Wet Weight Of Gastrocnemius Muscle Research Articles

KLF15/mTOR related proteins involved in effect of aerobic interval training on improving skeletal muscle lesions in rats with type 2 diabetes

Objective: To investigate the effects of aerobic intermittent exercise on the expressions of KLF15/mTOR related proteins to improve skeletal muscle lesions in type 2 diabetes rats. Methods: The experimental model of type 2 diabetes rats was established by feeding high-fat diet for 4 weeks and intraperitoneal injection of streptozotocin (STZ). After modeling, rats were randomly divided into two groups: diabetes model group (DM), diabetes+exercise group (DE), and normal rats were set as control group (C), 10 rats in each group. Group DE was given 8-week aerobic intermittent treadmill exercise intervention, while group C was not given any intervention. At the end of the experiment, the expressions of KLF15, mTOR, p-mTOR, and cleared caspase-3 in gastrocnemius muscle were detected by Western blot. The histopathologic changes of gastrocnemius were observed under microscope; skeletal muscle cells apoptosis rates and muscle mass were examined respectively using HE staining and TUNEL fluorescence staining. At the same time, changes of blood glucose and serum insulin, and weight were examined in the end of the experiment. Results: ①Compared with group C, the wet weight of gastrocnemius muscle and body weight, ratio of wet gastrocnemius muscle and body weight in group DM were decreased(P＜0.05 or P＜0.01); compared with group DM, the wet weight of gastrocnemius muscle, ratio of wet gastrocnemius muscle and body weight in the group DE were increased significantly (P＜0.05). ②Compared with group C, the fasting blood glucose level of group DM was increased significantly (P＜0.01), while serum insulin level of the group DM was decreased significantly(P＜0.01);compared with group DM, the above indexes were opposite in the group DE with intervention(P＜0.05). ③Compared with group C, the morphology of skeletal muscle cells in group DM was abnormal, the number of muscle nuclei was increased, the transverse lines were blurred and disappeared, the sarcomere was broken, and some muscle fibers were dissolved. Compared with group DM, the abnormal cell morphology, segmental injury of sarcomere and dissolution of muscle fibers in group DE were improved. The sarcolemma was more complete and the arrangement of muscle nuclei was more orderly. ④Compared with group C, the expressions of KLF15 and cleaved caspase-3, cells apoptosis rates in group DM were increased significantly(P＜0.01), while p-mTOR/mTOR level was decreased(P＜0.01) ; compared with group DM, the above indexes were opposite in the group with intervention(P＜0.05 or P＜0.01). Conclusion: Aerobic intermittent exercise is beneficial to improve the skeletal muscle pathological changes in type 2 diabetes rats, which may be due to the effective regulation of KLF15/mTOR related protein expression and the reduction of apoptosis damage.

Effects of Atrolnc-1 on immobilization induced muscular atrophy in mice hindlimbs

Objective: To investigate the effects of Atrolnc-1 on immobilization induced muscular atrophy in mice hindlimbs. Methods: Male C57BL/6 mice were randomly divided into control group and immobilization group (n=10 per group). The control group did not receive any treatment. The right hindlimb of the Iimmobilization group was fixed by self-made plastic tube. After 2 weeks' immobilization, the gastrocnemius muscle was separated. Hematoxylin-eosin (HE) staining was used to observe the morphological changes and the cross-sectional area was calculated. The expressions of Atrogin-1 and atrophy-specific long non-coding RNA Atrolnc-1 were detected by quantitative real-time PCR (QRT-PCR). Western blot (WB) was used to detect the expressions of muscular atrophy fbox-1 protein (MAFbx/Atrogin-1), muscle ring finger1 (MuRF-1) in whole cell and phosphonated of nuclear factor kappaB (p-NF-κB) in cytoplasm and nucleus. Results: The gastrocnemius muscle was atrophy after 2 weeks' immobilization. Compared with the control group, the wet weight of gastrocnemius muscle was decreased (P＞0.05) and the permillage of wet weight/weight of gastrocnemius muscle was decreased significantly (P＜0.05). HE staining showed that the number of muscle fibers in the immobilization group were reduced, the muscle fibers were dissolved and arranged disorderly and the interstitial inflammatory cells were infiltrated; the cross-sectional area of muscle fibers was decreased (P＜0.01).The expression level of atrolnc-1 was increased in immobilization group (P＜0.01). The expression level of p-NF-κB in cytoplasm was decreased (P＜0.01), while the expression level of p-NF-κB was increased in nucleus ( P＜0.01). Besides, the expressions of atrogin-1 (P＜0.01) and MuRF-1 (P＜0.01) were increased. Conclusion: Immobilization induced gastrocnemius atrophy in mice may be related to the activation of NF-κB by Atrolnc-1 and then promote MuRF-1 expression.

