The effect of free radicals on sperm DNA and antioxidant protective role; an assessment and review

Oxidative stress is an imbalance between the level of ROS and antioxidants. Sperm membranes are rich in polyunsaturated fatty acids and are very sensitive to increased free radicals. Increasing the level of ROS can lead to an increase in lipid peroxidation in sperm membrane, decrease in their flexibility, and ultimately a decrease in sperm motility. Also, oxidative stress may impair sperm axonemal and mitochondrial function, as well as DNA integrity, RNA and protein synthesis. Several studies have shown that antioxidants are beneficial to human health and are used to prevent cancer and coronary artery disease. Based on the present review, there are more documents in protective effects of antioxidants on sperm cells. Studies showed adding in vitro antioxidants to sperm samples can increase sperm parameters such as sperm motility, morphology and decrease sperm membrane lipid peroxidation and sperm DNA damage. Also in vivo or oral antioxidants supplementation has protective effects on sperm from ROS negative effects. Since the causes of infertility are various, the lack of antioxidants action in reducing the sperm DNA damage, the level of antioxidant activity depends on the type, dose and duration of intake, so more studies are needed to determine the appropriate antioxidant type, the dosage and timing of administration in vivo and in vitro.