Antioxidant enzymes glutathione peroxidase and glutathione reductase correlate with human embryo cell number

Abstract

OBJECTIVE: Glutathione peroxidase and glutathione reductase are antioxidant enzymes that assist cells in reducing destructive reactive oxygen species. Glutathione peroxidase expression in the oocyte has been associated with successful oocyte maturation. In this study, we evaluate the impact of these and other antioxidant enzymes in follicular fluid (FF) on human embryo cell number as a surrogate marker of oocyte competence during IVF.DESIGN: Prospective study.MATERIALS AND METHODS: FF from a single 18-20 mm follicle was obtained from 60 women (ages 23-44) undergoing IVF. Serum was also obtained at the time of oocyte retrieval. Antioxidant enzyme activities (glutathione peroxidase, glutathione reductase, glutathione s-transferase, superoxide dismutase) were measured by kinetic enzyme assay. Bivariate associations were evaluated among FF antioxidant enzymes and embryo cell number from the corresponding oocyte, controlling for day of embryo transfer.RESULTS: Glutathione peroxidase, glutathione reductase and glutathione s-transferase correlate with each other in FF (rsp> 0.35, P < 0.01), but only glutathione peroxidase and glutathione s-transferase correlate in serum (rsp > 0.28, P < 0.05) (Table 1). In 31 women with day three embryo transfer, glutathione peroxidase and glutathione reductase correlated positively with embryo cell number. Glutathione s-transferase and superoxide dismutase did not correlate with embryo cell number in a statistically significant fashion (P>0.05).Table 1Antioxidant EnzymeEmbryo Cell Number (n=31)Glutathione peroxidase0.40 (95% CI 0.04, 0.66)Glutathione reductase0.43 (95% CI 0.08, 0.68)Glutathione s-transferase0.01 (95% CI -0.35, 0.37)Superoxide dismutase-0.15 (95% CI -0.48, 0.23) Open table in a new tab OBJECTIVE: Glutathione peroxidase and glutathione reductase are antioxidant enzymes that assist cells in reducing destructive reactive oxygen species. Glutathione peroxidase expression in the oocyte has been associated with successful oocyte maturation. In this study, we evaluate the impact of these and other antioxidant enzymes in follicular fluid (FF) on human embryo cell number as a surrogate marker of oocyte competence during IVF. DESIGN: Prospective study. MATERIALS AND METHODS: FF from a single 18-20 mm follicle was obtained from 60 women (ages 23-44) undergoing IVF. Serum was also obtained at the time of oocyte retrieval. Antioxidant enzyme activities (glutathione peroxidase, glutathione reductase, glutathione s-transferase, superoxide dismutase) were measured by kinetic enzyme assay. Bivariate associations were evaluated among FF antioxidant enzymes and embryo cell number from the corresponding oocyte, controlling for day of embryo transfer. RESULTS: Glutathione peroxidase, glutathione reductase and glutathione s-transferase correlate with each other in FF (rsp> 0.35, P < 0.01), but only glutathione peroxidase and glutathione s-transferase correlate in serum (rsp > 0.28, P < 0.05) (Table 1). In 31 women with day three embryo transfer, glutathione peroxidase and glutathione reductase correlated positively with embryo cell number. Glutathione s-transferase and superoxide dismutase did not correlate with embryo cell number in a statistically significant fashion (P>0.05).