Genotoxicity of chromium (III) and cobalt (II) and interactions between them

Abstract

Abstract Introduction. Chromium and cobalt are essential trace elements that are required only in a small amount, otherwise their excess can cause toxic effects. Aim. The aim of this study was to determine the effects of chromium (III) and cobalt (II) and their combinations on genotoxicity in human fibroblasts cells (BJ). Material and methods. In this work, comet and micronucleus assays were used. The BJ cells were exposed to chromium chloride and cobalt chloride at concentration ranges from 100 to 1400 µM. Mixtures of these elements were prepared so as to examine interactions between them. Results. The present study shows the genotoxic effects of chromium (III) and cobalt (II) and their mixtures on BJ cells. In the comet assay, no comets were observed at the lowest concentrations; in the higher, a significant increase in their percentage was observed. In the other assay (formation of micronuclei), a statistically significant increase in the number of cells with micronuclei was observed in the BJ cells spiked with cobalt chloride and chromium chloride. In the case of simultaneous incubation of chromium chloride at 200 µM and cobalt chloride at 1000 µM in the BJ line, antagonism was observed. However, the interaction of chromium chloride at the 1000 µM and cobalt chloride at 200 µM leads to synergism between the studied elements. Conclusions. Cobalt (II) and chromium (III) show genotoxic properties, they induce breaks in double and single-stranded DNA and they cause formation of AP-sites that do not have purine or pyrimidine bases.