Risk to preimplantation mouse embryos of combinations of heavy metals and radiation

Abstract

The influence of arsenic, cadmium, lead or mercury on radiation risk to preimplantation mouse embryos in vitro was studied under various conditions. Morphological development, cell proliferation, and formation of micronuclei were used for assessment of risk after combined exposure to these metals and X-rays. No conditions were found under which arsenic altered radiation risk; the effects were merely additive. Cadmium acted similarly, though a few results indicated that morphological development might be impaired more strongly after combined exposure than expected from the addition of the single effects. Lead enhanced radiation risk with regard to micronucleus formation, but had an additive effect only in the case of morphological development and cell proliferation. Of all four metals, mercury had the greatest potential for enhancement of radiation risk, when morphological development and cell proliferation were studied. The observed combination effects exceeded even those effects which were calculated by taking into account the shape of the dose-effect curves (isobologram analysis, envelope of additivity). Mercury neither induced micronuclei nor enhanced their formation in combination experiments.