Gholipoor, F1; Gharzi, A1*, Azadbakht, M1 The Effect of Selenium on Spermatogenesis in Mice Treated with Flonicamid Gholipoor, F1; Gharzi, A1*, Azadbakht, M1 Department of Biology, Faculty of science, Razi University, Kermanshah, Iran. fatemehgholipoor71@yahoo.com, ahgharzi@yahoo.com, azadbakht_tmu@yahoo.com Objectives Results The use of pesticides in agriculture is necessary in these days. Pesticides produce free radicals and damage to the reproductive system, hence, antioxidants can be used to improve the adverse effect of pesticides. Antioxidants are substances that reduce or prevent cells damage by neutralizing free radicals. Selenium is essential for many basic physiological reaction to protect the cells from oxidative stress. In this study we studied the effect of Selenium on spermatogenesis process against the Flonicamid pestiside. Histological studies showed that Flonicamide significantly reduced the number of sertoli cells, spermatogonia, primary spermatocytes, round and elangated spermatids, and in the sperm parameters studies, decreased count, viability, motility of sperm and increased sperm abnormality compared to the control group and this damage was sharp in high dose. The results showed that sodium selenite whit flunicamide improved all tissue and sperm parameters damage Conclusions So, sodium selenite can reduce the negative effects of Flonicamide on spermatogenesis and improve the quality of sperm and can introduce as a good antioxidante for reduce the adverse effect of pesticide specially Flonicamid. Methods adult male NMRI mice 10 weeks old divided into 6 groups, Group 1: Control group received nothing. Group 2: Flonicamide 25 mg / kg, Group 3: Flonicamide 25 mg / kg and sodium selenite 0.5 mg / kg, Group 4: Flonicamide 50 mg/ kg, Group 5: Flonicamide 50 mg/ kg and sodium selenite 0.5 mg / kg; Group 6: sodium selenite 0.5 mg / kg. All groups were injected intraperitoneally daily for 21 days. After injection, the mice were sacrificed by displacement of the cervical vertebrae. Testes and caudal epididym were removed for histomorphological and sperm parameters studies. a Significant compared with control b Significant compared with Flonicamid­25 mg/kg. c Significant compared with F25/SE 0.5 mg/kg. d Significant compared with Flonicamid­50 mg/kg. e Significant compared with F50/SE 0.5 mg/kg. f Significant compared with Sodium selenite 0.5 mg/kg. Flo: Flonicamid, Se: Sodium selenite, PS: Primary Spermatocyte, RS: Round Spermatid, ES: Elongated Spermatid Control Flonicamid­50 mg/kg F50/SE 0.5 mg/kg Sodium selenite 0.5 mg/kg