oxidative stress and antioxidants in male infertility: a difficult balance

infertility is one of the most stressful conditions amongst married couples. male factor infertility is implicated in almost half of these cases. recent advances in the field of reproductive medicine have focused the attention of many researchers to consider reactive oxygen species (ros) as one of the mediators of infertility causing sperm dysfunction. although, ros is involved in many physiological functions of human spermatozoa, their excess production results in oxidative stress. mitochondria and sperm plasma membranes are the two locations of ros production that involves complex enzyme systems such as creatine kinase and diaphorase. ros causes damage to the spermatozoa dna, resulting in increased apoptosis of these cells. the production of ros is greatly enhanced under the influence of various environmental and life style factors such as pollution and smoking. an effective scavenging system is essential to counteract the effects of ros. various endogenous antioxidants belonging to both enzymatic and non-enzymatic groups can remove the excess ros and prevent oxidative stress. since, ros is essential for the normal sperm physiology, rationale use of antioxidants is advocated.