低氧对体外培养的神经干细胞中Wnt/β-catenin 信号通路相关分子表达的影响

目的     观察常氧(20%O2)和低氧［(3%±2%)O2］条件下体外培养的神经干细胞(NSCs)中Wnt/β-catenin信号通路相关分子的表达，探讨低氧促进NSCs增殖的机制。方法    体外分离培养新生小鼠海马NSCs，分别置于常氧和低氧条件下进行培养，采用RT-PCR法检测NSCs中Wnt/β-catenin通路关键分子的表达情况，通过电穿孔转染荧光素酶报告基因质粒检测NSCs内Wnt/β-catenin信号通路对低氧的反应性，采用Western blot法检测低氧对β-catenin和CyclinD1表达的影响。结果    NSCs表达Wnt/β catenin信号通路的主要分子，且该通路对低氧具有明显的反应；经低氧培养后NSCs表达β-catenin、CyclinD1较常氧组明显增加(P<0.05)。结论    Wnt/β-catenin通路可能通过增加β-catenin及CyclinD1的表达促进体外低氧条件下NSCs的增殖。

Influence of hypoxia on expressions of relative factors of the Wnt/β-catenin signal pathway in neural stem cells in vitro

 Objective    To observe expressions of relative factors of the Wnt/β-catenin signal pathway in neural stem cells (NSCs) cultured in vitro in normoxia(20%O2) and hypoxia (3±2%O2) and explore the mechanism of proliferation of NSCs in hypoxia. Methods    NSCs obtained from the hippocampus of a neonatal mouse were cultured in normoxia and hypoxia, then expressions of major factors of the Wnt/β-catenin pathway were detected by RT-PCR. After the luciferase reporter gene plasmid was transfected into NSCs by electroporation, responsive ability of the Wnt/β-catenin pathway to hypoxia was detected, and expressions of β-catenin and CyclinD1 in NSCs were detected by Western blot.  Results    The major factors in the Wnt/β-catenin signal pathway were detected in NSCs and the Wnt/β-catenin signal pathway was obviously responsive to hypoxia. The β-catenin and CyclinD1 protein levels were increased after hypoxia treatment compared with those in normoxia(P<0.05). Conclusion    The Wnt/β-catenin signal pathway may promote the proliferation of NSCs in hypoxia by increasing expressions of β-catenin and CyclinD1 in vitro.