Transformation and apoptosis of NIH/3T3 cells treated with nickel-smelting fumes

The purpose of this study was to investigate the transformation and apoptosis of NIH/3T3 cells treated with nickel (Ni) smelting fumes. Cytotoxicity of NIH/3T3 cells was detected with a methyl thiazolyl tetrazolium (MTT) colorimetric assay. The cell translation model was established by cell focus translation using two types of Ni-smelting fumes from a Ni smelting plant in China. The transformed focus was determined by soft agar culture assay. The apoptotic characteristics of NIH/3T3 cells treated with Ni-smelting fumes were detected by flow cytometry using Annexin V-FITC and PI as markers. The DNA fragment of apoptosis in NIH/3T3 cells treated with nickel smelting fumes was detected by observing agarose electrophoresis and morphological characteristics of cells under electron microscopy. With increase in exposure time, growth of NIH/3T3 cells was inhibited. The NIH/3T3 cell transformation model was established successfully using two Ni-smelting fumes, and the transformed cells grow in soft agar. No apoptosis peak was detected by flow cytometry. Apoptotic cells characterized by necrosis were observed using electron microscopy. There was no apparent "ladder" observed by DNA fragment analysis. Data indicated that Ni-smelting fumes produced cytotoxicity by mechanisms associated with necrosis but not apoptosis.