Many cases of male factor infertility are idiopathic, but 30–40% of cases may have excessive levels of reactive oxygen species (ROS) in their semen. The origins of endogenous ROS are leukocytes and immature spermatozoa, and external causes are various. On the contrary, seminal plasma contains various antioxidants. Low levels of ROS are essential for the fertilization process, but excessive levels of ROS lead to oxidative stress and can have harmful effects such as lipid peroxidation of a membrane, sperm deoxyribonucleic acid fragmentation, and apoptosis on the fertile capacity. In order to evaluate oxidative stress appropriately, ROS is measured by the chemiluminescence method with neat semen and quantification of 8-OH-2′-deoxyguanosine and malondialdehyde in seminal plasma. Antioxidant potential is often measured using total antioxidant capacity (TAC) assay. The oxidation-reduction potential measured by a MiOXSYS analyzer is a novel, easier, quicker, and less expensive technology to measure oxidative stress. In order to minimize oxidative stress and improve clinical outcomes, sperm-sorting methods, lifestyle modifications, shortening the ejaculatory abstinence, and treatments such as oral antioxidants, varicocelectomy, and testicular sperm extraction are taken into account. As a future prospect, proteomics, metabolomics, and genomics are still developing areas that have the potential to discover new findings and highly sensitive biomarkers.
Part of the book: Reactive Oxygen Species (ROS) in Living Cells