Exercise Reverses Disuse Atrophy In Rat Gastrocnemius Muscle

PURPOSE: To investigate the effects of different exercise interventions on disuse atrophy and atrophy-related proteins in rat gastrocnemius muscle. METHODS: Male Sprague-Dawley rats were randomly divided into a control group (C, n=16) and a suspension group (T, n=40). Rats in the T group were suspended by a tail suspension system for two weeks. Rats in the C group were further divided into a post-suspension blank group (C1) and a post-exercise blank group (C2), and rats in the T group were further divided into a post-suspension control group (T1), a post-exercise control group (T2), an endurance exercise group (TA), a resistance exercise group (TR) and a combined endurance and resistance exercise group (TAR). Rats in the TA, TR, and TAR groups were subjected to exercise training for four weeks. Body weight and wet weight of gastrocnemius muscle were measured immediately after suspension or at 24 hours after the last training session. Protein expression levels of Muscle Ring Finger 1 (MURF1), Muscle Atrophy F-Box (MAFbx), Insulin-Like Growth Factor-1 (IGF-1) and Cysteinyl Aspartate Specific Protease-3 (Caspase-3) in gastrocnemius muscle were determined by western blot. Student t-tests and one-way ANOVAs were used for data analysis. RESULTS: After suspension, body weight and wet weight of gastrocnemius muscle in the T1 group were significantly lower than those in the C1 group (p<0.05 to p<0.01). After exercise intervention, body weight, wet weight of gastrocnemius muscle, and the protein expression levels of MAFbx in the TA, TR, and TAR groups were significantly higher than those in the T2 and C2 groups, the protein expression levels of Caspase-3 in the TA, TR and TAR groups were significantly lower than those in the T2 and C2 groups, and the protein expression levels of MuRF1 in the TA and TR groups were significantly lower than those in the T2 group (p<0.05 to p<0.01). CONCLUSIONS: Exercise interventions, such as endurance exercise, resistance exercise, and combined endurance and resistance exercise, can effectively reverse disuse atrophy of gastrocnemius muscle in rats, which may be through altering the expression levels of several atrophy-related proteins.

Surface-Anchored Graphene Oxide Nanosheets on Cell-Scale Micropatterned Poly(d,l-lactide-co-caprolactone) Conduits Promote Peripheral Nerve Regeneration.

