arachidonic acid content, which was lower in the obese EDL and soleus muscles. There were no differences in the activation of either μ-calpain or calpain-3. This study highlights that atrophy of Zucker rat skeletal muscle is not related to sarcolemmal damage, sustained hyperactivation of the calpain proteases or excessive lipid peroxidation. As such, establishing the correct pathways involved in atrophy is highly important so as to develop more specific treatment options that target the underlying cause. This study has eliminated two of the potential pathways theorised to be responsible.

  11. Effects of exenatide therapy on insulin resistance in the skeletal muscles of high-fat diet and low-dose streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Wu, Hui; Sui, Chunhua; Xia, Fangzhen; Zhai, Hualing; Zhang, Huixin; Xu, Hui; Weng, Pan; Lu, Yingli

    2016-01-01

    The glucagon-like peptide (GLP)-1 agonist exenatide shows the same multiple effects on glucose homeostasis as native GLP-1, which can reduce blood glucose levels in individuals with type-2 diabetes mellitus (T2DM). However, its underlying action mechanism on glucose metabolism in the skeletal muscle of T2DM cases is unknown. We investigated the effects and action mechanisms of exenatide on insulin resistance (IR) in the skeletal muscle of high-fat diet and low-dose streptozotocin-induced T2DM rats. Four groups of Sprague-Dawley rats were studied: non-T2DM (control, C); non-T2DM + exenatide (C + E); T2DM (D); and T2DM + exenatide (D + E). After eight weeks, isotope-tracer methodology was applied to measure the total rate of appearance (Ra) of glucose and glucose infusion rate (GIR) using a hyperinsulinemic-euglycemic clamp with 3-(3)H-glucose infusion. Glucose uptake in gastrocnemius muscles was determined by measuring 2-deoxy-D-(14)C-glucose radioactivity. Simultaneously, ultrastructural changes in the cells of gastrocnemius muscles were studied. In the D + E group, body weight and levels of fasting plasma glucose, triglyceride, total cholesterol, low-density lipoprotein and insulin were decreased significantly (p decreased (p muscle (0.24 ± 0.02 versus 0.17 ± 0.02 μmol/g/min) were increased markedly (p muscle of T2DM rats. These data suggest that exenatide can significantly improve insulin sensitivity in skeletal muscle by increasing glucose uptake in T2DM rats.

  12. Ibuprofen augments bilirubin toxicity in rat cortical neuronal culture.

    Science.gov (United States)

    Berns, Monika; Toennessen, Margit; Koehne, Petra; Altmann, Rodica; Obladen, Michael

    2009-04-01

    Premature infants are at risk for bilirubin-associated brain damage. In cell cultures bilirubin causes neuronal apoptosis and necrosis. Ibuprofen is used to close the ductus arteriosus, and is often given when hyperbilirubinemia is at its maximum. Ibuprofen is known to interfere with bilirubin-albumin binding. We hypothesized that bilirubin toxicity to cultured rat embryonic cortical neurons is augmented by coincubation with ibuprofen. Incubation with ibuprofen above a concentration of 125 microg/mL reduced cell viability, measured by methylthiazole tetrazolium reduction, to 68% of controls (p < 0.05). Lactate dehydrogenase (LDH) release increased from 29 to 38% (p < 0.01). The vehicle solution did not affect cell viability. Coincubation with 10 microM unconjugated bilirubin (UCB)/human serum albumin in a molar ratio of 3:1 and 250 microg/mL ibuprofen caused additional loss of cell viability and increased LDH release (p < 0.01), DNA fragmentation, and activated caspase-3. Preincubation with the pan-caspase inhibitor z-val-ala-asp-fluoromethyl ketone abolished ibuprofen- and UCB-induced DNA fragmentation. The study demonstrates that bilirubin in low concentration of 10 microM reduces neuron viability and ibuprofen increases this effect. Apoptosis is the underlying cell death mechanism.

  13. Ethanol induces heterotopias in organotypic cultures of rat cerebral cortex.

    Science.gov (United States)

    Mooney, Sandra M; Siegenthaler, Julie A; Miller, Michael W

    2004-10-01

    Abnormalities in the migration of cortical neurons to ectopic sites can be caused by prenatal exposure to ethanol. In extreme cases, cells migrate past the pial surface and form suprapial heterotopias or 'warts'. We used organotypic slice cultures from 17-day-old rat fetuses to examine structural and molecular changes that accompany wart formation. Cultures were exposed to ethanol (0, 200, 400 or 800 mg/dl) and maintained for 2-32 h. Fixed slices were sectioned and immunolabeled with antibodies directed against calretinin, reelin, nestin, GFAP, doublecortin, MAP-2 and NeuN. Ethanol promoted the widespread infiltration of the marginal zone (MZ) with neurons and the focal formation of warts. The appearance of warts is time- and concentration-dependent. Heterotopias comprised migrating neurons and were not detected in control slices. Warts were associated with breaches in the array of Cajal-Retzius cells and with translocation of reelin-immunoexpression from the MZ to the outer limit of the wart. Ethanol also altered the morphology of the radial glia. Thus, damage to the integrity of superficial cortex allows neurons to infiltrate the MZ, and if the pial-subpial glial barrier is also compromised these ectopic neurons can move beyond the normal cerebral limit to form a wart.

  14. Effect of ETBE on reproductive steroids in male rats and rat Leydig cell cultures.

    Science.gov (United States)

    de Peyster, Ann; Stanard, Bradley; Westover, Christian

    2009-10-08

    These experiments were conducted to follow up on a report of testis seminiferous tubular degeneration in Fischer 344 rats treated with high doses of ethyl t-butyl ether (ETBE). Also, high doses of a related compound, methyl t-butyl ether (MTBE), had been shown to reduce circulating testosterone (T) in rats. Isolated rat Leydig cells were used to compare hCG-stimulated T production following exposure to ETBE, MTBE, and their common main metabolite, TBA. In addition, male Fischer 344 rats were gavaged daily with 600 mg/kg, 1200 mg/kg or 1800 mg/kg ETBE in corn oil (n=12) for 14 days, the 1200 mg/kg dose chosen for comparison with a prior 14-day MTBE gavage experiment. In cell culture experiments, TBA was more potent than either ETBE or MTBE, both of which caused similar inhibition of T production at equimolar concentrations. In the in vivo study, no significant plasma T reduction was seen 1h after the final 1200 mg/kg ETBE dose, whereas 1200 mg/kg MTBE had significantly lowered T when administered similarly to Sprague-Dawley rats. Some rats treated with 1800 mg/kg ETBE had noticeably lower T levels, and the group average T level was 66% of corn oil vehicle control (p>0.05) with high variability also evident in ETBE-treated rats. 17beta-Estradiol had been increased by 1200 mg/kg MTBE, and was elevated in the 1200 and 1800 mg/kg ETBE dose groups (p<0.05), both groups also experiencing significantly reduced body weight gain. None of these effects were seen with 600 mg/kg/day ETBE. No definitive evidence of androgen insufficiency was seen in accessory organ weights, and no testicular pathology was observed after 14 days in a small subset of 1800 mg/kg ETBE-treated animals. Like MTBE, ETBE appears to be capable of altering reproductive steroid levels in peripheral blood sampled 1h after treatment, but only with extremely high doses that inhibit body weight gain and may produce mortality.

  15. Chronaxie Measurements in Patterned Neuronal Cultures from Rat Hippocampus.

    Science.gov (United States)

    Stern, Shani; Agudelo-Toro, Andres; Rotem, Assaf; Moses, Elisha; Neef, Andreas

    2015-01-01

    Excitation of neurons by an externally induced electric field is a long standing question that has recently attracted attention due to its relevance in novel clinical intervention systems for the brain. Here we use patterned quasi one-dimensional neuronal cultures from rat hippocampus, exploiting the alignment of axons along the linear patterned culture to separate the contribution of dendrites to the excitation of the neuron from that of axons. Network disconnection by channel blockers, along with rotation of the electric field direction, allows the derivation of strength-duration (SD) curves that characterize the statistical ensemble of a population of cells. SD curves with the electric field aligned either parallel or perpendicular to the axons yield the chronaxie and rheobase of axons and dendrites respectively, and these differ considerably. Dendritic chronaxie is measured to be about 1 ms, while that of axons is on the order of 0.1 ms. Axons are thus more excitable at short time scales, but at longer time scales dendrites are more easily excited. We complement these studies with experiments on fully connected cultures. An explanation for the chronaxie of dendrites is found in the numerical simulations of passive, realistically structured dendritic trees under external stimulation. The much shorter chronaxie of axons is not captured in the passive model and may be related to active processes. The lower rheobase of dendrites at longer durations can improve brain stimulation protocols, since in the brain dendrites are less specifically oriented than axonal bundles, and the requirement for precise directional stimulation may be circumvented by using longer duration fields.

  16. Chronaxie Measurements in Patterned Neuronal Cultures from Rat Hippocampus.

    Directory of Open Access Journals (Sweden)

    Shani Stern

    Full Text Available Excitation of neurons by an externally induced electric field is a long standing question that has recently attracted attention due to its relevance in novel clinical intervention systems for the brain. Here we use patterned quasi one-dimensional neuronal cultures from rat hippocampus, exploiting the alignment of axons along the linear patterned culture to separate the contribution of dendrites to the excitation of the neuron from that of axons. Network disconnection by channel blockers, along with rotation of the electric field direction, allows the derivation of strength-duration (SD curves that characterize the statistical ensemble of a population of cells. SD curves with the electric field aligned either parallel or perpendicular to the axons yield the chronaxie and rheobase of axons and dendrites respectively, and these differ considerably. Dendritic chronaxie is measured to be about 1 ms, while that of axons is on the order of 0.1 ms. Axons are thus more excitable at short time scales, but at longer time scales dendrites are more easily excited. We complement these studies with experiments on fully connected cultures. An explanation for the chronaxie of dendrites is found in the numerical simulations of passive, realistically structured dendritic trees under external stimulation. The much shorter chronaxie of axons is not captured in the passive model and may be related to active processes. The lower rheobase of dendrites at longer durations can improve brain stimulation protocols, since in the brain dendrites are less specifically oriented than axonal bundles, and the requirement for precise directional stimulation may be circumvented by using longer duration fields.

  17. Postnatal exposure to a high-carbohydrate diet interferes epigenetically with thyroid hormone receptor induction of the adult male rat skeletal muscle glucose transporter isoform 4 expression.

    Science.gov (United States)

    Raychaudhuri, Nupur; Thamotharan, Shanthie; Srinivasan, Malathi; Mahmood, Saleh; Patel, Mulchand S; Devaskar, Sherin U

    2014-10-01

    Early life nutritional intervention causes adult-onset insulin resistance and obesity in rats. Thyroid hormone receptor (TR), in turn, transcriptionally enhances skeletal muscle Glut4 expression. We tested the hypothesis that reduced circulating thyroid-stimulating hormone and T4 concentrations encountered in postnatal (PN4-PN24) high-carbohydrate (HC) milk formula-fed versus the mother-fed controls (MF) would epigenetically interfere with TR induction of adult (100 days) male rat skeletal muscle Glut4 expression, thereby providing a molecular mechanism mediating insulin resistance. We observed increased DNA methylation of the CpG island with enhanced recruitment of Dnmt3a, Dnmt3b and MeCP2 in the glut4 promoter region along with reduced acetylation of histone (H)2A.Z and H4 particularly at the H4.lysine (K)16 residue, which was predominantly mediated by histone deacetylase 4 (HDAC4). This was followed by enhanced recruitment of heterochromatin protein 1β to the glut4 promoter with increased Suv39H1 methylase concentrations. These changes reduced TR binding of the T3 response element of the glut4 gene (TREs; -473 to -450 bp) detected qualitatively in vivo (electromobility shift assay) and quantified ex vivo (chromatin immunoprecipitation). In addition, the recruitment of steroid receptor coactivator and CREB-binding protein to the glut4 promoter-protein complex was reduced. Co-immunoprecipitation experiments confirmed the interaction between TR and CBP to be reduced and HDAC4 to be enhanced in HC versus MF groups. These molecular changes were associated with diminished skeletal muscle Glut4 mRNA and protein concentrations. We conclude that early postnatal exposure to HC diet epigenetically reduced TR induction of adult male skeletal muscle Glut4 expression, uncovering novel molecular mechanisms contributing to adult insulin resistance and obesity.

  18. Treadmill exercise promotes interleukin 15 expression in skeletal muscle and interleukin 15 receptor alpha expression in adipose tissue of high-fat diet rats.

    Science.gov (United States)

    Yang, Hongtao; Chang, Jinrui; Chen, Wenjia; Zhao, Lei; Qu, Bo; Tang, Chaoshu; Qi, Yongfen; Zhang, Jing

    2013-06-01

    Interleukin 15 (IL-15) has recently been proposed as a myokine involved in regulating lipid metabolism. We investigated the effect of exercise training on IL-15 content in skeletal muscle and expression of IL-15 receptor (IL-15R) in adipose tissue of obese rats. After 12 weeks of a high-fat diet, obese rats underwent treadmill running at 26 m/min (60 min each, 5 days/week for 8 weeks). High-fat diet induced obesity, with increased body weight, body fat, and lipid profile. The level of IL-15 immunoreactivity (IL-15-ir) in plasma and gastrocnemius muscle was lower in obese than control rats, and the mRNA level of IL-15 in gastrocnemius muscle was markedly decreased. The mRNA and protein levels of IL-15R in adipose tissue were markedly lower in obese rats. Compared with sedentary obese rats, treadmill running showed decreased body weight and elevated mRNA expression of IL-15 in muscle and elevated IL-15-ir level in plasma and muscle. The mRNA and protein level of IL-15R were increased in adipose tissue in treadmill running obese rats. Our results showed that exercise training improve obesity and reversed the downregulation of the IL-15 in muscle and IL-15R in adipose tissue induced by high-fat diet.

  19. Choice of cell-delivery route for skeletal myoblast transplantation for treating post-infarction chronic heart failure in rat.

    Science.gov (United States)

    Fukushima, Satsuki; Coppen, Steven R; Lee, Joon; Yamahara, Kenichi; Felkin, Leanne E; Terracciano, Cesare M N; Barton, Paul J R; Yacoub, Magdi H; Suzuki, Ken

    2008-08-27

    Intramyocardial injection of skeletal myoblasts (SMB) has been shown to be a promising strategy for treating post-infarction chronic heart failure. However, insufficient therapeutic benefit and occurrence of ventricular arrhythmias are concerns. We hypothesised that the use of a retrograde intracoronary route for SMB-delivery might favourably alter the behaviour of the grafted SMB, consequently modulating the therapeutic effects and arrhythmogenicity. Three weeks after coronary artery ligation in female wild-type rats, 5x10(6) GFP-expressing SMB or PBS only (control) were injected via either the intramyocardial or retrograde intracoronary routes. Injection of SMB via either route similarly improved cardiac performance and physical activity, associated with reduced cardiomyocyte-hypertrophy and fibrosis. Grafted SMB via either route were only present in low numbers in the myocardium, analysed by real-time PCR for the Y-chromosome specific gene, Sry. Cardiomyogenic differentiation of grafted SMB was extremely rare. Continuous ECG monitoring by telemetry revealed that only intramyocardial injection of SMB produced spontaneous ventricular tachycardia up to 14 days, associated with local myocardial heterogeneity generated by clusters of injected SMB and accumulated inflammatory cells. A small number of ventricular premature contractions with latent ventricular tachycardia were detected in the late-phase of SMB injection regardless of the injection-route. Retrograde intracoronary injection of SMB provided significant therapeutic benefits with attenuated early-phase arrhythmogenicity in treating ischaemic cardiomyopathy, indicating the promising utility of this route for SMB-delivery. Late-phase arrhythmogenicity remains a concern, regardless of the delivery route.

  20. Choice of cell-delivery route for skeletal myoblast transplantation for treating post-infarction chronic heart failure in rat.

    Directory of Open Access Journals (Sweden)

    Satsuki Fukushima

    Full Text Available BACKGROUND: Intramyocardial injection of skeletal myoblasts (SMB has been shown to be a promising strategy for treating post-infarction chronic heart failure. However, insufficient therapeutic benefit and occurrence of ventricular arrhythmias are concerns. We hypothesised that the use of a retrograde intracoronary route for SMB-delivery might favourably alter the behaviour of the grafted SMB, consequently modulating the therapeutic effects and arrhythmogenicity. METHODS AND RESULTS: Three weeks after coronary artery ligation in female wild-type rats, 5x10(6 GFP-expressing SMB or PBS only (control were injected via either the intramyocardial or retrograde intracoronary routes. Injection of SMB via either route similarly improved cardiac performance and physical activity, associated with reduced cardiomyocyte-hypertrophy and fibrosis. Grafted SMB via either route were only present in low numbers in the myocardium, analysed by real-time PCR for the Y-chromosome specific gene, Sry. Cardiomyogenic differentiation of grafted SMB was extremely rare. Continuous ECG monitoring by telemetry revealed that only intramyocardial injection of SMB produced spontaneous ventricular tachycardia up to 14 days, associated with local myocardial heterogeneity generated by clusters of injected SMB and accumulated inflammatory cells. A small number of ventricular premature contractions with latent ventricular tachycardia were detected in the late-phase of SMB injection regardless of the injection-route. CONCLUSION: Retrograde intracoronary injection of SMB provided significant therapeutic benefits with attenuated early-phase arrhythmogenicity in treating ischaemic cardiomyopathy, indicating the promising utility of this route for SMB-delivery. Late-phase arrhythmogenicity remains a concern, regardless of the delivery route.

