Oxidative Stress and Oocyte Developmental Competence: A Cell-Specific Analysis of Antioxidant Enzymes in Human...

Background and Objectives: Granulosa (GCs) and cumulus cells (CCs) play a key supportive role in oocyte developmental competence and in antioxidant defence mechanisms triggered by endogenous reactive oxygen species production. Assisted reproductive technology (ART) procedures are an additional source of oxidative stress (OS) that somatic cells must counteract to ensure healthy embryo production. In this study, we quantified the major antioxidant enzymes (CAT, GPx1, SOD-1 and 2) in GCs and CCs retrieved from human antral follicles classified as large (>18 mm, L) or small (<18 mm, S) using ELISA. We correlated their contents with ongoing pregnancy rate (OPR). Materials and Methods: Healthy women (n = 17) undergoing ART procedures were selected for this study. During pickup, antral follicles were classified by diameter as L or S, and their somatic cells were stored separately for ELISA. After intracytoplasmic sperm injection (ICSI), embryo quality was assessed morphologically, and the OPR was evaluated. Results: Results showed that embryo quality and OPR were positively correlated with higher antioxidant enzyme levels detected in both GCs and CCs independently of follicle size. Conclusions: The data suggest that adequate levels of antioxidant enzymes in GCs and CCs are necessary not only to protect the oocyte from oxidative damage, but may also help predict embryo quality and OPR.