Regeneration and functional recovery of peripheral nerves remain formidable due to the inefficient physical and chemical cues in the available nerve guidance conduits (NGCs). Introducing micropatterns and bioactive substances into the inner wall of NGCs can effectively regulate the behavior of Schwann cells, the elongation of axons, and the phenotype of macrophages, thereby aiding the regeneration of injured nerve. In this study, linear micropatterns with ridges and grooves of 3/3, 5/5, 10/10, and 30/30 μm were created on poly(d,l-lactide-co-caprolactone) (PLCL) films following with surface aminolysis and electrostatic adsorption of graphene oxide (GO) nanosheets. The GO-modified micropatterns could significantly accelerate the collective migration of Schwann cells (SCs) and migration of SCs from their spheroids in vitro. Moreover, the SCs migrated directionally along the stripes with a fastest rate on the 3/3-GO film that had the largest cell adhesion force. The neurites of N2a cells were oriented along the micropatterns, and the macrophages tended to differentiate into the M2 type on the 3/3-GO film judged by the higher expression of Arg 1 and IL-10. The systematic histological and functional assessments of the regenerated nerves at 4 and 8 weeks post-surgery in vivo confirmed that the 3/3-GO NGCs had better performance to promote the nerve regeneration, and the CMAP, NCV, wet weight of gastrocnemius muscle, positive S100β and NF200 area percentages, and average myelinated axon diameter were more close to those of the autograft group at 8 weeks. This type of NGCs thus has a great potential for nerve regeneration.

Effect of electroacupuncture on muscular atrophy and Slit/Robo signaling in sciatic nerve and lumbar spinal cord tissues in rats with sciatic nerve injury

To observe the effect of electroacupuncture (EA) of "Huantiao"(GB30) and" Zusanli"(ST36)on muscular atrophy and expression of Slit-Robo GTPase-activating protein(srGAP)1, 2 and 3 in the injured sciatic nerve and lumbar spinal cord tissues in sciatic nerve injury (SNI) rats, so as to reveal its mechanisms underlying improvement of peripheral nerve injury (PNI)．. A total of 120 healthy male SD rats were randomly divided into control, sham-operation, model and EA groups (n＝30 rats in each) which were further divided into 7, 15 and 23 d subgroups (n＝10 rats in each subgroup). The SNI model was established by transecting the right sciatic nerve beneath the piriformis and immediately subsequent end-to-end suture. Rats of the sham operation group received an incision of the corresponding skin and suture. EA (5 Hz/20 Hz, 2－3 mA) was applied to the right GB30 and ST36 for 15 min, once daily, 6 days a week separately for 1，2 and 3 weeks. Rats in the sham-operation and model groups were grasped in the similar procedure as the EA group. The wet weight of gastrocnemius muscles (WWG) on both sides was measured to calculate the recovery rate (weight of the right WWG/weight of the left WWG×100%), and the expression levels of srGAP1, srGAP2 and srGAP3 proteins in the sciatic nerve and the spinal cord (L4-L6) tissues were detected by Western blot. After modeling and compared with the control and sham-operation groups, the recovery rate of WWG was significantly reduced, and the expression levels of srGAP1, srGAP2 and srGAP3 proteins of the sciatic nerve and lumbar spinal cord on day 7, 15 and 23 were considerably increased in the model group (P<0.01). Following the EA treatment, the reco-very rate of WWG was obviously increased and the expression levels of srGAP1, srGAP2 and srGAP3 proteins of both sciatic nerve and spinal cord on day 7, 15 and 23 were further significantly up-regulated in the EA group relevant to the model group (P<0.05，P<0.01). In addition, the expression levels of the 3 proteins in both sciatic nerve and lumbar spinal cord peaked on day 15 and attenuated on day 23. EA of GB30 and ST36 may relieve gastrocnemius atrophy in SNI rats, which is related to its function in up-regulating the Slit/Robo signaling in the sciatic nerve and lumbar spinal cord to promote the axonal targeting regeneration and repair of axonal plasma nutrition transportation.

Effect of electroacupuncture on degradation of myosin heavy chain of gastrocnemius muscle in diabetes rats

