Effects of changes in Ca2+ concentration of the culture medium on the in vitro development of 11-day mouse embryos

The individual and combined effects of X-irradiation and hyperthermia on early somite mouse embryos in culture

The effects of 1) X-irradiation and 2) hyperthermia at a temperature of 43 degrees C individually and in combination have been investigated using cultured 8-day mouse embryos. B6C3F1 embryos were exposed to 0.3-2.0 Gy of X-rays, 5-20 min of heating, or 5 min of heating and irradiation at 0.3, 0.6, and 0.9 Gy. Irradiation alone at 0.3 Gy showed no apparent effect on embryonic development, but irradiation at 0.6-2.0 Gy caused a dose-dependent increase in malformed embryos. Heating alone for 5 min produced no malformed embryos, while heating for 10-20 min caused malformations as a function of heating time. Combined treatments produced higher frequencies (22.2-100%) of malformations than those of the sum of the separate treatments (0-41.7%). Malformations observed were primarily microphthalmia, microcephaly, and open neural tubes. The results indicate that in cultured mouse embryos irradiation combined with a "nonteratogenic dose" of hyperthermia directly exerts an additive effect on formation of the malformed embryos. In addition, a single occurrence of left-sided tail was produced by hyperthermia alone, while four occurrences were produced in combination with radiation.

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.