中文摘要：

目的：研究年龄相关microRNA-196a（miR-196a）对人骨髓间充质干细胞（hMSCs）增殖功能的调控作用。方法：通过MTT研究年龄对hMSCs增殖能力的影响。通过microRNA芯片和qRT—PCR检测年龄对miR-196a表达的影响。通过转染miR-196a模拟物或抑制物，研究其对hMSCs增殖能力的影响。通过萤光素酶报告基因系统证实HOXB7为miR-196a的靶基因。通过siRNA研究HOXB7对碱性成纤维细胞生f长因子（bFGF）表达及hMSCs增殖功能的影响和研究bFGF对hMSCs增殖功能的影响。结果：随年龄增加，hMSCs的增殖能力下降，miR-196a的表达增加。miR-196a可抑制hMSCs的增殖。抑制miR-196a的表达可促进hMSCs的增殖。同时抑制miR-196a和HOXB7的表达，使miR-196a失去对hMSCs增殖能力的调控作用。抑制HOXB7的表达可使bFGF的表达下调。直接抑制HOXB7或bFGF的表达可抑制hMSCs的增殖。结论：miR-196a通过抑制HOXB7及bFGF的表达导致hMSCs增殖能力下降。

英文摘要：

AIM： To investigate the effects of microRNA-196a （miR-196a） on the proliferation of human bone marrow mesenchymal stem ceils （hMSCs）. METHODS ： Cell growth was evaluated by MTT assay. The expression of miR- 196a was determined by microRNA array and quantitative real-time PCR （qRT-PCR）. The effect of miR-196a on hMSC proliferation was detected by transfection of miR-196a mimic or inhibitor. Using dual-luciferase reporter system, the target gene of miR-196a was identified. The effect of HOXB7 on basic fibroblast growth factor （bFGF） expression and hMSC pro- liferation was detected by siRNA. The effect of bFGF on hMSC proliferation was analyzed by siRNA. RESULTS ： The pro- liferation ability was decreased and the expression of miR-196a was up-regulated in the old hMSCs compared with the young hMSCs. Up-regulation of miR-196a resulted in increased proliferation of hMSCs. Conversely, down-regulation of miR-196a resulted in decreased cell proliferation. Homeobox B7 （HOXB7） was the target gene of miR-196a. The regulation of miR- 196a on hMSC proliferation was attenuated by inhibiting the expression of miR-196a and HOXB7 together. Down-regulation of miR-196a inhibited the expression of bFGF. Direct repression of HOXB7 or bFGF expression inhibited the hMSC prolif- eration. CONCLUSION： miR-196a inhibits the proliferation of hMSCs by repressing the expression of HOXB7 and bFGF.