  1. Palmitate-induced changes in energy demand cause reallocation of ATP supply in rat and human skeletal muscle cells.

    Science.gov (United States)

    Nisr, Raid B; Affourtit, Charles

    2016-09-01

    Mitochondrial dysfunction has been associated with obesity-related muscle insulin resistance, but the causality of this association is controversial. The notion that mitochondrial oxidative capacity may be insufficient to deal appropriately with excessive nutrient loads is for example disputed. Effective mitochondrial capacity is indirectly, but largely determined by ATP-consuming processes because skeletal muscle energy metabolism is mostly controlled by ATP demand. Probing the bioenergetics of rat and human myoblasts in real time we show here that the saturated fatty acid palmitate lowers the rate and coupling efficiency of oxidative phosphorylation under conditions it causes insulin resistance. Stearate affects the bioenergetic parameters similarly, whereas oleate and linoleate tend to decrease the rate but not the efficiency of ATP synthesis. Importantly, we reveal that palmitate influences how oxidative ATP supply is used to fuel ATP-consuming processes. Direct measurement of newly made protein demonstrates that palmitate lowers the rate of de novo protein synthesis by more than 30%. The anticipated decrease of energy demand linked to protein synthesis is confirmed by attenuated cycloheximide-sensitivity of mitochondrial respiratory activity used to make ATP. This indirect measure of ATP turnover indicates that palmitate lowers ATP supply reserved for protein synthesis by at least 40%. This decrease is also provoked by stearate, oleate and linoleate, albeit to a lesser extent. Moreover, palmitate lowers ATP supply for sodium pump activity by 60-70% and, in human cells, decreases ATP supply for DNA/RNA synthesis by almost three-quarters. These novel fatty acid effects on energy expenditure inform the 'mitochondrial insufficiency' debate.

  2. Measurement of contractile stress generated by cultured rat muscle on silicon cantilevers for toxin detection and muscle performance enhancement.

    Directory of Open Access Journals (Sweden)

    Kerry Wilson

    Full Text Available BACKGROUND: To date, biological components have been incorporated into MEMS devices to create cell-based sensors and assays, motors and actuators, and pumps. Bio-MEMS technologies present a unique opportunity to study fundamental biological processes at a level unrealized with previous methods. The capability to miniaturize analytical systems enables researchers to perform multiple experiments in parallel and with a high degree of control over experimental variables for high-content screening applications. METHODOLOGY/PRINCIPAL FINDINGS: We have demonstrated a biological microelectromechanical system (BioMEMS based on silicon cantilevers and an AFM detection system for studying the physiology and kinetics of myotubes derived from embryonic rat skeletal muscle. It was shown that it is possible to interrogate and observe muscle behavior in real time, as well as selectively stimulate the contraction of myotubes with the device. Stress generation of the tissue was estimated using a modification of Stoney's equation. Calculated stress values were in excellent agreement with previously published results for cultured myotubes, but not adult skeletal muscle. Other parameters such as time to peak tension (TPT, the time to half relaxation ((1/2RT were compared to the literature. It was observed that the myotubes grown on the BioMEMS device, while generating stress magnitudes comparable to those previously published, exhibited slower TPT and (1/2RT values. However, growth in an enhanced media increased these values. From these data it was concluded that the myotubes cultured on the cantilevers were of an embryonic phenotype. The system was also shown to be responsive to the application of a toxin, veratridine. CONCLUSIONS/SIGNIFICANCE: The device demonstrated here will provide a useful foundation for studying various aspects of muscle physiology and behavior in a controlled high-throughput manner as well as be useful for biosensor and drug discovery

  3. Microstructural, densitometric and metabolic variations in bones from rats with normal or altered skeletal states.

    Directory of Open Access Journals (Sweden)

    Andrew N Luu

    Full Text Available BACKGROUND: High resolution μCT, and combined μPET/CT have emerged as non-invasive techniques to enhance or even replace dual energy X-ray absorptiometry (DXA as the current preferred approach for fragility fracture risk assessment. The aim of this study was to assess the ability of µPET/CT imaging to differentiate changes in rat bone tissue density and microstructure induced by metabolic bone diseases more accurately than current available methods. METHODS: Thirty three rats were divided into three groups of control, ovariectomy and vitamin-D deficiency. At the conclusion of the study, animals were subjected to glucose ((18FDG and sodium fluoride (Na(18F PET/CT scanning. Then, specimens were subjected to µCT imaging and tensile mechanical testing. RESULTS: Compared to control, those allocated to ovariectomy and vitamin D deficiency groups showed 4% and 22% (significant increase in (18FDG uptake values, respectively. DXA-based bone mineral density was higher in the vitamin D deficiency group when compared to the other groups (cortical bone, yet μCT-based apparent and mineral density results were not different between groups. DXA-based bone mineral density was lower in the ovariectomy group when compared to the other groups (cancellous bone; yet μCT-based mineral density results were not different between groups, and the μCT-based apparent density results were lower in the ovariectomy group compared to the other groups. CONCLUSION: PET and micro-CT provide an accurate three-dimensional measurement of the changes in bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. As osteomalacia is characterized by impaired bone mineralization, the use of densitometric analyses may lead to misinterpretation of the condition as osteoporosis. In contrast, µCT alone and in combination with the PET component certainly provides an accurate three-dimensional measurement of the changes in both bone

  4. Time-dependent Appearances of Myofibroblasts during the Re-pair of Contused Skeletal Muscle in Rat and Its Application for Wound Age Determination

    Institute of Scientific and Technical Information of China (English)

    YU Tian-shui; GUAN Da-wei; CHANG Lin; WANG Xu; ZHAO Rui; ZHANG Hai-dong; BAI Ru-feng

    2015-01-01

    Objective To research the relation between the time-dependent appearances of myofibroblasts during the repair of contused skeletal muscle in rat and wound age determination. Methods A total of 35 SD male rats were divided into the control and six injured groups according to wound age as fol-lows: 12 h, 1 d, 5 d, 7 d, 10 d and 14 d after injury. The appearances of myofibroblasts were detected by HE staining, immunohistochemistry and confocal laser scanning microscopy. Masson’s trichrome staining was utilized to examine collagen accumulation in the contused areas. Results Immunohistochemical stain-ing showed that α-SMA+ myofibroblasts were initially observed at 5 d post-injury. The average ratio of myofibroblasts was highest at 14 d post-injury, with all samples, ratios more than 50%. In the other five groups, the average of α-SMA positive ratios were less than 50%. The collagen stained areas in the contused zones, concomitant with myofibroblast appearance, were increasingly augmented along with ad-vances of posttraumatic interval. Conclusion The immunohistochemical detection of myofibroblasts can be applied to wound age determination. The myofibroblasts might be involved in collagen deposition during the repair of contused skeletal muscle in rat.

  5. THREE INTERMITTENT SESSIONS OF CRYOTHERAPY REDUCE THE SECONDARY MUSCLE INJURY IN SKELETAL MUSCLE OF RAT

    Directory of Open Access Journals (Sweden)

    Nuno M. L. Oliveira

    2006-06-01

    Full Text Available Although cryotherapy associated to compression is recommended as immediate treatment after muscle injury, the effect of intermittent sessions of these procedures in the area of secondary muscle injury is not established. This study examined the effect of three sessions of cryotherapy (30 min of ice pack each 2h and muscle compression (sand pack in the muscle-injured area. Twenty-four Wistar rats (312 ± 20g were evaluated. In three groups, the middle belly of tibialis anterior (TA muscle was injured by a frozen iron bar and received one of the following treatments: a three sessions of cryotherapy; b three sessions of compression; c not treated. An uninjured group received sessions of cryotherapy. Frozen muscles were cross- sectioned (10 µm and stained for the measurement of injured and uninjured muscle area. Injured muscles submitted to cryotherapy showed the smallest injured area (29.83 ± 6.6%, compared to compressed (39.2 ± 2.8%, p= 0.003 and untreated muscles (41.74 ± 4.0%, p = 0.0008. No difference was found between injured compressed and injured untreated muscles. In conclusion, three intermittent sessions of cryotherapy applied immediately after muscle damage was able to reduce the secondary muscle injury, while only the muscle compression did not provide the same effectiveness

  6. Role of Ca(2+) in injury-induced changes in sodium current in rat skeletal muscle.

    Science.gov (United States)

    Filatov, Gregory N; Pinter, Martin J; Rich, Mark M

    2009-08-01

    Characteristics of voltage-dependent sodium current recorded from adult rat muscle fibers in loose patch mode were rapidly altered following nearby impalement with a microelectrode. Hyperpolarized shifts in the voltage dependence of activation and fast inactivation occurred within minutes. In addition, the amplitude of the maximal sodium current decreased within 30 min of impalement. Impalement triggered a sustained elevation of intracellular Ca(2+). However, buffering Ca(2+) by loading fibers with AM-BAPTA did not affect the hyperpolarized shifts in activation and inactivation, although it did prevent the reduction in current amplitude. Surprisingly, the rise in intracellular Ca(2+) occurred even in the absence of extracellular Ca(2+). This result indicated that the injury-induced Ca(2+) increase came from an intracellular source, but it was not blocked by an inhibitor of release from the sarcoplasmic reticulum, which suggested involvement of mitochondria. Ca(2+) release from mitochondria triggered by carbonyl cyanide 3-chlorophenylhydrazone was sufficient to cause a reduction in sodium current amplitude but had little effect of the voltage dependence of activation and fast inactivation. Our data suggest the effects of muscle injury can be separated into a Ca(2+)-dependent reduction in amplitude and a largely Ca(2+)-independent shift in activation and fast inactivation. Together, the impalement-induced changes in sodium current reduce the number of sodium channels available to open at the resting potential and may limit further depolarization and thus promote survival of muscle fibers following injury.

  7. Endurance training facilitates myoglobin desaturation during muscle contraction in rat skeletal muscle.

    Science.gov (United States)

    Takakura, Hisashi; Furuichi, Yasuro; Yamada, Tatsuya; Jue, Thomas; Ojino, Minoru; Hashimoto, Takeshi; Iwase, Satoshi; Hojo, Tatsuya; Izawa, Tetsuya; Masuda, Kazumi

    2015-03-24

    At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mVO2). However, whether the change in PmbO2 during muscle contraction modulates mVO2 and whether the O2 release rate from Mb increases in endurance-trained muscles remain unclear. The purpose of this study was, therefore, to determine the effect of endurance training on O2 saturation of Mb (SmbO2) and PmbO2 kinetics during muscle contraction. Male Wistar rats were subjected to a 4-week swimming training (Tr group; 6 days per week, 30 min × 4 sets per day) with a weight load of 2% body mass. After the training period, deoxygenated Mb kinetics during muscle contraction were measured using near-infrared spectroscopy under hemoglobin-free medium perfusion. In the Tr group, the VmO2peak significantly increased by 32%. Although the PmbO2 during muscle contraction did not affect the increased mVO2 in endurance-trained muscle, the O2 release rate from Mb increased because of the increased Mb concentration and faster decremental rate in SmbO2 at the maximal twitch tension. These results suggest that the Mb dynamics during muscle contraction are contributing factors to faster VO2 kinetics in endurance-trained muscle.

  8. Impaired sarcoplasmic reticulum Ca(2+) release rate after fatiguing stimulation in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ørtenblad, Niels; Sjøgaard, G; Madsen, Klavs

    2000-01-01

    to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which......The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate...... during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P

  9. 25-Hydroxyvitamin D requirement for maintaining skeletal health utilising a Sprague-Dawley rat model.

    Science.gov (United States)

    Anderson, P H; Sawyer, R K; May, B K; O'Loughlin, P D; Morris, H A

    2007-03-01

    To study the role of vitamin D to optimise bone architecture, we have developed an animal model to investigate the effects of frank vitamin D-deficiency as well as graded depletion of circulating 25-hydroxyvitamin D(3) (25D) levels on the skeleton. Rats fed on dietary vitamin D levels from 0 to 500 ng/day achieved diet-dependent circulating levels of 25D ranging from 11 to 115 nmol/L. Levels of serum 1,25-dihydroxyvitamin D(3) (1,25D) increased as dietary vitamin D increased between 0 and 200 ng/day at which point a maximum level was achieved and retained with higher vitamin D intakes. The renal levels of 25-hydroxyvitamin D-1alpha-hydroxylase (CYP27B1) mRNA were highest in animal groups fed on vitamin D between 0 and 300 ng/day. In contrast, renal 25-hydroxyvitamin D 24-hydroxylase (CYP24) mRNA levels increased as dietary vitamin D increased achieving maximum levels in animals receiving 500 ng vitamin D/day. This animal model of vitamin D depletion is suitable to provide invaluable information on the serum levels of 25D and dietary calcium intake necessary for optimal bone structure. Such information is essential for developing nutritional recommendations to reduce the incidence of osteoporotic hip fractures.

  10. l-Carnitine supplement reduces skeletal muscle atrophy induced by prolonged hindlimb suspension in rats.

    Science.gov (United States)

    Jang, Jiwoong; Park, Jonghoon; Chang, Hyukki; Lim, Kiwon

    2016-12-01

    l-Carnitine was recently found to downregulate the ubiquitin proteasome pathway (UPP) and increase insulin-like growth factor 1 concentrations in animal models. However, the effect of l-carnitine administration on disuse muscle atrophy induced by hindlimb suspension has not yet been studied. Thus, we hypothesized that l-carnitine may have a protective effect on muscle atrophy induced by hindlimb suspension via the Akt1/mTOR and/or UPP. Male Wistar rats were assigned to 3 groups: hindlimb suspension group, hindlimb suspension with l-carnitine administration (1250 mg·kg(-1)·day(-1)) group, and pair-fed group adjusted hindlimb suspension. l-Carnitine administration for 2 weeks of hindlimb suspension alleviated the decrease in weight and fiber size in the soleus muscle. In addition, l-carnitine suppressed atrogin-1 mRNA expression, which has been reported to play a pivotal role in muscle atrophy. The present study shows that l-carnitine has a protective effect against soleus muscle atrophy caused by hindlimb suspension and decreased E3 ligase messenger RNA expression, suggesting the possibility that l-carnitine protects against muscle atrophy, at least in part, through the inhibition of the UPP. These observations suggest that l-carnitine could serve as an effective supplement in the decrease of muscle atrophy caused by weightlessness in the fields of clinical and rehabilitative research.

  11. Effects of Caloric Restriction and Exercise Training on Skeletal Muscle Histochemistry in Aging Fischer 344 Rats

    Directory of Open Access Journals (Sweden)

    David T. Lowenthal

    2006-01-01

    Full Text Available The purpose of this study was to determine the effects of calorie restriction and exercise on hindlimb histochemistry and fiber type in Fischer 344 rats as they advanced from adulthood through senescence. At 10 months of age, animals were divided into sedentary fed ad libitum, exercise (18 m/min, 8% grade, 20 min/day, 5 days/week fed ad libitum, and calorie restricted by alternate days of feeding. Succinic dehydrogenase, myosin adenosine triphosphatase (mATPase at pH 9.4, nicotine adenonine dinucleotide reductase, and Periodic Acid Shiff histochemical stains were performed on plantaris and soleus muscles. The results indicated that aging resulted in a progressive decline in plantaris Type I muscle fiber in sedentary animals, while exercise resulted in maintenance of these fibers. The percent of plantaris Type II fibers increased between 10 and 24 months of age. Exercise also resulted in a small, but significant, increase in the percentage of plantaris Type IIa fibers at 24 months of age. The soleus fiber distribution for Type I fibers was unaffected by increasing age in all groups of animals. The implications of these results suggest the implementation of exercise as a lifestyle modification as early as possible.

  12. The experimental study of the damage of environmental neurotoxins on the cultured rat dopaminergic neurons

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; LU Chuanzhen; JIANG Yuping

    2000-01-01

    Objective To establish the culture system of rat dopaminergic neurons. and to determine whether Paraquat and Dieldrin selectively destroy cultured rat dopaminergic neurons respectively. Methods The cultured rat dopaminergic neurons were treated for 24h with Paraquat and Dieldrin(0.001 to 100 μ mol/L) respectively, Data were expressed as percentage of surviving TH-positive(TH+) cells and other cells per culture dish. Results Paraquat was not effective in selectively destroying TH+ neurons. Dieldrin (1 μ mol/L) selectively decreased the number of TH+ neurons without affecting other cells. The EC50 of Dieldrin on TH+ neurons was 27.6 l mol/L. Conclusion: Paraquat can not selectively destroy dopaminergic neurons in culture. Dieldrin (1 μ mol/L) can selectively destroy the dopaminergic neurons in culture, which make it a potential etiological agent for PD. The possible parkinsonogenic effect of Dieldrin is deserved for further investigation.

  13. Dietary fish oil delays hypoxic skeletal muscle fatigue and enhances caffeine-stimulated contractile recovery in the rat in vivo hindlimb.

    Science.gov (United States)

    Peoples, Gregory E; McLennan, Peter L

    2017-06-01

    Oxygen efficiency influences skeletal muscle contractile function during physiological hypoxia. Dietary fish oil, providing docosahexaenoic acid (DHA), reduces the oxygen cost of muscle contraction. This study used an autologous perfused rat hindlimb model to examine the effects of a fish oil diet on skeletal muscle fatigue during an acute hypoxic challenge. Male Wistar rats were fed a diet rich in saturated fat (SF), long-chain (LC) n-6 polyunsaturated fatty acids (n-6 PUFA), or LC n-3 PUFA DHA from fish oil (FO) (8 weeks). During anaesthetised and ventilated conditions (normoxia 21% O2 (SaO2-98%) and hypoxia 14% O2 (SaO2-89%)) the hindlimb was perfused at a constant flow and the gastrocnemius-plantaris-soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6-12V, 0.05 ms) to established fatigue. Caffeine (2.5, 5, 10 mM) was supplied to the contracting muscle bundle via the arterial cannula to assess force recovery. Hypoxia, independent of diet, attenuated maximal twitch tension (normoxia: 82 ± 8; hypoxia: 41 ± 2 g·g(-1) tissue w.w.). However, rats fed FO sustained higher peak twitch tension compared with the SF and n-6 PUFA groups (P recovery was enhanced in the FO-fed animals (SF: 41 ± 3; n-6 PUFA: 40 ± 4; FO: 52 ± 7% recovery; P < 0.05). These results support a physiological role of DHA in skeletal muscle membranes when exposed to low-oxygen stress that is consistent with the attenuation of muscle fatigue under physiologically normoxic conditions.

  14. Responses of skeletal muscle lipid metabolism in rat gastrocnemius to hypothyroidism and iodothyronine administration: a putative role for FAT/CD36.

