Comparative developmental toxicity study of indium in rats and mice

The developmental toxicity of indium was examined in both rats and mice using comparable experimental protocols. Pregnant rats received a single intravenous administration of indium trichloride (InCl(3)) at 0.4 mg In/kg, on day 9, 10, or 11 of pregnancy and their fetuses were examined on day 20. Pregnant mice were treated in the same manner at 0.8 or 1.6 mg In/kg on day 7, 8, or 9 of pregnancy and their fetuses were examined on day 18. In rats, indium caused fetal weight decrease and fetal gross malformations, such as brachyury, kinked tail, cleft palate, and oligodactyly, most severely by the administration on day 10. In mice, however, indium did not cause fetal gross malformations, although it caused fetal weight decrease at 0.8 mg In/kg or more and fetal death at 1.6 mg In/kg, most severely by the administration on day 8. It was concluded from these results that rats and mice were susceptible to the embryotoxicity of indium at similar developmental stages in the early organogenetic period, but mice were less susceptible to the teratogenicity of indium than rats in terms of gross malformation. Toxicokinetic factors may be involved in this different susceptibility. Teratogenesis Carcinog. Mutagen. 20:219-227, 2000.