Distribution and Genotoxic Effects After Successive Exposure to Different Uranium Oxide Particles Inhaled by Rats

Abstract

In nuclear fuel cycle facilities, workers may inhale airborne uranium compounds that lead to internal contamination, with various exposure scenarios depending on the workplace. These exposures can be chronic, repeated, or acute, and can involve many different compounds. The effect of uranium after multiple scenarios of exposure is unknown. The aim of this study, therefore, was to investigate the genotoxic and biokinetics consequences of exposure to depleted insoluble uranium dioxide (UO₂) by repeated or acute inhalation on subsequent acute inhalation of moderately soluble uranium peroxide (UO₄) in rats. The results show that UO₂ repeated preexposure by inhalation increases the genotoxic effects of UO₄ inhalation, assessed by comet assay, in different cell types, when UO₄ exposure alone has no effect. At the same time, the study of UO₄ bioaccumulation showed that the UO₄ biokinetics in the kidneys, gastrointestinal tract, and excreta, but not in the lungs, were slightly modified by previous UO₂ exposures. All these results show that both genotoxic and biokinetics effects of uranium may depend on preexposure and that repeated exposure induces a potentiation effect compared with acute exposure.