    Science.gov (United States)

    Lombardi, Assunta; De Matteis, Rita; Moreno, Maria; Napolitano, Laura; Busiello, Rosa Anna; Senese, Rosalba; de Lange, Pieter; Lanni, Antonia; Goglia, Fernando

    2012-11-15

    Iodothyronines such as triiodothyronine (T(3)) and 3,5-diiodothyronine (T(2)) influence energy expenditure and lipid metabolism. Skeletal muscle contributes significantly to energy homeostasis, and the above iodothyronines are known to act on this tissue. However, little is known about the cellular/molecular events underlying the effects of T(3) and T(2) on skeletal muscle lipid handling. Since FAT/CD36 is involved in the utilization of free fatty acids by skeletal muscle, specifically in their import into that tissue and presumably their oxidation at the mitochondrial level, we hypothesized that related changes in lipid handling and in FAT/CD36 expression and subcellular redistribution would occur due to hypothyroidism and to T(3) or T(2) administration to hypothyroid rats. In gastrocnemius muscles isolated from hypothyroid rats, FAT/CD36 was upregulated (mRNA levels and total tissue, sarcolemmal, and mitochondrial protein levels). Administration of either T(3) or T(2) to hypothyroid rats resulted in 1) little or no change in FAT/CD36 mRNA level, 2) a decreased total FAT/CD36 protein level, and 3) further increases in FAT/CD36 protein level in sarcolemma and mitochondria. Thus, the main effect of each iodothyronine seemed to be exerted at the level of FAT/CD36 cellular distribution. The effect of further increases in FAT/CD36 protein level in sarcolemma and mitochondria was already evident at 1 h after iodothyronine administration. Each iodothyronine increased the mitochondrial fatty acid oxidation rate. However, the mechanisms underlying their rapid effects seem to differ; T(2) and T(3) each induce FAT/CD36 translocation to mitochondria, but only T(2) induces increases in carnitine palmitoyl transferase system activity and in the mitochondrial substrate oxidation rate.

  15. The effects of orbital spaceflight on bone histomorphometry and messenger ribonucleic acid levels for bone matrix proteins and skeletal signaling peptides in ovariectomized growing rats

    Science.gov (United States)

    Cavolina, J. M.; Evans, G. L.; Harris, S. A.; Zhang, M.; Westerlind, K. C.; Turner, R. T.

    1997-01-01

    A 14-day orbital spaceflight was performed using ovariectomized Fisher 344 rats to determine the combined effects of estrogen deficiency and near weightlessness on tibia radial bone growth and cancellous bone turnover. Twelve ovariectomized rats with established cancellous osteopenia were flown aboard the space shuttle Columbia (STS-62). Thirty ovariectomized rats were housed on earth as ground controls: 12 in animal enclosure modules, 12 in vivarium cages, and 6 killed the day of launch for baseline measurements. An additional 18 ovary-intact rats were housed in vivarium cages as ground controls: 8 rats were killed as baseline controls and the remaining 10 rats were killed 14 days later. Ovariectomy increased periosteal bone formation at the tibia-fibula synostosis; cancellous bone resorption and formation in the secondary spongiosa of the proximal tibial metaphysis; and messenger RNA (mRNA) levels for the prepro-alpha2(1) subunit of type 1 collagen, osteocalcin, transforming growth factor-beta, and insulin-like growth factor I in the contralateral proximal tibial metaphysis and for the collagen subunit in periosteum pooled from tibiae and femora and decreased cancellous bone area. Compared to ovariectomized weight-bearing rats, the flight group experienced decreases in periosteal bone formation, collagen subunit mRNA levels, and cancellous bone area. The flight rats had a small decrease in the cancellous mineral apposition rate, but no change in the calculated bone formation rate. Also, spaceflight had no effect on cancellous osteoblast and osteoclast perimeters or on mRNA levels for bone matrix proteins and signaling peptides. On the other hand, spaceflight resulted in an increase in bone resorption, as ascertained from the diminished retention of a preflight fluorochrome label. This latter finding suggests that osteoclast activity was increased. In a follow-up ground-based experiment, unilateral sciatic neurotomy of ovariectomized rats resulted in cancellous

  16. The cellular stress response of rat skeletal muscle following lengthening contractions.

    Science.gov (United States)

    Pollock-Tahiri, Evan; Locke, Marius

    2017-07-01

    The cellular stress response of the rat tibialis anterior (TA) muscle was investigated following 20, 40, or 60 lengthening contractions (LCs) using an in vivo model of electrical stimulation. Muscles were removed at 0, 1, 3, or 24 h after LCs and assessed for heat shock transcription factor (HSF) activation, heat shock protein (HSP) content, and/or morphological evidence of muscle fibre damage. When compared with the first muscle contraction, peak muscle torque was reduced by 26% (p < 0.05) after 20 LCs and further reduced to 56% and 60% (p < 0.001) after 40 and 60 LCs, respectively. Following 60 LCs, HSF activation was detected at 0, 1, and 3 h but was undetectable at 24 h. Hsp72 content was elevated at 24 h after 20 LCs (2.34 ± 0.37 fold, p < 0.05), 40 LCs (3.02 ± 0.31 fold, p < 0.01), and 60 LCs (3.37 ± 0.21 fold, p < 0.001). Hsp25 content increased after 40 (2.36 ± 0.24 fold, p < 0.01) and 60 LCs (2.80 ± 0.37 fold, p < 0.01). Morphological assessment of TA morphology revealed that very few fibres were damaged following 20 LCs while multiple sets of LCs (40 and 60) caused greater amounts of fibre damage. Electron microscopy showed disrupted Z-lines and sarcomeres were detectable in some muscles fibres following 20 LCs but were more prevalent and severe in muscles subjected to 40 or 60 LCs. These results suggest LCs elevate HSP content by an HSF-mediated mechanism (60 LC) and a single set of 20 LCs is capable of increasing muscle HSP content without causing significant muscle fibre damage.

  17. Long-chain acyl-CoA synthetase 6 regulates lipid synthesis and mitochondrial oxidative capacity in human and rat skeletal muscle.

    Science.gov (United States)

    Teodoro, Bruno G; Sampaio, Igor H; Bomfim, Lucas H M; Queiroz, André L; Silveira, Leonardo R; Souza, Anderson O; Fernandes, Anna M A P; Eberlin, Marcos N; Huang, Tai-Yu; Zheng, Donghai; Neufer, P Darrell; Cortright, Ronald N; Alberici, Luciane C

    2017-02-01

    Long-chain acyl-CoA synthetase 6 (ACSL6) mRNA is present in human and rat skeletal muscle, and is modulated by nutritional status: exercise and fasting decrease ACSL6 mRNA, whereas acute lipid ingestion increase its expression. ACSL6 genic inhibition in rat primary myotubes decreased lipid accumulation, as well as activated the higher mitochondrial oxidative capacity programme and fatty acid oxidation through the AMPK/PGC1-α pathway. ACSL6 overexpression in human primary myotubes increased phospholipid species and decreased oxidative metabolism. Long-chain acyl-CoA synthetases (ACSL 1 to 6) are key enzymes regulating the partitioning of acyl-CoA species toward different metabolic fates such as lipid synthesis or β-oxidation. Despite our understanding of ecotopic lipid accumulation in skeletal muscle being associated with metabolic diseases such as obesity and type II diabetes, the role of specific ACSL isoforms in lipid synthesis remains unclear. In the present study, we describe for the first time the presence of ACSL6 mRNA in human skeletal muscle and the role that ACSL6 plays in lipid synthesis in both rodent and human skeletal muscle. ACSL6 mRNA was observed to be up-regulated by acute high-fat meal ingestion in both rodents and humans. In rats, we also demonstrated that fasting and chronic aerobic training negatively modulated the ACSL6 mRNA and other genes of lipid synthesis. Similar results were obtained following ACSL6 knockdown in rat myotubes, which was associated with a decreased accumulation of TAGs and lipid droplets. Under the same knockdown condition, we further demonstrate an increase in fatty acid content, p-AMPK, mitochondrial content, mitochondrial respiratory rates and palmitate oxidation. These results were associated with increased PGC-1α, UCP2 and UCP3 mRNA and decreased reactive oxygen species production. In human myotubes, ACSL6 overexpression reduced palmitate oxidation and PGC-1α mRNA. In conclusion, ACSL6 drives acyl-CoA toward lipid

  18. Co-culture of primary rat hepatocytes with rat liver epithelial cells enhances interleukin-6-induced acute-phase protein response

    NARCIS (Netherlands)

    Peters, S.J.A.C.; Vanhaecke, T.; Papeleu, P.; Rogiers, V.; Haagsman, H.P.; Norren, van K.

    2010-01-01

    Three different primary rat hepatocyte culture methods were compared for their ability to allow the secretion of fibrinogen and albumin under basal and IL-6- stimulated conditions. These culture methods comprised the co-culture of hepatocytes with rat liver epithelial cells (CCRLEC), a collagen type

  19. Effects of drotaverine hydrochloride on viability of rat cultured cerebellar granulocytes.

    Science.gov (United States)

    Demushkin, V P; Zhavoronkova, E V; Khaspekov, L G

    2012-02-01

    The neurocytotoxic effect of drotaverine hydrochloride was studied in culture of rat cerebellar granulocytes. Incubation of cells with 100 and 250 μM drotaverine reduced neuronal survival to 60 and 4%, respectively.

  20. Glutamate enhances the expression of vascular endothelial growth factor in cultured SD rat astrocytes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To study the effect of glutamate on the expression of vascular endothelial growth factor (VEGF) mRNA and protein in cultured rat astrocytes. Methods Cultured rat astrocytes were randomly divided into 6 groups:control group (C),glutamate group (G),QA group (Q),DCG-IV group (D),L-AP4 group (L) and glutamate+MCPG group (G+M). Cells were cultured under nomoxic condition (95% air,5% CO2). RT-PCR and ELISA methods were used to detect the expression of VEGF mRNA and protein in cultured astrocytes,respect...

  1. Oral chromium picolinate improves carbohydrate and lipid metabolism and enhances skeletal muscle Glut-4 translocation in obese, hyperinsulinemic (JCR-LA corpulent) rats.

    Science.gov (United States)

    Cefalu, William T; Wang, Zhong Q; Zhang, Xian H; Baldor, Linda C; Russell, James C

    2002-06-01

    Human studies suggest that chromium picolinate (CrPic) decreases insulin levels and improves glucose disposal in obese and type 2 diabetic populations. To evaluate whether CrPic may aid in treatment of the insulin resistance syndrome, we assessed its effects in JCR:LA-corpulent rats, a model of this syndrome. Male lean and obese hyperinsulinemic rats were randomly assigned to receive oral CrPic [80 microg/(kg. d); n = 5 or 6, respectively) in water or to control conditions (water, n = 5). After 3 mo, a 120-min intraperitoneal glucose tolerance test (IPGTT) and a 30-min insulin tolerance test were performed. Obese rats administered CrPic had significantly lower fasting insulin levels (1848 +/- 102 vs. 2688 +/- 234 pmol/L; P < 0.001; mean +/- SEM) and significantly improved glucose disappearance (P < 0.001) compared with obese controls. Glucose and insulin areas under the curve for IPGTT were significantly less for obese CrPic-treated rats than in obese controls (P < 0.001). Obese CrPic-treated rats had lower plasma total cholesterol (3.57 +/- 0.28 vs. 4.11 +/- 0.47 mmol/L, P < 0.05) and higher HDL cholesterol levels (1.92 +/- 0.09 vs. 1.37 +/- 0.36 mmol/L, P < 0.01) than obese controls. CrPic did not alter plasma glucose or cholesterol levels in lean rats. Total skeletal muscle glucose transporter (Glut)-4 did not differ among groups; however, CrPic significantly enhanced membrane-associated Glut-4 in obese rats after insulin stimulation. Thus, CrPic supplementation enhances insulin sensitivity and glucose disappearance, and improves lipids in male obese hyperinsulinemic JCR:LA-corpulent rats.

  2. Exercise-Induced Changes in Caveolin-1, Depletion of Mitochondrial Cholesterol, and the Inhibition of Mitochondrial Swelling in Rat Skeletal Muscle but Not in the Liver

    Directory of Open Access Journals (Sweden)

    Damian Jozef Flis

    2016-01-01

    Full Text Available The reduction in cholesterol in mitochondria, observed after exercise, is related to the inhibition of mitochondrial swelling. Caveolin-1 (Cav-1 plays an essential role in the regulation of cellular cholesterol metabolism and is required by various signalling pathways. Therefore, the aim of this study was to investigate the effect of prolonged swimming on the mitochondrial Cav-1 concentration; additionally, we identified the results of these changes as they relate to the induction of changes in the mitochondrial swelling and cholesterol in rat skeletal muscle and liver. Male Wistar rats were divided into a sedentary control group and an exercise group. The exercised rats swam for 3 hours and were burdened with an additional 3% of their body weight. After the cessation of exercise, their quadriceps femoris muscles and livers were immediately removed for experimentation. The exercise protocol caused an increase in the Cav-1 concentration in crude muscle mitochondria; this was related to a reduction in the cholesterol level and an inhibition of mitochondrial swelling. There were no changes in rat livers, with the exception of increased markers of oxidative stress in mitochondria. These data indicate the possible role of Cav-1 in the adaptive change in the rat muscle mitochondria following exercise.

  3. Age-related changes in expression of the neural cell adhesion molecule in skeletal muscle: a comparative study of newborn, adult and aged rats

    DEFF Research Database (Denmark)

    Andersson, A M; Olsen, M; Zhernosekov, D

    1993-01-01

    report quantitative and qualitative changes in NCAM protein and mRNA forms during aging in normal rat skeletal muscle. Determination of the amount of NCAM by e.l.i.s.a. showed that the level decreased from perinatal to adult age, followed by a considerable increase in 24-month-old rat muscle. Thus NCAM...... virtually unchanged at all ages examined. However, changes in the extent of sialylation of NCAM were demonstrated. Even though the relative amounts of the various NCAM polypeptides were unchanged during aging, distinct changes in NCAM mRNA classes were observed. Three NCAM mRNA classes of 6.7, 5.2 and 2......Neural cell adhesion molecule (NCAM) is expressed by muscle and involved in muscle-neuron and muscle-muscle cell interactions. The expression in muscle is regulated during myogenesis and by the state of innervation. In aged muscle, both neurogenic and myogenic degenerative processes occur. We here...

  4. Plasminogen binding to rat hepatocytes in primary culture and to thin slices of rat liver

    Energy Technology Data Exchange (ETDEWEB)

    Gonias, S.L.; Braud, L.L.; Geary, W.A.; VandenBerg, S.R. (Univ. of Virginia Health Sciences Center, Charlottesville (USA))

    1989-08-01

    Human {sup 125}I-plasminogen bound readily to rat hepatocytes in primary culture at 4 {degree}C and at 37{degree}C. Binding was inhibited by lysine and reversed by lysine, epsilon-aminocaproic acid, or nonradiolabeled plasminogen. The Kd for binding of {sup 125}I-plasminogen to hepatocytes was 0.59 +/- 0.16 mumol/L, as determined from the saturation isotherm by nonlinear regression (r2 = 0.99) and the Scatchard transformation by linear regression (r2 = 0.93). The number of sites per cell was 14.1 +/- 1.1 x 10(6). Fibrinogen synthesis and secretion by hepatocytes was insufficient to account for the major fraction of plasminogen binding, as determined by enzyme-linked immunosorbent assay (ELISA). Polyacrylamide gel electrophoresis and trichloroacetic acid precipitation studies demonstrated that plasminogen is neither activated nor degraded when bound to hepatocytes at 37{degree}C. Thin slices of whole rat liver (500 microns), isolated and prepared totally at 4{degree}C, bound {sup 125}I-plasminogen. Binding was inhibited by lysine. {sup 125}I-albumin binding to liver slices was minimal and not inhibited by lysine. Activation of plasminogen by tissue plasminogen activator (t-PA) was enhanced by hepatocytes in primary culture. When lysine was included in the media, the enhanced rate of activation was no longer observed. After activation with t-PA, much of the plasmin remained associated with hepatocyte surfaces and was partially protected from inhibition by alpha 2-antiplasmin. These studies suggest that hepatocyte plasminogen binding sites may provide important surface anticoagulant activity.

  5. Effects of trypan blue on rat and rabbit embryos cultured in vitro.

    Science.gov (United States)

    Ninomiya, H; Kishida, K; Ohno, Y; Tsurumi, K; Eto, K

    1993-11-01

    Mouse and rat whole embryo cultures are widely used in teratogenicity studies. We attempted to improve the technique of culturing rabbit embryo. Rabbit embryos of the Japanese White strain were explanted on day 9, 10 or 11 of gestation and cultured for 24 or 48 hr. Rabbit embryos on day 9 of gestation were cultured in 100% rabbit serum with a gas mixture containing 20% O(2) for the first 24 hr and 95% O(2) for the following 24 hr. Rabbit embryos on day 10 or 11 of gestation were cultured in 100, 80 or 60% rabbit serum with a gas mixture of 95% O(2) for 48 or 24 hr. The development of embryos cultured for 48 hr from day 9 or day 10 or for 24 hr from day 11 was nearly the same as that of embryos that had developed in vivo. These results indicate that rabbit embryo culture is a useful and promising technique in teratogenicity studies. We then examined the effects of trypan blue on cultured rat and rabbit embryos. Slc:SD rat embryos on day 9.5 of gestation were explanted and cultured in rat serum exposed to trypan blue (300-2700 mug/ml) for 48 hr. Rabbit embryos on day 9 or 10 of gestation were explanted and cultured in rabbit serum containing trypan blue (300-2700 mug/ml) for 48 or 24 hr. Cultured rat embryos exposed to trypan blue showed neural tube abnormalities, and all growth parameters were suppressed with increasing concentrations of trypan blue. However, trypan blue had no effect on cultured rabbit embryos. These results indicate that trypan blue has species-specific effects on embryos.

