Peritoneal fluid of women with endometriosis reduces SOD1 in bovine oocytes in vitro maturation

Studies have demonstrated oxidative stress in peritoneal fluid (PF) from women with endometriosis and the importance of enzymatic antioxidant machinery to avoid oocyte oxidative damage. Considering that PF constantly surrounds the ovaries and has direct contact with the oocyte at ovulation, we wonder if PF from women with endometriosis may affect antioxidant enzyme gene expression. Thus, the present study aims to evaluate the PF impact from infertile women with minimal and mild endometriosis and from fertile control women without endometriosis on SOD1, CAT, GSR gene's expression in experimental bovine oocytes matured in vitro. Samples of PF were obtained from women who underwent videolaparoscopy-7 infertile with EI/II and 7 fertile without endometriosis. Immature bovine oocytes underwent in vitro maturation in the absence of PF and in the presence of three concentrations (1, 5 and 10%) of PF from fertile and from infertile women with EI/II. After 22 to 24 h of IVM, oocytes were denuded and stored for analysis of SOD1, CAT and GSR by real-time polymerase chain reaction. Oocyte SOD1 expression was significantly lower in the 10% endometriosis group (0.67 +/- 0.32) when compared with no-peritoneal fluid (1.05 +/- 0.24, p < 0.008) and 10% control groups (1.06 +/- 0.22, p < 0.006). These findings raise the possibility of a deleterious influence of PF from women with EI/II on the oocyte, not only after ovulation but also during the maturation process, which could contribute to worsening oocyte quality, being one of the mechanisms related to infertility in patients with endometriosis.