The Study On The Effect And Mechanisms Of The Intervention In Skeletal Muscle Aging By Weight Training And Soy Polypeptide Supplement

With the increasing of the world aging country and the proportion of old people, many countries face with the new and projecting problem of aging population. The governments and societies focus on how to improve people's healthy life-span and life quality. The research in senescence and its correlated disease has been taking the worldwide medical subject invariably. At present, explore the essential of aging, search the effective antiaging agents and methods to prevent and postpone aging have become the hotspot study in the area of geriatric medicine. Recent years, the scientists pay more attention to the issue of decline of muscle function, because it can influence old people's health. It is close correlative between the muscle function and senescence.At present, most research about preventing and postponing aging focus on drugs. Although drugs have certain effect, their disadvantages of limitation and side effect are also obvious. Exercise is the basis of vital movement, and nutrition is the immediate guarantee of it. How to combine the exercise and nutrition together in an economic and safe way, make the organs and systems in a satisfactory condition, in order to confront the aging especially the muscle aging , it is worth to be studied thoroughly.There are some correlative reports of exercise interference in aging. Although, most research are about the influence of whole function, the parameteres are limited and lack of the study in certain organ and tissue ,especially be short of the research in mechanism and comprehensive parameter of exercise interference in aging. Also, the exercise styles are in aerobic and short term strength training mostly, the patterns in long term strength and weight training which are more effective to the skeletal muscle are less, the affect are indefinite either. There are many studies of nutrition interference in aging in and out doors, the relative nutritional supplements are also to come out one after the other. Though, there is no correlated reports about the mechanism and effect of the long term soy polypeptide supplement in skeletal muscle aging from the aspects of whole body, tissue and genes.The present research copys the rat subacute skeletal muscle aging model by the method of D-galactose hypodermic which is common in senescence study. And take the interference way in weight training and soy polypeptide supplement in and after the process of model making. The research aims to observe the general parameter, skeletal muscle tissue slice and biochemical parameter, in order to judge the prevention and postpone effect in skeletal muscle aging by the two interference ways. and to discuss the probable mechanisms by measuring serum & skeletal muscle superoxide dismutase (SOD) and malondealdehyde (MDA), serum testosterone(T), cortisol(C), growth hormone(GH) and insulin-like growth factor-1(IGF-I), skeletal muscle total protein level and lipofuscin, skeletal muscleα-actin,IGF-I and growth and differential factor-8(GDF-8) mRNA. With the purpose of accumulating the theory and experiment foundation in further human test, opening a new thinking and way to be against skeletal muscle aging in middle-old aged people by providing more direct exercise way and developing effective nutritional supplement. At the same time, it can provide some help of middle-old aged people in the direction of scientific body building, the reasonable recovery from chronic disease and the elevation of health level and quality of life.The experiment is consisted of two parts, prevention aging part and delaying senility part.Part I Prevention aging experimentFifty-six three month male Sprague-Dawley (SD) rats were randomly assigned into seven groups: adult group (C), D-galactose group (M), D-galactose small load exercise group(S), D-galactose big load exercise group (B), D-galactose peptide group (P), D-galactose peptide and small load exercise group(PS), D-galactose peptide and big load exercise group (PB). All the rats were taken the interference way in weight training and soy polypeptide supplement in the process of 6w D-galactose hypodermic. By the end of 6th week, all rats were killed and serum and skeletal muscle parameters were evaluated.1. General parameter: All the model rats showed up the aging appearances, the body weight were in normal increase trend, di-gastrocnemius &relative weight were in the decrease trend ,and all the rats in interference group could slow down the above trend; All the rats quotidie ingestion were in the decrease trend, the model groups were in obvious way. Results indicate that two interference way can improve the aging appearances effectively. 2. Skeletal muscle tissue slice: Under light microscope, the rats in group C were in normal skeletal muscle histologic characteristics, All the model rats showeg up muscle cell atrophy or regressive changes in a different level, especially the rats in group M. Results indicate that two interference way can prevent the premature appearance in skeletal muscle aging.3. Serum parameter: Compare with group C, the serum SOD, SOD/MDA, T, T/C and GH in group M were lower, MDA and C were higher.(significant or very significant difference, P<0.05 or P<0.01), but serum IGF-I was in decrease trend and had no statistic difference; Weight training or soy polypeptide supplement could reverse the trend, the groups of small load all had more obvious appearance, and they had notable interaction. Results indicate that two interference way can alleviate organism lipid peroxidation and hormone abnormality due to D-galactose.4. Skeletal muscle biochemical parameter: Compare with group C, the skeletal muscle SOD, MDA and Lipofuscin in group M were higher (significant or very significant difference, P<0.05 or P<0.01), but SOD/MDA was in decrease trend and had no statistic difference (P>0.05), skeletal muscle total protein level was lower(significant difference, P<0.05); Weight training or soy polypeptide supplement could make skeletal muscle SOD in a further increase and reverse the rest trend, the groups of small load had more obvious appearance in majority, also they had notable interaction. Results indicate that two interference way can alleviate skeletal muscle lipid peroxidation and