骨形态计量学观察睾酮对雄性去势大鼠皮质骨的影响

Bone histomorphometry evaluate the effects of testosterone on metabolism of cortical bone in orchidectomized rats

目的通过骨形态计量方法观察雄激素替代疗法对去睾丸大鼠皮质骨代谢的影响。方法30只4月龄SD雄性大鼠,随机分成基础对照组(A组、实验开始时处死),年龄对照组(B组)、去睾丸组(C组)和去睾丸加睾丸酮组(D组),B组和C组生理盐水5ml·kg-1·d-1,D组甲基睾丸酮片1.8mg·kg-1·d-1,灌胃90d。实验结束,处死全部大鼠,取胫骨中段进行不脱钙骨制片,用计算机全自动图象分析系统进行骨组织形态计量学分析。结果去睾丸后皮质骨静态参数如截面总面积、髓腔面积等无明显变化,动态参数骨外膜骨形成降低(P<0.05),内膜骨形成和吸收均有增加趋势。睾酮则使去睾丸大鼠皮质骨的静态参数有增加趋势,促使骨外膜形成增加,减少内膜骨吸收(P<0.05),对内膜骨形成影响不大。结论睾酮补充治疗短期内能对抗去睾丸引起的大鼠皮质骨内外膜的代谢变化,维持正常的皮质骨结构。

Objective To study the effects of testosterone on metabolism of cortical bone in orchidectomized(ORX) rats by bone histomorphometry. Methods Thirty four month old Sprague Dawley male rats were randomly divided into four groups: basal control (group A, sacrificed at the beginning), age control(group B), ORX group(group C)and ORX with methyltestosterone group (group D).Group B and C were po administered with saline 5ml·kg-1·d-1, group D were po given with methyltestosterone 1.8mg·kg-1·d-1.After 90 days,all rats were killed and their tibial diaphysis were processed undecalcified sections and measured by automatic image analysis system for bone histomorphometry. Results Static parameters of cortical bone such as total tissue area and marrow cavity changed no much in ORX group. Dynamic parameters such as periosteal bone formation decreased(P< 0.05), endosteal bone turnover inclined to increased. Testosterone trended to improve the static parameters. it could elevate periosteal formation and reduce endosteal bone resorption(P< 0.05)but had little effects on endosteal bone formation. Conclusion Testosterone could keep the structure of cortical bone by accelerating periosteal bone formation and inhibiting endosteal bone resorption in ORX rats.