ALBERT

Description: We examined the clastogenic and cell-transforming potential of ultrafine particulate matter fraction PM 0.056 of urban ambient aerosol using mammalian cells. PM 1.0 , PM 0.56 and PM 0.056 fractions were sampled from roadside atmosphere of an urban area using the cascade impactor MOUDI-NR-110. The potential to induce cytotoxicity, DNA damage and micronuclei formation was examined at the test concentrations of 3, 6, 12.5, 25, 50 and 100 μg/ml using the 3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the plasmid relaxation assay and the C3H10T1/2 (10T1/2) cells. The cell-transforming potential was investigated in vitro using 10T1/2 cell transformation assay and the soft agar assay. PM 1 , PM 0.56 and PM 0.056 fractions were found to be toxic in dose-dependent manner. These induced cytotoxicity at five test concentrations, the ultrafine particle fraction PM 0.056 showed greater cytotoxic potential. PM 0.056 induced micronucleus formation in 10T1/2 cells. The effect was statistically significant. The DNA-damaging potential was measured in a plasmid relaxation assay. Both fine and ultrafine particle fraction PM 0.56 and PM 0.056 displayed greater effect as compared to larger PM 1 fraction. DNA damage was found to be dependent on particulate matter intrinsic pro-oxidant chemicals. The ability of the ultrafine particle fraction PM 0.056 to induce morphological cell transformation was demonstrated by significant and dose-dependent increases in type III focus formation by morphologically transformed cells in culture flasks and their clonal expansion in soft agar. It is concluded that the traffic-linked ultrafine particle fraction PM 0.056 in the atmosphere by the roadside of an urban area is clastogenic and able to induce morphological transformation of mammalian cells.