中文摘要：

目的探讨神经生长因子（NGF）对体外培养的小鼠神经干细胞（NSCs）分化为神经元的作用及可能机制。方法以无血清培养法从孕13～14 d的昆明小鼠大脑皮质分离培养获得NSCs,传至3代后,进行NGF处理,并对培养的细胞进行MAP-2免疫细胞化学染色,荧光显微镜下对MAP-2阳性细胞进行计数。同时运用蛋白免疫印迹法（Western blot）考察NGF对TrkA、Akt、Erk磷酸化水平的影响;在研究NGF作用的信号转导通路时,预先给予各种信号通路抑制剂处理,再进行NGF干预,通过MAP-2染色及Western blot考察NGF促进神经干细胞分化为神经元的信号通路。结果 NGF可以显著促使NSCs分化为神经元并可以促进TrkA、Akt和Erk的磷酸化,呈现剂量和时间依赖性;各种通路抑制剂结果显示PI3K/Akt抑制剂可以阻断NGF对Akt的磷酸化作用,同时阻断了NGF对NSCs的促分化作用,MAPK抑制剂处理可以阻断NGF对Erk的磷酸化作用,但未见明显阻断NGF的促分化作用。结论 NGF可以促进NSCs分化为神经元,其作用机制可能与激活PI3K/Akt信号通路有关。

英文摘要：

Objective To study the effects of NGF on the differentiation of neural stem cells（NSCs） and the underlying mechanisms. Methods NSCs were isolated from E 13~14 d Kunming mice and cultured in serum-free medium.After three passages,NSCs were treated with NGF and differentiated neurons were identified by immunocytochemistry with MAP-2 antibody.The number of MAP-2 positive cells was assessed using microscope,while NGF-induced phosphorylation of TrkA,Akt and Erk was determined by Western blot.To study the signaling pathway involved,NSCs were pretreated with various pathway inhibitors and subsequently with NGF.Immunocytochemistry and Western blot were used to investigate the role of each pathway on the differentiation of NSCs induced by NGF. Results NGF promoted the differentiation of NSCs into neurons and increased the phosphorylation of TrkA,Akt and Erk in time-and dose-dependent manners.The effect of NGF was blocked by the PI3K/Akt pathway inhibitor LY294002 and the Akt inhibitor Akt VIII,but not by Erk inhibitors. Conclusion NGF induces the differentiation of NSCs into neurons through the activation of PI3K/Akt signaling pathways.