Effect of ascorbic acid on vitro growth and parthenogentic development of porcine oocyte derived from early antral follicle (1-1.5mm)

Abstract

The oocytes from early antral follicles (EAFs) have low developmental potential to reach blastocyst due to incomplete cytoplasmic maturation during in vitro growth (IVG). Thus, we developed an in vitro culture system for porcine oocytes derived from early antral follicles with L-Ascorbic acid to support their development to the blastocyst stage. Besides that, how IVG medium affects the surrounding cells of porcine oocytes with a particular focus on the expansion and attachment of cumulus cells will be elucidated. The in vitro culture process consisted of three steps. The first step is 90 hours of IVG, the second step is 6 hours of hCG treatment, and the last step is 40 hours of IVM. We utilized different concentrations of L-ascorbic acid supplement during IVG. There were two control groups (positive control: oocyte derived from large follicles; negative control: IVG medium without Lascorbic acid). The results show that the increase in the concentration of L-ascorbic acid improves growth in terms of diameter and chromatin confirmation. More specifically, Vit C 100 group can reach the maturation size compared to the large oocyte. In addition, L-ascorbic acid improves cumulus expansion and maintains cumulus attachment of isolated oocytes from EAFs after in vitro maturation. Based on the result of this procedure, we proposed the best culture condition in which L-ascorbic acid supplementation at 100 ug/mL in IVG. In addition, our study suggested that oocytes isolated in a 24-well low attachment dish sharply enhanced the expansion and attachment of cumulus cells, partially preventing them from adhering to the bottom of the dish