Effects Of Different Forms Of Exercise On IGF-I,MGF,MyoD And Myogenin MRNA In Skeletal Muscle Of SAMP8 Mice

In skeletal muscle aging, the most obvious symptoms are muscle attenuation (Sarcopenia), which is based on muscle mass, volume, and decreased muscle strength for the main features of a frequently-occurring disease symptoms in the elderly . The aging process in skeletal muscle, IGF-I may promote muscle cell proliferation and differentiation,and has a positive effect on skeletal muscle regeneration. IGF-I also can be induced by myogenin (myogenin) gene expression in muscle cells to stimulate the end of terminal differentiation, while high expression of MGF can promote regeneration and repair of skeletal muscle,and may be related to the activation or proliferation of Myod. Myod family can activate muscle cells to enhance differentiation and proliferation of muscle cells.Exercise as an important component of a healthy lifestyle, studies have proved resistance exercise will significantly increase the muscle mass and strength , to some extent it can delay the occurrence of skeletal muscle aging. Different forms of exercise effect on the skeletal muscle ageing is different. Because different sports impact on the express level of IGF-I, MGF and myogenic regulatory factor in the skeletal muscle, therefore different forms of exercise effect on skeletal muscle regeneration is differences .In this study, 30 subjects for SAMP8 mice were randomly divided into groups-youth resistance exercise (T), Units of youth running endurance exercise group (T), young control group (T). SAMP8 mice are the rapid aging model in this experiment. After 8 weeks of resistance exercise and endurance exercise, experiment through the semi-quantitative RT-PCR was observed the expression changes level in IGF-I mRNA, MGF mRNA , MyoD mRNA and myogenin mRNA of skeletal muscle .So we can explain the mechanism of skeletal muscle hypertrophy after exerciae.Results: SAMP8 mice after two months of endurance exercise and climbing with load exercise, the results showed that:(1) The gastrocnemius of endurance exercise group and climbing with load group on IGF-I. MGF, MyoD and myogenin mRNA expression levels compared with the control group arc significantly up-regulation (respectively P <0.05. P <0.01). (2) The gastrocnemius of climbing with load group on MGFmRNA expression compared with endurance exercise group is very notable increase (P <0.01); and IGF-I, MyoD and myogenin mRNA expression did not find significant differences (P> 0.05), but climbing with load group there is an increasing trend.(3) The gastrocnemius muscle fiber cross-sectional area of climbing with load group is significantly higher than the endurance exercise group and the control groupand(P <0.05); and there is no significant changes endurance exercise group compared with the control group(P> 0.05).Conclusion: (1) After 8 weeks of endurance exercise and climbing with load exercise, climbing with load exercise could promote the very notable expression of the gastrocnemius on IGF-ImRNA,MGFmRNA,MyodRNAå’ŒmyogeninmRNA, which indicates that climbing with load exercise is more effectively promote its expression, may have an important effect on regeneration. of the skeletal muscle.(2) After 8 weeks of endurance exercise and climbing with load exercise, climbing with load group is high expression of MGF mRNA, there is a very significant difference compared with endurance exercise, suggesting that MGF may occur in the skeletal muscle hypertrophy plays an important role.(3) After 8 weeks of endurance exercise and climbing with load exercise, climbing with load exercise nduce gastrocnemius muscle fiber hypertrophy, suggesting that climbing with load exercise has a more active role on preventing and postponing the occurrence of Sarcopenia.