evaluation of embryos derived from in vitro fertilized oocytes reconstructed by meiosis-ii chromosome transplantation from aged mice to ooplasms of young mice

background: to assess embryos derived by the transfer of meiosis-ii chromosomes (m-ii-t) from aged mice oocytes into ooplasms from younger mice to overcome the problem of age-related decline in female fertility. materials and methods: the developmental capacity karyotype and ultrastructure of reconstructed oocytes derived from meiosis-ii chromosome transplantation from aged mice into the ooplasms of young mice by piezo-micromanipulation were assessed. results: the survival rate of enucleated young oocytes was 54% and the percent of fertilized reconstructed oocytes was 23%. the rate of embryo development to the two-cell stage after cultivation was 40%. since 82.4% of the analyzed embryos derived from reconstructed oocytes had condensed nuclei it was not possible to analyze their chromosomal integrity. however 17.6% of analyzable reconstructed old oocyte derived embryos (old-odes) had normal diploid sets of chromosomes. major structural differences were not observed between young old and m-ii-t derived two-cell embryos. conclusion: our findings suggested that ooplasms from younger mice may overcome ageassociated problems in older mice.