Induction of genotoxicity by cadmium chloride inhalation in several organs of CD-1 mice.

In recent years, the concentration of metals in the environment has increased significantly. Metal compounds, as a group, are among the best-documented human carcinogens, but the mechanisms by which they act are not completely understood. In the present study a cadmium inhalation model in mice was implemented in order to detect the induction of genotoxic damage as single-strand breaks and alkali-labile sites in several organs (nasal epithelial cells, lung, whole blood, liver, kidney, bone marrow, brain and testicle) using the single cell gel electrophoresis (SCGE) or Comet assay. We found differences among the studied organs after a single and subsequent inhalations: in the organs analyzed we observed that major DNA damage was induced after a single inhalation; in subsequent inhalations there was a tendency to maintain the same magnitude of damage or in some cases it decreased. A correlation between length of exposure, DNA damage and metal tissue concentration was found. These results suggest that cadmium chloride inhalation induces systemic DNA damage; some organs showed less damage than others (liver, brain, etc.) and this finding could be as a consequence of the capacity to remove the damage induced by long periods of exposure, possibly because of the induction of detoxifying mechanisms such as induction of metallothionein.