Superoxide dismutase expression in human cumulus oophorus cells

Abstract

Success in assisted reproductive techniques (ART) is influenced by gamete and embryo quality but the assessment of these parameters has been thwarted by the lack of reliable biomarkers. Follicular fluid and cumulus oophorus cells may provide biomarkers due to their close relationship to the oocyte. These cells produce antioxidants and thus protect the oocyte from oxidative damage exerted by reactive oxygen species (ROS). ROS and antioxidants are known to intervene in reproductive physiology and pathology, but their roles are unclear. It is hypothesized that superoxide dismutase (SOD), a first line antioxidant enzyme, is associated with oocyte quality. Cells obtained in the course of ART for the treatment of infertility due to male factor or female pathology were processed for SOD intracellular isoforms (CuZnSOD and MnSOD) immunodetection, total SOD activity and isoforms content. Cells presented strong positive staining for CuZnSOD and MnSOD. SOD activity decreased with increasing female age but was increased in endometriosis and in ovulatory dysfunction. When male factor was the cause for infertility, successful ART was associated with higher SOD activity. Variations in SOD emphasize the relevance of oxidative stress in the oocyte maturation process. These variations also suggest that SOD is a potential biomarker for ART success.