Comparison effect of hypoxanthine and dibutyl cyclic adenosine monophosphate (dbcAMP) on nuclear morphology of growing pig oocyte from early antral follicles

Abstract

It is known well that dbcAMP is important for in vitro growth (IVG) culture of pig oocytes from early antral follicles. However, the effect of hypoxanthine in vitro growth of pig oocytes have not studied yet. This study aims to examine the effect of hypoxanthine on IVG of oocyte from early antral follicles, then the comparison effect of hypoxanthine and dbcAMP on nuclear morphology of IVG pig oocytes. Oocyte-granulosa cells (OGCs), which were isolated from early antral follicles (1.5-2 mm in diameter), was cultured in vitro growth with dbcAMP or hypoxanthine to examine the fully-grown stage of oocytes. Then, these oocytes were cultured in vitro maturation continuously to examine the meiotic competence. After in vitro growth culture, there are similarity of the cumulus proliferation of these oocytes were culture from medium containing dbcAMP or medium containing hypoxanthine. Importantly, high percentage of oocyte reaches to fully-grown stage were founded similarly in culture with dbcAMP or hypoxanthine (42.3% or 49.5%, respectively), while, none-culture IVG oocytes was only 2.8% fully-grown. In addition, the oocytes underwent germinal vesicle breakdown (GVBD) and the rate of GVBD of dbcAMP and hypoxanthine was similar. In conclusion, both hypoxanthine and dbcAMP can use for in vitro growth in pig oocytes. Keywords: preantral follicles, hypoxanthine, dbcAMP, in vitro growth, fully grown,in vitro maturation.