目的：研究血管内皮生长因子(vascular endothelial growth factor, VEGF)体外促进小鼠胚胎干细胞系ES-D3生成CD34+细胞的能力。方法将ES-D3形成拟胚体，将拟胚体细胞转入含不同浓度的VEGF和VEGF+干细胞因子（stem cell factor, SCF)的培养基中。实验分6组，分别为VEGF 5 μg/L组、VEGF 10 μg/L 组、VEGF 20 μg/L组、VEGF 5 μg/L＋SCF组、VEGF 10 μg/L＋SCF组、VEGF 20 μg/L＋SCF组，同时设不加因子的自发分化对照组。RT-PCR检测CD34 mRNA的表达，流式细胞仪检测CD34+细胞的比例，甲基纤维素半固体培养法检测生成造血集落的能力。结果：经过1周的诱导培养，实验组生成的细胞可以表达CD34 mRNA，CD34＋细胞的比例也升高，并可形成造血祖细胞的集落。从CD34 mRNA的表达水平、诱导生成CD34＋细胞的比例和生成的集落数量看，VEGF 20 μg/L＋SCF组和VEGF 10 μg/L＋SCF组的诱导效率最高。结论：VEGF能够促进ESC生成CD34＋细胞，尤以与SCF合用时，其诱导效率更高。

Objective:To study the promoting effect of vascular endothelial growth factor (VEGF) on the generation of CD34+ cells from mouse embryonic stem cell(ESC) in vitro.Methods: ES-D3 cells were allowed to grow on mouse fetal fibroblast feeder layer to form embryoid bodies(EB), then EB cells were transferred into medium supplemented with different concentration of VEGF and VEGF+SCF for 1 week. Six groups were designed , i.e. VEGF 5 μg/L, VEGF 10 μg/L, VEGF 20 μg/L, VEGF 5 μg/L＋SCF, VEGF 10 μg/L＋SCF and VEGF 20 μg/L＋SCF. The group of spontaneous differentiation without cytokine(s) was served as control. The expression of CD34 mRNA was detected by RT-PCR. The content of CD34+ cells in each group was measured by flow cytometry. The cells derived from ESC were incubated in semisolid methycellulose cultures. The numbers of total colony-forming units in culture(CFU-C) were counted by reverse microscope. Results：ES-D3 grew and formed EBs at day 4. VEGF gave the stimulatory effects on the expression of CD34 mRNA, the generation of CD34+ cells and CFU-C in EB as a single factor . The effects of VEGF＋SCF were the most effective in the experimental groups according to the percent of CD34+ cells and the numbers of hematopoietic colonies. The most highest inducing efficacy were achieved when VEGF 20 μg/L or VEGF 10 μg/L combined with SCF were used.Conclusion: VEGF can promote the differentiation of ESC into CD34+ cells in vitro. The strongest effects were achieved when VEGF was used in combination with SCF.

国家自然科学基金部分资助（30271248）