Influence of gonadotrophins and cysteine on reactive oxygen species production in porcine oocyte maturation in vitro

SERGIO ADRIÁN MORADO; GABRIEL MARTIN ALVAREZ; GABRIEL CARLOS DALVIT; PABLO DANIEL CETICA

Santiago, Chile.

Congreso; VI Meeting of the Society for Free Radical Biology and Medicine (SFRBM); 2009

Society for Free Radical Biology and Medicine (SFRBM)

In previous studies we have demonstrated that gonadotrophins influence the metabolic activity of porcine cumulus-oocyte complexes (COCs) depending on cumulus features. The higher oxygen concentration of in vitro environments compared to in vivo ones increases the production of reactive oxygen species (ROS). Higher glutathione levels induced by cysteine improve porcine oocyte in vitro maturation (IVM) and developmental competence rates. The aim of the present study was to evaluate the influence of gonadotrophins and cysteine on ROS generation in porcine oocyte IVM. COCs were obtained by aspiration of ovarian antral follicles (3-8 mm) from slaughtered gilts, classified according to cumulus characteristics and matured during 48 h in  medium 199 (control) in the absence or presence of 0.57 mM cysteine or 0.5 ìg/ml FSH + 0.5 ìg/ml LH. ROS levels were determined in immature and matured oocytes using the ratio 2’,7’-dichlorodihydrofluorescein diacetate to fluorescein diacetate. Meiotic maturation was determined by the presence of metaphase II chromosome configuration. ROS levels were lower in matured than in immature oocytes regardless of cumulus characteristics (P<0.05). In the presence of gonadotrophins no significant differences were detected in ROS levels. On the other hand, the presence of cysteine in the culture medium decreased ROS production (P<0.05). In porcine oocytes the cumulus features of COCs and the presence of gonadotrophins would not participate in the regulation of ROS production during IVM. The addition of cysteine to the culture medium would be important to control ROS production in the oocytes during IVM regardless of cumulus characteristics.