scholarly journals PO-306 The effect of four weeks hypoxic resistance training on myostatin and follistatin expression in skeletal muscle of rats

2018 ◽  
Vol 1 (5) ◽  
Author(s):  
Xuecheng Bai Bai ◽  
Yang Hu ◽  
Yanchun Li
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Mrna Expression ◽  
Muscle Atrophy ◽  
Biceps Brachii ◽  
Skeletal Muscle Atrophy ◽  
Significant Difference ◽  
Wet Weight ◽  
Hypoxic Resistance

Objective Loss of skeletal muscle weight is a common phenomenon in hypoxic environment. It has been recognized that resistance training can reduce hypoxia-induced skeletal muscle atrophy, but its molecular mechanism is still unclear. Myostatin is a major factor that inhibits muscle growth and differentiation, and Follistatin can inhibit Myostatin. Therefore, this study is to clarify the effect of 4-week hypoxic resistance exercise on Myostatin and Follistatin gene expression in skeletal muscle of rats. Methods Twenty four 8-week-old male SD rats were randomly divided into normoxic control group (group C: 6 rats), normoxic exercise group (group R: 6 rats), hypoxic control group (group H: 6 rats) and hypoxic exercise group (group HR: 6 rats). Rats in each hypoxic group were fed in a hypoxic chamber (atmospheric hypoxia) with oxygen concentration of 12.7% (simulated 4000m altitude). Rats in each exercise group were trained according to the rat's resistance training program developed in our laboratory. After all the intervention, DEXA was used to analyze the body composition. The soleus, extensor digitorum longus and biceps brachii muscles of rats were taken and the wet weight of individual muscles was measured. The data were processed by SPSS17.0 statistical software. The expression level of skeletal muscle mRNA was expressed as "median (25-75%)" and the data of body composition and muscle wet weight were expressed as"mean±standard deviation". The differences between the groups were evaluated using a one-way analysis of variance (ANOVA) test. The significance level for the study was less than 0.05. Results Body composition analysis after 4 weeks of hypoxic intervention showed that the body weight of rats in group H decreased significantly (p=0.012), and the muscle mass decreased more significantly (p<0.001). But resistance exercises obviously reduced the muscle atrophy (p<0.01) caused by hypoxia. After analyzing the changes of the wet weight of individual muscles, it was found that the wet weight of biceps brachii in HR group was significantly higher than that in H group (p=0.048). After 4 weeks of hypoxic intervention and hypoxic resistance exercise, the expression of Myostatin mRNA in individual muscles of each group changed differently. The expression of Myostatin mRNA in soleus muscle of H group was significantly higher than that of C group (371.2%) after 4 weeks of hypoxia intervention. Myostatin mRNA expression in soleus and biceps brachii of HR group was significantly lower than that of H group (591.1% and 478.4% respectively). However, there was no significant difference in the expression level of Myostatin mRNA in the extensor digitorum longus between each group (p=0.259). The change of Follistatin mRNA expression in different groups also showed a different trend. The expression of Follistatin mRNA in soleus muscle and biceps brachii muscle was significantly different among groups (p=0.003, p=0.004, respectively). However, there was no significant difference in the expression level of Follistatin mRNA in the extensor digitorum longus between each group (p=0.734). Myostatin mRNA/Follistatin mRNA ratio (M/F) showed a more significant difference. The M/F ratio of soleus muscle in group H was significantly lower than that in group C (p<0.001), but the M/F ratio in group HR was significantly higher than that in group H (p<0.001). The M/F ratio of biceps brachii in group H was significantly lower than that in group C (p<0.001), but the M/F ratio in group HR showed a higher trend than that in group H (p=0.051). Conclusions Hypoxic exposure results in an increase in Myostatin mRNA expression in skeletal muscle, but hypoxic resistance exercise reduces such an increase. On the contrary, the level of Follistatin mRNA expression in skeletal muscle decreased after hypoxic exposure, and hypoxic resistance exercise could slow down the decline. As a result, rat resistance exercise significantly slowed down hypoxia-induced muscle atrophy. In conclusion, the mutual restriction between Myostatin and Follistatin is one of the main links of resistance exercise to reduce hypoxia-induced skeletal muscle atrophy. However, the process of resistance training to reduce the hypoxia-induced skeletal muscle atrophy is very complex. There are many molecular signaling pathways involved, which need further study.

scholarly journals PO-109 Resistance Training prevents Skeletal Muscle Atrophy Induced by hypoxia through regulating Akt-FoxO1 pathway

