The effect of an organophosphorus pesticide, chlorpyrifos (from different local sources), on the testicular tissue in adult male albino rats

Chlorpyrifos is a widely used organophosphorus pesticide for agricultural purposes to control early disease in crops. Acting as an endocrine disrupting agent for male reproductive systems which leads to reproductive toxicity. Accordingly, this study aimed to investigate the potential mechanisms by which three commercial formulations of chlorpyrifos interfere with androgen receptor function and expression in male rats. The research was conducted according to the ethical guidelines established by the institutional animal care and use committee (IACUC), and the protocol received approval from Cairo University- Faculty of Science under approval number (CU/IF/12/23). Twenty-four male Wistar rats were equally allocated to four groups. The control group, chlorpyrifos groups orally received (17.43, 23.43, 21.40 mg/kg) for 28 days (5 days /week). The serum testosterone hormone was estimated, and the testes were collected, and fixed in 10% buffered formalin for histopathological and immunohistochemical examination. Results indicated that chlorpyrifos formulations caused a marked decrease in testosterone levels and downregulation of androgen receptor expression. Moreover, a significant reduction in tubular diameter, lumen diameter, and thickness of germinal epithelial cells was detected along with the Jonson score. In summary, exposure to the three chlorpyrifos formulations resulted in notable alterations in testosterone levels, decreased expression of androgen receptors, and compromised spermatogenesis, culminating in testicular damage and male infertility. Of the formulations assessed, chlorpyrifos-W was identified as the most effective disruptor of androgen signalling, demonstrating higher toxicity compared to the other formulations.