Effect of antioxidant on sperm freezing

A major cause of male infertility, which includes 50 causes of infertility, is oxidative stress.  The aerobic respiration in the sperm cell is associated with the production of reactive oxygen species (ROS). Some reactions such as sperm capacitation and acrosome reactions require moderate levels of ROS. However, when the amount of ROS production surpasses the natural antioxidant defense of the cell, it causes a harmful effect known as oxidative stress. This results in the oxidation of lipids, proteins, carbohydrates, and nucleotides. The production of ROS is increased by various factors including the presence of leukocytes, sperms with abnormal and immature morphology, centrifugation of samples, and changes in oxygen concentration, pH, and temperature. Sperm freezing is a method widely used in assisted reproductive methods (ART) as well as infertility treatment. The process of freezing also contributes to an increase in oxidative stress, as it alters the fluidity of the mitochondrial membrane and leads to an increase in the production and release of ROS. Sperm have defense mechanisms against oxidative stress caused by an increase in ROS production, which includes the presence of enzymatic and non-enzymatic antioxidants in semen. The utilization of supplementary antioxidants in the freezing environment is a strategy to combat oxidative stress. This review aims to summarize the current evidence on the effect of antioxidants on sperm freezing.