Oxidative Homeostasis in Follicular Fluid and Embryo Quality-A Pilot Study

The objective of this study was to measure the different redox biomarker levels within the follicular fluid (FF) and evaluate correlations with embryo quality using the one follicle-one oocyte/embryo approach. The prospective study included 54 women (average age 34.6 ± 3.0 years). Out of the 235 mature metaphase II cells that underwent intracytoplasmic sperm injection, fertilization was achieved in 177 cells, producing 92 Grade I embryos, 26 Grade II embryos, 39 Grade III embryos, and 20 Grade IV embryos. The activities of antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and glutathione transferase were significantly higher in the group consisting of lower-quality (Grades II-IV) embryos in comparison with top-quality (Grade I) embryos (p = 0.011; p = 0.021; p = 0.008, respectively). The concentration of oxidative stress markers, malondialdehyde, 8-hydroxy-2'-deoxyguanosine, and thiol groups was significantly increased in the group with lower-quality embryos (Grades II-IV) compared to top-quality embryos (0.027; 0.018; 0.021, respectively). Furthermore, a significant positive correlation between each oxidative marker and the activities of antioxidant enzymes was observed (p < 0.001). According to our findings, the best embryos and, consequently, better in vitro fertilization outcomes are linked to low levels of oxidative stress and low antioxidant enzyme activity.