低氧预适应减轻缺氧所致大鼠海马神经元线粒体膜改变

Effect of Hypoxic Preconditioning on Anoxia-induced Changes in Mitochondrial Membrane Potential in Rat Hippocampal Neurons

目的通过观察低氧预适应处理对缺氧引起的神经元bcl-2表达、线粒体膜电位变化的影响,探讨低氧预适应处理对神经元缺氧性损伤保护作用的机制。方法原代培养大鼠海马神经元细胞,分组处理后,采用免疫组织化学法对细胞bcl-2表达进行检测;采用罗丹明123染色测定线粒体膜电位,激光共聚焦扫描显微镜观察缺氧条件下各组细胞的线粒体膜电位变化。结果低氧预处理组海马神经细胞在急性缺氧1h复氧后,bcl-2表达阳性率为(74.5±9.8)%,较缺氧对照组(69.5±10.3)%明显提高,差异有统计学意义(P<0.05);线粒体膜电位测定发现,与缺氧对照组比较,低氧预处理组从缺氧第80s开始,各时间点线粒体膜电位均高于缺氧对照组(均P<0.05)。结论低氧预适应处理对原代培养大鼠海马神经元缺氧性损伤保护作用可能是通过增加缺氧后bcl-2表达,从而稳定线粒体膜,减慢神经元急性缺氧时线粒体膜电位降低的速度来实现的。

Objective To investigate the effect of hypoxic preconditioning（HP）on anoxia-induced expression of bcl-2and mitochondrial membrane potential（ΔΨm）in rat hippocampal neurons in an attempt to understand the mechanism by which HP protects against anoxia-induced neuronal injury.Methods Primary rat hippocampal neurons were cultured,subjected to HP and then to acute hypoxia.The expression of bcl-2was measured by immunohistochemistry,and the mitochondrial membrane potential by rhodamine-123 staining and laser confocal scanning microscopy.Results ①After 1-hour acute anoxia and then reoxygenation,the positive expression rate of Bcl-2was（74.5±9.8）%in hippocampal neurons,significantly higher than that in anoxia control group（69.5±10.3）%（P〈0.05）.②The mitochondrial membrane potential was significantly increased in HP group as compared with anoxia control group at detected time points after 80-second anoxia（P〈0.05）.Conclusion HP protects hippocampal neurons against anoxia-induced injury by increasing the expression of bcl-2,stabilizing the mitochondrial membrane potential and slowing down the decrease of the mitochondrial membrane potential in acute anoxia.