中文摘要：

目的 探讨内皮祖细胞（EPCs）在不同诱导因子作用下的体外分化潜能。方法 人脐血单个核细胞分别予50ng／ml血管内皮生长因子（VEGF组）或50ng／ml血小板源生长因子（PDGF组）诱导分化。光镜形态观察，免疫荧光鉴定。流式细胞分析CD133^＋EPCs分化特征。结果新鲜脐血分离单个核细胞培养1周后贴壁细胞的EPCs特异的Dil标记乙酰化低密度脂蛋白鉴定为80％阳性。在VEGF或PDGF诱导下1周，单个核细胞大量贴壁生长多呈圆形，少量梭形生长。2周时，被诱导细胞有近50％贴壁呈梭形生长，VEGF组和PDGF组无明显差异。至4周时两组出现明显的分化差异，其中VEGF组呈“铺路石”样细胞融合，血管性假血友病因子免疫荧光呈阳性；而PDGF组呈梭形或长多角形融合，予α-平滑肌肌动蛋白标记部分呈阳性。单个核细胞磁珠分选后得到CD133^＋较CD133ˉ更多分化为内皮样细胞（P〈0．05）；而在PDGF的诱导下CD133ˉ较CD133^＋更多分化为平滑肌样细胞（P〈0.05）。结论 单个核细胞在体外不同的诱导因子诱导下可以双向分化，CD133^＋ EPCs具有更强的内皮细胞分化潜能。

英文摘要：

Objective To investigate the differentiation characters of endothelial progenitor cells （EPCs） induced by different growth factors in vitro . Methods The mononuclear cells were cul tured with vascular endothelial growth factor （VEGF,50 ng/ml） or platelet derived growth factor （ PDGF, 50 ng/ml） respectively in vitro . Differentiation characters of these cells were analyzed by light microscopy and immunofluorescence staining after 1,2 and 4 weeks of culture. Differentia tion characters of CD133^＋ EPCs were also tested by flow cytometry. Results After induction by VEGF or PDGF for 1 week,most of adherent mononuclear cells became round and small, while few grew into spindle-shaped cells. Half of the cells became spindle-shaped after 2 week culture with VEGF or PDGF. The cells induced by the two growth factors showed no obvious difference at that time. After 4 weeks of induction, the cells induced by VEGF became confluent endotheliallike cells and immunofluorescence staining showed vWF positive,while the cells induced by PDGF grew into smooth muscle cell-like cells and some cells were α-SMA positive. CD133ˉ positive cells also differentiated in dual directions. After induction by VEGF,94. 1% of CD133^＋ positive cells and 77.2% of CD133ˉ cells differentiated into EC-like cells（CD31ˉ positive） ,but after induction by PDGF,less CD133^＋ cells differentiated into smooth muscle cell like cells than CD133ˉ cells （P〈0.05）. Conclusions The mononuclear cells may differentiate in dual directions if cultured with different growth factors. They have potential to grow into smooth muscle cell-like cells. CD133ˉ EPCs have higher potential to differentiate into EC-like cells than CD133ˉ EPCs.