  6. IGF-1 mRNA expression of adult rat thyroid cell cultured in vitro

    Institute of Scientific and Technical Information of China (English)

    HE Feng-ping(何凤屏); YIN Rui-xing(尹瑞兴); XUAN Su(冼苏); JEAN Joss

    2003-01-01

    Objective:To investigate the law of age-related changes of insulin-like growth factor-1(IGF-1)expression of rat thyroid cells cultured in vitro.Methods:Rat thyroid of different age(10,45,65,100,150 weeks)was isolated and thyrocytes cultured.Total RNA was extracted in different rat age group when thyroid cells had been cultured for two weeks,mRNA IGF-1 expression was measured with reverse-transcription polymerase chain reaction(RT-PCR)in each group and compared.Results:Quantity of total RNA in thyroid cells decreased with ageing when the rat thyroid cells had been cultured for 2 weeks.There is significant difference among groups(P < 0.05).Expression of IGF-1 mRNA could be detected in thyroid cells of different age cultured in vitro.Quantity of IGF-1 mRNA expression by RTPCR analysis increased from 10 to 45 weeks old,and then decreased with ageing.Conclusion:Rat thyroid cells from different age cultured in vitro can express IGF-1 mRNA.Quantity of total RNA in thyroid cells cultured in vitro decreased with aging.IGF-1 mRNA expression was correlated to age(r =0.401,P <0.05).

  7. A novel method for toxicology: in vitro culture system of a rat preantral follicle.

    Science.gov (United States)

    Wan Xuying; Zhu Jiangbo; Zhu Yuping; Xili, Ma; Liu Zhen; Wang Fei; Xu Guifeng; Zhang Tianbao

    2011-08-01

    Preantral follicle in vitro culture systems have been successfully or nearly successfully established for sheep, pig and mouse, and applied on follicle development and regulation research on reproductive biology and physiology. However, there have been few studies concerning rat preantral follicle in vitro development. The objective is to establish an in vitro culture system for rat preantral follicles which can be used for reproductive biology and toxicology research. Rat preantral follicles are mechanically separated, cultured in vitro in single follicle mode for continuous 12 days using 96-well plates, and then administrated ovulation induction. The observation on follicle development, hormone level, and ovum formation are recorded and assessed. Taking in vivo growth and in vitro maturation of oocytes group as control group, in vitro growth and maturation of oocytes group is assessed to see whether this in vitro culture method is successful. The conditions for rat follicle culture are determined based on the mouse pre-antral follicle culture. The in vitro culture system for rat preantral follicles established in this study is feasible and successful, and can serve as model for reproductive biology and toxicology research.

  8. Protein restriction during gestation alters histone modifications at the glucose transporter 4 (GLUT4) promoter region and induces GLUT4 expression in skeletal muscle of female rat offspring.

    Science.gov (United States)

    Zheng, Shasha; Rollet, Michelle; Pan, Yuan-Xiang

    2012-09-01

    Maternal nutrition during pregnancy is an intrauterine factor that results in alteration of the offspring genome and associates with disease risk in the offspring. We investigated the impact of a maternal low-protein (LP) diet on the expression of glucose transporter 4 (GLUT4) in offspring skeletal muscle. GLUT4 is an insulin-regulated glucose transporter involved in insulin sensitivity and carbohydrate metabolism in muscle cells. We observed sex-dependent GLUT4 mRNA expression and increased GLUT4 protein content in female pup skeletal muscle with maternal LP. Analysis of transcriptional and epigenetic regulation of increased skeletal muscle GLUT4 expression in offspring rats revealed the regulatory mechanisms involved. The protein level of myocyte enhancer factor 2A (MEF2A), which has been known as an activator of GLUT4 transcription via the ability to carry out specific binding to the GLUT4 MEF2 binding sequence, increased in female pups whose mothers were fed a LP diet. Modifications of chromatin structure, including acetylated histone H3, acetylated histone H4 and di-methylated histone H3 at lysine 4, were detected at a significantly increased level at the GLUT4 promoter region in female pup muscle following a maternal LP diet. Glycogen content was also detected as up-regulated, accompanied by increased glycogen synthase in LP female offspring muscle. These results document that maternal protein restriction during pregnancy induces GLUT4 expression in female offspring skeletal muscle but not in males, which may indicate sex-dependent adaptation of glucose metabolism to a maternal LP diet.

  9. Effects of diet-induced obesity on protein expression in insulin signaling pathways of skeletal muscle in male Wistar rats

    Directory of Open Access Journals (Sweden)

    Fatani S

    2012-07-01

    Full Text Available Sameer Fatani,1 Abdul-Razak Abubakari,2 Imose Itua,2 Christopher Wong,3 Cecil Thomas,3 Ebrahim K Naderali21Obesity Biology Unit, School of Clinical Sciences, University of Liverpool, 2Department of Health Sciences, Liverpool Hope University, Hope Park, 3Aintree University Hospital NHS Foundation Trust, Liverpool, UKBackground: The prevalence of diet-induced obesity is increasing globally, and posing significant health problems for millions of people worldwide. Diet-induced obesity is a major contributor to the global pandemic of type 2 diabetes mellitus. The reduced ability of muscle tissue to regulate glucose homeostasis plays a major role in the development and prognosis of type 2 diabetes. In this study, an animal model of diet-induced obesity was used to elucidate changes in skeletal muscle insulin signaling in obesity-induced diabetes.Methods: Adult male Wistar rats were randomized and assigned to either a control group or to a test group. Controls were fed a standard laboratory pellet diet (chow-fed, while the test group had free access to a highly palatable diet (diet-fed. After 8 weeks, the diet-fed animals were subdivided into three subgroups and their diets were altered as follows: diet-to-chow, diet-fed with addition of fenofibrate given by oral gavage for a further 7 weeks, or diet-fed with vehicle given by oral gavage for a further 7 weeks, respectively.Results: Untreated diet-fed animals had a significantly higher body weight and metabolic profile than the control chow-fed animals. Intramuscular triacylglyceride levels in the untreated obese animals were significantly higher than those in the control chow-fed group. Expression of protein kinase C beta, phosphatidylinositol 3, Shc, insulin receptor substrate 1, ERK1/2, and endothelial nitric oxide synthase was significantly increased by dietary obesity, while that of insulin receptor beta, insulin receptor substrate 1, and protein kinase B (Akt were not affected by obesity

  10. Effect of Huanglian Jiedu Decoction(黄连解毒汤)on Glucose Transporter 4 Expression in Adipose and Skeletal Muscle Tissues of Insulin Resistant Rats

    Institute of Scientific and Technical Information of China (English)

    CHEN Guang; LU Fu-er; JIN Dan; XU Li-jun; WANG Kai-fu

    2007-01-01

    Objective:To investigate the effects of Huanglian Jiedu Decoction (黄连解毒汤,HLJDD) on glucose transporter 4 (GLUT4) protein expressions in insulin-resistant murine target tissues.Methods:The experimental male Wistar rats were established into insulin resistant models by injecting streptozotocin (STZ 30 mg/kg) via caudal vein and feeding them with high fat high caloric diet,and randomly divided into the model group,the aspirin group and the HLJDD group.Besides,a normal group was set up for control.Changes of body weight (BW),levels of serum fasting blood glucose (FBG),serum fasting insulin (FINS) and oral glucose tolerance test (OGTT) were routinely determined.The expression of GLUT4 protein in adipose and skeletal muscle tissues before and after insulin stimulation was determined with Western blot.Results:In the HLJDD group after treatment.BW and FBG got decreased,OGTT improved,and the expression and translocation of GLUT4 protein elevated obviously,either before or after insulin stimulation,as compared with those in the model group,showing significant differences respectively.Conclusion:The mechanism of improving insulin resistance by HLJDD is probably associated with its effect in elevating GLUT4 protein expression and translocation in adipose and skeletal muscle tissues of insulin resistant rats.

  11. Effects of dietary omega-3 polyunsaturated Fatty acids on the skeletal-muscle blood-flow response to exercise in rats.

    Science.gov (United States)

    Stebbins, Charles L; Hammel, Lauren E; Marshal, Benjamin J; Spangenberg, Espen E; Musch, Timothy I

    2010-12-01

    The polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) affect vascular relaxation and involve factors (e.g., nitric oxide) that contribute to exercise-induced increases in skeletal-muscle blood flow (Q). The authors investigated whether DHA and EPA supplementation augments skeletal-muscle Q and vascular conductance (VC) and attenuates renal and splanchnic Q and VC in exercising rats. Rats were fed a diet of 5% lipids by weight, of which 20% was DHA and 30% EPA (PUFA group, n = 9), or 5% safflower oil (SO group, n = 8) for 6 wk. Heart rate (HR), blood pressure (MAP), and hind-limb, renal, and splanchnic Q were measured at rest and during moderate treadmill running. MAP, HR, and renal and splanchnic Q and VC were similar between the 2 groups at rest and during exercise. In the PUFA group, Q (158 ± 27 vs. 128 ± 28 ml × min⁻¹ × 100 g⁻¹) and VC (1.16 ± 0.21 vs. 0.92 ± 0.23 ml × min⁻¹ × 100 g⁻¹ × mm Hg⁻¹) were greater in the exercising hind-limb muscle. Q and VC were also higher in 8 of 28 and 11 of 28 muscles and muscle parts, respectively. These increases were positively correlated to the percent sum of Types I and IIa fibers. Results suggest that DHA+EPA (a) enhances Q and VC in active skeletal muscle (especially Type I and IIa fibers) and that the increase in Q is due to an increase in cardiac output secondary to increases in VC and (b) has no apparent influence on vasoconstriction in renal and splanchnic tissue.

  12. Chronic AMP-activated protein kinase activation and a high-fat diet have an additive effect on mitochondria in rat skeletal muscle.

    Science.gov (United States)

    Fillmore, Natasha; Jacobs, Daniel L; Mills, David B; Winder, William W; Hancock, Chad R

    2010-08-01

    Factors that stimulate mitochondrial biogenesis in skeletal muscle include AMP-activated protein kinase (AMPK), calcium, and circulating free fatty acids (FFAs). Chronic treatment with either 5-aminoimidazole-4-carboxamide riboside (AICAR), a chemical activator of AMPK, or increasing circulating FFAs with a high-fat diet increases mitochondria in rat skeletal muscle. The purpose of this study was to determine whether the combination of chronic chemical activation of AMPK and high-fat feeding would have an additive effect on skeletal muscle mitochondria levels. We treated Wistar male rats with a high-fat diet (HF), AICAR injections (AICAR), or a high-fat diet and AICAR injections (HF + AICAR) for 6 wk. At the end of the treatment period, markers of mitochondrial content were examined in white quadriceps, red quadriceps, and soleus muscles, predominantly composed of unique muscle-fiber types. In white quadriceps, there was a cumulative effect of treatments on long-chain acyl-CoA dehydrogenase, cytochrome c, and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) protein, as well as on citrate synthase and beta-hydroxyacyl-CoA dehydrogenase (beta-HAD) activity. In contrast, no additive effect was noted in the soleus, and in the red quadriceps only beta-HAD activity increased additively. The additive increase of mitochondrial markers observed in the white quadriceps may be explained by a combined effect of two separate mechanisms: high-fat diet-induced posttranscriptional increase in PGC-1alpha protein and AMPK-mediated increase in PGC-1alpha protein via a transcriptional mechanism. These data show that chronic chemical activation of AMPK and a high-fat diet have a muscle type specific additive effect on markers of fatty acid oxidation, the citric acid cycle, the electron transport chain, and transcriptional regulation.

  13. Ototoxicity of paclitaxel in rat cochlear organotypic cultures

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yang [Shanghai University of Traditional Chinese Medicine, Shanghai 201203 (China); Center for Hearing and Deafness, University at Buffalo, NY 14214 (United States); Ding, Dalian; Jiang, Haiyan [Center for Hearing and Deafness, University at Buffalo, NY 14214 (United States); Shi, Jian-rong [Shanghai University of Traditional Chinese Medicine, Shanghai 201203 (China); Salvi, Richard [Center for Hearing and Deafness, University at Buffalo, NY 14214 (United States); Roth, Jerome A., E-mail: jaroth@buffalo.edu [Department of Pharmacology and Toxicology, University at Buffalo, NY 14214 (United States)

    2014-11-01

    Paclitaxel (taxol) is a widely used antineoplastic drug employed alone or in combination to treat many forms of cancer. Paclitaxel blocks microtubule depolymerization thereby stabilizing microtubules and suppressing cell proliferation and other cellular processes. Previous reports indicate that paclitaxel can cause mild to moderate sensorineural hearing loss and some histopathologic changes in the mouse cochlea; however, damage to the neurons and the underlying cell death mechanisms are poorly understood. To evaluate the ototoxicity of paclitaxel in more detail, cochlear organotypic cultures from postnatal day 3 rats were treated with paclitaxel for 24 or 48 h with doses ranging from 1 to 30 μM. No obvious histopathologies were observed after 24 h treatment with any of the paclitaxel doses employed, but with 48 h treatment, paclitaxel damaged cochlear hair cells in a dose-dependent manner and also damaged auditory nerve fibers and spiral ganglion neurons (SGN) near the base of the cochlea. TUNEL labeling was negative in the organ of Corti, but positive in SGN with karyorrhexis 48 h after 30 μM paclitaxel treatment. In addition, caspase-6, caspase-8 and caspase-9 labeling was present in SGN treated with 30 μM paclitaxel for 48 h. These results suggest that caspase-dependent apoptotic pathways are involved in paclitaxel-induced damage of SGN, but not hair cells in cochlea. - Highlights: • Paclitaxel was toxic to cochlear hair cells and spiral ganglion neurons. • Paclitaxel-induced spiral ganglion degeneration was apoptotic. • Paclitaxel activated caspase-6, -8 and -8 in spiral ganglion neurons.

  14. Stimulation of DNA synthesis in cultured rat alveolar type II cells

    Energy Technology Data Exchange (ETDEWEB)

    Leslie, C.C.; McCormick-Shannon, K.; Robinson, P.C.; Mason, R.J.

    1985-01-01

    Restoration of the alveolar epithelium after injury is thought to be dependent on the proliferation of alveolar type II cells. To understand the factors that may be involved in promoting type II cell proliferation in vivo, we determined the effect of potential mitogens and culture substrata on DNA synthesis in rat alveolar type II cells in primary culture. Type II cells cultured in basal medium containing 10% fetal bovine serum (FBS) exhibited essentially no DNA synthesis. Factors that stimulated /sup 3/H-thymidine incorporation included cholera toxin, epidermal growth factor, and rat serum. The greatest degree of stimulation was achieved by plating type II cells on an extracellular matrix prepared from bovine corneal endothelial cells and then by culturing the pneumocytes in medium containing rat serum, cholera toxin, insulin, and epidermal growth factor. Under conditions of stimulation of /sup 3/H-thymidine incorporation there was an increased DNA content per culture dish but no increase in cell number. The ability of various culture conditions to promote DNA synthesis in type II cells was verified by autoradiography. Type II cells were identified by the presence of cytoplasmic inclusions, which were visualized by tannic acid staining before autoradiography. These results demonstrate the importance of soluble factors and culture substratum in stimulating DNA synthesis in rat alveolar type II cells in primary culture.

  15. Explant culture of rat colon: A model system for studying metabolism of chemical carcinogens

    DEFF Research Database (Denmark)

    Autrup, Herman; Stoner, G.D.; Jackson, F.

    1978-01-01

    An explant culture system has been developed for the long-term maintenance of colonic tissue from the rat. Explants of 1 cm2 in size were placed in tissue-culture dishes to which was added 2 ml of CMRL-1066 medium supplemented with glucose, hydrocortisone, beta-retinyl acetate, and either 2.5% bo...

  16. Control levels of acetylcholinesterase expression in the mammalian skeletal muscle.

    Science.gov (United States)

    Grubic, Z; Zajc-Kreft, K; Brank, M; Mars, T; Komel, R; Miranda, A F

    1999-05-14

    Protein expression can be controled at different levels. Understanding acetylcholinesterase (EC. 3.1.1.7, AChE) expression in the living organisms therefore necessitates: (1) determination and mapping of control levels of AChE metabolism; (2) identification of the regulatory factors acting at these levels; and (3) detailed insight into the mechanisms of action of these factors. Here we summarize the results of our studies on the regulation of AChE expression in the mammalian skeletal muscle. Three experimental models were employed: in vitro innervated human muscle, mechanically denervated adult fast rat muscle, and the glucocorticoid treated fast rat muscle. In situ hybridization of AChE mRNA, combined with AChE histochemistry, revealed that different distribution patterns of AChE, observed during in vitro ontogenesis and synaptogenesis of human skeletal muscle, reflect alterations in the distribution of AChE mRNA (Z. Grubic, R. Komel, W.F. Walker, A.F. Miranda, Myoblast fusion and innervation with rat motor nerve alter the distribution of acetylcholinesterase and its mRNA in human muscle cultures, Neuron 14 (1995) 317-327). To study the mechanisms of AChE mRNA loss in denervated adult rat skeletal muscle, we exposed deproteinated AChE mRNA to various subcellular fractions in vitro. Fractions were isolated from the normal and denervated rat sternomastoideus muscle. We found significantly increased, but non-specific AChE mRNA degradation capacities in the three fractions studied, suggesting that increased susceptibility of muscle mRNA to degradation might be at least partly responsible for the decreased AChE mRNA observed under such conditions (K. Zajc-Kreft, S. Kreft, Z. Grubic, Degradation of AChE mRNA in the normal and denervated rat skeletal muscle, Book of Abstracts, The Sixth International Meeting on Cholinesterases, La Jolla, CA, March 20-24, 1998, p. A3.). In adult fast rat muscle, treated chronically with glucocorticoids, we found the fraction of early

  17. Explant culture of rat colon: A model system for studying metabolism of chemical carcinogens

    DEFF Research Database (Denmark)

    Autrup, Herman; Stoner, G.D.; Jackson, F.

    1978-01-01

    An explant culture system has been developed for the long-term maintenance of colonic tissue from the rat. Explants of 1 cm2 in size were placed in tissue-culture dishes to which was added 2 ml of CMRL-1066 medium supplemented with glucose, hydrocortisone, beta-retinyl acetate, and either 2....... The explants were incubated at 30 degrees C. The viability of the tissue was measured both by incorporation of specific precursors into cellular macromolecules and by monitoring of tissue morphology with light and electron microscopy. Cultured rat colon was able to metabolize benzo[alpha]pyrene, 7...

