The Effect of Diazinon on Cell Proliferation and Apoptosis in Testicular Tissue of Rats and The Protective Effect of Vitamin E

BACKGROUND: Diazinon (DZN) is an organophosphate pesticide, and nowadays this pesticide is mostly used in agri- culture. In this study, we analyzed the effects of DZN and vitamin E (Vit E) on apoptosis and the proliferation of germ cells in rat testis. MATERIALS AND METHODS: In this experimental study, 30 male Wistar rats were divided into five groups (n=6 per group) consisting of control, sham (received olive oil), experimental group i (60 mg/kg DZN), experimental group ii (60 mg/kg DZN and 200 mg/kg Vit E), and experimental group iii (200 mg/kg Vit E). After six weeks, left testis of rats was removed for the detection of proliferative cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase end-labeling (TUNEL). RESULTS: Compared with the control group, DZN in the experimental group i decreased the number of PCNA-positive cells and increased the number of TUNEL-positive cells (P<0.001). Vit E improved detrimental changes by the de- crease in the rate of apoptosis and the increase in the proliferation of testicular germ cells (P<0.001). CONCLUSION: Vit E can decrease the number of TUNEL-positive cells and increase the number of PCNA-positive cells by the neutralization of the toxicity caused by DZN in the testicular tissue.