Influence of chromium (III), cobalt (II) and their mixtures on cell metabolic activity

Chromium (III) and cobalt (II) are necessary elements required for the proper functioning of the organism, but their excess can cause toxic effects. They are the basic components of implants and are also commonly used in medicine as components of dietary supplements, vitamin and mineral products and energy drinks. The aim of this study was to investigate the effect of cobalt (II) and chromium (III) and their combination on BJ cells. In the study, BJ cells were exposed to CoCl₂ or CrCl₃ at concentrations ranging from 100 to 1400 µM, and the cytotoxicity of chromium (III) and cobalt (II) and their mixtures was assessed by MTT reduction, LDH release and NRU assays. The outcome of this work reveals the cytotoxic effects of chromium (III) and cobalt (II) and their mixtures on BJ cells. In the cytotoxicity assays, at low concentrations of CoCl₂ and CrCl₃, stimulation of cell proliferation was observed. In higher concentrations, the cell viability decreased for the tested line in all the assays. During the simultaneous incubation of fibroblasts with 200 µM of CrCl₃ and 1000 µM of CoCl₂, antagonism was observed: chromium (III) at the concentration of 200 µM induced protection from cobalt (II) toxicity; in the case of interaction of chromium chloride at 1000 µm and cobalt chloride at 200 µM, the protective effect of CrCl₃ on CoCl₂ was not observed. In the latter case, synergism between these elements was noted. Our work indicates that cobalt (II) and chromium (III) show cytotoxic properties. These metals have a destructive effect on the cell membrane, lysosomes and mitochondria, which leads to disorders of cell metabolism.