  18. Effect of Opuntia humifusa Supplementation and Acute Exercise on Insulin Sensitivity and Associations with PPAR-γ and PGC-1α Protein Expression in Skeletal Muscle of Rats

    Directory of Open Access Journals (Sweden)

    Youngju Song

    2013-03-01

    Full Text Available This study examined whether Opuntia humifusa (O. humifusa, which is a member of the Cactaceae family, supplementation and acute swimming exercise affect insulin sensitivity and associations with PPAR-γ and PGC-1α protein expression in rats. Thirty-two rats were randomly divided into four groups (HS: high fat diet sedentary group, n = 8; HE: high fat diet acute exercise group, n = 8; OS: 5% O. humifusa supplemented high fat diet sedentary group, n = 8; OE: 5% O. humifusa supplemented high fat diet acute exercise group, n = 8. Rats in the HE and OE swam for 120 min. before being sacrificed. Our results indicated that serum glucose level, fasting insulin level and homeostasis model assessment of insulin resistance (HOMA-IR in OS were significantly lower compared to those of the HS (p < 0.01, p < 0.05, p < 0.05. In addition, PPAR-γ protein expression in the OS and OE was significantly higher than that of the HS and HE, respectively (p < 0.05, p < 0.01. PGC-1α and GLUT-4 protein expressions in the OS were significantly higher compared to those of the HS (p < 0.05, p < 0.05. From these results, O. humifusa supplementation might play an important role for improving insulin sensitivity through elevation of PPAR-γ, PGC-1α, and GLUT-4 protein expression in rat skeletal muscle.

  19. {sup 18}F-fluorodeoxyglucose and PET/CT for noninvasive study of exercise-induced glucose uptake in rat skeletal muscle and tendon

    Energy Technology Data Exchange (ETDEWEB)

    Skovgaard, Dorthe [University of Copenhagen, Cluster for Molecular Imaging, Faculty of Health Sciences, Copenhagen (Denmark); Bispebjerg Hospital, Institute of Sports Medicine, Copenhagen, NV (Denmark); Kjaer, Michael [Bispebjerg Hospital, Institute of Sports Medicine, Copenhagen, NV (Denmark); El-Ali, Henrik [University of Copenhagen, Cluster for Molecular Imaging, Faculty of Health Sciences, Copenhagen (Denmark); Kjaer, Andreas [University of Copenhagen, Cluster for Molecular Imaging, Faculty of Health Sciences, Copenhagen (Denmark); Rigshospitalet, Department Clinical Physiology, Nuclear Medicine and PET, Center of Diagnostic Investigations, Copenhagen (Denmark)

    2009-05-15

    To investigate exercise-related glucose uptake in rat muscle and tendon using PET/CT and to study possible explanatory changes in gene expression for the glucose transporters (GLUT1 and GLUT4). The sciatic nerve in eight Wistar rats was subjected to electrostimulation to cause unilateral isometric contractions of the calf muscle. {sup 18}F-Fluorodeoxyglucose was administered and a PET/CT scan of the hindlimbs was performed. SUVs were calculated in both Achilles tendons and the triceps surae muscles. To exclude a spill-over effect the tendons and muscles from an ex vivo group of eight rats were cut out and scanned separately (distance{>=}1 cm). Muscle contractions increased glucose uptake approximately sevenfold in muscles (p<0.001) and 36% in tendons (p<0.01). The ex vivo group confirmed the increase in glucose uptake in intact animals. GLUT1 and GLUT4 were expressed in both skeletal muscle and tendon, but no changes in mRNA levels could be detected. PET/CT can be used for studying glucose uptake in rat muscle and tendon in relation to muscle contractions; however, the increased uptake of glucose was not explained by changes in gene expression of GLUT1 and GLUT4. (orig.)

  20. Effect of Increased Cyclic AMP Concentration on Muscle Protein Synthesis and Beta-Adrenergic Receptor Expression in Chicken Skeletal Muscle Cells in Culture

    Science.gov (United States)

    Young, R. B.; Vaughn, J. R.; Bridge, K. Y.; Smith, C. K.

    1998-01-01

    Analogies of epinephrine are known to cause hypertrophy of skeletal muscle when fed to animals. These compounds presumably exert their physiological action through interaction with the P-adrenergic receptor. Since the intracellular signal generated by the Beta-adrenergic receptor is cyclic AMP (cAMP), experiments were initiated in cell culture to determine if artificial elevation of cAMP by treatment with forskolin would alter muscle protein metabolism and P-adrenergic receptor expression. Chicken skeletal muscle cells after 7 days in culture were treated with 0.2-30 micrometers forskolin for a total of three days. At the end of the treatment period, both the concentration of cAMP and the quantity of myosin heavy chain (MHC) were measured. Concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. In contrast, the quantity of MHC was increased approximately 50% above control cells at 0.2 micrometers forskolin, but exhibited a gradual decline at higher levels of forskolin so that the quantity of MHC in cells treated with 30 micrometers forskolin was not significantly different from controls. Curiously, the intracellular concentration of cAMP which elicited the maximum increase in the quantity of MHC was only 40% higher than cAMP concentration in control cells.

  1. Upregulation of endothelin ETB receptor-mediated vasoconstriction in rat coronary artery after organ culture

    DEFF Research Database (Denmark)

    Eskesen, Karen; Edvinsson, Lars

    2006-01-01

    The aim of this study was to examine if endothelin ET(B) receptor-mediated contraction occurred in isolated segments of rat coronary arteries during organ culture. Presence of contractile endothelin ET(B) receptors was studied by measuring the change in isometric tension in rings of left anterior...... descending coronary arteries isolated from hearts of rats as response to application of the selective endothelin ET(B) receptor agonist, Sarafotoxin 6c and endothelin-1. In segments cultured 1 day in serum free Dulbecco's Modified Eagle's Medium, Sarafotoxin 6c induced a concentration dependent contraction......(+)-solution was not modified after 1 day in culture medium. The experiments indicate that organ culture of rat coronary arteries upregulate endothelin ET(B) receptor-mediated contraction by inducing synthesis of new protein....

  2. Stimulation of Mucosal Mast Cell Growth in Normal and Nude Rat Bone Marrow Cultures

    Science.gov (United States)

    Haig, David M.; McMenamin, Christine; Gunneberg, Christian; Woodbury, Richard; Jarrett, Ellen E. E.

    1983-07-01

    Mast cells with the morphological and biochemical properties of mucosal mast cells (MMC) appear and proliferate to form the predominant cell type in rat bone marrow cultures stimulated with factors from antigen- or mitogen-activated lymphocytes. Conditioned media causing a selective proliferation of MMC were derived from mesenteric lymph node cells of Nippostrongylus brasiliensis-infected rats restimulated in vitro with specific antigen or from normal or infected rat mesenteric lymph node cells stimulated with concanavalin A. MMC growth factor is not produced by T-cell-depleted mesenteric lymph node cells or by the mesenteric lymph node cells of athymic rats. By contrast, MMC precursors are present in the bone marrow of athymic rats and are normally receptive to the growth factor produced by the lymphocytes of thymus-intact rats. The thymus dependence of MMC hyperplasia is thus based on the requirement of a thymus-independent precursor for a T-cell-derived growth promoter.

  3. Comparison of coumarin-induced toxicity between sandwich-cultured primary rat hepatocytes and rats in vivo: A toxicogenomics approach

    NARCIS (Netherlands)

    Kienhuis, A.S.; Wortelboer, H.M.; Hoflack, J.C.; Moonen, E.J.; Kleinjans, J.C.S.; Ommen, B. van; Delft, J.H.M. van; Stierum, R.H.

    2006-01-01

    Sandwich-cultured primary rat hepatocytes are often used as an in vitro model in toxicology and pharmacology. However, loss of liver-specific functions, in particular, the decline of cytochrome P450 (P450) enzyme activity, limits the value of this model for prediction of in vivo toxicity. In this st

  4. Bilaminar co-culture of primary rat cortical neurons and glia.

    Science.gov (United States)

    Shimizu, Saori; Abt, Anna; Meucci, Olimpia

    2011-11-12

    This video will guide you through the process of culturing rat cortical neurons in the presence of a glial feeder layer, a system known as a bilaminar or co-culture model. This system is suitable for a variety of experimental needs requiring either a glass or plastic growth substrate and can also be used for culture of other types of neurons. Rat cortical neurons obtained from the late embryonic stage (E17) are plated on glass coverslips or tissue culture dishes facing a feeder layer of glia grown on dishes or plastic coverslips (known as Thermanox), respectively. The choice between the two configurations depends on the specific experimental technique used, which may require, or not, that neurons are grown on glass (e.g. calcium imaging versus Western blot). The glial feeder layer, an astroglia-enriched secondary culture of mixed glia, is separately prepared from the cortices of newborn rat pups (P2-4) prior to the neuronal dissection. A major advantage of this culture system as compared to a culture of neurons only is the support of neuronal growth, survival, and differentiation provided by trophic factors secreted from the glial feeder layer, which more accurately resembles the brain environment in vivo. Furthermore, the co-culture can be used to study neuronal-glial interactions(1). At the same time, glia contamination in the neuronal layer is prevented by different means (low density culture, addition of mitotic inhibitors, lack of serum and use of optimized culture medium) leading to a virtually pure neuronal layer, comparable to other established methods(1-3). Neurons can be easily separated from the glial layer at any time during culture and used for different experimental applications ranging from electrophysiology(4), cellular and molecular biology(5-8), biochemistry(5), imaging and microscopy(4,6,7,9,10). The primary neurons extend axons and dendrites to form functional synapses(11), a process which is not observed in neuronal cell lines, although some

  5. Comparison of coumarin-induced toxicity between sandwich-cultured primary rat hepatocytes and rats in vivo: a toxicogenomics approach.

    Science.gov (United States)

    Kienhuis, Anne S; Wortelboer, Heleen M; Hoflack, Jean-Christophe; Moonen, Edwin J; Kleinjans, Jos C S; van Ommen, Ben; van Delft, Joost H M; Stierum, Rob H

    2006-12-01

    Sandwich-cultured primary rat hepatocytes are often used as an in vitro model in toxicology and pharmacology. However, loss of liver-specific functions, in particular, the decline of cytochrome P450 (P450) enzyme activity, limits the value of this model for prediction of in vivo toxicity. In this study, we investigated whether a hepatic in vitro system with improved metabolic competence enhances the predictability for coumarin-induced in vivo toxicity by using a toxicogenomics approach. Therefore, primary rat hepatocytes were cultured in sandwich configuration in medium containing a mixture of low concentrations of P450 inducers, phenobarbital, dexamethasone, and beta-naphthoflavone. The toxicogenomics approach used enabled comparison of similar mechanistic end-points at the molecular level between in vitro and in vivo conditions, namely, compound-induced changes in multiple genes and signaling pathways. Toxicant-induced cytotoxic effects and gene expression profiles observed in hepatocytes cultured in modified medium and hepatocytes cultured in standard medium (without inducers) were compared with results from a rat in vivo study. Coumarin was used as a model compound because its toxicity depends on bioactivation by P450 enzymes. Metabolism of coumarin toward active metabolites, coumarin-induced cytotoxicity, and gene expression modulation were more pronounced in hepatocytes cultured in modified medium compared with hepatocytes cultured in standard medium. In addition, more genes and biological pathways were similarly affected by coumarin in hepatocytes cultured in modified medium and in vivo. In conclusion, these experiments showed that for coumarin-induced toxicity, sandwich-cultured hepatocytes maintained in modified medium better represent the situation in vivo compared with hepatocytes cultured in standard medium.

  6. Effects of contraction on localization of GLUT4 and v-SNARE isoforms in rat skeletal muscle

    DEFF Research Database (Denmark)

    Rose, Adam John; Jeppesen, Jacob; Kiens, Bente

    2009-01-01

    In skeletal muscle, contractions increase glucose uptake due to a translocation of GLUT4 glucose transporters from intracellular storage sites to the surface membrane. Vesicle associated membrane proteins (VAMPs) are believed to play an important role in docking and fusion of the GLUT4 transporters...... at the surface membrane. However, knowledge about which VAMP isoforms in fact co-localize with GLUT4 vesicles in mature skeletal muscle and whether they translocate during muscle contractions is incomplete. The aim of the present study was to further identify VAMP isoforms which are associated with GLUT4...... vesicles and examine which VAMP isoforms translocate to surface membranes in skeletal muscles undergoing contractions. VAMP2, VAMP3, VAMP5 and VAMP7 were enriched in immuno-precipitated GLUT4 vesicles. In response to 20 min of in situ contractions, there was a redistribution of GLUT4 (+64 +/- 13...

  7. Mitigation of Insulin Resistance by Mangiferin in a Rat Model of Fructose-Induced Metabolic Syndrome Is Associated with Modulation of CD36 Redistribution in the Skeletal Muscle.

    Science.gov (United States)

    Zhou, Liang; Pan, Yongquan; Chonan, Ritsu; Batey, Robert; Rong, Xianglu; Yamahara, Johji; Wang, Jianwei; Li, Yuhao

    2016-01-01

    Mangiferin is one of the prominent active components responsible for the antidiabetic property of many traditional herbs, but its underlying mechanisms of action remain unclear. CD36 in skeletal muscle is known to contribute to the etiology of insulin resistance by facilitating fatty acid uptake. This study investigated the effect of mangiferin on insulin resistance. The results showed that treatment of Wistar-Kyoto rats with mangiferin (15 mg/kg, once daily, by oral gavage) for 7 weeks inhibited chronic liquid fructose consumption-induced increases in plasma insulin concentrations at the baseline and during oral glucose tolerance test (OGTT), and the homeostasis model assessment of insulin resistance index. It also suppressed the increases in fasted plasma nonesterified fatty acid (NEFA) concentration and the adipose tissue insulin resistance index. Mechanistically, mangiferin neither affected intakes of fructose and chow, and the increase in epididymal and perirenal fat, nor attenuated fructose-induced hypertension. In contrast, mangiferin attenuated fructose-induced acceleration of plasma NEFA clearance during OGTT, and tended to decrease excessive triglyceride accumulation in gastrocnemius. Immunofluorescence staining and subsequent rating of CD36-expressing fibers in gastrocnemius revealed that mangiferin restored fructose-stimulated sarcolemmal CD36 overexpression and decreased intracellular CD36 distribution. In addition, the effects of mangiferin on the parameters associated with insulin resistance and abnormal fatty acid metabolism were absent in the spontaneously hypertensive rats carrying numerous nonfunctional mutations in the CD36 gene. Thus, these results suggest that mangiferin treatment mitigates insulin resistance in a rat model of fructose-induced metabolic syndrome by modulating sarcolemmal and intracellular CD36 redistribution in the skeletal muscle.

  8. Glutamine deficiency in extracellular fluid exerts adverse effects on protein and amino acid metabolism in skeletal muscle of healthy, laparotomized, and septic rats.

    Science.gov (United States)

    Holecek, Milan; Sispera, Ludek

    2014-05-01

    Characteristic feature of critical illness, such as trauma and sepsis, is muscle wasting associated with activated oxidation of branched-chain amino acids (valine, leucine, isoleucine) and enhanced release of glutamine (GLN) to the blood. GLN consumption in visceral tissues frequently exceeds its release from muscle resulting in GLN deficiency that may exert adverse effects on the course of the disease. In the present study, we investigated the effects of GLN depletion in extracellular fluid on GLN production and protein and amino acid metabolism in skeletal muscle of healthy, laparotomized, and septic rats. Cecal ligation and puncture (CLP) was used as a model of sepsis. After 24 h, soleus muscle (SOL, slow-twitch, red muscle) and extensor digitorum longus (EDL, fast-twitch, white muscle) were isolated and incubated in a medium containing 0.5 mM GLN or without GLN. L-[1-(14)C]leucine was used to estimate protein synthesis and leucine oxidation, 3-methylhistidine release was used to evaluate myofibrillar protein breakdown. CLP increased GLN release from muscle, protein breakdown and leucine oxidation, and decreased protein synthesis. The effects were more pronounced in EDL. Alterations induced by laparotomy were similar to those observed in sepsis, but of a lower extent. GLN deficiency in medium enhanced GLN release and decreased intramuscular GLN concentration, decreased protein synthesis in muscles of intact and laparotomized rats, and enhanced leucine oxidation in SOL of intact and protein breakdown in SOL of laparotomized rats. It is concluded that (1) fast-twitch fibers are more sensitive to septic stimuli than slow-twitch fibers, (2) extracellular GLN deficiency may exert adverse effects on protein and amino acid metabolism in skeletal muscle, and (3) muscles of healthy and laparotomized animals are more sensitive to GLN deficiency than muscles of septic animals.

  9. Expression of vesicle-associated membrane protein 2 (VAMP-2)/synaptobrevin II and cellubrevin in rat skeletal muscle and in a muscle cell line.

    Science.gov (United States)

    Volchuk, A; Mitsumoto, Y; He, L; Liu, Z; Habermann, E; Trimble, W; Klip, A

    1994-01-01

    Molecular studies have identified a family of synaptic vesicle-associated membrane proteins (VAMPs, also known as synaptobrevins) which have been implicated in synaptic vesicle docking and/or fusion with plasma membrane proteins. Here we demonstrate the expression of two members of this family, VAMP-2/synaptobrevin II and cellubrevin, in skeletal muscle, a tissue with both constitutive and regulated membrane traffic. The 18 kDa VAMP-2 polypeptide was detected in purified membrane fractions from adult skeletal muscle and from L6 myotubes in culture, demonstrating that the presence of this protein in the isolated muscle membrane fractions is not the result of contamination by ancillary tissues such as peripheral nerve. Furthermore, skeletal muscle and the muscle cell line also expressed cellubrevin, a VAMP-2 homologue of 17 kDa; which is much less abundant in brain cells. Both VAMP-2 and cellubrevin were preferentially isolated in membrane fractions rich in plasma membranes, and were less concentrated in light microsomes and other internal membrane fractions of mature muscle or muscle cells in culture. Interestingly, both VAMP-2 and cellubrevin were much more abundant in the differentiated L6 myotubes than in their precursor myoblasts, suggesting that they are required for functions of differentiated muscle cells. The identity of both polypeptides was further confirmed by their susceptibility to proteolysis by Clostridium tetanus toxin. Expression of these products was further established by the presence of mRNA transcripts of VAMP-2 and cellubrevin, but not of VAMP-1, in both skeletal muscle and L6 myotubes. In contrast, other synaptic vesicle and docking/fusion components were undetectable, such as VAMP-1, SNAP25 and syntaxin 1A/1B, as were synaptophysin and synapsin Ia/Ib, proteins which are believed to be involved in sensing the signal for neuronal exocytosis. It is concluded that VAMP-2 and cellubrevin are expressed in skeletal muscle cells and may each

  10. Taenia taeniaeformis: inhibition of rat testosterone production by excretory-secretory product of the cultured metacestode.

