FURTHER OBSERVATIONS ON CARBENDAZIM-INDUCED ABNORMALITIES OF SPERMATID MORPHOLOGY IN RATS

The effects of a microtubule poison, carbendazim, on rat spermiogenesi s were examined for abnormalities of nuclei, acrosome and manchette in round and elongating spermatids in Stages VII-XII on days 7.5, 9.5, 1 0.0 and 10.5 post-treatment using routine electron microscopy. Spermat id nuclear abnormalities were observed in Stages IX-XI on day 9.5 and at greater post-treatment intervals. Nuclear abnormalities included nu clear distortions, various types of nuclear invaginations and abnormal positioning of the modified nuclear envelope. Acrosomal abnormalities were noted on day 7.5 and at greater intervals. Discontinuous, multip le granular and fragmentary acrosomes were observed in Stages VII-XI. In addition, spermatids with complete absence of acrosome (acrosome-de ficient spermatids) were observed in Stages VII-X. Poorly-formed and a bsent ectoplasmic specializations were seen in the cytoplasm of Sertol i cells next to the acrosome-deficient spermatids. A major abnormality of the manchette was irregular positioning of the manchette microtubu les in steps 9-11 spermatids on day 9.5 and at greater intervals, whic h resulted in nuclear invagination. The results indicate that carbenda zim induces abnormalities in spermatid morphology that are common to t hose reported in testes treated with several chemical compounds and in testes of mutant animals.