To explore the effect of electroacupuncture（EA）on the expression of muscle-specific ring finger protein 1（MuRF1/Trim63），F-box only protein 32（Fbxo32），myosin heavy chain-IIa（Myh2），myosin heavy chain-IIb（Myh4）and myosin heavy chain-I（Myh7）in diabetes rats. Thirty-six male Wistar rats were equally randomized into control, model and EA groups. The diabetes model was established by intraperitoneal injection of 0.1% Streptozocin (STZ) solution (50 mg/kg). After that, EA (2 Hz, 1 mA) was applied to bilateral "Zusanli" (ST36), "Yinlingquan" (SP9) and "Shenshu" (BL23) for 10 min, once a day, 6 times a week for 2 weeks. The fasting blood glucose (FBG) and fasting serum insulin (FINS) contents were assayed by using ELISA, and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. The body weight, and wet weight of bilateral gastrocnemius muscles were measured. The cross-sectional area (CSA) of the gastrocnemius muscle was measured after H.E. stai-ning. The expression of MuRF1, Fbxo32, Myh2, Myh4 and Myh7 mRNAs in the gastrocnemius tissue was tested using quantitative real time-PCR. Compared with the control group, the FBG and HOMA-IR were significantly higher (P<0.05), and the FINS, body weight were significantly lower (P<0.05) after intravenous injection of STZ for 1, 2, 3, 4, 5 weeks respectively. Following EA treatment and compared with the model group, the FBG and HOMA-IR were significantly down-regulated (P<0.05), and the FINS and body weight were considerably increased (P<0.05). Following modeling and compared with the control group, the wet weight of gastrocnemius muscle, CSA, and expression levels of Myh2, Myh4 and Myh7 mRNAs were obviously decreased, and the expression of MuRF1 and Fbxo32 mRNA was obviously increased in the model group (P<0.05). After EA treatment, the gastrocnemius muscle wet weight, CSA, expression levels of Myh2, Myh4 and Myh7 mRNA were significantly up-regulated (P<0.05), and the expression levels of MuRF1 and Fbxo32 mRNA were markedly down-regulated in comparison with those of the model group (P<0.05). EA treatment can delay the atrophy of gastrocnemius muscle (skeletal muscle) in diabetes rats possibly by improving the degradation of myosin heavy chain via regulating the expression of muscular MuRF1, Fbxo32, Myh2, Myh4 and Myh7 mRNAs.

G-CSF prevents caspase 3 activation in Schwann cells after sciatic nerve transection, but does not improve nerve regeneration

Exogenous granulocyte-colony stimulating factor (G-CSF) has emerged as a drug candidate for improving the outcome after peripheral nerve injuries. We raised the question if exogenous G-CSF can improve nerve regeneration following a clinically relevant model – nerve transection and repair – in healthy and diabetic rats.In short-term experiments, distance of axonal regeneration and extent of injury-induced Schwann cell death was quantified by staining for neurofilaments and cleaved caspase 3, respectively, seven days after repair. There was no difference in axonal outgrowth between G-CSF-treated and non-treated rats, regardless if healthy Wistar or diabetic Goto-Kakizaki (GK) rats were examined. However, G-CSF treatment caused a significant 13% decrease of cleaved caspase 3-positive Schwann cells at the lesion site in healthy rats, but only a trend in diabetic rats. In the distal nerve segments of healthy rats a similar trend was observed.In long-term experiments of healthy rats, regeneration outcome was evaluated at 90days after repair by presence of neurofilaments, wet weight of gastrocnemius muscle, and perception of touch (von Frey monofilament testing weekly). The presence of neurofilaments distal to the suture line was similar in G-CSF-treated and non-treated rats. The weight ratio of ipsi-over contralateral gastrocnemius muscles, and perception of touch at any time point, were likewise not affected by G-CSF treatment.In addition, the inflammatory response in short- and long-term experiments was studied by analyzing ED1 stainable macrophages in healthy rats, but in neither case was any attenuation seen at the injury site or distal to it.G-CSF can prevent caspase 3 activation in Schwann cells in the short-term, but does not detectably affect the inflammatory response, nor improve early or late axonal outgrowth or functional recovery.

Combination of acellular nerve graft and schwann cells-like cells for rat sciatic nerve regeneration.

