The Expressions Of DNA Methyltransferase、Reelin And Protein Phosphatase-1in The Hippocampus Of Hypoxic Preconditioned Mice

Objective The aim of this study is to observe the expressions of three DNAmethyltransferase enzymes and reelin and pp1in hippocampus of hypoxic preconditionedMice. We proposed that DNA methylation may contribute to it. Methods Animal model:Male adult KunMing mice(body weight18.0–22.0g) were randomly divided into threegroups: blank control group with no exposure to hypoxia(H0), the hypoxia control groupexposed to hypoxia once(H1), and the hypoxia preconditioning group exposed to4runs ofhypoxia(H4). The procedure of the hypoxic experiment was performed as previouslydescribed. Briefly, the mouse was placed into a125-ml jar with fresh air, and the jar wassealed with a rubber plug. The mouse was removed from the jar as soon as the first gaspingbreath appeared, then it was switched to another fresh-air-containing jar of similar volume.This procedure was performed once(group H1) or repeated four times (group H4).Real-time polymerase chain reaction(PCR) was used to examine the mRNA levels of threekinds of DNA methyltransferase enzymes and reelin and PP1in the mouse hippocampusafter them exposured to hypoxia. Western blot was used to examine the protein levels ofthree kinds of DNA methyltransferase enzymes and reelin and PP1in the mousehippocampus after them exposured to hypoxia. The mRNA and potein relative abundancevalues of DNA methyltransferases enzymes and reelin and PP1in each group werecalculated to β-actin. Results （1） The mRNA and protein levels of DNMT1wereunchanged in H1and H4（P>0.05, H0vs H1and H4）.（2） The mRNA and protein levelsof DNMT3A were decreased in H1andH4（P<0.05, H0vs H1and H4）.（3） The mRNAand protein levels of DNMT3B were decreased in H4（P<0.05, H0vs H4）.（4） ThemRNA and protein levels of PP1were decreased in H4（P<0.05, H0vs H4）.（5） ThemRNA and protein levels of reelin were increased in H4（P<0.05, H0vs H4）. ConclusionsIn hippocampus of hypoxic preconditioned mice, the expressions of DNMT3A andDNMT3B and PP1were decreased and the expression of reelin was increased. Thechanges of these molecules may play roles in hypoxia neuroprotection.