Impacto do estresse oxidativo na maturação de oócitos in vitro: efeito antioxidante do tanino.

Abstract

In vitro conditions can end up promoting damage to oocytes due to oxidative stress, compromising their quality and success rates in embryo production. Research has reported that supplementing the in vitro maturation medium with different antioxidants helped mitigate damage from oxidative stress. Thes, tannin, which has antioxidant action, arouses interest in studies on its antioxidant potential in oocyte maturation. This study was carried out to promote greater scientific knowledge about the action of tannin on oocyte maturation. Ovaries from adult cows obtained from a commercial slaughterhouse were used. These antral follicles were aspirated to select oocytes with homogeneous cytoplasm and one or more compact layers of cumulus cells. After maturation, these cells were removed by pipetting for subsequent preparation of slides and reading regarding the cellular meiotic stage. The experimental groups consist of different concentrations of Tannin (Sigma), being: TA0 = no addition of Tannin (control); TA1 = 1 μg/mL Tannin; TA10 = μg/mL of Tannin and TA100 = 100 μg/mL of Tannin. With the experiment, similar maturation rates were obtained for all treatments tested: TA0 (79.31%) TA1 (72.63%) TA10 (80.95%) TA100 (73.11%). Regarding the cleavage rates obtained after fertilization, it was observed that treatments TA0 (73.13%) TA1 (63.38%) TA10 (70.90%) presented similar results, while treatment T100 (47.91 %) showed a deleterious effect with a significant decrease in cleavage rates. Therefore, it is recommended that tannin supplementation be carried out in amounts below 100 μg/mL.