Effects Of Intrauterine Chronic Hypoxia On DNA Methylation And Expression Of Ephrin-A4 In Heart Tissue Of Offspring Mice

Objective Cardiovascular disease is the main cause of human death due to illness today,has become a major global public health problem.Studies have demonstrated that intrauterine chronic hypoxia associated with the onset of adult cardiovascular disease.In recent years,it has been paid more attention to explaining how the intrauterine environment influences the development of the fetus through an epigenetic mechanism.Ephrin-A4,as a member of the Eph family of proteins,plays an important role in cerebral vascular development and ocular angiogenesis.But so far,little is known about the role of Ephrin-A4 in the development of heart,large vessels and the development of cardiovascular diseases.This study was designed to investigate the effect of intrauterine chronic hypoxia on DNA methylation in the promoter region of newborn mice heart tissue and the expression of Ephrin-A4 gene in the heart tissue of offspring male mice.To investigate the possible mechanism of intrauterine chronic hypoxia induced cardiovascular disease.Methods Twenty pregnant mice were divided into control group and intrauterine chronic hypoxia group(10 mice in each group).Then the model of intrauterine chronic hypoxia was established.One offspring mice was randomly selected from each nest when they were1day?3 months and 6 months old.The mouse heart tissue samples were taken and only male offspring mice were taken when they were 3 months and 6 months old.Use MeDIP-chip analysis the differences in DNA methylation level between the control and ICH groups in 1-day-old offspring mice heart tissue gene promoter region.Real-time RT-PCR was used to detect the expression of Ephrin-A4 mRNA in the hearts of3-month-old and 6-month-old offspring male mice.Western blotting and immunohistochemistry were used to detect the expression of Ephrin-A4 protein in thehearts of 3-month-old and 6-month-old offspring male mice.MeDIP-qPCR was used to detect the DNA methylation level of Ephrin-A4 gene promoter in the hearts of3-month-old and 6-month-old offspring male mice.Results1.A total of 1418 gene promoters with different methylation level were found between the control and ICH groups(1-day-old).Compared with the control group,the promoter region of the heart tissue gene in the offspring of ICH group was hypermethylated as a whole.2.Compared with the control group,the expression of Ephrin-A4 mRNA in heart tissue of ICH group was significantly up-regulated in the male mice of 3-month-old offspring(P<0.05)and down-regulated in the male mice of 6-month-old offspring(P<0.05).3.Compared with the control group,the expression level of Ephrin-A4 protein in heart tissue of ICH group was increased in the male mice of 3-month-old offspring(P<0.05)and decreased in the male mice of 6-month-old offspring(using Western blotting detection,P>0.05;Using immunohistochemical detection,P<0.05).4.Compared with the control group,the promoter region of Ephrin-A4 gene in heart tissue of ICH group showed hypomethylation in the male mice of 3-month-old offspring(P<0.05)and without significant difference in the male mice of 6-month-old offspring(P>0.05).Conclusions1.Intrauterine chronic hypoxia induces DNA methylation modification in newborn offspring mice(1-day-old)heart tissue gene promoter region.2.Intrauterine chronic hypoxia induces Ephrin-A4 gene expression abnormalities in the offspring male mice heart tissue and DNA methylation may plays an important role in the regulation of its expression.