Dysmorphogenic effects of di-n-butyltin dichloride in cultured rat embryos.

Dysmorphogenic effects of di-n-butyltin dichloride (DBTC) were evaluated in vitro using the rat whole embryo culture system. Wistar rat embryos were explanted on day 8 of gestation and cultured for 68 hr. DBTC was added to the culture medium at the start of culture to achieve final concentrations of 3, 10 and 30 ng/ml. At the end of culture, the embryos were examined for vascularization development in the body and yolk sac, yolk sac diameter, crown-rump length, number of somite pairs, morphological score and external anomalies. Significantly and markedly decreased incidences of embryos with well developed vascularization in the body and yolk sac, yolk sac diameter, crown-rump length and number of somite pairs were found at 30 ng/ml. A concentration-dependent decrease in the morphological score and increase in the incidence of embryos with anomalies were noted, and the differences were significant for embryos exposed to 10 and 30 ng/ml DBTC. Open anterior neuropore and craniofacial abnormality were predominantly observed. It is concluded that DBTC possesses dysmorphogenic effects on postimplantation embryos in vitro.