EGF、bFGF、NGF、RA对小鼠神经干细胞定向分化的调控

Regulation of EGF,bFGF,NGF and RA on orientating differentiation of mouse neural stem cells

目的观察EGF、bFGF、NGF、RA对小鼠神经干细胞(NSCs)增殖及定向分化的影响。方法用无血清培养与单细胞克隆技术对小鼠胚胎脑组织进行分离、培养,随后分别加入EGF、bFGF、NGF、RA等因子观察其对NSCs定向分化的影响。结果EGF培养的小鼠NSCs,2d后见细胞集落形成(典型克隆球);克隆球中的细胞成圆形,形态规则,未见细胞突起,呈桑椹状聚集;经血清诱导分化后,则主要为星形胶质细胞,仅有个别的神经元。而bFGF培养的NSCs,生长良好,但克隆球数目较EGF组少,克隆球体积略小。3bFGF与EGF共同培养的NSCs,除诱导分化后,分化的细胞性质与EGF组的不同外,其余同EGF组。NGF对神经球的形成无明显的影响。RA组的克隆球数目量很少,形态以球形为主,部分细胞贴壁并出现突起。结论EGF,bFGF对NSCs的增殖及分化种类均有一定的影响。而NGF与RA则主要影响其细胞的分化,且两者的共同点都是促使其向神经元方向分化。

Objective To investigate the regulation of epidermal growth factor (EGF),basic fibroblast growth factor (bFGF),retinoic acid (RA) and nerve growth factor (NGF) on the proliferation and orientating differentiation of neural stem cells (NSCs) in mice. Methods Serum-free medium and single-cell monoclone technique were used to isolate and incubate NSCs from the cortex of embryonic mouse brain. Then,EGF,bFGF,RA and NGF were added into the medium to observe the effect of them on the differentiation of NSCs by immunocytochemical staining methods. Results The neurospheres were formed 48 h after incubation in EGF group. The cell processes were not observed at that time. However,cultured cells could be induced to differentiate into glial cells mostly and a few neurons only,when NSCs were cultured in DMEM medium supplemented with fetal bovine serum. The NSCs presented well growth in the medium with bFGF,except that neurospheres were less in number and smaller in size than that in EGF group. Both the neurospheres and NSCs developed well in the medium containing bFGE with EGF,but the ratio of NSCs differentiation into glial cells and neurons was not the same as in EGF group. There was no significant influence on neurospheres formation in NGF group. The results showed that neurosphere formed slowly and smaller in size in RA group. RA mainly induced NSCs to differentiate into neurons. Conclusion EGF,bFGF have an ability to effect the proliferation and orientating differentiation of NSCs from the cortex of embryonic mouse. The main effect of NGF and RA is to promote the NSCs’ differentiation into neurons. Otherwise,both NGF and RA do not produce any work on the proliferation of NSCs.