轻度承重活动对卵巢切除大鼠骨密度组织计量和生物力学的影响

【目的】探讨轻度承重活动对绝经后骨质疏松的防治作用。【方法】4月龄36只雌性大鼠分组①假去势组，②去势组，③去势加制动组。②、③组行双侧卵巢切除术，③组还用胶布带将其右后肢制动于腹部（使右后肢不能进行承重活动）。各组大鼠分笼喂养，保持日常活动，术后12周分别检测和分析大鼠右侧股骨骨密度、组织计量学和生物力学的变化。【结果】与假去势组比较，去势组大鼠股骨骨密度下降，骨小梁体积比下降，骨小梁平均厚度和骨皮质平均厚度减少，骨吸收表面和类骨质表面明显增加，同时其生物力学性能变差，但骨密度、骨皮质平均厚度及骨强度指标在统计学上与假去势组无显著性差异；而去势加制动组大鼠其股骨骨密度下降、骨小梁体积比下降及骨小梁平均厚度和骨皮质平均厚度减少更加明显，生物力学性能更差，骨密度、骨皮质平均厚度及股骨强度指标在统计学上与假去势组有显著性差异。【结论】去势雌性大鼠若保持轻度承重运动，则能保持相对较好的骨质量，缺乏承重运动则骨质量显著变差，提示轻度承重活动对防治绝经后骨质疏松具有显著性作用。

Effect of Light Weight-bearing Activity on Bone Mineral Density,Histomorphometry and Biomechanics in Ovarietomized Rats

【Objective】To study the effect of light weight-bearing activity on postmenopausal osteoporosis.【Methods】36 female rats were randomly divided into 3 groups:① 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.