衰老性骨质疏松微环境对颌骨骨髓间充质干细胞生物学功能的影响

Effect of aging osteoporosis microenvironment on the biological function of jaw bone marrow mesenchymal stem cells

目的:探讨衰老性骨质疏松微环境对颌骨骨髓间充质干细胞(Jaw bone-marrow-derived mesenchymal stem cells,JBMMSCs)生物学功能的影响。方法:分别取2月龄和20月龄SD(Sprague Daw ley)大鼠,分离其颌骨和股骨,并进行Micro-CT扫描,确定衰老性骨质疏松大鼠模型建立成功;体外分离、培养并鉴定两组大鼠的JBMMSCs,通过克隆形成实验、CCK8实验和成骨诱导观察其增殖和成骨分化能力;并采用实时定量荧光PCR技术(Real-time PCR)对成骨诱导7d后的JBMMSCs成骨重要相关基因Runx2、OCN进行检测。结果:与2月龄大鼠相比,20月龄大鼠颌骨、股骨均出现了明显的骨质疏松,主要表现为骨密度及骨小梁强度下降;年轻和衰老大鼠JBMMSCs阳性表达CD29、CD90,阴性表达CD34、CD45,符合间充质干细胞特性;衰老组JBMMSCs的增殖、成骨分化能力以及Runx2 mRNA、OCN mRNA表达水平均显著下降(*P<0. 05)。结论:JBMMSCs增殖和成骨分化能力降低可能是导致颌骨骨质疏松的重要原因。

Objective:To investigate the effects of aging osteoporosis microenvironment on the biological function of jaw bone marrow mesenchymal stem cells(JBMMSCs).Methods:To confirm the establishment of a rat model of aging osteoporosis,the three dimensional images of mandibular and furmur of 2 month and 20 month old SD rat were observed by Micro-CT.JBMMSCs were isolated,cultured and identified in vitro from the rat of the 2 groups.JBMMSCs from the rat of the 2 groups were observed by clonal formation assay,CCK8 assay and osteogenic induction to observe their proliferation and osteogenesis differentiation.JBMMSCs were induced by osteogenic medium for 7 days,and then the osteogenesis-associated gene Runx2 expression and OCN expression was determined by Real-time PCR.Results:Compared with 2-month-old rats,osteoporosis appeared in the jaw and femur of 20-month-old rats,mainly due to decreased bone mineral density and trabecular strength.The positive expression of CD29 and CD90 in young and aging rat JBMMSCs,negative expression of CD34,CD45,consistent with mesenchymal stem cell characteristics;Proliferation and osteogenic differentiation and Runx2 m RNA,OCN m RNA expression levels of JBMMSCs of the aging group were significantly reduced.Conclusion:Age-related changes in the biological function of JBMMSCs may be an important cause of aging bone osteoporosis in the jaw.