Effect of ascorbic acid on in vitro growth culture and the acquisition of meiotic competence of pig oocytes from early antral follicle

Abstract

Normally, very small proportion of growing oocyte can enter growth phase. Several in vitro growth culture systems have been developed to establish more suitable alternative environment for maintaining the viability and promoting the growth of oocyte. The purpose of this study is to examine the effect of Ascorbic acid on in vitro growth culture and the acquisition of meiotic competence of pig oocytes from early antral follicles. Pig oocyte-granulosa cell complexes (OGCs) isolated from early antral follicles (1-1.5 mm in diameter) are grown in vitro in culture medium containing ascorbic acid with two different concentrations, 100μg/ml and 200μg/ml, for 4 days and subsequently matured in vitro. The result showed that the percentage of oocytes acquiring meiotic competence reaching to Metaphase I stage after culturing with 100μg/ml of Ascorbic acid and maturing in vitro is five time higher than that after culturing with basic medium in the absence of ascorbic acid (14.7% and 3.1%, respectively). Therefore, we can conclude that the addition of Ascorbic acid into in vitro growth culture system improved the competence of oocytes to undergo meiotic maturation. However, it still not enhance the oocytes with full meiotic competence. Keywords: Ascorbic acid, early antral follicle, growing oocytes, in vitro growth (IVG), fully grown oocytes, in vitro maturation (IVM)