    Science.gov (United States)

    Rikihisa, Y; Lin, Y C; Fukaya, T

    1985-06-01

    In 3- to 5-month-old male Sprague-Dawley rats infected with the hepatic metacestode, Taenia taeniaeformis, the serum testosterone level was significantly lower than in comparable uninfected controls. By transmission electron microscopy, testicular Leydig cells of infected rats had less smooth endoplasmic reticulum than control Leydig cells. Cultured metacestodes isolated from the hepatic cysts secreted or excreted substances into the incubation medium. The effect of the excretory-secretory product on testosterone concentration in the sera and testes of 15-day-old rats was examined. Subcutaneous injection of 50-200 micrograms of excretory-secretory product/0.1 ml saline/rat for 2 days significantly reduced human chorionic gonadotropin-stimulated serum and testicular testosterone concentrations. Furthermore, the effect of the excretory-secretory product on isolated rat Leydig cell testosterone production was examined. Rat Leydig cells produced testosterone in vitro and, in the presence of 50 IU human chorionic gonadotropin/ml incubation medium, they responded with approximately 100% increase in testosterone production. Addition of 2-10 micrograms excretory-secretory product protein/ml of culture medium significantly reduced the testosterone production by rat Leydig cells in vitro. These results indicate that excretory-secretory product of cultured T. taeniaeformis metacestodes has a direct inhibitory effect on Leydig cell testosterone production under stimulation with human chorionic gonadotropin.

  11. The effect of enterocystoplasty on bone strength assessed at four different skeletal sites in a rat model

    DEFF Research Database (Denmark)

    Gerharz, E.W.; Mosekilde, Li.; Thomsen, J.S.

    2003-01-01

    ; colocystoplasty; or sham operation (controls). After 8 months the lumbar vertebrae, femora, and tibiae were harvested at necropsy. Bone strength was assessed biomechanically at four different skeletal sites: vertebra L3, femoral middiaphysis, femoral neck, and distal femoral metaphysis. Bone mass and architecture...... were assessed using standard static histomorphometry of the proximal tibial metaphysis (trabecular bone volume [BV/TV]; trabecular number [Tb.N]) and ash weight. Statistically significant differences of biomechanical parameters between groups were observed at three skeletal sites with corresponding......, this is the first experimental study to demonstrate the relevance of histomorphometrically proven bone loss after enterocystoplasty in terms of biomechanical variables....

  12. Clearance and clearance inhibition of the HIV-1 protease inhibitors ritonavir and saquinavir in sandwich-cultured rat hepatocytes and rat microsomes

    NARCIS (Netherlands)

    Treijtel, N.; Eijkeren, J.C.H.v.; Nijmeijer, S.; Greef de - Sandt, I.C.J. van der; Freidig, A.P.

    2009-01-01

    The metabolism and active transport of ritonavir and saquinavir were studied using sandwich-cultured rat hepatoyctes and rat liver microsomes. For ritonavir four comparable metabolites were observed in the sandwich-culture and in microsomes. For saquinavir eight metabolites were observed in sandwich

  13. Clearance and clearance inhibition of the HIV-1 protease inhibitors ritonavir and saquinavir in sandwich-cultured rat hepatocytes and rat microsomes.

    NARCIS (Netherlands)

    Treijtel, N.; van Eijkeren, J.C.; Nijmeijer, S.; de Greef-van der Sandt, I.C.; Freidig, A.

    2009-01-01

    The metabolism and active transport of ritonavir and saquinavir were studied using sandwich-cultured rat hepatoyctes and rat liver microsomes. For ritonavir four comparable metabolites were observed in the sandwich-culture and in microsomes. For saquinavir eight metabolites were observed in sandwich

  14. Transplantation of primary cultured embryonic mesencephalic neural precursor cells for treating Parkinsonian rats

    Institute of Scientific and Technical Information of China (English)

    Li Fei; Chengchuan Jiang; Linyin Feng; Yaodong Ji; Zhongliang Ding

    2006-01-01

    BACKGROUND: Choosing proper donor cells is one of keys in experimental and clinical studies on cell replacement therapy (CRT) for treating Parkinson disease (PD). Embryonic mesencephalic precursor cells (MPCs) can stably differentiate into dopaminergic neuron after in vitro proliferated culture. As compared with embryonic stem cell and neural stem cell strains, cell composition of embryonic MPCs after primary culture is also the most close to that of embryonic mesencephalic ventral cell suspension without proliferated culture. Successful experience accumulated in the latter suggests that primary cultured embryonic MPCs might be the most potential donor cells in clinical application with CRT for treating PD so far.OBJECTIVE: To investigate the feasibility of primary cultured embryonic precursor cells cultured primarily as donor cells in CRT for treating PD in rats.DESIGN: A randomized and controlled trial taking SD rats as experimental animals.SETTING: Department of Neurosurgery, Huashan Hospital Affiliated to Fudan University.MATERIALS: This experiment was carried out at the Institute of Neuroscience, Shanghai Institute for Biological Science, Chinese Academy of Sciences from July 2003 to June 2004. Totally 26 female SD rats,with body mass of 200 to 220 g, were provided by Shanghai Experimental Animal Center of Chinese Academy of Sciences.METHODS: Stereotaxic injection of 6-hydroxydopamine into the medial forebrain bundle were perfored to develop PD model rat. Among 26 SD rats, 20 rats achieved a more than 5 turns/min in apomorphine induced rotation test, reaching the standard of PD model rats. Immunohistochemical detection was performed on 1out of 20 model rats after execution, and the other 19 rats were randomly divided into control group (n=5),sham transplantation group (n=5)and cell grafted group (n=9). Primary cultured E12 MPC cell suspension (1.2×1011 L-1)were used as donor cells. 4 μL primary cultured E12 MPC cell suspension prepared freshly was injected

  15. Light effects on the isotopic fractionation of skeletal oxygen and carbon in the cultured zooxanthellate coral, Acropora: implications for coral-growth rates

    Directory of Open Access Journals (Sweden)

    S. Reynaud

    2009-11-01

    Full Text Available Skeletal isotopic and metabolic measurements of the branching coral Acropora cultured in constant conditions and subjected to two light intensities were revisited. We individually compared the data recorded at low light (LL and high light (HL for 24 colonies, all derived from the same parent colony. Metabolic and isotopic responses to the different light levels were highly variable. High light led to productivity enhancement, reduction of surface extension, doubling of aragonite deposited weight and increased δ18O levels in all nubbins; responses in respiration and δ13C were not clear. The partitioning of the colonies into two groups, one showing a δ13C increase and the other a δ13C decrease with increased light, revealed common behaviors. Samples showing an increase in δ13C were associated with the co-variation of low surface extension and high productivity while samples showing a decrease in δ13C were associated with the co-variation of higher surface extension and limited productivity. This experiment, which allowed for the separation of temperature and light effects on the coral, highlighted the significant light influences on both skeletal δ18O and δ13C. The high scattering of inter-colony δ18O observed at one site could be due to the differing photosynthetic responses of symbiotic algal assemblages. The δ13C responses could also be related to differing algal distributions in different skeletal portions. Our results were compared to observations by Gladfelter on Acropora cervicornis (1982. Both set of results highlight the relationships between coral-growth rates, micro-structures and photosynthetic activity. It appears that extension growth and accretion are two separate growth modes, and accretion is light-enhanced while extension is light-repressed. There are multiple consequences of these findings for paleoclimatic reconstructions involving corals.

  16. Beneficial Effects of Physical Exercise on Functional Capacity and Skeletal Muscle Oxidative Stress in Rats with Aortic Stenosis-Induced Heart Failure

    Directory of Open Access Journals (Sweden)

    Mariana Janini Gomes

    2016-01-01

    Full Text Available Objective. We evaluated the influence of exercise on functional capacity, cardiac remodeling, and skeletal muscle oxidative stress, MAPK, and NF-κB pathway in rats with aortic stenosis- (AS- induced heart failure (HF. Methods and Results. Eighteen weeks after AS induction, rats were assigned into sedentary control (C-Sed, exercised control (C-Ex, sedentary AS (AS-Sed, and exercised AS (AS-Ex groups. Exercise was performed on treadmill for eight weeks. Statistical analyses were performed with Goodman and ANOVA or Mann-Whitney. HF features frequency and mortality did not differ between AS groups. Exercise improved functional capacity, assessed by maximal exercise test on treadmill, without changing echocardiographic parameters. Soleus cross-sectional areas did not differ between groups. Lipid hydroperoxide concentration was higher in AS-Sed than C-Sed and AS-Ex. Activity of antioxidant enzymes superoxide dismutase and glutathione peroxidase was changed in AS-Sed and restored in AS-Ex. NADPH oxidase activity and gene expression of its subunits did not differ between AS groups. Total ROS generation was lower in AS-Ex than C-Ex. Exercise modulated MAPK in AS-Ex and did not change NF-κB pathway proteins. Conclusion. Exercise improves functional capacity in rats with AS-induced HF regardless of echocardiographic parameter changes. In soleus, exercise reduces oxidative stress, preserves antioxidant enzyme activity, and modulates MAPK expression.

  17. Protective effects of berberine against amyloid beta-induced toxicity in cultured rat cortical neurons

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Yanjun Zhang; Shuai Du; Mixia Zhang

    2011-01-01

    Berberine, a major constituent of Coptidis rhizoma, exhibits neural protective effects. The present study analyzed the potential protective effect of berberine against amyloid G-induced cytotoxicity in rat cerebral cortical neurons. Alzheimer's disease cell models were treated with 0.5 and 2 μmol/Lberberine for 36 hours to inhibit amyloid G-induced toxicity. Methyl thiazolyl tetrazolium assay and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining results showed that berberine significantly increased cell viability and reduced cell apoptosis in primary cultured rat cortical neurons. In addition, western blot analysis revealed a protective effect of berberine against amyloid β-induced toxicity in cultured cortical neurons, which coincided with significantly decreased abnormal up-regulation of activated caspase-3. These results showed that berberine exhibited a protective effect against amyloid 13-induced cytotoxicity in cultured rat cortical neurons.

  18. [Actomyosin ATPase activity of skeletal muscles and the markers of tissue damage in the blood of rats under prolonged chronic alcoholization].

    Science.gov (United States)

    Tseĭslier, Iu V; Podpalova, O M; Nuryshchenko, N Ie; Martyniuk, V S

    2014-01-01

    The activity of creatine kinase and indices of lipid metabolism in the blood and also actomyosin ATPase activity of skeletal muscles of rats under chronic 8-month alcohol abuse were investigated. It is shown that actomyosin K+-ATPase activity of skeletal muscles increases from two months of ethanol use, but actomyosin Mg2+-ATPase activity decreases during 6-8 months of alcoholization. From two months of ethanol use the creatine kinase activity, as an enzyme marker of muscle tissue damage, statistically significantly increases during all the period of the animals alcoholization. The level of total lipid increases after two months of alcohol consumption (in blood plasma by 30% and in erythrocyte mass by 65%). For longer periods of alcoholization (4-8 months) the level of lipids remains almost the same, whereas in erythrocyte mass it does not differ from control values. The level of diene conjugates in the blood plasma reduces and the amount of ketone derivatives of fatty acid residues increases that points to the inhibition of some components of the antioxidant system that control detoxification of hydroperoxides of fatty acids and also to activation of free radical damage of tissues. There were no significant changes of lipid peroxidation level in erythrocyte mass at any stage of alcoholization.

  19. Exercise-induced changes of MCT1 in cardiac and skeletal muscles of diabetic rats induced by high-fat diet and STZ.

    Science.gov (United States)

    Nikooie, Rohollah; Rajabi, Hamid; Gharakhanlu, Reza; Atabi, Fereshteh; Omidfar, Kobra; Aveseh, Malihe; Larijani, Bagher

    2013-12-01

    We hypothesized that a part of therapeutic effects of endurance training on insulin resistance is mediated by increase in cardiac and skeletal muscle mitochondrial lactate transporter, monocarboxylate transporter 1 (MCT1). Therefore, we examined the effect of 7 weeks endurance training on the mRNA and protein expression of MCT1 and MCT4 and their chaperon, CD147, on both sarcolemmal and mitochondrial membrane, separately, in healthy and type 2 diabetic rats. Diabetes was induced by injection of low dose of streptozotocin and feeding with high-fat diet. Insulin resistance was confirmed by homeostasis model assessment-estimated insulin resistance index and accuracy of two membranes separation was confirmed by negative control markers (glucose transporter 1 and cytochrome c oxidase. Real-time PCR and western blotting were used for mRNA and protein expression, respectively. Diabetes dramatically reduced MCT1 and MCT4 mRNA and their expression on sarcolemmal membrane whereas the reduction in MCT1 expression was less in mitochondrial membrane. Training increased the MCT1 mRNA and protein expression in both membranes and decreased insulin resistance as an adaptive consequence. In both tissues increase in CD147 mRNA was only parallel to MCT1 expression. The response of MCT1 on sarcolemmal and mitochondrial membranes was different between cardiac and skeletal muscles which indicate that intracellular lactate kinetic is tissue specific that allows a tissue to coordinate whole organism metabolism.

  20. Passive Repetitive Stretching for a Short Duration within a Week Increases Myogenic Regulatory Factors and Myosin Heavy Chain mRNA in Rats' Skeletal Muscles

    Directory of Open Access Journals (Sweden)

    Yurie Kamikawa

    2013-01-01

    Full Text Available Stretching is a stimulation of muscle growth. Stretching for hours or days has an effect on muscle hypertrophy. However, differences of continuous stretching and repetitive stretching to affect muscle growth are not well known. To clarify the difference of continuous and repetitive stretching within a short duration, we investigated the gene expression of muscle-related genes on stretched skeletal muscles. We used 8-week-old male Wistar rats ( for this study. Animals medial gastrocnemius muscle was stretched continuously or repetitively for 15 min daily and 4 times/week under anesthesia. After stretching, muscles were removed and total RNA was extracted. Then, reverse transcriptional quantitative real-time PCR was done to evaluate the mRNA expression of MyoD, myogenin, and embryonic myosin heavy chain (MyHC. Muscles, either stretched continuously or repetitively, increased mRNA expression of MyoD, myogenin, and embryonic MyHC more than unstretched muscles. Notably, repetitive stretching resulted in more substantial effects on embryonic MyHC gene expression than continuous stretching. In conclusion, passive stretching for a short duration within a week is effective in increasing myogenic factor expression, and repetitive stretching had more effects than continuous stretching for skeletal muscle on muscle growth. These findings are applicable in clinical muscle-strengthening therapy.

  1. Ca2+ effects on glucose transport and fatty acid oxidation in L6 skeletal muscle cell cultures

    Directory of Open Access Journals (Sweden)

    Darrick Balu

    2016-03-01

    We did find a Ca2+ stimulation (using either caffeine or ionomycin of fatty acid oxidation. This was observed in the absence (but not the presence of added glucose. We conclude that Ca2+ stimulates fatty acid oxidation at a mitochondrial site, secondary to malonyl CoA inhibition (represented by the presence of glucose in our experiments. In summary, the experiments resolve a controversy on Ca2+ stimulation of glucose transport by skeletal muscle, introduce an important experimental consideration for the measurement of glucose transport, and uncover a new site of action for Ca2+ stimulation of fatty acid oxidation.

  2. Tumor necrosis factor-α regulates distinct molecular pathways and gene networks in cultured skeletal muscle cells.

    Directory of Open Access Journals (Sweden)

    Shephali Bhatnagar

    Full Text Available BACKGROUND: Skeletal muscle wasting is a debilitating consequence of large number of disease states and conditions. Tumor necrosis factor-α (TNF-α is one of the most important muscle-wasting cytokine, elevated levels of which cause significant muscular abnormalities. However, the underpinning molecular mechanisms by which TNF-α causes skeletal muscle wasting are less well-understood. METHODOLOGY/PRINCIPAL FINDINGS: We have used microarray, quantitative real-time PCR (QRT-PCR, Western blot, and bioinformatics tools to study the effects of TNF-α on various molecular pathways and gene networks in C2C12 cells (a mouse myoblastic cell line. Microarray analyses of C2C12 myotubes treated with TNF-α (10 ng/ml for 18h showed differential expression of a number of genes involved in distinct molecular pathways. The genes involved in nuclear factor-kappa B (NF-kappaB signaling, 26s proteasome pathway, Notch1 signaling, and chemokine networks are the most important ones affected by TNF-α. The expression of some of the genes in microarray dataset showed good correlation in independent QRT-PCR and Western blot assays. Analysis of TNF-treated myotubes showed that TNF-α augments the activity of both canonical and alternative NF-κB signaling pathways in myotubes. Bioinformatics analyses of microarray dataset revealed that TNF-α affects the activity of several important pathways including those involved in oxidative stress, hepatic fibrosis, mitochondrial dysfunction, cholesterol biosynthesis, and TGF-β signaling. Furthermore, TNF-α was found to affect the gene networks related to drug metabolism, cell cycle, cancer, neurological disease, organismal injury, and abnormalities in myotubes. CONCLUSIONS: TNF-α regulates the expression of multiple genes involved in various toxic pathways which may be responsible for TNF-induced muscle loss in catabolic conditions. Our study suggests that TNF-α activates both canonical and alternative NF-κB signaling

  3. Expression of miR-15/107 family microRNAs in human tissues and cultured rat brain cells.

    Science.gov (United States)

    Wang, Wang-Xia; Danaher, Robert J; Miller, Craig S; Berger, Joseph R; Nubia, Vega G; Wilfred, Bernard S; Neltner, Janna H; Norris, Christopher M; Nelson, Peter T

    2014-02-01

    The miR-15/107 family comprises a group of 10 paralogous microRNAs (miRNAs), sharing a 5' AGCAGC sequence. These miRNAs have overlapping targets. In order to characterize the expression of miR-15/107 family miRNAs, we employed customized TaqMan Low-Density micro-fluid PCR-array to investigate the expression of miR-15/107 family members, and other selected miRNAs, in 11 human tissues obtained at autopsy including the cerebral cortex, frontal cortex, primary visual cortex, thalamus, heart, lung, liver, kidney, spleen, stomach and skeletal muscle. miR-103, miR-195 and miR-497 were expressed at similar levels across various tissues, whereas miR-107 is enriched in brain samples. We also examined the expression patterns of evolutionarily conserved miR-15/107 miRNAs in three distinct primary rat brain cell preparations (enriched for cortical neurons, astrocytes and microglia, respectively). In primary cultures of rat brain cells, several members of the miR-15/107 family are enriched in neurons compared to other cell types in the central nervous system (CNS). In addition to mature miRNAs, we also examined the expression of precursors (pri-miRNAs). Our data suggested a generally poor correlation between the expression of mature miRNAs and their precursors. In summary, we provide a detailed study of the tissue and cell type-specific expression profile of this highly expressed and phylogenetically conserved family of miRNA genes.

