Exposure of either gametes or embryos to conditions and/or factors that generate oxidative stress has been associated with impaired early embryogenesis. The effects of reactive oxygen species (ROS) on mouse preimplantation development, depending of the ROS-concentration and time of exposition, were studied. Two-cell embryos were incubated with 5, 10, 25 and 50 μM of hydrogen peroxide (H2O2) for 30 and 60 minutes of exposition and allowed to develop for 72 h to study the quality of development. The incubation with 50 μM2HO2 for 30 or 60 minutes, strongly inhibited the 2-cell embryo development as compared to the control (p<0.001). Twenty-five μM2HO2 produced inhibition of blastocyst formation (p<0.001) and 10 μM... |