Exposure to Chlorpyrifos Influences Epididymal Development in Pubescent Rats

The epididymis is responsible for sperm maturation, but is sensitive to the action of external agents, especially during the peripubertal period. Chlorpyrifos is an organophosphate class pesticide to which humans are constantly exposed. Currently, there are few studies that evaluate the effects of this insecticide on the epididymis; therefore, the objective of the present study was to assess the effects of chlorpyrifos on the postnatal development of the epididymis during the peripubertal period. Thirty Wistar rats were divided into three groups: Control, C5, and C15. The control group received only the vehicle and the C5 and C15 groups received, respectively, 5 and 15 mg/kg of chlorpyrifos via gavage during 40 days (DPN25-DPN65). On DPN 66, the animals were euthanized. The epididymis was used for sperm count, histopathological, stereological, and oxidative stress analyses. Sperm from the vas deferens was used for motility and mitochondrial activity analyses. There was a difference in the proportion of luminal, stromal, and epithelial compartments in the groups exposed to chlorpyrifos. An increase in sperm transit time in the caput epididymis was also observed in the C5 group and a decrease in mitochondrial activity in sperm from the C15 group. Oxidative stress analyses showed a decrease in GST activity in the C5 and C15 groups. Sperm motility remained unchanged. These results suggest that the exposure to chlorpyrifos during peripuberty harms the postnatal development of the epididymis. This study is the first to evaluate the morphology and function of the epididymis in peripubertal rats.