Reactive oxygen species in bovine oocyte maturation in vitro

SERGIO MORADO; PABLO CETICA; MARTHA BECONI; GABRIEL DALVIT

REPRODUCTION FERTILITY AND DEVELOPMENT

CSIRO PUBLISHING

Año: 2009 vol. 21 p. 608 - 614

1031-3613

The role of reactive oxygen species (ROS) in oocyte in vitro maturation (IVM) is still controversial. The aim of this work was to determine the possible fluctuation in ROS production during bovine oocyte IVM in the presence of different modulators of ROS generation. Cumulus-oocyte complexes were cultured in medium 199 (control) with the addition of cysteine, 1-choro-2,4-dinitro benzene (CDNB), diphenyliodonium, N-nitro-L-arginine methyl ester or sodium nitroprusside (SNP) at 39°C, 5% CO2 in humidified air for 22h. Respiratory chain effectors, potassium cyanide (KCN) or carbonyl cyanide m-chlorophenylhydrazone, were also used. Meiotic maturation was determined by the presence of metaphase II. ROS production was evaluated in denuded oocytes at different time points by the ratio between 2´,7´-dichlorodihydrofluorescein diacetate (DCHFDA) and fluorescein diacetate (FDA) assays. ROS levels, expressed as DCHFDA/FDA, fluctuated throughout the 22h of maturation depending on different treatments. At 12h KCN and SNP increased ROS levels, while cysteine reduced them (P