Effect of Light Weight-bearing Activity on Bone Mineral Density,Histomorphometry and Biomechanics in Ovarietomized Rats / 中山大学学报(医学科学版)

ABSTRACT

【Objective】To study the effect of light weight-bearing activity on postmenopausal osteoporosis.【Methods】36 female rats were randomly divided into 3 groups① Sham,② Ovx (ovarietomized),③ Ovx+Im (ovarietomized and immobilized).All the group's maintained daily activity.And because of being immobilized,the right hind limbs of the third group lacked weight-bearing activity.12 weeks after ovarietomy,the BMD (bone mineral density),histomorphometry and biomechanics of the right femurs of rats were measured and analyzed.【Results】Comparing with the Sham group,the Ovx group's right femurs were manifested with the decrease of BMD,TBV (trabecular bone volume),MTT(mean trabecular thickness) and MCT(mean cortex thickness),while the increase of RS(resorption surface) and OS(osteotoid surface).Meanwhile their biomechanic nature declined.But statistically the BMD,MCT and the criteria of mechanical strength were not significant decrease.Otherwise,the Ovx+Im group's right femurs showed more apparent decrease of BMD,TBV,MTT and MCT.And the biomechanic nature was worse.Comparing with the Sham group,the BMD,MCT and the criteria of mechanical strength of the Ovx+Im group were statistically significant decreased.【Conclusion】If maintaining light weight-bearing activity,the ovarietomized rats were able to maintain relatively better bone quality.A lack of light weight-bearing activity wouldcause thedecline of bone quality.Thusthestudy suggested light weight-bearing activity was significantly effective on the prevention and treatment of postmenopausal osteoporosis.