The influence of passive stretch on the growth and protein turnover of the denervated extensor digitorum longus muscle.
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ABSTRACT:
SUBMITTER: Goldspink DF
PROVIDER: S-EPMC1185952 | biostudies-other | 1978 Aug
REPOSITORIES: biostudies-other
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Project description:Among patients with intensive care unit-acquired weakness (ICUAW), skeletal muscle strength often decreases significantly. The present study aimed to explore the effects of testosterone propotionate on skeletal muscle using rat model of sepsis. Male SD rats were randomly divided into experimental group, model control group, sham operation group and blank control group. Rats in experimental group were given testosterone propionate two times a week, 10 mg/kg for 3 weeks. Maximal contraction force, fatigue index and cross-sectional area of the extensor digitorum longus (EDL) were measured. Myosin, IGF-1, p-AKT and p-mTOR levels in EDL were detected by Western blot. Histological changes of the testis and prostate were detected by hematoxylin and eosin staining. We found that maximal contraction force and fatigue index of EDL in experimental group were significantly higher than in model control group. Cross-sectional area of fast MHC muscle fiber of EDL in group was significantly higher than in model control group. The levels of myosin, IGF-1, p-AKT and p-mTOR of EDL in experimental group were significantly higher than in model control group. In addition, no testicle atrophy and prostate hyperplasia were detected in experimental group. In conclusion, these results suggest that testosterone propionate can significantly improve skeletal muscle strength, endurance and volume of septic rats, and the mechanism may be related to the activation of IGF-1/AKT pathway. Moreover, testosterone propionate with short duration does not cause testicular atrophy and prostate hyperplasia in septic rats. Therefore, testosterone propionate is a potential treatment for muscle malfunction in ICUAW patients.
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Project description:Recent studies of the ketogenic diet, an extremely high-fat diet with extremely low carbohydrates, suggest that it changes the energy metabolism properties of skeletal muscle. However, ketogenic diet effects on muscle metabolic characteristics are diverse and sometimes countervailing. Furthermore, ketogenic diet effects on skeletal muscle performance are unknown. After male Wistar rats (8 weeks of age) were assigned randomly to a control group (CON) and a ketogenic diet group (KD), they were fed for 4 weeks respectively with a control diet (10% fat, 10% protein, 80% carbohydrate) and a ketogenic diet (90% fat, 10% protein, 0% carbohydrate). After the 4-week feeding period, the extensor digitorum longus (EDL) muscle was evaluated ex vivo for twitch force, tetanic force, and fatigue. We also analyzed the myosin heavy chain composition, protein expression of metabolic enzymes and regulatory factors, and citrate synthase activity. No significant difference was found between CON and KD in twitch or tetanic forces or muscle fatigue. However, the KD citrate synthase activity and the protein expression of Sema3A, citrate synthase, succinate dehydrogenase, cytochrome c oxidase subunit 4, and 3-hydroxyacyl-CoA dehydrogenase were significantly higher than those of CON. Moreover, a myosin heavy chain shift occurred from type IIb to IIx in KD. These results demonstrated that the 4-week ketogenic diet improves skeletal muscle aerobic capacity without obstructing muscle contractile function in sedentary male rats and suggest involvement of Sema3A in the myosin heavy chain shift of EDL muscle.
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Project description:AbstractGanglion is the most common soft tissue mass in the foot and can be painful and affect comfort wearing shoes. The usual treatment of a ganglion is conservative: careful neglect, manual rupture, or aspiration. When the lesion is recurrent or painful, surgical excision is recommended. The purpose of this Technical Note is to describe the extraganglionic approach of endoscopic ganglionectomy of the extensor digitorum longus tendon. This surgery has the advantage of being minimally invasive and having better cosmetic result, with less surgical trauma to the soft tissue.Level of evidenceLevel 1: foot and ankle; Level 2: other (ganglion).
