P-10: Proliferative Activity of Adult Mouse Male Germ Cells Following Administration of Graded Doses of Nicotine

Background: Nicotine is considered as one of the most agents in cigarette smoking and has side effects on many organs and body systems such as reproductive tract. Nicotine can induce sub fertility or infertility both in males and females. The aim of this study was to evaluate the proliferative activity of adult mouse male germ cells following treatment with different doses of nicotine. Materials and Methods: Adult male NMRI mice were divided into four groups. The control group received normal saline and the other animals in groups of 2, 3 and 4 were treated with nicotine in doses of 0.1, 0.2 and 0.4 mg/kg, respectively. Nicotine was administered intraperitoneally once a day for 14 days. All animals were dissected on 15th day, and evaluations were made by Ki67 immunohistochemistry staining and Johnson’s scoring for assessment of spermatogenic cells proliferative activity and evaluation of maturity of spermatogenesis respectively, and Elisa for serum testosterone level. Statistical analyses were performed using ANOVA and Tukey tests. Results: Nicotine in dose of 0.1 mg/kg has not affect on both maturity and proliferative activity of male germ cells. However nicotine in doses of 0.2 mg/kg and 0.4 mg/kg significantly reduced maturity of spermatogenic cells in compare with controls (p<0.05). nicotine in dose of 0.4 mg/kg significantly reduced the percent of ki67 positive male germ cells (39.25 ± 6.61 vs. 60.77 ± 5.35, p<0.001) in compare with controls. there was not significant statistical differences in percent of ki67 positive male germ cells in groups treated with 0.1 and 0.2 mg/kg nicotine (58.87 ± 2.72 and 58.55 ± 4.75 vs. 60.77 ± 5.35, p>0.05) and controls. Serum level of testosterone in all nicotine treated groups were significantly reduced in compare with control group (p<0.05). Conclusion: This study indicated that nicotine has adverse effects on spermatogenesis process and it acts in a dose dependent manner. However in lower doses, proliferative activity is not altered therefore it seems that probably the other mechanisms are involved in reducing of maturity and quality of spermatogenesis.