Impact of cumulus cell removal on oocytes' nuclear maturation and development in the domestic cat

Female genomes do not currently contribute to genome resource banks due to complications collecting and preserving oocytes. One option is to preserve immature oocytes without cumulus cells (CCs). This study therefore examines the effects of denuding germinal vesicle stage domestic cat oocytes and to insure nuclear maturation and developmental competence of denuded oocytes (DOs) in vitro. In experiment 1, DOs were compared with intact oocytes through in vitro maturation, fertilization and development. In experiment 2, DOs were cultured alone or in a 1:1 ratio with intact oocytes. DOs cultured alone showed considerable impairment compared to intact oocytes (p < 0.05). When co-cultured, all DO processes were improved compared to DO cultured alone (p < 0.05), indicating for the first time that direct CC-oocyte communication is unnecessary for domestic cat oocyte maturation, fertilization and development - suggesting a diffusible factor as the actual initiator of oocyte maturation and development.