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Project description:We previously reported the significant increase in limb muscle strength and cross-sectional area of the type IIb muscle fibers in the extensor digitorum longus (EDL) muscle in a type 2 diabetic animal model, with Spontaneously Diabetic Torii (SDT) fatty rats (n = 6) undergoing regular treadmill exercise from 8 to 16 weeks of age compared with sedentary SDT fatty rats (n = 6). This study investigated the mechanism by which exercise training prevented skeletal muscle wasting in the EDL muscle of the SDT fatty rats. The endurance exercise for 8 weeks downregulated the expression of muscle RING-finger protein-1 (an E3 ubiquitin ligase) and upregulated the expression of CD31, insulin receptor substrate-2, and phosphorylated endothelial nitric oxide synthase in the EDL muscle of 16-week-old SDT fatty rats.Endurance exercise training might reduce muscle wasting by preventing muscle degradation and increasing the angiogenic response in the EDL muscle in type 2 diabetes.
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Project description:I. Experimental Design: a. Type of experiment: Time course b. Experimental factors: 3 month old mice subjected to lengthening contractions of the extensor digitorum longus muscle (EDL). Samples of EDL collected at 6 and 72 h and compared to non-treated control. c. How many hybridizations in exp: 9 d. Common reference used for all hyb: no e. Quality control steps: All arrays used from same lot. Triplicate hybridizations performed for each time point. II. Samples used, extracts, preparation and labeling: Animals. Nine male C57BL/6 mice (3-4 mo of age, 27.8 ± 3.3 g body mass, Harlan Sprague-Dawley, Indianapolis, IN). Muscle Injury. The extensor digitorum longus (EDL) muscle of six mice were exposed to lengthening contractions. Mice were anesthetized with 2% avertin (0.015 ml/kg) and supplemental doses were administered if the mouse responded to a toe pinch. Animals were placed on a plexiglass platform that was maintained at 37°C. The distal femur of the right hindlimb was fixed between screws and the foot was taped to the platform. The distal tendons of the EDL were exposed by incision and tied to the lever arm of a servomotor (Aurora Scientific, Richmond Hill ON, Canada) with 4-0 silk suture. Needle electrodes were placed adjacent to the peroneal nerve to stimulate dorsiflexor contraction (Grass Instruments, West Warwick, RI). Maximal isometric force (Po) was determined by stimulating the dorsiflexors maximally at optimum length (Lo) for force development. To induce muscle injury, 75 lengthening contractions were performed at 0.25 Hz for 5 min. For each lengthening contraction, the muscle was stimulated at 150 Hz and stretched 100 ms after the initiation of stimulation. Muscle stretch involved 20 % strain relative to Lo. Force deficit was evaluated 10 min after the 75 contractions and then the incision was closed with 7-0 silk suture. Animals were returned to their cage to recover until the time of sacrifice. Prior to sacrifice by cervical dislocation, animals were anesthetized with avertin and the EDL muscles were excised and flash frozen in liquid nitrogen. Muscles were stored in liquid nitrogen until RNA isolation. RNA Isolation. Total RNA was isolated from EDL muscles from control mice (n=3) and mice sacrificed at 6 h (n=3) and 72 h (n=3) after lengthening contractions according to the modified protocol of Chomzynski et al.. Frozen muscles were added to preweighed tubes containing TriReagent (Sigma-Aldrich, St. Louis, MO). Tissue was homogenized in TriReagent using a Tissue Tearor (Fischer, Pittsburgh, PA) at 30,000 rpm for 1 minute. Homogenates were transferred to sterile, RNAase free microcentrifuge tubes and incubated for 10 min at room temperature. Chloroform (0.2 ml; Sigma-Aldrich, St. Louis, MO) was added and after incubation, the samples were centrifuged for 15 min at 12,000 g and 4°C. Total RNA was precipitated from the aqueous phase by the addition of isopropanol (Sigma-Aldrich), and pelleted by centrifugation. Pellets were washed in ethanol (75 and 95 %) and air dried before resuspension in diethylpyrocarbonate (DEPC) treated water. RNA concentration was determined by optical density at 260 nm. III. Hybridization procedures and parameters: Microarray Hybridization and Analysis. To reduce measurement error, all membranes (Atlas mouse 1.2; Clontech, Palo Alto, CA) were prepared from the same lot. Additionally, each membrane was hybridized only once to avoid errors associated with stripping and multiple hybridizations. In order to minimize individual biological variability, total RNA was pooled from three animals for hybridization of arrays. Three arrays were used for the pooled sample at each time point. First strand cDNA probe generation from total RNA and microarray hybridization were performed according to manufacturer’s instructions (Atlas cDNA Expression Arrays User Manual, Clontech). 