Reproductive toxicity of a nano-insecticide (chlorpyrifos) on male albino mice.

Chlorpyrifos (CPF) is a commonly used organophosphorus insecticide in agriculture, and it is linked to reproductive toxicity in males by disrupting the endocrine system. Most previous studies focus on its traditional form, neglecting its nanoform, which may pose a greater risk due to enhanced bioavailability. Our study evaluated the reproductive toxicity of a nano-emulsion of CPF (CPF-NE) in male albino mice. Mice were divided into four groups (n = 10 per group): a control and three treated groups receiving CPF-NE via oral gavage at doses of 3.79, 7.58, and 15.16 mg/kg body weight daily for 35 days. We assessed gonadosomatic index (GSI), reproductive performance (mating success and fertility rate), sperm parameters, DNA fragmentation, hormonal levels (testosterone, FSH, LH), total antioxidant capacity (TAC), malondialdehyde (MDA), and catalase (CAT). Post-treatment testes were examined histologically. Results showed that CPF-NE significantly decreased GSI (from 0.66 ± 0.02 in controls to 0.31 ± 0.02 in high-dose, p < 0.001), reproductive performance (fertility index dropped to zero at high dose), sperm viability (from 74 ± 1.6% to 43.1 ± 1.7%, p < 0.001), and testosterone (from 4.2 ± 0.3 ng/mL to 1.8 ± 0.2 ng/mL, p < 0.001), while increasing FSH, LH, MDA, and DNA fragmentation. Histopathological findings indicated reduced tubular diameters, decreased epithelial heights, and disrupted testicular structure. In conclusion, CPF-NE adversely affects male fertility by increasing oxidative stress and DNA damage.