Differential reactive oxygen species generation during bovine oocyte in vitro maturation

SERGIO MORADO; PABLO CETICA; MARTHA BECONI; GABRIEL DALVIT

Davos (Suiza)

Congreso; 13th Biennial Meeting of the Society for Free Radical Research International; 2006

Society for Free Radical Research International

Differential reactive oxygen species generation during bovine oocyte in vitro maturation Morado S., Cetica P., Beconi M. and Dalvit G. Química Biológica, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires. smorado@fvet.uba.ar   Immature and matured bovine oocytes generate similar ROS levels. The addition of cysteine to the maturation medium increase reduced glutathione (GSH). The aim of this work was to determine the possible variation of ROS production during bovine oocyte in vitro maturation. Cumulus-oocyte complexes were recovered by aspiration of antral follicles from ovaries obtained from slaughtered cows and cultured in medium 199 (control), 0.6 mM cysteine and 1 mM choro-dinitro benzene (CDNB, GSH removal) at 39ºC, 5% CO2 in humidified air for 22 h. Meiotic maturation was determined by the presence of metaphase II. ROS production was determined in denuded oocytes at 0, 6, 10, 18 and 22 h by the ratio between 2´,7´-dichlorodihydrofluorescein diacetate (DCHFDA) and fluorescein diacetate (FDA) assays, analysing digital microphotographs. Maturation percentages of control, GSH and CDNB were 78, 80 and 32%, respectively. ROS levels expressed as DCHFDA/FDA ratio fluctuated throughout the 22 h of maturation, showing a similar pattern with the different treatments. A significant decrease at 10 h was observed (P