33P labeled cDNA was generated from sample RNA using [33P]-dATP (3000 Ci/mmol; ICN, Costa Mesa, CA) and Maloney murine leukemia virus (MMLV) reverse transcriptase (Clontech). Labeled probes were purified using nucleospin columns (Clontech). Array membranes were prehybridized in Express Hyb containing sheared Salmon testes DNA (Gibco BRL, Rockville, MD) for 30 min at 71°C in rotating hybridization tubes. Radiolabeled probe (3 x 106 cpm) was incubated in denaturing solution (Clontech) for 20 min at 71°C, after which Cot1 DNA/neutralizing solution was added and incubation continued for 10 min. The probe mixture was added to the hybridization tube and incubated with rotation overnight. Following hybridization, membranes were washed four times for 30 min in 2X saturated sodium citrate (SSC) and 1 % sodium dodecyl sulphate (SDS) at 71°C, once for 30 min in 0.1X SSC and 0.5% SDS at 71°C, and once for 5 min in 2X SSC at room temperature. Membranes were removed and immediately wrapped in plastic and exposed to a phosphor storage screen (Molecular Dynamics, Sunnyvale, CA) for four days. IV. Measurement data and specifications: Data Analysis. The membrane image was acquired using a Storm phosporimager (Molecular Dynamics) and Image Quant software. Array images were analyzed using Atlas Image 2.0 (Clontech) software to determine raw intensity levels of expression. Raw intensity data was imported into GeneSpring (Silicon Genetics, Redwood City, CA) expression analysis software. Intensity levels were normalized to the median expressed intensity on each of the arrays and averaged for the three arrays at each time point. Normalized expression levels for control arrays were established as a value of 1 and data from 6 and 72 h were expressed as fold changes relative to control. In order to simplify interpretation of the resulting dataset, a k-means cluster analysis was employed to group genes based on similarities in patterns of expression. To reduce the likelihood of false positives, the data was filtered using a criterion 2 fold change in expression prior to clustering. Miller et al. (61) have calculated that using an array of 10,000 features with a coefficient of variation (CV) of 20 percent, a 2 fold criterion for altered gene expression would result in zero false positives. The mean and median CV (15.8 and 14.3%, respectively) for all arrays in the current study fell within these guidelines for the elimination of false positives. Keywords: time-course
2004-01-27 | GSE992 | GEO
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Project description:Emerging evidence suggests that undercarboxylated osteocalcin (ucOC) improves muscle glucose uptake in rodents. However, whether ucOC can directly increase glucose uptake in both glycolytic and oxidative muscles and the possible mechanisms of action still need further exploration. We tested the hypothesis that ucOC per se stimulates muscle glucose uptake via extracellular signal-regulated kinase (ERK), adenosine monophosphate-activated protein kinase (AMPK), and/or the mechanistic target of rapamycin complex 2 (mTORC2)-protein kinase B (AKT)-AKT substrate of 160?kDa (AS160) signaling cascade. Extensor digitorum longus (EDL) and soleus muscles from male C57BL/6 mice were isolated, divided into halves, and then incubated with ucOC with or without the pretreatment of ERK inhibitor U0126. ucOC increased muscle glucose uptake in both EDL and soleus. It also enhanced phosphorylation of ERK2 (Thr202/Tyr204) and AS160 (Thr642) in both muscle types and increased mTOR phosphorylation (Ser2481) in EDL only. ucOC had no significant effect on the phosphorylation of AMPK? (Thr172). The inhibition of ucOC-induced ERK phosphorylation had limited effect on ucOC-stimulated glucose uptake and AS160 phosphorylation in both muscle types, but appeared to inhibit the elevation in AKT phosphorylation only in EDL. Taken together, ucOC at the physiological range directly increased glucose uptake in both EDL and soleus muscles in mouse. The molecular mechanisms behind this ucOC effect on muscle glucose uptake seem to be muscle type-specific, involving enhanced phosphorylation of AS160 but limitedly modulated by ERK phosphorylation. Our study suggests that, since ucOC increases muscle glucose uptake without insulin, it could be considered as a potential agent to improve muscle glucose uptake in insulin resistant conditions.
