Effect of postovulatory oocyte aging on DNA methylation imprinting acquisition in offspring oocytes

ObjectiveTo investigate whether postovulatory aging of oocytes in the mother affects DNA methylation acquisition of imprinted genes in oocytes from the offspring.DesignRandomized research experimental study.SettingAcademic basic research laboratory.Animal(s)Mice.Intervention(s)Fresh oocytes and aged oocytes from mothers were artificially inseminated, and oocytes were collected from the resultant offspring.Main Outcome Measure(s)Methylation status was evaluated at differentially methylated regions (DMRs) in oocytes of maternally imprinted genes Peg3, Snrpn, and Peg1 and paternally imprinted gene H19.Result(s)Our results showed that methylation patterns at DMRs of Peg3, Snrpn, Peg1, and H19 in oocytes from aged-oocyte offspring were mainly normal, with only a small number of oocytes showing aberrant methylation in the DMR of Peg3.Conclusion(s)Postovulatory oocyte aging causes a decline in reproductive outcomes but does not evidently lead to defects in DNA methylation imprinting acquisition in the oocytes from viable offspring.