增龄及去睾丸大鼠的骨形态计量学研究

Bone histomorphometric study of the aging and orchiectomized rats

目的探讨4月龄雄性大鼠增龄及去睾丸后不同部位骨量的变化,了解两者对成熟期大鼠骨代谢的影响。方法30只4月龄SD雄性大鼠,随机分为基础对照组、年龄对照组和去睾丸组,同等条件下饲养90d。90d后取胫骨上段、腰椎和胫骨中段行不脱钙制片进行骨形态计量学观察。结果年龄对照组(7月龄)与基础对照组(4月龄)比较,胫骨上段骨形成和骨吸收都下降(骨小梁面积百分率减少28.6%);腰椎骨形成和骨吸收有下降趋势。去睾丸组与年龄对照组比较,胫骨上段骨量进一步丢失(骨小梁面积百分率减少57.1%);腰椎骨量也下降,表现为骨形成下降,骨吸收增加;胫骨中段皮质骨外膜的骨形成动态参数如矿化沉积率、骨形成率下降(P﹤0.05),内膜骨形成和吸收均有增加趋势。结论4月龄大鼠增龄及去睾丸90d均能引起大鼠骨量丢失。胫骨上段出现较早和更严重,腰椎和胫骨中段皮质骨丢失表现滞后。去睾丸后的大鼠主要表现为松质骨的骨量在增龄基础上进一步丢失。

Objective To study the skeletal effects of aging and orchiect omy(ORX) on different parts of the concellous bone and cortical bone by bone his tomorphometry and to distinguish the differences between them. Methods Thirty f our monthold Sprague Dawley male rats were randomly divided into three groups: b asal control group(sacrificed at the beginning), age control group and ORX group . Ninety days after initiation of the experiment, all rats were killed and th eir proximal tibial metaphysis(PTM), the fifth lumbar vertebra and middle tibial metaphysis were processed undecalcified sections and measured by automatic imag e-analysis system for bone histomorphometry. Results Compared with basal group , age group had less bone formation and resorption rate in PTM and downtrend of bone formation and resorption in lumbar. Bone mass decreased much more in ORX ra ts in PTM and less bone mass of lumbar vertebra with higher bone resorption and lower bone formation rate(P<0.05); Dynamic pameters of cortical bone such as per iosteal bone formation decreased(P<0.05), endosteal bone turnover inclined to in creased in ORX group. Conclusions Aging and orchidectomy after 90 days could re sult in osteoporosis in male rats and the trabecular bone loss of PTM was more o bvious and sensitive than that in lumbar and cortical bone. Bone mass decreased on the base of the aging in the ORX rats.