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

Objective: To investigate whether postovulatory aging of oocytes in the mother affects DNA methylation acquisition of imprinted genes in oocytes from the offspring.

Methods: Randomized research experimental study. Methods: Academic basic research laboratory. Methods: Mice. Methods: Fresh oocytes and aged oocytes from mothers were artificially inseminated, and oocytes were collected from the resultant offspring. Methods: Methylation status was evaluated at differentially methylated regions (DMRs) in oocytes of maternally imprinted genes Peg3, Snrpn, and Peg1 and paternally imprinted gene H19.

Results: 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.

Conclusions: 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.