Cytotoxicity of metal ions to human oligodendroglial cells and human gingival fibroblasts assessed by mitochondrial dehydrogenase activity.

To assess the variable concentrations of several metal salts on human oligodendrocyte MO3.13 and human gingival fibroblasts HGF and to enable any difference in cell type sensitivity to be examined. Cytotoxicity was measured as mitochondrial dehydrogenase activity assessed by MTT assay. The mean of the 50% response (TC50) was calculated by using equation-fitting software (TableCurve 2D). The results of the MTT assay showed that metal ions induce reproducible cytotoxic effects in MO3.13 oligodendroglia and human gingival fibroblasts, that is dose dependent on the tested agent. Cadmium relatively showed the highest cytotoxic effects on MO3.13 cells (TC50 9.8 microM) whereas mercury showed the highest cytotoxic effects on HGF (TC50 74 microM) comparing with other tested metals. The two cell types responded differently. MO3.13 cells were more sensitive than the HGF to most of the metals. Metals have a wide range of toxicity to human oligodendroglial cells (MO3.13) and human gingival fibroblasts. Fortunately, however, in vivo the normal levels of these metals are much lower than those determined as toxic in vitro.