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Jiabei Yu ◽  
Hang Yu ◽  
Yanchun Li ◽  
Tianyu Han ◽  
Xuecheng Bai ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Muscle Atrophy ◽  
Biceps Brachii ◽  
Training Group ◽  
Skeletal Muscle Atrophy ◽  
Control Group ◽  
Immunofluorescence Technique ◽  
Hypoxia Group ◽  
Wet Weight

Objective Skeletal muscle atrophy induced by hypoxia on the plateau will lead to the decrease of muscle strength and the degeneration of athletic ability. Resistance training is an efficient method to stimulate the growth of muscle and improve protein synthesis. Akt-FoxO1 (Fork head box protein 1) pathway plays a significant role in the regulation of skeletal muscle protein degradation. However, it is not clear whether resistance training could prevent skeletal muscle atrophy induced by hypoxia and what is the regulation role of Akt-FoxO1 pathway. This study built a rat model that resistance training inhibited the skeletal muscle atrophy induced by hypoxia and explore the variation of Akt, FoxO1, Murf and Atrogin-1. Methods 40 male 8-week-old Sprague-Dawley (SD) rats were divided into 4 groups randomly: control group (C), resistance training group (R), hypoxia group (H) and hypoxia resistance training group (HR). H and HR group were placed into simulated 4000m altitude (12.4%, O2%) and R and HR group received ladder resistance training. Their incremental load is calculated by using average body weight. After 4 weeks intervention of hypoxia and resistance training, body composition, wet weight of skeletal muscle (soleus, musculus gastrocnemius,extensor digitorum longus and muscelus biceps brachii) and skeletal muscle cross-sectional area (CSA) were measured. The expression of Akt, FoxO1, Murf and Atrogin-1 were detected by Western blot and RT-PCR.Moreover,immunofluorescence technique was used to locate the phosphorylation of FoxO1.  Results The lean body mass of HR group was significantly higher than H group (P<0.05). The wet weight and CSA of muscelus biceps brachii in HR group were also higher than H group obviously (P<0.05). The results of real-time fluorescence quantitative PCR and western blot showed that the expression of FoxO1 and MuRF of hypoxia group (H group) were significantly higher than control group. However after the intervention of resistance training, the expression of Akt was significantly up-regulate and FoxO1, MuRF were significantly down-regulate. Immunofluorescence technique was used to observe the location of FoxO1 phosphorylation and the expression out of nucleus. Conclusions Resistance training contribute to prevent the occurrence of skeletal muscle atrophy induced by hypoxia and the form of climbing ladder training can stimulate the hypertrophy of biceps in rats. The results revealed that FoxO1 phosphorylation out of nucleus became higher after resistance training. All above revealed that resistance training could inhibit skeletal muscle atrophy induced by hypoxia. Akt promoted FoxO1 phosphorylation may become the molecular mechanisms that resistance training can inhibit the atrophy of skeletal muscle induced by hypoxia.

Aerobic exercise and resistance exercise alleviate skeletal muscle atrophy through IGF-1/IGF-1R-PI3K/Akt pathway in mice with myocardial infarction

2021 ◽  
Author(s):  
Feng Li-Li ◽  
Li Bo-Wen ◽  
Xi Yue ◽  
Tian Zhen-Jun ◽  
Cai Meng-Xin
Keyword(s):  
Myocardial Infarction ◽  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Muscle Atrophy ◽  
Cell Apoptosis ◽  
Exercise Group ◽  
Skeletal Muscle Atrophy ◽  
Akt Pathway

Objectives: Myocardial infarction (MI)-induced heart failure (HF) is commonly accompanied with profound effects on skeletal muscle. With the process of MI-induced HF, perturbations in skeletal muscle contribute to muscle atrophy. Exercise is viewed as a feasible strategy to prevent muscle atrophy. The aims of this study were to investigate whether exercise could alleviate MI-induced skeletal muscle atrophy via insulin-like growth factor 1 (IGF-1) pathway in mice. Materials and Methods: Male C57/BL6 mice were used to establish the MI model and divided into three groups: sedentary MI group, MI with aerobic exercise group and MI with resistance exercise group, sham-operated group was used as control. Exercise-trained animals were subjected to four-weeks of aerobic exercise (AE) or resistance exercise (RE). Cardiac function, muscle weight, myofiber size, levels of IGF-1 signaling and proteins related to myogenesis, protein synthesis and degradation and cell apoptosis in gastrocnemius muscle were detected. And H2O2-treated C2C12 cells were intervened with recombinant human IGF-1, IGF-1R inhibitor NVP-AEW541 and PI3K inhibitor LY294002 to explore the mechanism. Results：Exercises up-regulated the IGF-1/IGF-1R-phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling, increased the expressions of Pax7, myogenic regulatory factors (MRFs) and protein synthesis, reduced protein degradation and cell apoptosis in MI-mice. In vitro, IGF-1 up-regulated the levels of Pax7 and MRFs, mTOR and P70S6K, reduced MuRF1, MAFbx and inhibited cell apoptosis via IGF-1R-PI3K/Akt pathway. Conclusion: AE and RE, safely and effectively, alleviate skeletal muscle atrophy by regulating the levels of myogenesis, protein degradation and cells apoptosis in mice with MI via activating IGF-1/IGF-1R-PI3K/Akt pathway.

