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目的观察染料木素和小剂量17β-雌二醇对去卵巢(OVX)大鼠松质骨微结构的作用。方法90只7月龄SD大鼠被随机分为基线组、OVX组、假手术(SHAM)组、小剂量17β-雌二醇干预组(10μg·kg~(-1)·d~(-1),EST组)和染料木素干预组(5 mg·kg~(-1)·d~(-1),GEN组),分别在基线时、手术后3周和15周处死。分离左胫骨行显微CT扫描,分析距生长板远端1.6 mm、层厚0.5 mm骨组织的感兴趣区域松质骨结构。结果去卵巢后第3周,GEN组的组织骨密度和骨小梁厚度明显大于OVX组和EST组(均P<0.05);EST组的骨小梁数目显著多于GEN组(P<0.05),骨小梁间隔则明显小于GEN组(P<0.05);OVX组、GEN组和EST组3组的体积骨密度和骨体积分数差异无统计学意义,但均明显小于SHAM组(均P<0.05)。第15周时,OVX组、GEN组和EST组3组间的体积骨密度、骨体积分数、骨小梁数目和联接密度差异无统计学意义,但均小于SHAM组(均P<0.05),结构模型指数和骨小梁间隔则大于SHAM组(均P<0.05)。纵向观察发现,OVX组、GEN组和EST组3组的体积骨密度、骨体积分数、骨表面积分数和联接密度随时间出现下降,而组织骨密度、结构模型指数、骨小梁厚度和骨小梁间隔等参数随时间增加(均P<0.05),其中OVX组和EST组组织骨密度和骨小梁厚度在第3周和第15周之间出现明显增长(均P<0.05),GEN组组织骨密度增长主要发生在去卵巢后的第3周内,骨小梁厚度则在3周和15周均有增长(均P<0.05)。SHAM组骨小梁厚度和骨小梁间隔亦随时间增加,骨表面积分数和联接密度则下降,其他参数随时间无明显变化。结论染料木素能促进松质骨矿物质沉积和骨小梁增厚,17β-雌二醇则对抗雌激素缺乏引起的骨小梁数目减少和骨小梁间隔增大。
Objective To observe the effect of genistein and small dose of 17β-estradiol on the microstructure of cancellous bone in ovariectomized rats. Methods Ninety SD rats of 7 months old were randomly divided into baseline group, OVX group, sham operation group, low dose 17β-estradiol intervention group (10μg · kg -1 d -1 ), EST group and genistein intervention group (5 mg · kg -1 · d -1, GEN group) were killed at 3 weeks and 15 weeks after surgery respectively. The left tibia was isolated by microscopic CT scan and the cancellous bone structure of the region of interest was analyzed at a distance of 1.6 mm from the distal end of the growth plate and 0.5 mm in thickness. Results At the third week after ovariectomy, the BMD and trabecular thickness of GEN group were significantly higher than that of OVX and EST groups (all P <0.05). The number of trabecular in EST group was significantly more than that of GEN group (P <0.05) (P <0.05). There was no significant difference in volumetric BMD and bone volume between the OVX, GEN and EST groups (all P <0.05), but both were significantly lower than those in the SHAM group (P < 0.05). There was no significant difference in volume BMD, bone volume fraction, number of trabecular meshwork and connection density between the OVX, GEN and EST groups at the 15th week (all P <0.05) Structural model index and trabecular spacing were greater than those in SHAM group (all P <0.05). Longitudinal observation showed that volume BMD, bone volume fraction, bone surface area fraction and joint density of OVX, GEN and EST groups decreased with time, but BMD, structural model index, trabecular thickness and bone The parameters of trabecular separation increased with time (all P <0.05). The BMD and trabecular thickness of OVX group and EST group increased significantly between the 3rd week and the 15th week (all P <0.05) Bone mineral density increased mainly in the third week after ovariectomy, while the trabecular thickness increased at 3 weeks and 15 weeks (all P <0.05). The trabecular thickness and trabecular spacing of SHAM group also increased with time, the bone surface area fraction and the coupling density decreased, and other parameters had no significant changes with time. Conclusions Genistein can promote the deposition of cancellous bone mineral and the thickening of trabecular bone. 17β-estradiol decreases the number of trabecular meshwork and the increase of trabecular spacing in response to estrogen deficiency.