辛伐他汀对幼鼠骨发育及骨髓基质干细胞成骨分化的影响

Effect of simvastatin on bone formation and osteogenic differentiation of bone marrow stromal cells in young rats

背景:辛伐他汀作为常用降脂类药物,表现出一定的促成骨分化和骨形成作用,但目前的研究结果尚有争论,尤其对幼鼠骨发育的影响并无报道。目的:课题创新性设计观察辛伐他汀对幼鼠骨小梁骨形成相关因子表达以及骨髓基质干细胞成骨分化的影响。方法:1周龄雄性SD大鼠20只,随机分为实验组和对照组,每组10只。实验组皮下注射辛伐他汀[5mg/(kg·d)]2周,对照组给与安慰剂2周。采用免疫组织化学方法检测胫骨上端骨小梁成骨相关因子骨形态发生蛋白2、基质金属蛋白酶13、血管内皮生长因子等因子的表达情况;取双侧股骨骨髓基质干细胞向成骨方向诱导培养。培养14d分别进行碱性磷酸酶染色,21d采用Real-timePCR法检测骨形态发生蛋白2、RUNX2、Osterix、MSX2、DLX3、DLX5等成骨过程中相关因子mRNA的表达,28d进行vonKossa染色。结果与结论:①实验组和对照组胫骨上端骨小梁骨形态发生蛋白2、基质金属蛋白酶13、血管内皮生长因子等因子的表达差异无显著性意义。②两组碱性磷酸酶染色阳性细胞(胞浆蓝黑色)比例均在30%左右,差异无显著性意义(P>0.05)。③骨髓基质干细胞向成骨细胞诱导分化过程中相关因子骨形态发生蛋白2、RUNX2、Osterix、DLX3、DLX5、MSX2mRNA表达水平差异无显著性意义。④vonKossa染色可见大小不等染为棕黑色的钙化点,其大小和密度两组比较差异无显著性意义。结果表明,皮下注射辛伐他汀[5mg/(kg·d)]2周不能显著影响幼鼠骨小梁骨形成相关因子表达以及骨髓基质干细胞成骨分化。

BACKGROUND： Recently simvastatin has been shown to stimulate osteogenic differentiation and bone formation, but there is no report about the effect of simvastatin on the bone development of young rats. OBJECTIVE： To evaluate the effects of simvastatin on osteogenic relative genes of proximal tibia trabecular bone and osteogenic differentiation of bone marrow stromal cells （BMSCs）. METHODS： Twenty 1-week-old Sprague-Dawley young rats were randomly and equally divided into simvastatin and control groups. Rats in the simvastatin group were treated with a subcutaneous injection of simvastatin [5 mg/（kg·d）] for 2 weeks, while rats in the control group were treated with placebo for 2 weeks. The expressions of bone morphogenetic protein-2 （BMP-2）, matrix metalloproteinase-13 （MMP-13）, and vascular endothelial growth factor （VEGF） of trabecular bone in the tibia were analyzed by immunohistochemical staining. BMSCs harvested from the rat femur were osteogenic-differentiation cultured. Alkaline phosphatase （ALP） staining was performed on day 14, real-time PCR analysis was applied to investigate the BMP2, RUNX2, Osterix, MSX2, DLX3, DLX5 mRNA expressions during osteogenic differentiation in vitro on day 21, and von Kossa staining was detected on day 28. RESULTS AND CONCLUSION： ① There was no significant difference in the expressions of BMP-2, MMP-13, and VEGF between simvastatin and control groups. ② The percentages of ALP positive-stained cells were about 30% and there was no significant difference between the two groups （P 0.05）. ③ There was no significant difference in the expressions of BMP-2, RUNX2, Osterix, MSX2, DLX3, DLX5 mRNA in osteogenic differentiation-induced BMSCs. ④ von Kossa staining demonstrated that dark brown calcified spots in various sizes were observed, but there was no significant difference in size and density between simvastatin and control groups. A subcutaneous injection of simvastatin [5 mg/（kg·d）] for 2 weeks could not remarkably affect osteogenic relative genes of bone trabecula and osteogenic differentiation of BMSCs.