Objective. To investigate the effect of tissue engineering nerve on repair of rat sciatic nerve defect. Methods. Forty-five rats with defective sciatic nerve were randomly divided into three groups. Rats in group A were repaired by acellular nerve grafts only. Rats in group B were repaired by tissue engineering nerve. In group C, rats were repaired by autogenous nerve grafts. After six and twelve weeks, sciatic nerve functional index (SFI), neural electrophysiology (NEP), histological and transmission electron microscope observation, recovery ratio of wet weight of gastrocnemius muscle, regenerated myelinated nerve fibers number, nerve fiber diameter, and thickness of the myelin sheath were measured to assess the effect. Results. After six and twelve weeks, the recovery ratio of SFI and wet weight of gastrocnemius muscle, NEP, and the result of regenerated myelinated nerve fibers in groups B and C were superior to that of group A (P < 0.05), and the difference between groups B and C was not statistically significant (P > 0.05). Conclusion. The tissue engineering nerve composed of acellular allogenic nerve scaffold and Schwann cells-like cells can effectively repair the nerve defect in rats and its effect was similar to that of the autogenous nerve grafts.

Treatment of cancer cachexia in mice by combination of dsRNA-dependent protein kinase inhibitor and medroxyprogesterone acetate

Inhibitor of dsRNA-dependent protein kinase (PKRI) and medroxyprogesterone acetate (MPA) improve cancer cachexia via different mechanisms. We aimed to compare these two drugs, alone or in combination, in cancer cachexia in mice. Forty male BABL/c mice aged 6-8 weeks were randomly divided into PKRI, MPA, PKRI+MPA, placebo, and healthy control groups. The first 4 groups were injected with colon-26 adenocarcinoma and fed for 12 days and then treated with PKRI and MPA alone or in combination for 7 days. Body weight, tumor volume, wet weight of gastrocnemius muscle, serum levels of nutritional markers and cytokines were measured. The tumor growth (volume and weight) of mice treated with PKRI, MPA alone or PKRI+MPA was slower than that of placebo group. Wet weight of gastrocnemius muscle was significantly higher in PKRI and PKRI+MPA-treated than in placebo animals (P<0.01). All tumor-bearing mice had a significantly lower level of blood glucose, higher level of serum triglyceride and lower level of serum albumin compared with healthy control (P<0.001). However, PKRI, MPA and PKRI+MPA groups had a significant higher level of blood glucose and lower level of serum triglyceride compared with placebo group (P<0.001). All tumor bearing mice had a significant higher level of serum TNF-α, IL-1 and IL-6 compared with healthy control (P<0.001). Serum level of TNF-α and IL-6 was significantly lower in PKRI and PKRI+MPA-treated than in placebo animals (P<0.01). PKRI alone and combination therapy with PKRI and MPA reduce tumor growth and may alleviate cachexia.

Costimulation blockade in transplantation of nerve allografts: long‐term effects

Costimulation blockade can prevent rejection of nerve allografts in short-term studies. We tested if costimulation blockade also prevented rejection of nerve allografts in long-term experiments, thereby improving functional recovery. A 7-mm sciatic nerve defect in C57/BL6 mice was bridged either by nerve allografts from Balb/C mice or by isogenic nerve grafts (isografts) from C57/BL6 mice. Costimulation blockade in the form of a triple treatment with anti-LFA-1, anti-CD40L, and CTLA4Ig was given at post-operative days 0, 2, 4, and 6 (intraperitoneal). Control mice (placebo; allografts) with nerve grafts were treated with isotype antibodies during the same time period. After 49 days, tetanic muscle force, wet weight of gastrocnemius muscle, histology, and morphometry in the tibial nerve were evaluated. Costimulation blockade diminished rejection of the nerve allografts. Axons bridged the graft. Treatment increased wet weight of the gastrocnemius muscle and resulted in a higher mean myelin area/nerve fiber in the tibial nerve distal to the nerve grafts. Tetanic muscle force and number of axons in tibial nerve showed no differences between groups. We conclude that rejection is suppressed by costimulation blockade. Treatment improves recovery of target muscle and myelination after nerve allografting.