Effects of nickel-smelting fumes on the regulation of NIH/3T3 cell viability, necrosis, and expression of hMLH1 and RASSF1A.

Nickel is widely used and distributed in various industries. This study investigated the effect of nickel-smelting fumes on the regulation of NIH/3T3 cell viability, apoptosis, and necrosis and the expression of the tumor suppressor genes hMLH1 and RASSF1A. Cell viability was determined using a methylthiazolyl tetrazolium colorimetric assay. NIH/3T3 cell viability was reduced after exposure to different concentrations of nickel-smelting fumes, but cell apoptosis and necrosis were induced. Moreover, cell morphology changed significantly after exposure to different concentrations of nickel-smelting fumes, as determined using an inverted microscope or transmission electron microscope. Real-time RT-PCR and Western blot analyses showed that exposure of cells to concentrations of ≥100 µg/mL of nickel-smelting fumes upregulated the expression of hMLH1 and RASSF1A compared to the negative controls. These data suggest that nickel-smelting fumes could be toxic to cells, upregulating the expression of hMLH1 and RASSF1A and in turn inducing cell apoptosis and necrosis.