目的 探讨去势骨质疏松模型骨组织中miR-21及其调控蛋白Smad7的含量变化,及其与骨密度的相关性.方法 将30只12周龄WTC57BL/6J雌性小鼠双侧卵巢切除,建立骨质疏松模型,应用免疫组化检测切除卵巢后不同时间点(0周、1周、2周、4周、6周及8周)骨组织中Smad7的表达水平,实时PCR方法检测不同时间点骨组织中miR-21及靶基因Smad7的m RNA水平,检测不同时间点股骨远端骨密度.结果 免疫组化研究发现,骨质疏松小鼠骨组织中Smad7随着时间的延长,其表达逐渐增强.实时PCR检测结果显示,骨组织中miR-21随着卵巢切除的时间逐渐延长,其表达逐渐降低,而Smad7随着卵巢切除的时间逐渐延长,表达逐渐增强.通过检测小鼠骨组织骨密度值并进行相关分析发现,随着时间的推移,小鼠的骨密度逐渐下降.结论 小鼠去势后,骨密度逐渐降低,miR-21表达与骨密度值呈正相关,而Smad7与骨密度值呈负相关.%Objective To investigate the changes in the expression levels of miR-21 and its regulatory proteins in bone tissues of osteoporotic mouse model, and its correlation with bone mineral density. Methods Thirty ovariectomized (ovx) female mice were randomly divided into six groups according to different observation time (0 week, 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks, respectively). Smad7 expression level in the tissues of the distal femur of these mice was immunohistochemically analyzed. Real time PCR was performed at different time points for detecting changes in the mRNA levels of miR-21 and Smad7 target genes in the bone tissue. Dual-energy X-ray absorptiometry (DXA) was used to measure the distal femoral bone density in mice of each group. Results Immunohistochemical study revealed that the expression of Smad7 in the bone tissue of osteoporostic mouse gradually increased over time. Real time PCR analysis showed that the expression of mi R-21 gradually decreased, whereas the expression of Smad7 gradually increased. Over time, the bone density of mice gradually decreased, indicating that miR-21 was positively correlated with bone density, whereas Smad7 was negatively correlated with bone density. Conclusion Bone density of the osteoporotic mice gradually decreases. The expression of miR-21 is positively correlated with bone density, while that of Smad7 is negatively correlated with bone density.
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