Effect of hydrogen peroxide on bovine oocyte in vitro maturation

SERGIO MORADO; PABLO CETICA; MARTHA BECONI; GABRIEL DALVIT

Ciudad Autónoma de Buenos Aires

Jornada; II Jornadas del Instituto de Investigación y Tecnología en Reproducción Animal; 2010

Facultad de Ciencias Veterinarias

EFFECT OF HYDROGEN PEROXIDE ON BOVINE OOCYTE IN VITRO MATURATION MORADO SA, CETICA PD, BECONI MT, DALVIT GC Area of Biochemistry, Institute of Research and Technology in Animal Reproduction (INITRA), School of Veterinary Science, University of Buenos Aires The role of reactive oxygen species (ROS) in the processes associated with the handling and culture of gametes and embryos in vitro is controversial. In cattle, it was observed that the maturation of oocytes in glucose-rich media with high oxygen tension increases ROS production affecting their developmental competence. However, the supplementation of maturation medium with antioxidants (ascorbic acid, β-mercaptoethanol, superoxide dismutase) did not increase the competence of embryonic development and maturation of the oocyte. By contrast, maintaining an environment for the cultivation reduced antioxidant capacity of nuclear maturation and / or cytoplasm of the oocyte in rats and cattle. Similarly, the addition of antioxidants through in vitro fertilization (IVF) in cattle negatively affected the process. The aim of this study was to determine the influence of a generator of hydrogen peroxide (H2O2) in ROS production and in the maturation of bovine oocytes in vitro. Cumulus-oocyte complexes were collected from ovaries of slaughtered cows and cultured in medium 199 for 22 hours at 39 ° C in the presence and absence of xanthine (2 mM) + xanthine oxidase (1 mU / ml). ROS production was determined in previously denuded immature and matured oocytes by the ratio of 2',7'-diclorodihydro fluorescein diacetate and fluorescein diacetate techniques. The analysis was performed by digital microphotography. Meiotic maturation was assessed by the presence of metaphase II. ROS production in the presence of H2O2-generating system showed no significant differences. However, there was a significant decrease in the percentage of meiotic maturation of oocytes cultured in the presence of xanthine + xanthine oxidase (33.1%) compared to the control (86.5%) (P