Melatonin and male oxidative stress infertility

Among couples unable to conceive a child, infertility is explained by the male factor in about 50% of cases. The etiology of male infertility remains uncertain in 30-50% of patients. One of the frequent etiological factors of male infertility is oxidative stress, a statusin which an unbalance between the production of reactive oxygen species and the mechanisms of antioxidant protection. Today, the term «male oxidative stressinfertility» has been proposed as a new descriptor for infertile men with a combination of abnormalsperm characteristics and oxidative stress. Along with the use of traditional antioxidants, it is necessary to search for new moleculesto combat oxidative stressin infertile men. A promising strategy is to use melatonin, a hormone secreted by the pineal gland, as an antioxidant. The review examinesthe antioxidant effects of the melatonin metabolic cascade. The results ofstudies on the relationship between the level of melatonin in seminal plasma and male fertility are presented. New scientific data on the protective potential of melatonin against oxidative stress caused by various metabolic disorders, anticancer chemo- and radiation therapy and other pathogenetic conditions and negative effects are presented. The research on the prospects of using melatonin to protectspermatozoa from oxidative damage in the implementation of assisted reproductive technologiesis analyzed. The interim results ofstudies on the possibility of using melatonin as a dietary supplement in infertile men are summarized.