Developmental competence of buffalo (Bubalus bubalis) denuded oocytes cocultured with cumulus cells: Protective role of cumulus cells

Abstract The objectives of the present study were to evaluate the developmental competence of buffalo denuded oocytes (DOs) cocultured with cumulus cells (CCs) during in vitro maturation, and to investigate the mechanisms by which CCs promote oocyte maturation and development. Buffalo oocytes were matured in vitro for 24 h in three groups: (1) intact cumulus–oocyte complexes (COCs) (2) DOs cocultured with CCs (DOsCC), and (3) DOs cultured alone (DOs). Matured oocytes were used to determine the relative mRNA abundance of Gdf-9 , Bmp15 , Zar1 , Caspase-3 , Bcl-2 , Zp2 , Zp3 , Cd9 and Pde3a by Rt-qPCR and CASPASE-3 protein expression by immunofluorescence. The intracellular content of cGMP, cAMP and MPF activity and the rate of embryonic development were also assessed. Results of the present study showed that in DOs, the relative mRNA abundance of Gdf-9 , Bmp15, and Cd9 significantly ( P Bcl-2 , and Pde3a exhibited higher expression than DOsCC and COCs. However, there was no significant difference among the groups in the expression level of Zar-1 , Zp2 , and Zp3 . The intracellular content of cAMP and MPF activity was notably higher ( P P Cd9 .