Change in the ability of bovine granulosa cells to elongate transzonal projections and their transcriptome changes during follicle development.

Granulosa cells (GCs) in secondary follicles differentiate into cumulus cells (CCs) and mural granulosa cells (MGCs) in the antral follicle. Only CCs maintain direct connections with oocytes through transzonal projections (TZPs) and support oocyte growth. Here, we examined whether granulosa cells (GCs) from secondary follicles and MGCs from early and late antral follicles were able to reconstruct complexes with TZP-free denuded oocytes (DOs) and regenerate TZPs.

Reestablishment of transzonal projections and growth of bovine oocytes in vitro.

Transzonal projections (TZPs) that maintain bidirectional communication between oocytes and granulosa cells or cumulus cells are important structures for oocyte growth. However, whether TZPs develop between TZP-free oocytes and granulosa cells, and whether reestablished TZPs support oocyte growth, is unknown. We first examined changes in TZPs after denudation of bovine oocytes collected from early antral follicles (0.

In vitro growth of bovine oocytes in oocyte-cumulus cell complexes and the effect of follicle stimulating hormone on the growth of oocytes.

Several successful in vitro culture experiments have used oocyte-cumulus cell-mural granulosa cell complexes (OCGCs) from early antral follicles (0.5-0.7 mm) for the growth of bovine oocytes.