中文摘要：

目的：观察常氧和低氧环境下大鼠大脑皮层神经干细胞（NSCs）体外分化情况，并比较P13K／Akt、JNK和Notch三条信号通路在不同氧环境下神经干细胞分化时所发挥作用的异同。方法：将体外悬浮培养48h的神经干细胞转移至4％低氧和常氧中贴壁培养。更换培养基诱导分化，同时加入LY294002（P13．K／Akt抑制剂）、SP600125（JNK抑制剂）和DAPT（Notch抑制剂），48h后行p一微管蛋白m（p-TubulinIII）和胶质纤维酸性蛋白（GFAP）免疫细胞荧光染色。对神经元和星形胶质细胞进行计数并分别计算各占的比例。结果：（1）低氧对照组神经元所占比例高于常氧对照组，星形胶质细胞低于常氧对照组，均具有统计学差异（P〈0．01）。（2）在常氧环境下，LY294002组神经元所占比例显著低于常氧DMSO对照组（P〈0．01），星形胶质细胞所占比例显著高于常氧DMSO对照组（P〈0．01）；和常氧DMSO组相比，SP600125组和DAPT组神经元和星形胶质细胞所占比例均无显著差异。（3）在低氧环境下，和低氧DMSO组比较，LY294002组和SP600125组神经元和星形胶质细胞所占比例均无显著性差异；DAPT组神经元所占比例显著高于常氧DMSO对照组（P〈0．01），星形胶质细胞所占比例低于常氧DMSO对照组，无显著性差异。结论：P13K／Akt介导了常氧条件下神经干细胞向神经元方向的分化；低氧可能通过抑制Notch信号通路促进神经干细胞向神经元方向分化。

英文摘要：

Objective ： To observe the differentiation of neural stem cell（ NSCs ） of rats in cerebral cortex under normoxia and hypoxia in vitro. The role of PI3K/Akt, JNK and Notch signaling pathway on the differentiation of NSCs under different oxygen condition is compared. Methods ： NSCs cultured 48 h in vitro is transferred to adherent culture in 4% oxygen concentration and normoxia. After differentiation medium is replaced, LY294002/SP600125/DAPT is added into the medium and β-TubulinIII and GFAP is stained with immune fluorescence. Then number of neurons and astrocytes is counted and its proportion is calculated respectively. Results ： （ 1 ） Proportion of neurons of hypoxia control group was exceeded than hypoxia control group（ P 〈0.01 ）, while proportion of astrocytes of hypoxia control group was lower than hy- poxia control group（P 〈 0.01 ）. （2） In normal oxygen concentration, proportion of neurons normal oxygen ＋ LY group was lower than normal oxygen ＋ DMSO group（ P 〈 0.01 ）, while proportion of astrocytes was higher than normal oxygen ＋ DMSO group（P 〈 0.01 ）. The proportion of neurons and astrocytes of normal oxygen ＋ SP600125 and normal oxygen ＋ DAPT groups was no significant difference compared to normal oxygen ＋ DMSO group. （ 3 ） In low oxygen concentration,the proportion of neurons and astrocytes of hypoxia ＋ LY294002 and hypoxia ＋ SP600125 groups was no significant differ- enee eompared to hypoxia ＋ DMSO group. The proportion neurons of hypoxia ＋ DAPT group was extremely higher than hy- poxia ＋ DMSO group（ P 〈 0.01 ）, while there was no signifieanee about astroeytes between the two groups. Conclusion： It is suggested that PI3-K/Akt mediates neuronal differentiation in normoxia, while hypoxia might promote the neuronal differentiation through inhibiting Notch pathway.