Trivalent chromium is neither cytotoxic nor mutagenic in permeabilized hamster fibroblasts

BHK cells became reversibly permeable by a 30-min incubation in hypertonic medium. During permeabilization they were exposed to water-soluble Cr(VI) (K2Cr2O7) and Cr(III) (CrCl3). Thymidine uptake in the intracellular nucleotide pool, DNA replication, DNA damage and repair and sister-chromatid exchanges (SCE) were examined to detect the cytotoxic and genetic effects of Cr compounds. Cr(III) remained inactive also in permeabilized cells. An apparent induction of DNA damage by Cr(III), suggested by the Painter's test, was considered unreliable. Cr(VI) cytotoxic and genetic activity was enhanced in permeabilized cells, as demonstrated by increased inhibition of DNA replication and higher frequency of SCE.