low myoprotein synthesis due to D-galactose.5. Skeletal muscle molecular biological parameter:Compare with group C, the skeletal muscleα-actin mRNA and IGF-I mRNA in group M were lower,but GDF-8 mRNA was higher(very significant difference, P< 0.01); Weight training or soy polypeptide supplement could reverse the trend, the groups of small load all had more obvious appearance, and they had notable interaction. Results indicate that two interference way can increase the low expression ofα-actin mRNA and IGF-I mRNA and decrease the high of GDF-8 mRNA due to D-galactose.Part II Delaying senility experimentSixty three month male SD rats were randomly assigned into eight groups: 6w control group (C6), 6w model group (M6), 12w model group (M12), small load exercise group(S12), big load exercise group (B12), peptide group (P12), peptide and big load exercise group (PB12),peptide and small load exercise group(PS12)), eight fourteen month male SD rats were taken the natural aging group(OC). Besides the group C6, M6, M12 and OC, all the other rats were taken the interference way in weight training and soy polypeptide supplement after 6w D-galactose hypodermic. By the end of 6th week and 12th week, the corresponding rats were killed and serum and skeletal muscle parameters are evaluated.1.Comparison between group C6 and M6: Compare with group C6, the di-gastrocnemius &relative weight in group M6 were in the decrease trend, though they had no statistic difference; the serum SOD in group M6 was lower (significant difference, P<0.05), serum MDA and skeletal muscle lipofuscin were higher (very significant difference P<0.01), All the skeletal muscle tissue slices showed up muscle cell atrophy or regressive changes in a different level. These results indicate that the skeletal muscle aging model is successful.2. General parameter of 12 week: All the model rats and group OC showed up the aging appearances, the rats in interference group could slow down the above trend; The body weight in all groups were in normal increase trend, the rats in interference group could slow down it obviously(significant difference, P<0.05),and two interference way had notable interaction; two interference way could make di-gastrocnemius &relative weight in the decrease trend(significant or very significant difference, P<0.05 or P<0.01), and maked it relative weight in a decrease trend; All the rats quotidie ingestion were in the increase trend, two interference way could make it in a reverse way, but had no notable interaction .Results indicate that two interference way can improve the aging appearances effectively after the process of model.3. Skeletal muscle tissue slice of 12 week: Under light microscope, All the model rats showed up muscle cell atrophy or regressive changes in a different level, especially the rats in group M12 and OC. Results indicate that two interference way can postpone the course in skeletal muscle aging after the process of model.4.Serum parameter of 12 week: Compare with group OC, the serum SOD, MDA, SOD/MDA, T, C, T/C, GH and IGF-I in group M12 had no statistic difference. Weight training or soy polypeptide supplement could increase the content of serum SOD, SOD/MDA, T, T/C, GH and IGF-I, decreased the content of serum MDA and C, the groups of small load had more obvious appearance in majority, and they had notable interaction. (significant or very significant difference, P<0.05 or P<0.01).Results indicate that two interference way can alleviate organism lipid peroxidation and hormone abnormality after the process of model.5. Skeletal muscle biochemical parameter of 12 week: Compare with group OC, the skeletal muscle SOD, MDA, SOD/MDA, total protein level and lipofuscin in group M12 had no statistic difference. Weight training or soy polypeptide supplement could increase the content of skeletal muscle SOD, SOD/MDA and total protein level, decreased the content of skeletal muscle MDA and lipofuscin, the groups of small load had more obvious appearance in majority, and they had notable interaction. (significant or very significant difference, P<0.05 or P<0.01). Results indicate that two interference way can alleviate skeletal muscle lipid peroxidation and low myoprotein synthesis after the process of model.6. Skeletal muscle molecular biological parameter of 12 week:Compare with group OC, the skeletal muscleα-actin mRNA and IGF-I mRNA in group M12 had no statistic difference. Weight training or soy polypeptide supplement could increase the expression ofα-actin mRNA and IGF-I mRNA, decreased the expression of GDF-8 mRNA, the groups of small load all had more obvious appearance, and they had notable interaction. Results indicate that two interference way can increase the low expression ofα-actin mRNA and IGF-I mRNA , decrease the high of GDF-8 mRNA after the process of model.Conclusions1. Rat skeletal muscle aging model can be copied successfully by 6 week D-galactose hypodermic and the probable pathogenesy are as follows:①increase the blood free radical;②increase skeletal muscle oxidative stress and lipid peroxidation;③increase the deposition of lipofuscin in skeletal muscle;④promote the metabolic disorder of hormone and correlation factors;⑤decrease the expression of skeletal muscleα-actin mRNA and IGF-I mRNA, increase the expression of skeletal muscle GDF-8 mRNA.2. Weight training or soy polypeptide supplement can prevent the premature appearance in skeletal muscle aging resulted from 6 week D-galactose model effectively, the exercise of small load has the best result, and the two interference way united can have more obvious effect.3. 6 week weight training or soy polypeptide supplement can have an active postpone effect of skeletal muscle aging after the 6 week D-galactose model, the exercise of small load has the best result, and the two interference way united can have more obvious effect.4. The mechanisms of preventive and postponed effect of weight training and soy polypeptide supplement in skeletal muscle aging are probably as follows:①decrease the blood free radical;②decrease skeletal muscle oxidative stress and lipid peroxidation;③decrease the deposition of lipofuscin in skeletal muscle;④correct the metabolic disorder of hormone and correlation factors;⑤i ncrease the expression of skeletal muscleα-actin mRNA and IGF-I mRNA, decrease the expression of skeletal muscle GDF-8 mRNA.