Sodium selenite improves the in vitro follicular development by reducing the reactive oxygen species level and increasing the total antioxidant capacity and glutathione peroxide activity.

BACKGROUND The aim of this study was to investigate the effect of sodium selenite (SS) on reactive oxygen species (ROS) production, total antioxidant capacity (TAC) and glutathione peroxide (GPx) activity of cultured pre-antral follicles derived from vitrified and non-vitrified ovarian tissue. METHODS Immature mouse ovaries were vitrified, and mechanically isolated pre-antral follicles from vitrified and non-vitrified samples were cultured in TCM 199 medium supplemented with different concentrations (0, 5 and 10 ng/ml) of SS. Follicular, oocyte and embryo development was assessed. In parallel, ROS, TAC and GPx levels were analyzed after 0, 12, 24, 48, 72 and 96 h of culture. RESULTS Development rates of follicles, oocytes and embryos were significantly higher in SS-supplemented groups (P < 0.005). ROS production was increased, and TAC levels and GPx activities were decreased after 24 h of culture of pre-antral follicles in vitrified and non-vitrified groups, whereas in the presence of SS, ROS production was decreased and TAC levels and selenium-dependent GPx-specific activities were increased after 96 h of culture. Vitrified and non-vitrified samples responded in a similar manner. CONCLUSION SS caused an increase in follicular TAC level and GPx activity and a decrease in ROS level, thus improving the in vitro development of follicles.