去卵巢大鼠腰椎骨微结构变化的动态观察

Dynamic Change of Bone Microarchitecture in Lumbar Vertebrae of Ovariectomized Osteoporosis Rats

目的:动态观察去卵巢大鼠腰椎骨微结构的变化。方法:将90只3月龄雌性SD大鼠按体重进行分层随机抽样分组,分为基础组(10只)、假手术组(40只)和去卵巢组(40只)。手术前(0周)处死基础组大鼠,手术后3、6、12、24周时,分批处死假手术和去卵巢组大鼠各8-10只。从每组随机取6只大鼠的第5腰椎行micro-CT扫描及三维结构重建,选取椎体1 mm处,2.0 mm×3.5mm,厚0.9 mm的骨组织为感兴趣区域(interesting area),进行骨形态计量学分析。结果:与同一时间点假手术组大鼠比较,去卵巢3周时,第5腰椎体积骨密度(v BMD)、骨体积分数(BV/TV)、骨小梁数目(Tb.N)、骨小梁厚度(Tb.Th)、骨小梁间隙(Tb.Sp)和结构模型指数(SMI)均无显著变化;去卵巢6周时,Tb.Th显著下降(P<0.05),而其他指标均无显著变化;从去卵巢12周到24周时,不仅Tb.Th显著下降(P<0.05),而且v BMD、BV/TV和Tb.N也显著下降(P<0.05),同时Tb.Sp和SMI显著增加(P<0.05)。结论:3月龄大鼠在去卵巢后的6周时骨小梁厚度变薄,12周以后,体积骨密度和骨体积分数下降,骨小梁数目减少。

Objective： To investigate the dynamic changes of bone microarchitecture in the lumbar vertebrae of ovariectomized osteoporostic rats. Methods： 90 healthy 3-months old female SD rats were randomly divided into the following three groups by body weight： baseline（base）, sham-operation（Sham）, and ovariectomized（OVX） groups. Before the surgical operation and 3, 6, 12 or 24 weeks after operation, respectively, the trabecular bone microarchitecture of the fifth lumbar vertebrae was detected by micro-CT in vitro.Results： At 3 weeks after operation, there were no significant differences in all detected parameters between the sham group and OVX group. At 6 weeks after operation, only the thickness of trabecular bone（Tb.Th） in the OVX group was significantly decreased compared with that of the sham group（P0.05）. From the 12 th to 24 th week after operation, the volume bone mineral density（v BMD）, the fraction of bone tissues（BV/TV）, the Tb.Th, and the number of trabecular bone（Tb.N） in the OVX group were significantly decreased compared with those of the sham group（P0.05） while the separation of trabecular bone（Tb.Sp） and the bone structure index（SMI） were significantly increased（P0.05）. Conclusions： At 6 weeks after ovariectomy, the Tb.Th in the rat fifth lumbar trabeculae became thin. At12 weeks after operation, the v BMD and the BV/TV was decreased and the Tb.N reduced.