Effects Of Resistance Training On Bone Metabolism And Bone Histomorphometry In Aged Rats

With the increasing of aging population in the world, the problems concerning with aged society become an obvious contravention in many countries. The governments focus on people's healthy life-span and life quality. Meanwhile, the senescence is also a new field for scientists. Recent years, the scientists pay more attention to the issue of decline. Exercise is one of the important methods of improving bone metabolism, enhancing bone density and preventing osteoporosis, and taking different sports in different ages will make different effects in bone organ, tissue and cell. The present study observed the effect of different intensity resistance training on the bone metabolism and bone modality structural of aged rats. The purpose is to prove the theory that resistance exercise can promote bone density and reduce the loss of the bone mass. At the same time, as a means of exercise to prevent osteoporosis and provide a theoretical basis.Thirty-two Sprague-Dawley rats, 14 months of age, eight Sprague-Dawley rats, 3 months of age, were assigned to 5 groups: quiet youth group, quiet aging group, aging non-weight-bearing exercise group, the aging group of small weight-bearing exercise, aging large weight-bearing exercise group. The mode of motion is resistance training (weight-bearing exercise) (load for the aged rats respectively is the largest load of 0%, 30%, 70%), 6 days/weeks, last 8 weeks. After 8 weeks, test the tibial weight of all the rats, ALP, StrACP, Ca, P, and organizational structure parameters(including trabecular bone area, trabecular bone thickness, trabecular bone number and tabecular bone separation).The results: (l)From the comparing of the aging male rats and young male rats, we can see that tibial Tb.Ar%, Tb.N and serum ALP are lower than young, but Tb.Sp is significantly higher(p<0.01), in addition serum Ca, P, StrACP have not changed any more(p>0.05). (2) Small weight-bearing exercise can significantly improve the serum ALP, tibial Tb.Ar%, Tb.N of aging male rats when compared with quiet aging group(p<0.05), and lower serum Ca, P, StrACP and tibia Tb.Sp(p<0.05). (3) Large weight-bearing exercise will increase serum Ca, P, StrACP and tibial Tb.Sp when compared with the aging group of small weight-bearing exercise(p<0.05), and lower serum ALP, tibial Tb.Ar%, Tb.N(p<0.01).The result of this study showed that appropriate weight-bearing exercise can significantly increase serum alkaline phosphatase, the percentage of tibial trabecular bone, trabecular number, trabecular thickness of the aging male rats, and reduce the rate of the bone loss and the reduction of the bone metabolism associated with aging. Moreover, the appropriate weight-bearing exercise with a small load is more useful on improving the level of bone metabolism and bone structure of the aging male rats. These results suggest that weight-bearing exercise is a suitable fitness activity for elderly men, and suitable weight-bearing exercise can prevent senile osteoporosis.