Reactive oxygen species and redox state participation in bovine oocyte activation in vitro

SERGIO MORADO; PABLO CETICA; MARTHA BECONI; JEREMY THOMPSON; GABRIEL DALVIT

Buenos Aires

Jornada; III Jornadas Internacionales del Instituto de Investigación y Tecnología en Reproducción Animal; 2012

Facultad de Ciencias Veterinarias, Universidad de Buenos Aires

The metabolic profile of bovine oocytes during in vitro fertilization (IVF) are not well known. Although reactive oxygen species (ROS) have been associated with harmful effects within somatic cells and embryos, at physiological levels they regulate signalling pathways thereby modifying cell function. The aim of this work was to determine if fluctuations in reduction-oxidation (redox) state and ROS levels during IVF accompanied either sperm or parthenogenetic activation. Cumulus-oocyte complexes (COCs) were cultured in medium 199 with the addition of fetal calf serum and gonadotropins at 39°C, 5% CO2 in humidified air for 22h. Then, COCs were co-incubated with a suspension of 1x106 motile spermatozoa/ml for 24h in IVF-mSOF or activated with ionomycin and 6-DMAP + cytochalacin B. ROS production and redox state were evaluated in zygotes every 2h, beginning at 7h of activation, by DCHFDA/FDA and RedoxSensor Red fluorescent assays, respectively. In sperm activated oocytes ROS levels fluctuated throughout the 24h of development, presenting clearly discernable peaks around 7, 19 and 24h (p