تاثير تمرين مقاومتي بر قدرت عضلاني، هايپرتروفي و سطوح پروتئين ميوژنين عضلات دوقلو در موش هاي صحرايي سالمند

The effects of resistance training on muscle strength, hypertrophy and myogenin protein level of gastrocnemius in elderly rats

زمينه و هدف: تمرين مقاومتي (RT) يكي از موثرترين استراتژي‌ها براي پيشگيري از تضعيف و تخريب عضلاني ناشي از سن است؛ زيرا قدرت و عملكرد عضلاني را بهبود مي بخشد. از آنجايي كه كاهش توده عضلاني در ايجاد ساركوپني مشاركت دارد، اثر تمرين مقاومتي بر هايپرتروفي عضلاني و فرآيندهاي ميوژنيك آن در سالمندي مهم و بحث‌برانگيز است. هدف از اين تحقيق بررسي اثر تمرين مقاومتي بر قدرت، توده عضلاني و سطوح پروتئين ميوژنين در عضلات دوقلوي موش‌هاي سالمند بود. روش تحقيق: 16 سر موش صحرايي نر سالمند (24 ماهه) به طور مساوي به دو گروه تمرين مقاومتي و كنترل تقسيم شدند. گروه تمرين مقاومتي تحت هشت هفته تمرين مقاومتي پيشرونده (3 جلسه در هفته) بالا رفتن از نردبان با وزنه بسته‌شده به دم قرار گرفت. 48 ساعت پس از آخرين جلسه، نيروي ايزومتريك، وزن عضله و سطوح پروتئين ميوژنين عضله دو قلو هر دو گروه اندازه‌گيري شد. براي تجزيه و تحليل از آزمون t مستقل در سطح معني­ داري 0/05

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.