  4. Dietary Salba (Salvia hispanica L) seed rich in α-linolenic acid improves adipose tissue dysfunction and the altered skeletal muscle glucose and lipid metabolism in dyslipidemic insulin-resistant rats.

    Science.gov (United States)

    Oliva, M E; Ferreira, M R; Chicco, A; Lombardo, Y B

    2013-10-01

    This work reports the effect of dietary Salba (chia) seed rich in n-3 α-linolenic acid on the morphological and metabolic aspects involved in adipose tissue dysfunction and the mechanisms underlying the impaired glucose and lipid metabolism in the skeletal muscle of rats fed a sucrose-rich diet (SRD). Rats were fed a SRD for 3 months. Thereafter, half the rats continued with SRD while in the other half, corn oil (CO) was replaced by chia seed for 3 months (SRD+chia). In control group, corn starch replaced sucrose. The replacement of CO by chia seed in the SRD reduced adipocyte hypertrophy, cell volume and size distribution, improved lipogenic enzyme activities, lipolysis and the anti-lipolytic action of insulin. In the skeletal muscle lipid storage, glucose phosphorylation and oxidation were normalized. Chia seed reversed the impaired insulin stimulated glycogen synthase activity, glycogen, glucose-6-phosphate and GLUT-4 protein levels as well as insulin resistance and dyslipidemia.

  5. Leptin Modulates Norepinephrine-Mediated Melatonin Synthesis in Cultured Rat Pineal Gland

    OpenAIRE

    Rodrigo Antonio Peliciari-Garcia; Jéssica Andrade-Silva; José Cipolla-Neto; Carla Roberta de Oliveira Carvalho

    2013-01-01

    Pineal melatonin synthesis can be modulated by many peptides, including insulin. Because melatonin appears to alter leptin synthesis, in this work we aimed to investigate whether leptin would have a role on norepinephrine- (NE-)mediated melatonin synthesis in cultured rat pineal glands. According to our data, cultured rat pineal glands express leptin receptor isoform b (Ob-Rb). Pineal expression of Ob-Rb mRNA was also observed in vivo. Administration of leptin (1 nM) associated with NE (1 µM)...

  6. Microarray analysis of gene expression in liver, adipose tissue and skeletal muscle in response to chronic dietary administration of NDGA to high-fructose fed dyslipidemic rats.

    Science.gov (United States)

    Zhang, Haiyan; Shen, Wen-Jun; Li, Yihang; Bittner, Alex; Bittner, Stefanie; Tabassum, Juveria; Cortez, Yuan F; Kraemer, Fredric B; Azhar, Salman

    2016-01-01

    Nordihydroguaiaretic acid (NDGA), the main metabolite of Creosote Bush, has been shown to have profound effects on the core components of metabolic syndrome, including lowering of blood glucose, free fatty acids and triglyceride levels, attenuating elevated blood pressure in several rodent models of dyslipidemia, and improving body weight, insulin resistance, diabetes and hypertension. In the present study, a high-fructose diet fed rat model of hypertriglyceridemia, dyslipidemia, insulin resistance and hepatic steatosis was employed to investigate the global transcriptional changes in the lipid metabolizing pathways in three insulin sensitive tissues: liver, skeletal muscle and adipose tissue in response to chronic dietary administration of NDGA. Sprague-Dawley male rats (SD) were fed a chow (control) diet, high-fructose diet (HFrD) or HFrD supplemented with NDGA (2.5 g/kg diet) for eight weeks. Dietary administration of NDGA decreased plasma levels of TG, glucose, and insulin, and attenuated hepatic TG accumulation. DNA microarray expression profiling indicated that dietary administration of NDGA upregulated the expression of certain genes involved in fatty acid oxidation and their transcription regulator, PPARα, decreased the expression of a number of lipogenic genes and relevant transcription factors, and differentially impacted the genes of fatty acid transporters, acetyl CoA synthetases, elongases, fatty acid desaturases and lipid clearance proteins in liver, skeletal muscle and adipose tissues. These findings suggest that NDGA ameliorates hypertriglyceridemia and steatosis primarily by inhibiting lipogenesis and enhancing fatty acid catabolism in three major insulin responsive tissues by altering the expression of key enzyme genes and transcription factors involved in de novo lipogenesis and fatty acid oxidation.

  7. Effects of cold-water immersion on VEGF mRNA and protein expression in heart and skeletal muscles of rats.

    Science.gov (United States)

    Kim, J C; Yi, H K; Hwang, P H; Yoon, J S; Kim, H J; Kawano, F; Ohira, Y; Kim, C K

    2005-04-01

    The effects of cold exposure on gene and protein expression of vascular endothelial growth factor (VEGF), in heart and skeletal muscles, were studied in male adult Wistar rats. Cold immersion was accomplished by submerging the rats in shoulder-deep water maintained at approximately 18 degrees C, either acutely (1 h) or chronically (1 h day(-1), 5 days week(-1) for 20 weeks). The expressions of VEGF mRNA and protein in heart, gastrocnemius, and soleus muscles were examined by Northern and Western blotting and competitive-polymerase chain reaction techniques. The expressions of VEGF mRNA and protein were markedly increased in cardiac muscle of the cold-immersed group, particularly in the 1-hour exposure group, whereas VEGF mRNA and protein in gastrocnemius were decreased significantly after an acute exposure. Although the protein level in gastrocnemius remained low in the chronically exposed group, the expression of mRNA of VEGF(165) with chronic exposure in this group returned to the control level and that of VEGF(206) was 15% greater than that in controls. The expression of mRNA for VEGF(165) in soleus was also lowered by acute cold exposure, although that for VEGF(206) was stable. However, VEGF protein was increased by 50%. After 20 weeks, all of these parameters were increased over the levels found in the controls. These results suggest that the VEGF gene may be a major regulatory factor in cardiac and skeletal muscle adaptation to the cold environment stimulating angiogenesis and thermogenesis.

  8. A MRI-Compatible Combined Mechanical Loading and MR Elastography Setup to Study Deformation-Induced Skeletal Muscle Damage in Rats

    Science.gov (United States)

    de Graaf, Larry; Traa, Willeke A.; Schreurs, Tom J. L.; Moerman, Kevin M.; Nederveen, Aart J.; Sinkus, Ralph; Oomens, Cees W. J.; Nicolay, Klaas; Strijkers, Gustav J.

    2017-01-01

    Deformation of skeletal muscle in the proximity of bony structures may lead to deep tissue injury category of pressure ulcers. Changes in mechanical properties have been proposed as a risk factor in the development of deep tissue injury and may be useful as a diagnostic tool for early detection. MRE allows for the estimation of mechanical properties of soft tissue through analysis of shear wave data. The shear waves originate from vibrations induced by an external actuator placed on the tissue surface. In this study a combined Magnetic Resonance (MR) compatible indentation and MR Elastography (MRE) setup is presented to study mechanical properties associated with deep tissue injury in rats. The proposed setup allows for MRE investigations combined with damage-inducing large strain indentation of the Tibialis Anterior muscle in the rat hind leg inside a small animal MR scanner. An alginate cast allowed proper fixation of the animal leg with anatomical perfect fit, provided boundary condition information for FEA and provided good susceptibility matching. MR Elastography data could be recorded for the Tibialis Anterior muscle prior to, during, and after indentation. A decaying shear wave with an average amplitude of approximately 2 μm propagated in the whole muscle. MRE elastograms representing local tissue shear storage modulus Gd showed significant increased mean values due to damage-inducing indentation (from 4.2 ± 0.1 kPa before to 5.1 ± 0.6 kPa after, p<0.05). The proposed setup enables controlled deformation under MRI-guidance, monitoring of the wound development by MRI, and quantification of tissue mechanical properties by MRE. We expect that improved knowledge of changes in soft tissue mechanical properties due to deep tissue injury, will provide new insights in the etiology of deep tissue injuries, skeletal muscle damage and other related muscle pathologies. PMID:28076414

  9. Caffeine and contraction synergistically stimulate 5'-AMP-activated protein kinase and insulin-independent glucose transport in rat skeletal muscle.

    Science.gov (United States)

    Tsuda, Satoshi; Egawa, Tatsuro; Kitani, Kazuto; Oshima, Rieko; Ma, Xiao; Hayashi, Tatsuya

    2015-10-01

    5'-Adenosine monophosphate-activated protein kinase (AMPK) has been identified as a key mediator of contraction-stimulated insulin-independent glucose transport in skeletal muscle. Caffeine acutely stimulates AMPK in resting skeletal muscle, but it is unknown whether caffeine affects AMPK in contracting muscle. Isolated rat epitrochlearis muscle was preincubated and then incubated in the absence or presence of 3 mmol/L caffeine for 30 or 120 min. Electrical stimulation (ES) was used to evoke tetanic contractions during the last 10 min of the incubation period. The combination of caffeine plus contraction had additive effects on AMPKα Thr(172) phosphorylation, α-isoform-specific AMPK activity, and 3-O-methylglucose (3MG) transport. In contrast, caffeine inhibited basal and contraction-stimulated Akt Ser(473) phosphorylation. Caffeine significantly delayed muscle fatigue during contraction, and the combination of caffeine and contraction additively decreased ATP and phosphocreatine contents. Caffeine did not affect resting tension. Next, rats were given an intraperitoneal injection of caffeine (60 mg/kg body weight) or saline, and the extensor digitorum longus muscle was dissected 15 min later. ES of the sciatic nerve was performed to evoke tetanic contractions for 5 min before dissection. Similar to the findings from isolated muscles incubated in vitro, the combination of caffeine plus contraction in vivo had additive effects on AMPK phosphorylation, AMPK activity, and 3MG transport. Caffeine also inhibited basal and contraction-stimulated Akt phosphorylation in vivo. These findings suggest that caffeine and contraction synergistically stimulate AMPK activity and insulin-independent glucose transport, at least in part by decreasing muscle fatigue and thereby promoting energy consumption during contraction.

  10. Effect of high fat diet enriched with unsaturated and diet rich in saturated fatty acids on sphingolipid metabolism in rat skeletal muscle.

    Science.gov (United States)

    Blachnio-Zabielska, Agnieszka; Baranowski, Marcin; Zabielski, Piotr; Gorski, Jan

    2010-11-01

    Consumption of high fat diet leads to muscle lipid accumulation which is an important factor involved in induction of insulin resistance. Ceramide is likely to partially inhibit insulin signaling cascade. The aim of this study was to examine the effect of different high fat diets on ceramide metabolism in rat skeletal muscles. The experiments were carried out on rats fed for 5 weeks: (1) a standard chow and (2) high fat diet rich in polyunsaturated fatty acids (PUFA) and (3) diet enriched with saturated fatty acids (SAT). Assays were performed on three types of muscles: slow-twitch oxidative (soleus), fast-twitch oxidative-glycolytic, and fast-twitch glycolytic (red and white section of the gastrocnemius, respectively). The activity of serine palmitoyltransferase (SPT), neutral and acid sphingomyelinase (n- and aSMase), and neutral and alkaline ceramidase (n- and alCDase) was examined. The content of ceramide, sphinganine, sphingosine, and sphingosine-1-phosphate was also measured. The ceramide content did not change in any muscle from PUFA diet group but increased in the SAT diet group by 46% and 52% in the soleus and red section of the gastrocnemius, respectively. Elevated ceramide content in the SAT diet group could be a result of increased SPT activity and simultaneously decreased activity of nCDase. Unchanged ceramide content in the PUFA diet group might be a result of increased activity of SPT and alCDase and simultaneously decreased activity of SMases. We conclude that regulation of muscle ceramide level depends on the diet and type of skeletal muscle. © 2010 Wiley-Liss, Inc.

  11. Evaluation of PFOS-mediated neurotoxicity in rat primary neurons and astrocytes cultured separately or in co-culture.

    Science.gov (United States)

    Li, Zhenwei; Liu, Qi; Liu, Chang; Li, Chunna; Li, Yachen; Li, Shuangyue; Liu, Xiaohui; Shao, Jing

    2017-02-01

    Perfluorooctane sulfonate (PFOS) is a potential neurotoxicant reported by epidemiological investigations and experimental studies, while the underlying mechanisms are still unclear. Astrocytes not only support for the construction of neurons, but also conduct neuronal functions through glutamate-glutamine cycle in astrocyte-neuron crosstalk. In the present study, the effect of PFOS exposure on rat primary hippocampal neurons or cortex astrocytes was evaluated. Then the role of the astrocytes in PFOS-induced toxic effect on neurons was explored with astrocyte-neuron co-culture system. Exposure of rat primary hippocampal neurons to PFOS has led to oxidation-antioxidation imbalance, increased apoptosis and abnormal autophagy. The adverse effect of PFOS on rat primary cortex astrocytes manifested in the form of altered extracellular glutamate and glutamine concentrations, decreased glutamine synthase activity, as well as decreased gene expression of glutamine synthase, glutamate transporters and glutamine transporters in the glutamate-glutamine cycle. Especially, the alleviation of PFOS-inhibited neurite outgrowth in neurons could be observed in astrocyte-neuron co-culture system, though the ability of astrocytes in fostering neurite outgrowth was affected by PFOS. These results indicated that both astrocytes and neurons might be the targets of PFOS-induced neurotoxicity, and astrocytes could protect against PFOS-inhibited neurite outgrowth in primary cultured neurons. Our research might render some information in explaining the mechanisms of PFOS-induced neurotoxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. TERATOGENIC EFFECTS OF TRANSPLACENTAL TRANSFUSION OF HETEROLOGOUS ANTISERA SIMULATED IN AN EXPERIMENTAL-MODEL USING INVITRO WHOLE RAT EMBRYO CULTURE

    NARCIS (Netherlands)

    VANDERZEE, DC; POELMANN, RE; ZWIERSTRA, RP; MENTINK, MMT; VERMEIJKEERS, C

    1991-01-01

    The effects of the transplacental transfusion of heterologous rabbit-anti-rat antiserum (RAR antiserum) and subsequent immunological interaction on the development of 9-10 days old rat embryos (stages 8-10 somites) were studied using an in vitro whole rat embryo culture. Transplacental transfusion w

  13. Reduced lipid oxidation in skeletal muscle from type 2 diabetic subjects may be of genetic origin: evidence from cultured myotubes.

    Science.gov (United States)

    Gaster, Michael; Rustan, Arild C; Aas, Vigdis; Beck-Nielsen, Henning

    2004-03-01

    Insulin resistance in skeletal muscle in vivo is associated with reduced lipid oxidation and lipid accumulation. It is still uncertain whether changes in lipid metabolism represent an adaptive compensation at the cellular level or a direct expression of a genetic trait. Studies of palmitate metabolism in human myotubes established from control and type 2 diabetic subjects may solve this problem, as genetic defects are preserved and expressed in vitro. In this study, total uptake of palmitic acid was similar in myotubes established from both control and type 2 diabetic subjects under basal conditions and acute insulin stimulation. Myotubes established from diabetic subjects expressed a primary reduced palmitic acid oxidation to carbon dioxide with a concomitantly increased esterification of palmitic acid into phospholipids compared with control myotubes under basal conditions. Triacylglycerol (TAG) content and the incorporation of palmitic acid into diacylglycerol (DAG) and TAG at basal conditions did not vary between the groups. Acute insulin treatment significantly increased palmitate uptake and incorporation of palmitic acid into DAG and TAG in myotubes established from both study groups, but no difference was found in myotubes established from control and diabetic subjects. These results indicate that the reduced lipid oxidation in diabetic skeletal muscle in vivo may be of genetic origin; it also appears that TAG metabolism is not primarily affected in diabetic muscles under basal physiological conditions.

  14. Organ explant culture of neonatal rat ventricles: a new model to study gene and cell therapy.

    Directory of Open Access Journals (Sweden)

    A Dénise den Haan

    Full Text Available Testing cardiac gene and cell therapies in vitro requires a tissue substrate that survives for several days in culture while maintaining its physiological properties. The purpose of this study was to test whether culture of intact cardiac tissue of neonatal rat ventricles (organ explant culture may be used as a model to study gene and cell therapy. We compared (immuno histology and electrophysiology of organ explant cultures to both freshly isolated neonatal rat ventricular tissue and monolayers. (Immuno histologic studies showed that organ explant cultures retained their fiber orientation, and that expression patterns of α-actinin, connexin-43, and α-smooth muscle actin did not change during culture. Intracellular voltage recordings showed that spontaneous beating was rare in organ explant cultures (20% and freshly isolated tissue (17%, but common (82% in monolayers. Accordingly, resting membrane potential was -83.9±4.4 mV in organ explant cultures, -80.5±3.5 mV in freshly isolated tissue, and -60.9±4.3 mV in monolayers. Conduction velocity, measured by optical mapping, was 18.2±1.0 cm/s in organ explant cultures, 18.0±1.2 cm/s in freshly isolated tissue, and 24.3±0.7 cm/s in monolayers. We found no differences in action potential duration (APD between organ explant cultures and freshly isolated tissue, while APD of monolayers was prolonged (APD at 70% repolarization 88.8±7.8, 79.1±2.9, and 134.0±4.5 ms, respectively. Organ explant cultures and freshly isolated tissue could be paced up to frequencies within the normal range for neonatal rat (CL 150 ms, while monolayers could not. Successful lentiviral (LV transduction was shown via Egfp gene transfer. Co-culture of organ explant cultures with spontaneously beating cardiomyocytes increased the occurrence of spontaneous beating activity of organ explant cultures to 86%. We conclude that organ explant cultures of neonatal rat ventricle are structurally and electrophysiologically similar

  15. Effect of acute and chronic eccentric exercise on FOXO1 mRNA expression as fiber type transition factor in rat skeletal muscles.

