雄激素对雄性去势大鼠骨微结构及力学性能的影响

目的：运用骨密度、骨生物力学、骨形态计量学检测、Micro CT分析及三维结构重建的方法，从“骨密度检测-形态性观察-功能学测试”角度出发，观察雄激素对老龄雄性去势大鼠骨微结构及力学性能的影响。方法：30只12月龄雄性Wistar大鼠随机分为去势组、治疗组和假手术组，每组10只。治疗组大鼠睾丸及附睾切除术后第2天开始，用睾丸酮水溶液灌胃给药，12周后取材，运用双能X线骨矿含量测定仪（DXA）检测治疗前后大鼠骨密度（BMD）。取大鼠L5椎体做生物力学测试，取左胫骨近端做骨形态计量学测试，取L3椎体行Micro CT分析及三维结构重建。结果：治疗组大鼠经雄激素干预后，骨密度升高24．5％。生物力学测试结果表明，治疗组骨最大载荷、吸收能量、最大应力、弹性模量值较去势组显著升高（P〈0．05）。MicroCT分析表明，治疗组骨小梁体积、骨小梁数目值升高，骨小梁分离度值降低。四环素单、双标面等骨形成、骨吸收及骨矿化参数值较去势组均明显升高，骨形成大于骨吸收。结论：雄激素能增加去势老龄雄鼠骨密度，促进骨形成及骨转换，改善骨微结构，提高骨的力学性能。

Effects of androgen on microstructure and mechanics nature of bone in orchiechtomied male rats

Objective: To investigate the effect of androgen on microstructure and mechanics nature of bone in orchiechtomied (ORX) male rats and reveal its mechanism by using the Micro CT analysis,bone biomechanics test,bone histomorphometric parameter test, and total body bone mineral density(BMD) measured by dual-energy X-ray absorptiomery(DXA). Methods: Thirty 12-month-old male Wister rats were randomly divided into three groups including ORX,sham-operated(Sham) and androgen(AD) group,ten rats in every group. Total body BMD was measured by DXA. Femurs and vertebrae were then harvested at the 12 th week after ORX for micro-computed tomography(Micro CT),histology and biomechanical were tested. Results: The administration of testosterone may reverse the decreasing BMD of total body and may prevent the decreasing weight. The biomechanical values of Maximum load,Enery,Maximum stress,Elastic Modulus of AD group significantly enhanced compared with ORX group(P<0.05). The results of histomorphometric parameters showed that cancellous bone volume,osteoblast-osteoid interface,linear extent of bone formation,mineralizing surfaces,mineral apposition rate increased in the therapy group. Conclusion: Androgen can accelerate cancellous bone formation and bone turnover,improve bone microstructure and enhance bone intensity and BMD.