洛伐他汀对尾悬吊大鼠骨量及生物力学性能的影响

Effects of lovastatin on bone mass and biomechanical property in tail-suspended rats

目的 通过尾悬吊法制作拟失重大鼠骨质疏松动物模型,观察洛伐他汀体内给药对尾悬吊大鼠骨量、微观结构、生物力学性能的作用潜能.方法 将24只10周龄雄性SD大鼠随机分成3组,每组各8只：正常对照组（G1组,8只,每日予蒸馏水灌胃）、尾悬吊组（G2组,将大鼠在悬吊笼中尾部悬吊,后肢离地,使躯干与地面成40°角,同时每日予每天蒸馏水灌胃）、尾悬吊加洛伐他汀组（G3组,在尾部悬吊基础上,每日予20mg/kg洛伐他汀灌胃）;4周后处死所有大鼠,取大鼠右侧股骨用双能X线骨密度仪测量骨密度,并取胫骨近端进行骨组织形态计量学测定;同时取大鼠左侧股骨行生物力学检测.结果 G1组的右股骨各段骨密度和骨小梁相对体积、左股骨最大载荷量显著高于G2、G3组（均P＜0.05）,G1组的骨小梁分离度及骨吸收周长百分数、破骨细胞数、类骨质周长百分数显著低于G2、G3组（均P＜0.05）,且G2、G3组上述指标的差异均无统计学意义（均P ＞0.05）.结论 尾悬吊4周可导致大鼠骨量丢失;洛伐他汀体内给药不能阻止尾悬吊大鼠股骨骨量丢失.

Objective To investigate the effects of Iovastatin on bone mass,microarchitecture and biomechanical property, and to observe the potential protective effect of Iovastatin on unloading-induced osteoporosis. Methods Twenty-four 10- week-old male Sprague-Dawley rats were randomized into three groups of eight animals each： G1, control group; G2, the tail-suspended group with vehicle; G3, the tail-suspended group and administered daily with 20 mg/kg of Iovastatin by gavage. The experiment was lasted for four weeks, and all animals were sacrificed one day after the final Iovastatin administration. The right femurs were harvested for the measurement of bone histomorphometry, and bone mineral density （BMD） measured by du- al-energy X-ray absorptiometry.The left femurs were collected for biomechanical test. Results The tBMD,pBMD and dBMD of G1 were significantly higher than those of G2 and G3, with no significant difference between G2 and G3. BV/TV of G1 was significantly higher than G2 and G3,Th.Sp and Er.Pm,Qc.N,O.Pm were significantly lower than G2 and G3;The maximal loading of G1 was markedly higher than those of G2 and G3. Conclusion the rats with tail-suspention for four weeks showed markedly decreased bone loss. Lovastatin treatment could not prevent tail-suspention-induced bone loss.