Postovulatory aging of oocytes decreases reproductive fitness and longevity of offspring

We analyzed the long-term effects of postovulatory aging of mouse oocytes on reproductive fitness and longevity of offspring. Hybrid (C57BL/6JIco X CBA/JIco) parental generation (F-0) females were artificially inseminated at 13 h (similar to1 h postovulation) or 22 h (similar to10 h postovulation) after GnRH injection. Reproductive fitness of first generation (F-1) females was tested from the age of 28 wk until the end of their reproductive life. In males, the testing period ranged from the age of 2 yr until their natural death. Experimental F-1 females exhibited longer between-labor intervals, decreased frequency of litters, and lower total number of litters and offspring born. Experimental second generation (F-1) pups displayed teratogenic defects, higher preweaning mortality, and decreased body weight at weaning. Incidence of infertility was higher in experimental F-1 males, which translated into lower total number of offspring born when compared with the control group. Life expectancy of F-1 offspring was decreased in the experimental group. These results clearly show that postovulatory aging of mouse oocytes decreases reproductive fitness and longevity of offspring.