Induction of micronuclei in cultured murine splenocytes exposed to elevated levels of ferrous ions, hydrogen peroxide and ultraviolet irradiation.

The frequency of micronuclei in cultured mouse splenocytes increased positively and in a dose-related manner to exposure to ferrous ions and ultraviolet irradiation, but not to hydrogen peroxide. Combined treatments, especially when ferrous ions were present with hydrogen peroxide or with ultraviolet irradiation, led to a synergistic enhancement in micronucleus frequency. The results indicate that a significant level of chromosome damage is associated with exposure to ultraviolet light and to general cellular pro-oxidative stress, and indicate that under these conditions the micronucleus assay can provide an effective in vitro model for the study of genotoxicity in relation to oxygen-derived free radicals.