he present work was designed to investigate the reproductive toxicity induced by oral administration of chlorpyrifos (CPF), cypermethrin (CYP) and their combination in adult male albino rats. Forty mature male albino rats were separated into four groups (10 each), the first group was used as control, while second, third and fourth groups received orally 1/20 LD50 of CPF (10 mg/kg b.wt), 1/20 LD50 of CYP (17.22 mg/kg b.wt) and 1/40 LD50 of CPF plus 1/40 LD50 of CYP (5 mg/kg b.wt CPF plus 8.61 mg/kg b.wt CYP) respectively for 26 days. The results revealed that exposure to CPF and/or CYP induced a significant decrease in the reproductive organs weight. Moreover, a significant decrease in spermatic picture (sperm cell concentration and viability) was observed with high percent of sperm abnormalities. Serum levels of testosterone and pituitary gonadotropins (FSH and LH) have been declined significantly in all treated groups. Significant elevations were observed in malondialdehyde and nitric oxide concentrations, while antioxidant enzymes superoxide dismutase and glutathione-S-transferase activities were decreased significantly as a result of induced oxidative stress. A significant drop in prostatic acid phosphatase activity was observed. Additionally, the results showed some histopathological alterations in the reproductive organs as well as neurological lesions in brain and pituitary glands. In conclusion, CPF and CYP induce deleterious effects on reproductive efficiency of male rats which reflect more obvious impacts when both combined
