缺血、缺氧对小鼠海马DNA甲基化的影响

Effects of ischemia and hypoxia on DNA methylation in mouse hippocampus

目的建立缺血、缺氧脑片模型,探讨缺血、缺氧对小鼠海马的损伤及其机制。方法利用C57BL/6J小鼠建立海马脑片缺血、缺氧性脑损伤(HIBD)模型,采用免疫组织化学染色法和Western blotting法分析正常对照组海马脑片与HIBD实验组海马脑片炎症损伤、DNA甲基化相关酶的表达情况。结果 HIBD实验组海马脑片氧化应激、炎症损伤细胞明显多于对照组(P<0.01),诱发海马应激损伤;同时HIBD实验组海马脑片DNA甲基化水平高于对照组(P<0.01)。结论脑片缺血、缺氧可促发炎症反应对海马组织造成损伤,DNA甲基化水平升高,提示DNA甲基化可能参与缺血、缺氧组织损伤过程;机制可能是HIBD影响DNA代谢活动,诱导DNA甲基化水平升高,DNA甲基化调控相关基因表达产生氧化应激,促发炎症反应,对海马造成损伤。

Objective To establish a hypoxic-ischemic brain slice model,and to investigate the neuronal injuries and DNA methylations on the mouse hippocampus after hypoxic-ischemic brain damage. Methods Healthy adult C57 BL /6J mouse hippocampal slices were used to establish a HIBD model. The hypoxic-ischemic model was tested with TTC staining,and the changes of inflammatory injury and the expression of enzymes relating to DNA methylationwas were visualized by immunohistochemical and Western blotting. Results Cells＇ oxidative stress and inflammatory damage of HIBD hippocampal slices were much more serious than that in the control group（ P〈0. 01）,while the level of DNA methylation was higher,compared to the control group（ P〈0. 01）. Conclusion Hypoxic-ischemic can induce the hippocampal inflammatory damages,and enhance the level of DNA methylation,suggesting that DNA methylation is involved in the process of hypoxic-ischemic tissue injury. The relative mechanism may be that HIBD can cause the DNA methylation. Conversely,DNA methylation can increase oxidative stress and hippocampal damage.