Resistance exercise and growth hormone as countermeasures for skeletal muscle atrophy in hindlimb-suspended rats

1994 ◽  
Vol 267 (2) ◽  
pp. R365-R371 ◽  
Author(s):  
J. K. Linderman ◽  
K. L. Gosselink ◽  
F. W. Booth ◽  
V. R. Mukku ◽  
R. E. Grindeland
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Resistance Exercise ◽  
Protein Content ◽  
Muscle Atrophy ◽  
Myofibrillar Protein ◽  
Hindlimb Suspension ◽  
Skeletal Muscle Atrophy ◽  
Plantar Flexor ◽  
Fast Twitch

Unweighting of rat hindlimb muscles results in skeletal muscle atrophy, decreased protein synthesis, and reduced growth hormone (GH) secretion. Resistance exercise (ladder climbing) and GH treatment partially attenuate skeletal muscle atrophy in hypophysectomized hindlimb-suspended rats. It was hypothesized that a combination of multiple bouts of daily resistance exercise and GH (1 mg.kg-1.day-1) would prevent skeletal muscle atrophy in growing nonhypophysectomized hindlimb-suspended rats. Hindlimb suspension decreased the absolute (mg/pair) and relative (mg/100 g body wt) weights of the soleus, a slow-twitch plantar flexor, by 30 and 21%, respectively, and the absolute and relative weights of the gastrocnemius, a predominantly fast-twitch plantar flexor, by 20 and 11%, respectively (P < 0.05). Exercise did not increase soleus mass but attenuated loss of relative wet weight in the gastrocnemius muscles of hindlimb-suspended rats (P < 0.05). Hindlimb suspension decreased gastrocnemius myofibrillar protein content and synthesis (mg/day) by 26 and 64%, respectively (P < 0.05). The combination of exercise and GH attenuated loss of gastrocnemius myofibrillar protein content and synthesis by 70 and 23%, respectively (P < 0.05). Results of the present investigation indicate that a combination of GH and resistance exercise attenuates atrophy of unweighted fast-twitch skeletal muscles.

AMP-activated protein kinase agonists increase mRNA content of the muscle-specific ubiquitin ligases MAFbx and MuRF1 in C2C12 cells

2007 ◽  
Vol 292 (6) ◽  
pp. E1555-E1567 ◽  
Author(s):  
Brian J. Krawiec ◽  
Gerald J. Nystrom ◽  
Robert A. Frost ◽  
Leonard S. Jefferson ◽  
Charles H. Lang
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Mrna Expression ◽  
Muscle Atrophy ◽  
Ubiquitin Ligases ◽  
C2c12 Cells ◽  
Skeletal Muscle Atrophy ◽  
Compound C ◽  
Mrna Content ◽  
Amp Activated Protein Kinase

The hypothesis of the present study was that exposure of differentiated muscle cells to agonists of the AMP-activated protein kinase (AMPK) would increase the mRNA content of the muscle-specific ubiquitin ligases muscle atrophy F-box (MAFbx) and muscle RING finger 1 (MuRF1). C2C12 cells were incubated with incremental doses of 5-aminoimidazol-4-carboximide ribonucleoside (AICAR) or metformin for 24 h. Both MAFbx and MuRF1 mRNA increased dose dependently in response to these AMPK activators. AICAR, metformin, and 2-deoxy-d-glucose produced time-dependent alterations in ubiquitin ligase expression, typified by a biphasic pattern of expression marked by an acute repression followed by a sustained induction. AMPK-activating treatments in conjunction with dexamethasone produced a pronounced synergistic effect on ligase mRNA expression at later time points. This cooperative response occurred in the absence of a dexamethasone-dependent increase in AMPK expression or activity, as determined by immunoblotting for phosphorylation and expression of AMPKα and its downstream target acetyl-CoA carboxylase (ACC). These responses elicited by AMPK activation singly or in combination with dexamethasone did not extend to the mRNA expression of the UBR box family E3s UBR1/E3αI and UBR2/E3αII. Treatment with the AMPK inhibitor compound C prevented increases in MAFbx and MuRF1 mRNA in response to serum deprivation, as well as AICAR and dexamethasone treatment individually or jointly. Stimulation of AMPK activity in vivo via AICAR injection increased both MAFbx and MuRF1 mRNA in murine skeletal muscle. These data suggest that activation of AMPK in skeletal muscle results in a specific upregulation of MAFbx and MuRF1, responses that are reminiscent of the proposed atrophic transcriptional program executed under various conditions of skeletal muscle wasting. Therefore, AMPK may be a critical component of the intercalated network of signaling pathways governing skeletal muscle atrophy, where its input acts to modify anti- and proatrophic signals to influence gene expression in reaction to catabolic perturbations.

