低氧诱导神经干细胞凋亡和miR-26a低表达

目的:初步探讨氯化钴(cobalt chloride,Co Cl2)是否诱导神经干细胞(neural stem cells,NSCs)凋亡及其机制,探讨NSCs凋亡是否引起microRNA-26a(miR-26a)表达变化。方法:用不同剂量的Co Cl2处理NSCs,CCK-8检测细胞活力;TUNEL检测细胞凋亡;建立Co Cl2诱导NSCs凋亡的模型,将NSCs分为对照组和凋亡组,real-time PCR检测miR-26a-3p、miR-26a-5p、GSK-3β、Bcl-2、Bax和caspase-3的表达;Western blotting检测Bcl-2和Bax的蛋白水平。结果:CCK-8结果显示不同浓度(200、400和600μmol/L)Co Cl2作用24 h,NSCs活力呈剂量依赖性下降(P0.05)。TUNEL检测显示Co Cl2(200、400和600μmol/L)作用24 h后NSCs凋亡率呈剂量依赖性增加(P0.05)。Real-time PCR和Western blotting结果表明凋亡组miR-26a、GSK-3β、Bax和caspase-3表达增加,Bcl-2、Bcl-2/Bax蛋白水平下降(P0.05)。结论:Co Cl2(400μmol/L)作用24 h可建立NSCs凋亡模型,其机制可能与线粒体凋亡通路有关;NSCs凋亡时miR-26a表达减少。

Hypoxia promotes apoptosis of neural stem cells and down-regulates miR-26 a

AIM: To investigate the effect of cobalt chloride (CoCl₂) on the apoptosis of neural stem cells (NSCs) and the expression of microRNA-26a (miR-26a) in vitro, and to explore the mechanisms of NSC apoptosis induced by CoCl₂. METHODS: NSCs were exposed to CoCl₂ at different doses (200~600 μmol/L) for 24 h. The cell viability and apoptosis were measured by CCK-8 assay and TUNEL method. The expression of miR-26a-3p, miR-26a-5p, GSK-3β, caspase-3, Bcl-2 and Bax was examined by real-time PCR. The protein levels of Bcl-2 and Bax were detected by Western blotting. RESULTS: The cell viability was inhibited and the apoptosis of NSCs was increased significantly by CoCl₂ in a dose-dependent manner (P<0.05). CoCl₂ at concentration of 400 μmol/L for 24 h was used to induce apoptosis and the expression of miR-26a was down-regulated compared with control (P<0.05). Exposure to CoCl₂ at concentration of 400 μmol/L up-regulated the expression of GSK-3β, caspase-3 and Bax, down-regulated the expression of Bcl-2 and Bcl-2/Bax (P<0.05). CONCLUSION: CoCl₂ at concentration of 400 μmol/L induces the apoptosis of NSCs obviously. CoCl₂ may induce the NSC apoptosis by mitochondrial apoptotic pathway. Declining miR-26a may be related to NSC apoptosis.