Occurrence of chromosomal aneuploidy in rabbit oocytes and embryos at different developmental stages.

The aim of our study was to analyse chromosomal aneuploidy occurrence in rabbit oocytes and embryos. Chromosomal analysis was done in rabbit oocytes and rabbit preimplantation embryos at 2-, 4- and 8-cell stages derived from in vivo fertilization. For mitotic cycle synchronization at the metaphase stage, 2-, 4- and 8-cell embryos were incubated in k-DMEM medium, supplemented with colcemid (1 microg/ml), for 7, 12 or 13h respectively. Success of metaphase synchronization was at values of 100, 86.1 and 92.2% for 2-, 4- and 8-cell embryos respectively. Recovery rate of analysable metaphase plates was reached at 58.8%, 83.9% and 59.8% for 2-, 4- and 8-cell embryos and 100% for oocytes. Significant difference (p < 0.01) in aneuploidy rate between oocytes (40.7%) and 2-cell embryos (62.5%) was found. These results demonstrate higher efficiency of synchronization of embryo cells at the metaphase stage, what may contribute to elevating the proportion of analysable nuclei.