中文摘要：

目的探讨Sox2在神经营养因子3（neurotrophin-3,NT-3）促进原代大鼠神经干细胞（neural stem cells,NSCs）分化中的作用及其机制。方法选取孕14-15 d SD胎鼠,培养原代脑源性NSCs。观察NT-3对NSCs中Sox2表达及NSCs分化的影响：采用不同浓度NT-3（25、50、100 ng/m L）刺激NSCs24 h后,检测Sox2、DCX、Olig2、GFAP蛋白的表达量。探索NT-3对Sox2产生影响的机制：使用PI3K/AKT通路阻断剂（10μmol/L LY294002）选择性阻断NT-3的作用后,检测AKT、p-AKT和Sox2在蛋白水平表达量的变化。结果随着NT-3浓度的升高,NSCs中Sox2蛋白水平的表达明显上调（P〈0.05）,各NT-3处理组的NSCs向神经元前体细胞分化的比例明显增加（P〈0.05）,100 ng/m L NT-3组效果最强,呈现出明显的剂量依赖性;与对照组相比,100 ng/m L NT-3组的p-AKT及Sox2蛋白水平显著上调（P〈0.05）,且LY294002可阻断此作用（P〈0.05）。结论 NT-3能够上调NSCs中Sox2的表达,后者进而诱导NSCs向神经元方向分化,其可能是通过激活PI3K/AKT信号通路起作用。

英文摘要：

Objective To investigate the effect of SRY（ sex determining region Y）-box 2（ Sox2） on neutrotrophin-3（ NT-3）-induced differentiation of rat brain-derived neural stem cells（ NSCs）. Methods NSCs were isolated from Sprague-Dawley（ SD） rat embryos（ 14- 15 d） and cultured in vitro. Then,NSCs were randomized into control group,25 ng / m L NT-3 group,50 ng / m L NT-3 group,and 100 ng / m L NT-3group. After the cells in all the groups were cultured for 24 h,the expressions of Sox2,doublecortin（ DCX）,oligodendrocyte transcription factor 2（ Olig2）,and glial fibrillary acidic protein（ GFAP） were assessed by Western blotting and immunofluorescence assay. Besides, NSCs were randomized into control group,10 μmol / L PI3 K / AKT pathway inhibitor（ LY294002） group,100 ng / m L NT-3 group,and LY294002（ 10 μmol/L） ＋ NT-3（ 100 ng /m L） group. After the cells were cultured for 24 h,the expressions of AKT,p-AKT and Sox2 proteins were detected. Results The Sox2 protein expression was significantly up-regulated along with the concentration increase of NT-3（ P〈0. 05）,and the proportion of neuronal precursor cells differentiated from the NSCs was increased in a dose-dependent manner（ P〈0. 05）. The 100 ng / m L NT-3group markedly up-regulated the expression of p-AKT and Sox2 proteins as compared with the control group（ P〈0. 05）,and the up-regulation could be blocked with LY294002（ P〈0. 05）. Conclusion Sox2 induces the differentiation of NSCs to neuronal precursor cells,and NT-3 up-regulates the Sox2 expression through activating PI3 K / AKT signal pathway.