The Role of the Natural Antioxidant Mechanism in Sperm Cells.

Molecular studies of the causes of male infertility revealed a significant contribution of oxidative stress. When excessive amounts of reactive oxygen species (ROS) are produced or antioxidant activity fails, the equilibrium between oxidation and reduction is disrupted, causing oxidative stress (OS). High levels of ROS can have an adverse effect on sperm function through the initiation of DNA damage, lipid peroxidation, loss of membrane integrity and increased permeability, inactivation of cellular enzymes, and cell apoptosis. In addition to endogenous factors such as immature sperm, leukocytes, and varicocele, potential causes of excessive ROS can also be found exogenously in males with testicular hyperthermia or exposed to environmental toxicity. To maintain the optimal functioning of sperm cells, it is, therefore, necessary to balance the redox potential, i.e., to balance ROS by antioxidants. The purpose of this review is to present the antioxidant defense systems in semen.