The Study On The Effect And Expression Of MGF Gene In Skeletal Muscle Of Aging Rat By Weight Treadmill Training

The aging of the word's population has become prominent social problems in many countries. In the face of the rapidly growing elderly population, how to extend the life of the elderly and improve the quality of the elderly have been great concern by the governments and the community. The prevention of aging and anti-aging has become hotspot research in gerontology. Recent studies have found that there have been important links between the decline of life quality and decline of muscle strength of the elderly. The decay of muscle function accelerate the aging process of human body, so it is very important of slowing down skeletal muscle aging and restoring skeletal muscle to improve the health and life quality of the elderly.Many researches have confirmed that exercise is methods of anti-aging, but the researchers actively explored how to prevent and delay the decrease of skeletal muscle mass and strength decline which were caused by the aging. The most research are about aerobic and short term strength training, the patterns of long resistance and weight training which are effective to the skeletal muscle are lack, especially be short of researches in mechanism and comprehensive index of exercise interference skeletal muscle aging, and the effect also need to be further research.In the study, measuring and comparing gastrocnemius muscle weight, relative weight, muscle total protein, muscle glycogen, creatine kinase, muscle histopathology and electron microscopy, mechanical growth factor, actin, myosin heavy chain mRNA, we discuss the age-related changes of rat skeletal muscle and effect of weight training on young and aged rats, reveal further the mechanism of appropriate weight training in the prevention and delay skeletal muscle aging, to provide experimental evidence and theoretical reference to guide the science fitness and improve health and quality life.Experiment was divided into three parts.1. Experiment of age-related changes and MGF gene expression of rat skeletal musclesix 5 month (Q), six 17 month (Z), six 30 month (L) male Wistar rats were taken full gastrocnemius to compare the weight and relative weight, skeletal muscle biopsy, electron microscopy, molecular biology index of three groups, in order to explore the characteristics of age-related changes and MGF gene expression of rat skeletal muscle.2. Experiment of the effect of weighting training and MGF gene expression on young rat skeletal muscleFifty-six 3 month male Wistar rats were randomly divided into 7 groups: sedentary control group (QD), small load short time group (XD), small load long time group (XC), middle load short time group (ZD), middle load long time group (ZC), big load short time group (DD), and big load long time group (DC). Except sedentary control group, other groups had done weight treadmill training. After 8 weeks, all rats were killed, indicators were the same with experimental 1, and we discussed the effect of weight training on young rat skeletal muscle and MGF gene expression changes.3. Experiment of the effect of weighting training and MGF gene expression on young rat skeletal muscleFifty-six 15 month male Wistar rats were randomly divided into 7 groups: sedentary control group (LD), small load short time group (LXD), small load long time group (LXC), middle load short time group (LZD), middle load long time group (LZC), big load short time group (LDD), and big load long time group (LDC). Except sedentary control group, other groups had done weight treadmill training. After 8 weeks, all rats were killed, indicators were the same with experimental 1, and we discussed the effect of weight training on old rat skeletal muscle and MGF gene expression changes.Results1. Gastrocnemius muscle weight and the relative weight: compared with group Q, rat gastrocnemius muscle weight and the relative weight in group L and group Z were significantly higher(P<0.01); Compared with group Z, group L were significantly lower(P<0.01). Weight treadmill training increased gastrocnemius muscle weight and the relative weight in all young groups rats and old groups rats. Results indicated that skeletal muscle mass decreased with age, and weight treadmill training can alleviate the trend.2. Skeletal muscle biochemical indicators: compared with group Q, skeletal muscle protein, muscle glycogen, creatine kinase level significantly decreased in group L and group Z (P<0.01, P<0.05). Weight treadmill training could increase skeletal muscle protein, muscle glycogen, creatine kinase level of all young and old groups , group DC and group ZC had more obvious appearance in young rats (P<0.05), group LZC had more obvious appearance in old rats (P<0.05). Result indicated that skeletal muscle protein, muscle glycogen, creatine kinase level decreased with age, and weight treadmill training could alleviate the trend.3. Skeletal muscle biopsy: rats in group Q were normal skeletal muscle characteristics through light microscope, and group L and group Z appeared different degree of muscle cell atrophy or degenerative changes characteristics, especially the rats in group L. Weight training changed the skeletal muscle histology characteristics of young rats and old rats. Result indicated that weight training changed skeletal muscle cell morphology and slowed down skeletal muscle aging.4. Skeletal muscle electron microscopy: rats in group Q were normal skeletal muscle ultrastructure through electron miscroscopy, and group L and group Z appeared different degree of abnormal arrangement myofibrils and organelles degenerative changes characteristic, especially the rats in group L. Weight training changed the skeletal muscle ultrastructure of young rats and old rats. Result indicated that weight training changed skeletal muscle ultrastructure and slowed down skeletal muscle aging.5. Skeletal muscle molecular biological markers: compared with group Q, skeletal muscle MGF mRNA,α-actin mRNA,MHCⅡa mRNA,MHCⅡx mRNA expression in group L and group Z were lower (P<0.01), MHCⅠmRNA expression did not change, and MHCⅡb mRNA expression was higher (P<0.01). Weight training could increase MGF mRNA,α-actin mRNA,MHCⅠmRNA,MHCⅡa mRNA,MHCⅡx mRNA expression of young rats and old rats, group DC and group ZC had more obvious appearance in young rats (P<0.01), and group LZC had more obvious appearance in old rats (P<0.01). It could decrease MHCⅡb mRNA expression (P<0.01), group DC and group ZC had more obvious appearance in young rats (P<0.01), and group LZC had more obvious appearance in old rats (P<0.01). Result indicated that skeletal muscle MGF mRNA expression decreased with aging, but weight training increased skeletal MGF mRNA expression, and changeα-actin, various types MGF mRNA expression. Conclusion1. Rats skeletal muscle biochemical indicators, microscopic structure, and molecular indicators showed degression trend, MGF mRNA expression was significant low, anabolism reduced and function decreased with ageing.2. 8-week weight training could effective improve skeletal muscle biochemical indicators, pathological indicators and molecular biological indicators. The effect of different load and time on skeletal muscle was different, big load long time group had more appearance in young rats, and middle load long time group had more appearance in old rats.3. After different load and time weight training,α-actin,MHCⅠ,Ⅱa,Ⅱx andⅡb mRNA expression of old rat skeletal muscle were tested, we founded that aged skeletal muscle had obvious trainability, and proper intensity and time training could effectively improve skeletal muscle protein metabolism.4. Weight training improved structure and function of aging skeletal muscle, and delayed skeletal muscle aging. Its mechanism: MGF as a sensitive indicator was stimulated to express by appropriate force, which improved skeletal muscle metabolic level and athletic ability through some channels such as induced skeletal muscle hypertrophy.