DNMT1、DNMT3A和蛋白磷酸酶1γmRNA在低氧预适应晚期相小鼠海马组织变化

The changes of DNMT1,DNMT3A and Protein Phosphatase 1γmRNA in later phase of hypoxic preconditioning mice

目的研究小鼠低氧预适应模型中DNA甲基化和PP1γ基因表达伴随低氧后时间的变化机制,阐明低氧是否通过DNA甲基化来调控PP1γ表达,发挥其脑保护作用。方法小鼠侧脑室注射5-aza-cdR(10μM,5μl),之后进行低氧处理,分别于低氧后0、1、2、3、4天处死小鼠,利用实时荧光定量PCR检测甲基转移酶DNMTs和PP1γmRNA的表达变化。结果低氧后1天DNMT1和低氧后2天DNMT3A的mRNA表达受到抑制(P<0.05),且不受甲基转移酶活性的影响。5-aza-cdR对DNMT1的表达没有影响(P>0.05);但明显抑制DNMT3A的表达(P<0.05)。低氧抑制PP1γmRNA表达(P<0.05),且有低氧后时间依赖性。甲基转移酶对PP1γ表达有抑制作用(P<0.05),且与低氧后时间有关。结论随着低氧后时间的延长,低氧通过改变DNA甲基化,尤其是DNMTs表达变化,调控PP1γ基因表达,实现其脑保护作用。

Objective：In hypoxic preconditioned mouse model, to study the changes of DNA methylation and protein phosphatase 1 expressions with the time after hypoxia.To reveal the hypoxia may regulate the PP1γ expression via the DNA methylation to play role in brain neuroprotection.Methods：The experimental group mice were injected with 5-aza-cdR（10 μmol/L, 5 μl）, then they were treated by hypoxia and last they were euthanasia after zero/one/two/three/four day＇s hypoxia.Real-time PCR was used to examine the mRNA levels of DNMTs and PP1γ in the mice hippocampus.Results：The results showed that the mRNA level of DNMT1 was decreased after one day since hypoxia and DNMT3A decreased after two day since hypoxia（P〈0.05）, those changes might not be affected by the activity of DNA methyltransferases.The mRNA level of DNMT3B was restrained by 5-aza-cdR（P〈0.05）, but not DNMT1（P〉0.05）.The mRNA levels of PP1γ were down-regulated by hypoxia（P〈0.05）.The mRNA levels of PP1γ were increased with 5-aza-cdR（P〈0.05）, and the increases had the relationship with the time after hypoxia.Conclusion：As the extension of time after hypoxia, the hypoxia may regulate the expression of PP1γ via the change in DNA methylation, especially DNMTs expression, to take part in the brain neuroprotection.