Mohsen Mohammadi; Mohammad Reza Fadaei Chafy
Abstract
Background and Aim: Among the many variables that affect muscle growth are myokines and myostatin. This study looked at how resistance-aerobic training affected the expression of genes related to fibronectin type III domain-containing protein 5 (FNDC5), myostatin and hypertrophy or hyperplasia in the ...
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Background and Aim: Among the many variables that affect muscle growth are myokines and myostatin. This study looked at how resistance-aerobic training affected the expression of genes related to fibronectin type III domain-containing protein 5 (FNDC5), myostatin and hypertrophy or hyperplasia in the immature rats’ gastrocnemius muscle. Materials and Methods: A total of ten male Wistar rats, aged two weeks were randomly divided into two control (five rats) and training (five rats) groups. The resistance training program consisted of three sessions each week for six weeks, during which time the participants would carry a weight and climb a one-meter ladder 26 times. For six weeks, on alternate days, aerobic exercise consisted of jogging on a treadmill at an intensity between 25 and 50% of a rat’s maximum speed. All of the rats were dissected and their skeletal muscles isolated 48 hours after the previous training session and after fasting for 8 hours. FNDC5 and myostatin expression were measured using Real-Time PCR. Using light microscopy, hypertrophy and hyperplasia were quantified. Prism software was used to analyze the data using an independent t-test at the p≤0.05 level. Results: Following six weeks of training, the training group had higher gene expression of FNDC5 (p=0.04) and hypertrophy (p=0.004) than the control group, but decreased gene expression of myostatin (p=0.01) in comparison. Nonetheless, there was no statistically significant difference between the two groups gastrocnemius muscle hyperplasia (p=0.22). Conclusion: It appears that resistance-aerobic exercise accompanied by increased expression of FNDC5 genes and decreased myostatin gene expression increased fast twitch fiber hypertrophy. This approach shows that muscle tissue in animal samples before puberty is trainable, independent of natural growth.
Taher Afsharnezhad Roudsari; AliReza Amani
Abstract
Background and Aim: Resistance training (RT) is the most effective strategy to prevent age-related muscle wasting and weakness, because it promotes muscle strength and function. As the loss of muscle mass contributes to sarcopenia, the effects of RT on hypertrophy and its myogenic processes is controversial ...
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Background and Aim: Resistance training (RT) is the most effective strategy to prevent age-related muscle wasting and weakness, because it promotes muscle strength and function. As the loss of muscle mass contributes to sarcopenia, the effects of RT on hypertrophy and its myogenic processes is controversial in old age. The purpose of this study was to examine the effects of RT on strength, mass and protein level of myogenin in gastrocnemius muscle of elderly rats. Materials and Methods: Sixteen elderly male Sprague-Dawley rats (24-month age) divided equally to two groups (control and RT). RT group underwent 8weeks (3-days/week) of resistance training by climbing a wooden ladder with weights attached to their tails. 48h after last session, isometric force, muscle wet mass and protein level of myogenin of gastrocnemius muscle were measured in both groups. For statistical analysis, independent sample t-test was used with a significance level of 0.05. Results: Absolute and relative (to body mass) isometric force of RT group were significantly greater than those in control group. There was not any significant difference in wet muscle mass between groups. Western blot analysis of muscle tissue also showed that the levels of myogenin did not significantly differ between two groups. Conclusion: Force production capacity and muscle quality (force to muscle mass ratio) were increased following resistance training in elderly rats through events are likely caused by neuromuscular adaptations. Additionally, the results suggest that increase in strength after resistance training in aged rats cannot be explained in terms of the changing in muscle mass and myogenin expression values.