    Science.gov (United States)

    Azad, Milad; Khaledi, Neda; Hedayati, Mehdi

    2016-06-15

    Skeletal muscle is a highly elastic tissue which can respond to various functional demands by altering fiber-type composition. Exercise affects muscle fiber phenotype. One of the transcription factors that induce fiber-type transition is forkhead box O1 (FOXO1). Since eccentric contraction considered an essential part of exercise, so we are interested to see the effects of eccentric exercise (acute/chronic) on FOXO1 as an important factor of fiber-type transition in rat skeletal muscles. Twenty-four Sprague-Dawley rats (190-235g) were divided to 3 groups of 8 rats: 1) chronic eccentric exercise (CEE), 2) acute eccentric exercise (AEE), and 3) control (C). The exercise groups underwent downhill running protocol. CEE was running on treadmill in 3 days of week for 9 weeks, that slope and duration gradually managed from -4° to -16° and 15 to 90 min, respectively. AEE group was running with 16 m/min on -16° slope for 3 consecutive days that included 18 sets of 5 min with rest interval of 2 min in between. Soleus and super vastus lateralis (SVL) muscles mRNA were analyzed by real-time RT-PCR. SVL FOXO1 mRNA levels increased by 3.92-fold in the AEE and decreased 0.56-fold in the CEE group and were not significant in soleus muscle. In soleus muscle, myosin heavy chain (MHC) IIa, IIx, and IIb decreased in the AEE group and MHC IIa and IIx decreased in the CEE group. In SVL muscle, MHC I, IIa, and IIx increased in the AEE group and MHC IIa and IIX increased in the CEE group. In summary, both acute and chronic eccentric exercise could lead to change in FOXO1 mRNA only in fast SVL muscle of rat and so could induce fiber-type transition in both muscles regardless of changes in expression of FOXO1. So, oxidative stress can play important role in change of FOXO1. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Induction of lymphokine-activated killer activity in rat splenocyte cultures: The importance of 2-mercaptoethanol and indomethacin

    NARCIS (Netherlands)

    P.J.K. Kuppen (P. J K); A.M.M. Eggermont (Alexander); A.W. Marinelli (Andreas); E. de Heer (Emile); C.J.H. van de Velde (Cornelis); G.J. Fleuren (G.)

    1991-01-01

    textabstractThe role of 2-mercaptoethanol and indomethacin in the induction of lymphokine-activated killer (LAK) activity by interleukin-2 (IL-2) in rat splenocyte cultures was investigated. Spleens from 4-month-old male rats of five different strains were tested. Splenocytes were cultured for 3-5 d

  17. An Optimized Culture Method of Rat Dorsal Root Ganglion Neurons

    Institute of Scientific and Technical Information of China (English)

    LIUYin; CHENJing-Hong; GONGZe-Hui

    2004-01-01

    AIM: To establish a primary culture technique of acutely isolated dorsal root ganglion (DRG) neurons, and provide a simple & useful in vitro model for study of analgesia. Methods: Acutely isolated dorsal root ganglion (DRG) neurons were planted and cultured; the configuration and growth characters of DRG neurons were observed through inverted microscope.

  18. Effect of Microcystin-LR on Cultured Rat Endothelial Cells

    Science.gov (United States)

    1990-02-26

    mmol, New England Nuclear Corp., Boston, MA), tissue culture media and fetal bovine serum albumin (Gibco, Grand Island, NY), tissue culture ware (Becton...WAGNER, H. AND FIEBIG, M. (1984) Actions of flavonoligans from silybum marianum fruits. Planta Med. 50, 248-250. JACKSON, A. R., RUNNEGAR, M. T

  19. Human serum teratogenicity studies using in vitro cultures of rat embryos

    Energy Technology Data Exchange (ETDEWEB)

    Klein, N.W.; Chatot, C.L.; Plenefisch, J.D.; Carey, S.W.

    1982-01-01

    Those conditions that constitute reproductive risks to man are being analyzed. Particular concern is with those conditions that cannot be or have not been identified by present methodologies. These conditions constitute the majority of factors causing fetal wastages and birth defects. The test system uses intact rat embryos that are cultured in vitro for 2 days. Findings to date suggest that this system may have a number of distinct advantages: (1) whole-embryo culture provides the test with the entire repertoire of processes involved in embryonic development; (2) whole-rat embryos can be cultured on high levels of blood serum; and (3) they can be cultured on serum from human subjects, which provides a direct and unique evaluation of the principal organism of concern. In regard to this last point, it is important to recognize that there is a large range of teratogenic responses and sensitivities to teratogens dependent upon both individual and species differences. (ERB)

  20. Light effects on the isotopic fractionation of skeletal oxygen and carbon in the cultured zooxanthellate coral, Acropora: implications for coral-growth rates

    Directory of Open Access Journals (Sweden)

    S. Reynaud

    2010-03-01

    Full Text Available Skeletal isotopic and metabolic measurements of the branching coral Acropora cultured in constant conditions and subjected to two light intensities were revisited. We individually compared the data recorded at low light (LL and high light (HL for 24 colonies, all derived from the same parent colony. Metabolic and isotopic responses to the different light levels were highly variable. High light led to productivity enhancement, reduction of surface extension, doubling of aragonite deposited weight and increased δ18O levels in all nubbins; responses in respiration and δ13C were not clear. The partitioning of the colonies cultured at HL into two groups, one showing a δ13C enrichment and the other a δ13C decrease revealed common behaviors. Samples showing an increase in δ13C were associated with the co-variation of low surface extension and high productivity while samples showing a decrease in δ13C were associated with the co-variation of higher surface extension and limited productivity. This experiment, which allowed for the separation of temperature and light effects on the coral, highlighted the significant light influences on both skeletal δ18O and δ13C. The high scattering of inter-colony δ18O observed at one site could be due to the differing photosynthetic responses of symbiotic algal assemblages. We compared our results with observations by Gladfelter on Acropora cervicornis (1982. Both set of results highlight the relationships between coral-growth rates, micro-structures and photosynthetic activity. It appears that extension growth and skeleton thickening are two separate growth modes, and thickening is light-enhanced while extension is light-suppressed. There are multiple consequences of these findings for paleoclimatic reconstructions involving corals.

  1. Light effects on the isotopic fractionation of skeletal oxygen and carbon in the cultured zooxanthellate coral, Acropora: implications for coral-growth rates

    Science.gov (United States)

    Juillet-Leclerc, A.; Reynaud, S.

    2010-03-01

    Skeletal isotopic and metabolic measurements of the branching coral Acropora cultured in constant conditions and subjected to two light intensities were revisited. We individually compared the data recorded at low light (LL) and high light (HL) for 24 colonies, all derived from the same parent colony. Metabolic and isotopic responses to the different light levels were highly variable. High light led to productivity enhancement, reduction of surface extension, doubling of aragonite deposited weight and increased δ18O levels in all nubbins; responses in respiration and δ13C were not clear. The partitioning of the colonies cultured at HL into two groups, one showing a δ13C enrichment and the other a δ13C decrease revealed common behaviors. Samples showing an increase in δ13C were associated with the co-variation of low surface extension and high productivity while samples showing a decrease in δ13C were associated with the co-variation of higher surface extension and limited productivity. This experiment, which allowed for the separation of temperature and light effects on the coral, highlighted the significant light influences on both skeletal δ18O and δ13C. The high scattering of inter-colony δ18O observed at one site could be due to the differing photosynthetic responses of symbiotic algal assemblages. We compared our results with observations by Gladfelter on Acropora cervicornis (1982). Both set of results highlight the relationships between coral-growth rates, micro-structures and photosynthetic activity. It appears that extension growth and skeleton thickening are two separate growth modes, and thickening is light-enhanced while extension is light-suppressed. There are multiple consequences of these findings for paleoclimatic reconstructions involving corals.

  2. Basic fibroblast growth factor is pro-adipogenic in rat skeletal muscle progenitor clone, 2G11 cells.

    Science.gov (United States)

    Nakano, Shin-ichi; Nakamura, Katsuyuki; Teramoto, Naomi; Yamanouchi, Keitaro; Nishihara, Masugi

    2016-01-01

    Intramuscular adipose tissue (IMAT) formation is a hallmark of marbling in cattle. IMAT is considered to originate from skeletal muscle progenitor cells with adipogenic potential. However, the mechanism involved in IMAT formation from these progenitor cells in vivo remains unclear. In the present study, among the growth factors tested, which were known to be expressed in skeletal muscle, we found only basic fibroblast growth factor (bFGF) has a pro-adipogenic effect on skeletal muscle derived adipogenic progenitor clone, 2G11 cells. Pre-exposure of 2G11 cells to bFGF did not affect initial gene expressions of CCAAT/enhancer-binding protein (C/EBP)β and C/EBPδ, while resulting in an enhancement of subsequent expressions of C/EBPα and proliferator-activated receptor gamma (PPARγ) during adipogenesis, indicating that bFGF is acting on the transcriptional regulation of C/EBPα and PPARγ. In addition, the effect of bFGF is mediated via two types of FGF receptor (FGFR) isoforms: FGFR1 and FGFR2 IIIc, and both receptors are prerequisite for bFGF to express its pro-adipogenic effect. These results suggest that bFGF plays an important role as a key trigger of IMAT formation in vivo.

  3. Selection of medium for serum-free primary culture of adult rat hepatocytes.

    Directory of Open Access Journals (Sweden)

    Miyazaki,Masahiro

    1990-02-01

    Full Text Available To select a suitable medium for serum-free primary culture of adult rat hepatocytes, ten commercially-available synthetic media were compared for their ability to maintain the cells under serum-free and serum-supplemented conditions with special reference to attachment, survival and albumin secretion. It was found that Williams' medium E and DM-160 medium were the best among the ten media for maintaining hepatocytes under serum-free conditions in primary culture.

  4. Stimulation of DNA and Collagen Synthesis by Autologous Growth Factor in Cultured Fetal Rat Calvaria

    Science.gov (United States)

    Canalis, Ernesto; Peck, William A.; Raisz, Lawrence G.

    1980-11-01

    Conditioned medium derived from organ or cell cultures prepared from 19- to 21-day fetal rat calvaria stimulated the incorporation of [3H]proline into collagen and of [3H]thymidine into DNA in organ cultures of the same tissue. Addition of cortisol enhanced the effect on collagen but not on DNA synthesis. These effects appeared to be due to a nondialyzable and heat-stable growth factor.

  5. Effects of Fixatives and Buffers upon the Morphology of Heart and Skeletal Muscle Mitochondria from Exhausted Rats.

    Science.gov (United States)

    Gale, James B.

    This study describes the effects of several fixatives and buffers on the morphology of mitochondria from resting and exhausted rats. Rats were run to exhaustion and adjacent portions from the left ventricle or from the soleus were treated with the following fixation procedures: (a) glutaraldehyde buffered with cacodylate, S-collidine, or phosphate…

  6. Activation of the ATP-ubiquitin-proteasome pathway in skeletal muscle of cachectic rats bearing a hepatoma

    Science.gov (United States)

    Baracos, V. E.; DeVivo, C.; Hoyle, D. H.; Goldberg, A. L.

    1995-01-01

    Rats implanted with Yoshida ascites hepatoma (YAH) show a rapid and selective loss of muscle protein due mainly to a marked increase (63-95%) in the rate of protein degradation (compared with rates in muscles of pair-fed controls). To define which proteolytic pathways contribute to this increase, epitrochlearis muscles from YAH-bearing and control rats were incubated under conditions that modify different proteolytic systems. Overall proteolysis in either group of rats was not affected by removal of Ca2+ or by blocking the Ca(2+)-dependent proteolytic system. Inhibition of lysosomal function with methylamine reduced proteolysis (-12%) in muscles from YAH-bearing rats, but not in muscles of pair-fed rats. When ATP production was also inhibited, the remaining accelerated proteolysis in muscles of tumor-bearing rats fell to control levels. Muscles of YAH-bearing rats showed increased levels of ubiquitin-conjugated proteins and a 27-kDa proteasome subunit in Western blot analysis. Levels of mRNA encoding components of proteolytic systems were quantitated using Northern hybridization analysis. Although their total RNA content decreased 20-38%, pale muscles of YAH-bearing rats showed increased levels of ubiquitin mRNA (590-880%) and mRNA for multiple subunits of the proteasome (100-215%). Liver, kidney, heart, and brain showed no weight loss and no change in these mRNA species. Muscles of YAH-bearing rats also showed small increases (30-40%) in mRNA for cathepsins B and D, but not for calpain I or heat shock protein 70. Our findings suggest that accelerated muscle proteolysis and muscle wasting in tumor-bearing rats result primarily from activation of the ATP-dependent pathway involving ubiquitin and the proteasome.

  7. THE LOCALIZATION OF ADRENOMEDULLIN IN RAT KIDNEY TISSUE AND ITS INHIBITORY EFFECT ON THE GROWTH OF CULTURED RAT MESANGIAL CELLS

    Institute of Scientific and Technical Information of China (English)

    刘学光; 张志刚; 张秀荣; 朱虹光; 陈琦; 郭慕依

    2002-01-01

    Objective. To observe the localization of adrenomedullin (AM) in rat kidney tissue and its inhibitory effect on the growth of cultured rat mesangial cells (MsC). Methods. A monoclonal antibody against AM developed by our laboratory was used to detect the localization of AM protein in rat kidney tissue by avidin-biotin complex immunohistochemistry. The expressions of AM and its receptor CRLR mRNA on cultured glomerular epithelial cells (GEC) and MsC were investigated by Northern blot assay, and the possible effect of AM secreted by GEC on MsC proliferation was observed using [3H]thymidine incorporation as an index. Results. A specific monoclonal antibody against AM was successfully developed. AM was immunohistochemically localized mainly in glomeruli (GEC and endothelial cells), some cortical proximal tubules, medullary collecting duct cells, interstitial cells, vascular smooth muscle cells and endothelial cells. Northern blot assay showed that AM mRNA was expressed only on cultured GEC, but not on MsC, however, AM receptor CRLR mRNA was only expressed on MsC. GEC conditioned medium containing AM can inhibit MsC growth and AM receptor blocker CGRP8-37 may partially decreased this inhibitory effect. Conclusion. AM produced by GEC inhibits the proliferation of MsC, which suggests that AM as an important regulator is involved in glomerular normal physiological functions and pathologic processes.

  8. THE LOCALIZATION OF ADRENOMEDULLIN IN RAT KIDNEY TISSUE AND ITS INHIBITORY EFFECT ON THE GROWTH OF CULTURED RAT MESANGIAL CELLSA

    Institute of Scientific and Technical Information of China (English)

    刘学光; 张志刚; 等

    2002-01-01

    Objective:To observe the localization of adrenomedullin(AM) in rat kidney tissue and its inhibitory effect on the growth of cultured rat mesangial cells (MsC).Methods:A monoclonal antibody against AM developed by our laboratory was used to detect the localization of AM protein in rat kidney tissue by avidin-biotin complex immunohistochemistry.The expressions of AM and its receptor CRLR mRNA on cultured glomerular epithelial cells (GEC)and MsC were investigated by Northern blot assay,and the possible effect of AM secreted by GEC on MsC proliferation was observed using [3H] thymidine incorporation as an index.Results:A specific monoclonal antibody against AM was successfull developed.AM was immunohistochemically localized mainly in glomeruli (GEC and endothelial cells),some cortical proximal tubules,medullary collecting duct cells,interstitial cells,vascular smooth muscle cells and endothelial cells.Northern blot assay showed the AM mRNA was expressed only on cultured GEC,but not on MsC,however,AM receptor CRLR mRNA was only expressed on MsC.GEC conditioned medium containing AM can inhibit MsC growth and AM receptor blocker CGRP8-37 may partially decreased this inhibitory effect.Conclusion:AM produced by GEC inhibits the proliferation of MsC,which suggests that AM as an important regulator is involved in glomerular normal physiological functions and pathologic processes.

  9. GLUT4 in cultured skeletal myotubes is segregated from the transferrin receptor and stored in vesicles associated with TGN

    DEFF Research Database (Denmark)

    Ralston, E; Ploug, Thorkil

    1996-01-01

    of the constitutive endosomal-lysosomal pathway. To address this question, we have investigated the localization of the endogenous GLUT4 in non-stimulated skeletal myotubes from the cell line C2, by immunofluorescence and immunoelectron microscopy. We have used a panel of antibodies to markers of the Golgi complex...... (alpha mannosidase II and giantin), of the trans-Golgi network (TGN38), of lysosomes (lgp110), and of early and late endosomes (transferrin receptor and mannose-6-phosphate receptor, respectively), to define the position of their subcellular compartments. By immunofluorescence, GLUT4 appears concentrated...... in the core of the myotubes. It is primarily found around the nuclei, in a pattern suggesting an association with the Golgi complex, which is further supported by colocalization with giantin and by immunogold electron microscopy. GLUT4 appears to be in the trans-most cisternae of the Golgi complex...

  10. Endogenous bile acid disposition in rat and human sandwich-cultured hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Tracy L., E-mail: tracylmarion@qualyst.com [Curriculum in Toxicology, UNC School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7270 (United States); Perry, Cassandra H., E-mail: cassandraperry@qualyst.com [Qualyst, Inc., Durham, NC 27713 (United States); St Claire, Robert L., E-mail: bobstclaire@qualyst.com [Qualyst, Inc., Durham, NC 27713 (United States); Brouwer, Kim L.R., E-mail: kbrouwer@unc.edu [Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, CB 7569 Kerr Hall, Chapel Hill, NC 27599-7569 (United States)

    2012-05-15

    Sandwich-cultured hepatocytes (SCH) are used commonly to investigate hepatic transport protein-mediated uptake and biliary excretion of substrates. However, little is known about the disposition of endogenous bile acids (BAs) in SCH. In this study, four endogenous conjugated BAs common to rats and humans [taurocholic acid (TCA), glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), and glycochenodeoxycholic acid (GCDCA)], as well as two BA species specific to rodents (α- and β-tauromuricholic acid; α/β TMCA), were profiled in primary rat a