The effects of extracellular ATP and its receptor antagonists on pig oocytes during in vitro maturation

Abstract

We measured the ATP concentrations in the porcine follicular fluid derived from three sizes of follicles (small: 6 mm in diameter). Then, the effects of pre-treatment (100 μM each for 30 min before maturation) with antagonists for extracellular ATP receptor P2X or P2Y on the nuclear maturation rate of cumulus-cell-enclosed (COs) or -denuded oocytes (DOs) up to the preovulatory stage in the presence or absence of 20 nM ATP (a similar concentration to that of medium-sized follicle fluid) were investigated. The antagonists used were pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) or reactive blue 2 (RB2), for extracellular ATP receptor P2X and P2Y, respectively. In addition, the embryonic development rates of COs pre-treated with RB2 were also evaluated. It was found that when the follicular sizes increased, the ATP concentrations significantly decreased (P < 0.05). No differences were observed in the nuclear maturation rates among all COs, regardless of pre-treatment with (+) or without (-) PPADS and in the presence (+) or absence (-) of ATP during maturation. In contrast, the nuclear maturation rate of the COs, but not DOs, in the ATP(-) RB2(+) group was significantly lower (P < 0.05) than that of the ATP(-) RB2(-) and ATP(+)RB2(-) groups. The pronuclear formation and blastocyst formation rates by parthenogenetic activation in the ATP(-) RB2(+) and ATP(+) RB2(+) groups were significantly lower (P < 0.05) than those in the ATP(-) RB2(-) group. In conclusion, it is suggested that the nuclear maturation of porcine oocytes may be influenced by the ATP receptor P2Y present in the cumulus cells.

Chromatin openness of donor cells is directly correlated with the in vitro developmental capabilities of cloned buffalo embryos

“…ATP levels in cumulus cells and follicular fluid could affect the quality of oocyte maturation, and normally high levels of ATP promoted oocyte development (Wakizoe et al, 2015; Yu et al, 2010). Treatment of MII stage oocytes with exogenous ATP (DMNPE‐caged ATP) was found to fail to improve the developmental rate of bovine SCNT blastocysts (Xue et al, 2004).…”

“…The results showed that with F I G U R E 1 BFF3 have a higher G0/G1 phase ratio and SWI/SNF complex gene expression after contact inhibition. ATP levels in cumulus cells and follicular fluid could affect the quality of oocyte maturation, and normally high levels of ATP promoted oocyte development (Wakizoe et al, 2015;Yu et al, 2010).…”