去卵巢大鼠股骨颈力学强度与股骨近段髓腔面积的时序性变化

Sequential changes in biomechanical competence of femoral neck and marrow cavity of proximal femur in ovariectomized rats

目的:研究去势大鼠股骨颈力学强度和股骨近段髓腔面积的时序性变化。方法:6月龄雌性SD大鼠随机分组后,分别行去势术(OVX组)和假手术(Sham组),术后0、3、6、9、12、15、18、21周动态测量股骨颈骨矿物密度(BMD)、股骨颈最大抗压力和近段髓腔面积大小。结果:去卵巢后6周OVX组大鼠股骨颈BMD较Sham组低15%,分别为(0.195±0.028)g/mm2和(0.225±0.036)g/mm2(P=0.03);去卵巢后9周OVX组大鼠股骨颈最大抗压力较Sham组低10%,分别为(89.6±7.7)N和(96.7±7.5)N(P=0.05);髓腔面积在去卵巢后15周两组间开始出现差异,分别为(3.834±0.115)mm2和(3.713±0.114)mm2(P=0.03)。结论:大鼠去势后股骨颈骨量减少,生物力学强度下降和股骨近段髓腔面积扩大,而且髓腔面积的扩大晚于生物力学强度的下降。这可能成为绝经后骨质疏松妇女假体松动的一个重要影响因素。

Objective： To observe the sequential changes in biomechanical competence of the femoral neck and marrow cavity of the proximal femur in ovariectomlzed rats. Methods： Bone mineral density （BMD） and biomechanical properties of the femoral neck and the structural dimension of the proximal femur were measured 0, 3,6,9,12,15,18,21 weeks after ovariectomy （OVX） or sham operation （Sham） in 6-month-old female SD rats. Results： The BMD of femoral neck in OVX rats was significantly lower than that in Sham group 6 weeks after operation,（0. 195±0. 028） g/mm^2 vs （0. 225±0. 036） g/mm^2（P=0. 03）. Nine weeks after operation,the failure load of femoral neck decreased about 10% in OVX group to that in Sham group,（89.6±7.7）N vs （96.7±7.5）N （P=0.05）. The medullary cavity of proximal femur started to show difference 15 weeks after operation （3. 834±0.115） mm^2 vs （3. 713±0. 114 ） mm^2 （P = 0. 03 ）. Conclusion： BMD loss after ovariectomy is associated with a medullary expansion in proximal femur and biomechanical strength deterioration in femoral neck,which might be an important factor of prostheses loosening in the postmenopausal osteoporotic women.