Nitric Oxide Levels and Total Antioxidant Capacity in The Seminal Plasma of Infertile Smoking Men

OBJECTIVE: Cigarette is a rich source of oxidants and reactive nitrogen species. Nitric oxide (NO) in high concentration has deleterious effects on human sperm function. Antioxidant defense system in seminal plasma protects spermatozoa from the attack of reactive oxygen metabolites. The purpose of this study was to determine the correlation between cigarette smoking with the NO levels and the total antioxidant capacity (TAC) of the seminal plasma in infertile smoker men and to compare severity of oxidative stress (OS) in them with fertile and infertile non-smoking men. MATERIALS AND METHODS: In this cross sectional study, a total of 95 male participants attended the Infertility Clinic of the Fatehmeh-zahra Hospital in Babol, Mazandaran Province, Iran, between 2010 and 2011. They were divided into three groups: I. fertile non-smokers (F.ns; n=32), II. infertile non-smokers (IF.ns; n=30) and III. infertile smokers (IF.s; n=33) according to semen analysis World Health Organization guidelines (WHO, 2001) and smoking data. TAC concentration and NO levels of seminal plasma were measured using the ferric reducing ability of plasma (FRAP) method and the Griess reagent, respectively. RESULTS: Standard sperm parameters were significantly higher in the fertile group than those in the infertile groups, but these differences between the IF.ns and IF.s were not statistically significant. The mean TAC in the seminal plasma was higher in the F.ns>IF.ns>IF.s, respectively, but these differences were not statistically significant among three groups (p= 0.096). In contrast, the mean NO level in the seminal plasma was lower in the F.ns<IF.ns< IF.s, respectively. These differences were statistically significant among the three groups (p= 0.018). CONCLUSION: It argued that the increased NO levels associated with smoking might exceed the capacity of antioxidant defense system, leading to increased oxidative damage of seminal plasma and decreased fertility in men.