Co-culture of cumulus-enclosed bovine oocytes with theca cells induces the meiotic arrest but does not inhibit germinal vesicle development.

摘要

The effects of maturation inhibitors and follicular cells on germinal vesicle development and meiotic resumption in cattle oocytes were examined. Oocytes from larger diameter follicles developed more rapidly. Although culture of cumulus-oocyte complexes in the presence of dibutyryl-cAMP, 8-bromo-cAMP or N6-monobutyryl-cAMP did not inhibit meiotic maturation, culture in the presence of cycloheximide did. Cycloheximide completely inhibited development of the germinal vesicle, assessed by changes in morphology. Co-culture of cumulus-oocyte complexes with theca cells or theca and granulosa cells inhibited meiotic resumption but allowed germinal vesicle development to the most advanced stage (stage V). Co-culture with theca cells synchronized oocytes at the stage just prior to germinal vesicles breakdown. When removed from co-culture, the majority of oocytes were able to resume meiosis if co-cultured in a sufficiently large volume of medium.