Effect of chlorpyrifos on sperm characteristics and testicular tissue changes in adult male rats.

Chlorpyrifos (CPF) is a broad spectrum organophosphate pesticide used for agricultural health purposes. Its principal mechanism of toxicity is the inhibition of acetylcholinesterase. The purpose of present study was to investigate the effects of CPF on testicular tissue and sperm parameters in male rats. Thirty-two healthy male rats were divided into two groups: a CPF-exposed group and a control-sham group. Control-sham group received corn oil (0.20 mL per day). The CPF was administered orally to male rats at 37 mg kg-1 BW for 45 days to evaluate the reproductive toxicity. In all rats, sampling for histological and sperm analyses was performed on days 5, 15, 30 and 45. The CPF caused a significant ( p < 0.05) decrease in sperm count, viability and motility and increased immature sperms and DNA damage in sperm cells. Light microscopic analyses revealed increased arrested spermatogenesis, negative tubular differentiation and repopulation indexes and decreased Leydig cells number. These findings indicate that CPF has adverse effects on sperm cells and reproductive system of male rats.