OBJECTIVETo explore the effects of carbendazim on the testicular development and spermatogenic function of male rats and its action mechanism.

METHODSForty clean-grade impubic male Wistar rats were equally randomized into a low-dose, a medium-dose, a high-dose and a control group, treated respectively with carbendazim at 20, 100 and 200 mg/kg (bw) and Tween-80 solution, all by oral gavage once a day for 80 days. After treatment, the rats were weighed, their testes and epididymides immediately excised, their morphological changes observed and the weights of the right testis and epididymis obtained. Sperm motility and counts in the left cauda epididymis were determined. Histopathological changes, cell apoptosis and the expression of Bcl-2/Bax in the testis were detected by HE staining, TUNEL and immunohistochemical SABC method.

RESULTSThe medium- and high-dose groups showed obviously atrophic testes and epididymides, marked histopathological abnormality of the testis, reduced weight of the right testis and epididymis, and decreased sperm motility and counts in the left cauda epididymis (P < 0.01). With the increasing dose of carbendazim, the apoptosis rate and Bax expression were significantly raised, while the expression of Bcl-2 significantly decreased (P < 0.05, P < 0.01).

CONCLUSIONCarbendazim affects the testicular development and spermatogenic function of male rats, and the mechanism may involve cell apoptosis induced by down-regulation of Bcl-2 and up-regulation of Bax.