| S-EPMC5698688 | biostudies-literature
Project description:I. Experimental Design: a. Type of experiment: Time course b. Experimental factors: 3 month old mice subjected to lengthening contractions of the extensor digitorum longus muscle (EDL). Samples of EDL collected at 6 and 72 h and compared to non-treated control. c. How many hybridizations in exp: 9 d. Common reference used for all hyb: no e. Quality control steps: All arrays used from same lot. Triplicate hybridizations performed for each time point. II. Samples used, extracts, preparation and labeling: Animals. Nine male C57BL/6 mice (3-4 mo of age, 27.8 ± 3.3 g body mass, Harlan Sprague-Dawley, Indianapolis, IN). Muscle Injury. The extensor digitorum longus (EDL) muscle of six mice were exposed to lengthening contractions. Mice were anesthetized with 2% avertin (0.015 ml/kg) and supplemental doses were administered if the mouse responded to a toe pinch. Animals were placed on a plexiglass platform that was maintained at 37°C. The distal femur of the right hindlimb was fixed between screws and the foot was taped to the platform. The distal tendons of the EDL were exposed by incision and tied to the lever arm of a servomotor (Aurora Scientific, Richmond Hill ON, Canada) with 4-0 silk suture. Needle electrodes were placed adjacent to the peroneal nerve to stimulate dorsiflexor contraction (Grass Instruments, West Warwick, RI). Maximal isometric force (Po) was determined by stimulating the dorsiflexors maximally at optimum length (Lo) for force development. To induce muscle injury, 75 lengthening contractions were performed at 0.25 Hz for 5 min. For each lengthening contraction, the muscle was stimulated at 150 Hz and stretched 100 ms after the initiation of stimulation. Muscle stretch involved 20 % strain relative to Lo. Force deficit was evaluated 10 min after the 75 contractions and then the incision was closed with 7-0 silk suture. Animals were returned to their cage to recover until the time of sacrifice. Prior to sacrifice by cervical dislocation, animals were anesthetized with avertin and the EDL muscles were excised and flash frozen in liquid nitrogen. Muscles were stored in liquid nitrogen until RNA isolation. RNA Isolation. Total RNA was isolated from EDL muscles from control mice (n=3) and mice sacrificed at 6 h (n=3) and 72 h (n=3) after lengthening contractions according to the modified protocol of Chomzynski et al.. Frozen muscles were added to preweighed tubes containing TriReagent (Sigma-Aldrich, St. Louis, MO). Tissue was homogenized in TriReagent using a Tissue Tearor (Fischer, Pittsburgh, PA) at 30,000 rpm for 1 minute. Homogenates were transferred to sterile, RNAase free microcentrifuge tubes and incubated for 10 min at room temperature. Chloroform (0.2 ml; Sigma-Aldrich, St. Louis, MO) was added and after incubation, the samples were centrifuged for 15 min at 12,000 g and 4°C. Total RNA was precipitated from the aqueous phase by the addition of isopropanol (Sigma-Aldrich), and pelleted by centrifugation. Pellets were washed in ethanol (75 and 95 %) and air dried before resuspension in diethylpyrocarbonate (DEPC) treated water. RNA concentration was determined by optical density at 260 nm. III. Hybridization procedures and parameters: Microarray Hybridization and Analysis. To reduce measurement error, all membranes (Atlas mouse 1.2; Clontech, Palo Alto, CA) were prepared from the same lot. Additionally, each membrane was hybridized only once to avoid errors associated with stripping and multiple hybridizations. In order to minimize individual biological variability, total RNA was pooled from three animals for hybridization of arrays. Three arrays were used for the pooled sample at each time point. First strand cDNA probe generation from total RNA and microarray hybridization were performed according to manufacturerâs instructions (Atlas cDNA Expression Arrays User Manual, Clontech). 