去卵巢对大鼠皮质骨微结构、骨密度及生物力学的影响

The effect of ovariectomy on microarchitecture,bone mineral density,and bone biomechanics of the cortical bone in rats

目的应用显微CT和四点弯曲实验观察去卵巢对大鼠股骨皮质骨骨密度、微结构及生物力学性能的影响。方法 24只7月龄雌性SD大鼠随机分为去卵巢(OVX)组和假手术(Sham)组,于手术后3周、15周各处死6只,显微CT扫描左侧股骨中段。右侧股骨行四点弯曲试验。结果去卵巢3周至15周,OVX组股骨皮质骨内径周长、外径周长、皮质骨面积、骨髓腔面积、截面总面积骨密度、最大力、弹性模量、断裂强度与Sham组相比无明显差异(P>0.05)。OVX组15周弹性模量比3周低36%(P<0.05)。结论去卵巢15周内大鼠股骨中段皮质骨微结构及其骨密度和股骨力学性能无明显变化,但去卵巢组股骨生物力学性能减退较快。

Objective To observe the effect of ovariectomy on bone mineral density （BMD）, bone microarchitecture, and biomechanics of the femur cortical bone in rats using microcomputed tomography and 4point bending test. Methods Twentyfour 7monthold SD female rats were randomly divided into ovariectomized （OVX） group and sham-operated （Sham） group. After 3 and 15 weeks, 6 rats of each group were killed and the middle part of left femurs was scanned using microCT. The right femurs were performed with 4point bending test. Results From 3 to 15 weeks after the surgery, the inner perimeter, outer perimeter, cortical bone area, the medullary cavity area, total area, bone mineral density, maximum load, elastic modulus, and breaking strength of the rats in OVX group had no significant difference compared to those in the Sham group （P 〉0.05）. The elastic modulus of rats in the OVX group on 15 weeks after the surgery was 36% lower than that on 3 weeks （P 〈 0. 05）. Conclusion The microarchitecture, bone mineral density, and biomechanics of cortical bone of the middle shaft of the femur have no significant change in rats 15 weeks after ovarietomy. But the bone biomechanics decrease fast in rats of OVX group.