CARBENDAZIM-INDUCED ABNORMAL-DEVELOPMENT OF THE ACROSOME DURING EARLYPHASES OF SPERMIOGENESIS IN THE RAT TESTIS

Effects of a single, high dose of orally administered carbendazim (100 mg/kg) on acrosome formation in the early phases of spermiogenesis we re examined by electron microscopy and immunocytochemistry up to day 7 .5 post-treatment. No obvious abnormality of acrosome development was noted in the Golgi phase spermatids on day 1.5 post-treatment. On day 3, step 1 spermatids were seen in stage III seminiferous tubules. In s tage V tubules at this post-treatment interval, direct connections bet ween the trans-side saccules of the Golgi stacks and the outer acrosom ic membranes were observed in step 5 spermatids. Similar direct connec tions between these two organelles were also observed in the advanced round spermatids in later stages at days 4.5 and 7.5. On day 4.5, step 1 and 3 spermatids were seen in stage V tubules. On day 7.5, round sp ermatids with various abnormalities of acrosome development were obser ved in stage VII tubules, in addition to the discontinuous and granula r acrosomes reported previously. These features were not observed in t estes of control animals. In the immunocytochemical analysis using an antibody mMN7 that recognizes a protein delivered from the Golgi appar atus to the acrosome, spermatids exposed to carbendazim showed various abnormal immunostaining patterns in the acrosomes. On the other hand, strong immunoreactivity was observed in the Golgi saccules connecting to the acrosomes. These results suggest that in testis treated with c arbendazim acrosome development is impaired during the early phases of spermiogenesis, and material supply from the Golgi apparatus to the a crosome is perturbed, which is a possible cause of the abnormal develo pment.