scholarly journals mRNA Expression Signatures of Human Skeletal Muscle Atrophy Identify a Natural Compound that Increases Muscle Mass

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Steven D Kunkel ◽  
Manish Suneja ◽  
Scott M Ebert ◽  
Kale S Bongers ◽  
Daniel K Fox ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Natural Compound ◽  
Human Skeletal Muscle ◽  
Skeletal Muscle Atrophy

scholarly journals PO-094 p38 MAPK controls of E3-ligases expression and soleus atrophy attenuation in rat upon hindlimb unloading

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Tatiana Nemirovskaya ◽  
Svetlana Belova ◽  
Boris Shenkman ◽  
Ekaterina Mochalova
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
P38 Mapk ◽  
Muscle Atrophy ◽  
Mapk Signaling ◽  
Hindlimb Unloading ◽  
Hindlimb Suspension ◽  
Skeletal Muscle Atrophy ◽  
Control Group ◽  
E3 Ligases

Objective Unloading causes rapid skeletal muscle atrophy mainly due to the increased protein degradation. Muscle proteolysis results from the activation of ubiquitin-proteasome systems. The ubiquitination proteins are carried out by muscle-specific E3 ubiquitin ligases – MuRF-1 and MAFbx. It is known that MuRF-1 and MAFbx expression significantly increases on the third day of muscle unloading. We tested the hypothesis that p38 MAPK participates in the regulation of E3 ligases expression and the development of skeletal muscle atrophy during unloading. To check this idea we inhibited p38 MAPK by VX-745. Methods 21 male Wistar rats were divided into 3 groups (7 rats in each group): intact control (C), rats suspended for 3 days (HS) and rats suspended and injected i.p. with VX-745 (10 mg/kg/day) (VX). The hindlimb suspension was carried out according to Morey-Holton technique. The animals were anaesthetised with an i.p. injection of tribromoethanol (240 mg/kg). Under anesthesia, the m.soleus were excised, frozen in liquid nitrogen, and stored at -80°C until further analysis. All procedures with the animals were approved by the Biomedicine Ethics Committee of the Institute of Biomedical Problems of the Russian Academy of Sciences/Physiology section of the Russian Bioethics Committee. The statistical analysis was performed using the REST 2009 v.2.0.12 and Origin Pro programs at the significance level set at 0,05. The results are given as median in percent and interquartile range (0.25-0.75). Results The muscle weight in HS group was significantly reduced (72,3±2,5 mg) compared to C (83,0±3 mg), p<0.05, while the soleus weight of VX group didn’t differ from the control (84.2±5 mg). The MuRF1 mRNA expression was elevated dramatically in HS group (165 (138-210) %) when compared with the control (100 (64.6-112.5) %), p<0.05.  In the VX group the level of MuRF1 mRNA expression (127 (105-138) %) didn’t differ from the control group. The MAFbx mRNA expression was observed to increase equally in both suspended groups (294 (265-342) % and (271 (239-309) %).) vs C (100 (91-106) %) so, VX-745 administration did not have any significant effect on its expression. We also found that the level of ubiquitin mRNA expression in the soleus of HS rats was higher (423 (325-485) %) in comparison with the C group (100 (78-166) %, p<0.05) while VX-745 injection prevented increasing the  mRNA ubiquitin expression (200 (190-237) %). We discovered that the elevation of calpain-1 mRNA expression upon HS was prevented by VX-745 administration and its level didn’t differ from the control group (C - 100 (97-105) %, HS – 120 (116-133) %, VX - 107 (100-115) %, p<0.05). Conclusions Thus, the results indicate that the p38 MAPK signaling pathway takes part in the regulation of E3-ligase MuRF1 but not MAFbx expression. The p38 MAPK inhibition prevents muscle atrophy and the elevation of ubiquitin and calpain mRNA expression at the early stage of hindlimb unloading. This work was supported by RFBR grant No.17-04-01838.

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