Spermatids of prepubertal male rats are susceptible to carbendazim during early spermiogenesis.

The fungicide carbendazim, a male reproductive system toxicant, affects the adult testis, while prepubertal animals are assumed to be unsusceptible to the chemical. The present study was conducted to re-evaluate the susceptibility of rat prepubertal testis (25-30 days old) to carbendazim based on the incidence of spermatid abnormalities, including nuclear enlargement (megaspermatids) and binucleate round spermatids. In control prepubertal rats treated orally with corn oil vehicle alone, seminiferous tubules containing magno- and/or binucleate round spermatids were often observed in the groups at stages II-III, IV-V and VI-VII. At 3.0 days after treatment with carbendazim (100 mg/kg), seminiferous tubules containing spermatids with identical abnormalities were significantly increased, including groups at all stages. Significant increases were also observed at stages IV-V and VI-VII at day 4.5, and VI-VII at day 7.5. In contrast, the frequency of spermatids with these abnormalities was reduced in the groups at stages II-III and IV-V at day 7.5. These findings confirm that the prepubertal rat testis is susceptible to carbendazim during early spermiogenesis.