Lipid Peroxidation and Nitric Oxide Levels in Male Smokers' Spermatozoa and their Relation with Sperm Motility

BACKGROUND Nitric oxide (NO) is synthesized from L-arginine by a family of enzymes known as nitric oxide synthases. Low concentrations of NO is essential in biology and physiology of spermatozoa, but high amounts of NO is toxic and has negative effects on sperm functions. Moreover, sperm membrane contains high concentrations of polyunsaturated fatty acids that are highly susceptible to oxidative damage that interferes with fertilization ability. Therefore, we investigated the correlation between levels of sperm malondialdehyde (MDA) and NO with sperm motility in male smokers. METHODS Semen samples were collected from normozoospermic smoker (n=64) and nonsmoker (n=83) men. The content of sperm lipid peroxidation was determined by measuring malondialdehyde (MDA). The sperm NO were also measured using Griess reagent. Data was analyzed by SPSS, (version 15.0), using independent t-test and Pearson analysis. RESULTS The mean MDA and NO concentrations in the sperm of normozoospermic male smokers were significantly higher than the control group or normozoospermic nonsmokers, (p <0.001). A significant negative relationship was noted between sperm motility and sperm MDA levels (r=-0.32, p=0.01); and sperm motility and sperm NO concentration (for nitrite, r=-0.34, p=0.006 and for nitrate, r=-0.38, p=0.002). CONCLUSION It was concluded that the increase in MDA and NO production in sperm can influence sperm motility in normozoospermic smokers. Therefore, it seems that cigarette smoking may affect the fertility of male smokers via increasing the amount of sperm MDA/lipid peroxidation and NO concentrations.