bFGF和EGF对胚胎神经干细胞分化为神经元及神经胶质细胞的影响

目的：观察碱性成纤维生长因子（bFGF）和表皮生长因子（EGF）对体外培养胚胎神经管神经干细胞生长和分化的影响。方法：从孕12天大鼠胚胎神经管分离神经干细胞，进行原代培养，分为bFGF组、EGF组、bFGF＋EGF组及对照组：培养过程中观察干细胞的生长，培养2小时做nestin染色鉴定神经干细胞，培养第5天用免疫组化方法检测培养细胞神经元特异烯醇化酶（NSE）和胶质纤维酸性蛋白（GFAP）的表达，以观察神经干细胞分化为神经元及神经胶质细胞的状况。结果：取材细胞大部分为nestin免疫阳性细胞；各实验组均可促进培养细胞的生长和分 化。免疫组化中，EGF使神经干细胞增殖成团，增加GFAP的表达（P＜0．01）；bFGF能明显增加NSE及GFAP的表达（P＜0．01）；两种因子联合应用，神经元和神经胶质细胞均比对照组增多（P＜0．01）。结论：EGF和bFGF两类生长因子均能促进胚胎神经干细胞的生长，在分化方面，EGF倾向于诱导干细胞增并向着胶质细胞分化，bFGF则诱导干细胞分 成更多的神经元。

Basic fibroblast growth factor and epidermal growth factor affecting the outgrowth and differentiation of embryonic neural stem cells

Objective:To study the effect of bFGF, EGF and the combination of the two on the differentiation of embryonic stem cells in culture. Methods; Embryonic E12 rats were obtained from anesthetized timed pregnant Sprague-Dawley rats. Neural stem cells were dissociated from embryonic neural tube. The expression of nestin was examineed at 2 h in culture. Following 5 d in culture, the immunocytochemical analysis was used to identify the expression of neuro-specific eno-lase (NSE) and glial fibrillary acidic protein (GFAP) in cultured cells. The immunostaining positive cells were counted at high fields in different groups. Results; Most of culture cells were nestin-positive. Four groups all promoted stem cells to grow and differentiate,EGF mainly affected the proliferation of neural stem cells and induced more cells differentiate into GFAP-positive cells (F<0.01 vs control). bFGF not only affected the outgrowth of stem cells,but also promoted them to differentiation into NSE-positive cells. In bFGF + EGF group, more neurons and astrocytes could be seen in the immunostaining than control group (P<0. 01). Conclusion .-Both bFGF and EGF can promote the outgrowth of embryonic stem cells,bFGF exerts a preferential effect on neuronal development and to a lesser extent,glial development,EGF may function as a stem cell survival factor,and induce stem cell to differentiate into astrocytes.