33P labeled cDNA was generated from sample RNA using [33P]-dATP (3000 Ci/mmol; ICN, Costa Mesa, CA) and Maloney murine leukemia virus (MMLV) reverse transcriptase (Clontech). Labeled probes were purified using nucleospin columns (Clontech). Array membranes were prehybridized in Express Hyb containing sheared Salmon testes DNA (Gibco BRL, Rockville, MD) for 30 min at 71°C in rotating hybridization tubes. Radiolabeled probe (3 x 106 cpm) was incubated in denaturing solution (Clontech) for 20 min at 71°C, after which Cot1 DNA/neutralizing solution was added and incubation continued for 10 min. The probe mixture was added to the hybridization tube and incubated with rotation overnight. Following hybridization, membranes were washed four times for 30 min in 2X saturated sodium citrate (SSC) and 1 % sodium dodecyl sulphate (SDS) at 71°C, once for 30 min in 0.1X SSC and 0.5% SDS at 71°C, and once for 5 min in 2X SSC at room temperature. Membranes were removed and immediately wrapped in plastic and exposed to a phosphor storage screen (Molecular Dynamics, Sunnyvale, CA) for four days. IV. Measurement data and specifications: Data Analysis. The membrane image was acquired using a Storm phosporimager (Molecular Dynamics) and Image Quant software. Array images were analyzed using Atlas Image 2.0 (Clontech) software to determine raw intensity levels of expression. Raw intensity data was imported into GeneSpring (Silicon Genetics, Redwood City, CA) expression analysis software. Intensity levels were normalized to the median expressed intensity on each of the arrays and averaged for the three arrays at each time point. Normalized expression levels for control arrays were established as a value of 1 and data from 6 and 72 h were expressed as fold changes relative to control. In order to simplify interpretation of the resulting dataset, a k-means cluster analysis was employed to group genes based on similarities in patterns of expression. To reduce the likelihood of false positives, the data was filtered using a criterion 2 fold change in expression prior to clustering. Miller et al. (61) have calculated that using an array of 10,000 features with a coefficient of variation (CV) of 20 percent, a 2 fold criterion for altered gene expression would result in zero false positives. The mean and median CV (15.8 and 14.3%, respectively) for all arrays in the current study fell within these guidelines for the elimination of false positives.
2010-06-09 | E-GEOD-992 | biostudies-arrayexpress
Project description:INTRODUCTION:Because impaired excitation-contraction coupling and reduced sarcoplasmic reticulum (SR) Ca2+ release may contribute to the age-associated decline in skeletal muscle strength, we investigated the effect of aging on regulation of the skeletal muscle isoform of the ryanodine receptor (RyR1) by physiological channel ligands. METHODS:[3 H]Ryanodine binding to membranes from 8- and 26-month-old Fischer 344 extensor digitorum longus (EDL) and soleus muscles was used to investigate the effects of age on RyR1 modulation by Ca2+ and calmodulin (CaM). RESULTS:Aging reduced maximal Ca2+ -stimulated binding to EDL membranes. In 0.3 ?M Ca2+ , age reduced binding and CaM increased binding to EDL membranes. In 300 ?M Ca2+ , CaM reduced binding, but the age effect was not significant. Aging did not affect Ca2+ or CaM regulation of soleus RyR1. DISCUSSION:In aged fast-twitch muscle, impaired RyR1 Ca2+ regulation may contribute to lower SR Ca2+ release and reduced muscle function. Muscle Nerve 57: 1022-1025, 2018.
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Project description:Anaerobic exercise has been advocated as a prescribed treatment for the management of diabetes: however, alterations in exercise-induced signaling remain largely unexplored in the diabetic muscle. Here, we compare the basal and the in situ contraction-induced phosphorylation of the mitogen-activated protein kinases (MAPKs) ERK 1/2, p38, and JNK in the lean and obese (fa/fa) Zucker rat extensor digitorum longus (EDL) muscle following a single bout of contractile stimuli. This article represents data associated with prior publications from our (Katta et al., 2009a, 2009b, 2008) [1-3] and concurrent Data in Brief articles (Ginjupalli et al., 2017a, 2017b; Rice et al., 2017a, 2017b) [4-7].
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