Abstract: Objective: To study the effect of Co²⁺ on the cytotoxicity of human renal tubular epithelial cells and the gene expression of Bax and Bcl-2. Methods: HK-2 cells were cultured and incubated with five different concentrations of Co²⁺ solution(0-10 μmol/L)for 12h, 24h and 48h in vitro. Cells were observed and recorded under inverted phase contrast microscope. Cell proliferation of each culture group was detected by MTT and the expression of Bax and Bcl-2 were detected by RT-PCR at different time points. Results: Co²⁺ had no toxicity on HK-2 cells when the concentration was lower than 7.5 μmol/L during the observation time. While when the concentration was higher than 7.5 μmol/L, Co²⁺ had mild toxicity on HK-2 cells after 24h. As to the increase of Co²⁺ concentration and time of duration, the mRNA expression of Bax in each experimental group gradually increased, while the mRNA expression of Bcl-2 gradually decreased and the value of Bax/Bcl-2 increased. Conclusion: Co²⁺ inhibited the proliferation of HK-2 cells. It has no toxicity on human renal tubular epithelial cells at low concentration,but has mild toxicity and promotes cell apoptosis at high concentration(≥7.5 μmol/L).

Key words: Cobaltion, Human renal tubular epithelial cells, Cytotoxicity