Effect of cumulus cells on vitrification of matured bovine oocytes

Tsvetelina Todorova

Abstract: In order to implement the best vitrification protocol one must minimize the damage that the oocytes suffer during the process and achieve a higher rate of survival and development. To realize this goal, it is necessary to determine the effect of cumulus cells during vitrification of matured bovine oocytes.
The survival rate of fresh oocytes was very close to 100%, with no significant differences between groups. However, the survival rates of vitrified denuded oocytes (vDO) in groups (91.0%) and vitrified denuded oocytes with cumulus cells (vDO + cc) (93%) were higher than vitrified cumulus-oocyte
complexes (COC) (79.6%), P < 0.05. Vitrified COCs had significantly lower survival rates (79.6%) compared to their fresh counterparts 97.3% respectively, (P < 0.05). Our results indicate that it is advisable to remove at least some of the cumulus cells before vitrification of matured bovine oocytes. Denuded oocytes undergo vitrification at a higher rate than cumulusoocyte complexes, although their fertilization and subsequent embryo development are compromised due to the lack of cumulus cells. Addition of intact COCs can restore the situation, providing denuded oocytes with similar rates of fertilization and embryo development as vitrified COCs.

Keywords: bovine; cumulus cells; in vitro; oocytes; vitrification

Date published: 2023-02-27