Background and purpose: Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanoparticles in the industry, medicine, pharmacy, cosmetic and nutrition. Due to the widespread use of ZnO NPs in various industries, evaluation of toxic effects of this nanoparticle in biological systems, espacially its effects on male reproductive organs and fertility potential are essential. Studies have shown that antioxidants can reduce the harmful effects of nanoparticles. N-acetylcysteine has gained considerable interest as a reactive oxygen species cleanser have shown, that is the potential for its antioxidant effect. The aim of this study was to investigate the effect of N-acetylcysteine as a potent antioxidant on the adverse effects of ZnO NPs on sperm parameters and biochemical factors. Materials and methods: In this study, 24 adult male NMRI mice (37±2gr) were randomly divided into four groups (n=6 ) consist of control group (saline, 1 ml/kg), group treated with Zno NPs (50mg/kg/day), group treated with N-acetylcysteine (150mg/kg/day) and group treated with N-acetylcysteine (150mg/kg/day) + Zno NPs (50mg/kg/day). After 28 days of intraperitoneal treatments, sperm parameters and oxidative stress factors were measured. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test. Results: Injections of ZnO NPs significantly reduced sperm count (P<0.001), progressive motility percentage (P<0.05), viability (P<0.001), total antioxidant capacity (P<0.001), the amount of serum testosterone (P<0.001) and LH level (P<0.001) and increased plasma MDA level (P<0.001) compared to the control group. In the group of N-acetylcysteine + ZnO NPs, N-acetylcysteine improved the effect of ZnO NPs on Sperm and Biochemical Parameters compared to the ZnO NPs group (p<0/01) and improved to the control group. These parameters did not show any significant differences between the control group and the group that received N-acetylcysteine alone (P> 0.05). Conclusion: Accord
