The effects of varying load swimming on ossein in aged male mice

Introduction

The studies about the effects of aging and exercise on bone, until now, focus mainly on the bone mineral content, and they pay little attention to the bone organic substance. In fact, the bone organic substance is also very important. Ossein is the main component of the bone organic substance, and hydroxyproline is a specific component part of ossein. The purpose of this study is to investigate the effect of aging and varying load swimming exercise on ossein through the change of the content of hydroxyproline.

Methods

The effect of a 8-week swim training was studied in male mice. Forty Kunming strain of male mice at twelve months old (aged male mice) were randomly assigned to one of five groups: (TM).thirty-minute group; (SM).sixty-minute group; (SW).sixty-minute group loaded with 2.5% of body weight; (EC).experimental control; (SC).sedentary control. At the end of the training period all mice were sacrificed, the femur and thoracic vertebral bones were removed for the measurements of the content of hydroxyproline(HOP).

Results

(1) The content of HOP in thoracic vertebral bones was significantly lower (P<0.05) in the aged male mice than in the young male mice. However，there were no significant differences in the content of HOP in the femur. (2) The content of HOP in the femur was significantly higher (P<0.05) in the SM and the SW groups than in the EC and the SC groups. Moreover，the range of increase of bone mineral content index and the content of HOP was greater in the SW group than in the SM group(P<0.05). (3) The content of HOP in the femur was significantly higher (P<0.05) in the SW group than in the young male mice group. However, there were no significant differences in the TM and the SM groups.

Conclusion

The results of this study showed that : (1) the content of ossein in thoracic vertebral bones decreases significantly with age. (2) suitable load swimming exercises for the aged male mice could suppress age-associated ossein loss，and moreover，the preventive effect of swimming exercise on ossein loss becomes much greater with the augmentation of physical work. These results suggest suitable load swimming can prevent the ossein loss and osteoporosis.

References

[1]. Liu Zhonghou. (1998). Osteoporosis. Beijing, Science Publisher.
[2]. Ge Xuelin and Cai Guiying. (1999). Chin J . Osteoporo, 5(2):85-88
[3]. Dai Liyang and Zhangjia. (1995). Chin J. Orthop, 15(5):302-305
[4].Francis R.M. (1990). Osteoporosis. pathogenesis & management. Lancaster, UK. Kiuwer Academic Publisher.
[5]. Wishart J.M., et al. (1995). Clin Endocrinol, 42(2):141-146