Dose-response relationship of cadmium embryotoxicity in cultured mouse embryos

Mouse embryos were exposed in vitro to 1.2 to 2.2 microM cadmium, and effects on embryotoxicity were examined after 39 h of culture. Teratogenic responses similar to in vivo were obtained at 1.2 to 2.2 microM with concomitant reduction in embryonic protein, while embryo deaths were increased from 13.8 to 93.3% at 2.0 to 2.2 microM. The response data of both teratogenicity and growth parameters, including embryonic protein, head length, crown-rump length, somite number, and protein and diameter of yolk sac, were acceptably fitted to a linear log-probit regression. These results suggest that (a) In chronic exposure conditions, the concentration of cadmium is a critical parameter in the manifestation of teratogenic potential, (b) as an estimation of interference in the growth of embryos, embryonic protein is one of the most sensitive endpoints while somite number is an insensitive criterion, and (c) a linear log-probit regression is applicable to the analyses of embryotoxicity data, including growth parameters in whole-embryo culture systems.