| Abstract
| - The genotoxicity of Cr(V) complexes in mammalian cells (V79Chinese hamster lung cells)has been studied for the first time using the in vitro micronucleusassay. Two complexes wereinvestigated, [CrO(ehba)2]-, whichundergoes ligand-exchange and disproportionation reactionsin the cell growth medium, and [CrO(mampa)]-,which is chemically inert in the medium forthe duration of the exposure period. Results of in vitromicronucleus assays show that bothcomplexes are genotoxic and exhibit similar potencies to that of[Cr2O7]2-. Thepermeabilitiesof the Cr(V) complexes were also investigated for the first timeusing particle-induced X-rayemission (PIXE) analysis of individual cells. The Cr uptakeincreased in the order: [Cr(phen)2(H2O)2]3+<[CrO(ehba)2]-<[CrO(mampa)]-<[Cr2O7]2-.Clonal assays showed that Cr(VI)exhibits an expectedly higher cytotoxicity than the Cr(V)complexes. While the genotoxicitiesof the Cr(V) and Cr(VI) complexes increase according to theirpermeabilities, the genotoxicitiesof the Cr(V) complexes are equal to, if not greater than, that ofCr(VI) in terms of the amountof Cr entering the cell. This supports other evidence thatCr(V), produced as a metabolicintermediate from the intracellular reduction of Cr(VI), may beimportant in Cr-induced cancers.
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