histopathological effects of single dose treatment of diazinon on testes structure in rat

background: diazinon (dzn) is an organophosphorate synthetic insecticide widely used in agriculture. dzn has been observed to cause many changes, such as alterations in androgenic hormones. in the present study, the effect of dzn treatment on the structure of the testes and spermatogenesis in young adult albino rats was evaluated. materials and methods: adult rats were randomly divided into three groups including: controls (n=6), dzn-treatment group a (n=6) and dzn-treatment group b (n=6). commercial dzn was injected intraperitoneally in a single dose (a=25 mg/kg and b=2.5mg/ kg), corresponding to ld50. thirty five days after injection, animals were sacrificed for morphological and histological examinations. results: there was a significant reduction in seminiferous tubule size in group a in comparison with both controls and group b (p<0.001). the number of spermatocytes, leydig and germinal cells were significantly decreased (p<0.001). these differences were not significant between the controls and group b; however, the number of spermatocytes in group b was significantly lower than in the controls (p<0.01). conclusion: this study revealed that the reproductive function of adult rats and spermatogenesis are sensitive to dzn treatment. in addition, the effect of dzn on morphological parameters was significantly dose dependent. further study of the control dzn and the actual mechanism whereby it exerts toxic effects on male infertility is required.