Cytotoxic and genotoxic effects of extract of particulate emission from a gasoline-powered engine.

Extract of particulate matter (EPM) from gasoline engine exhaust has been investigated for cytotoxic and genotoxic effects in the concentration range 0.16-10 micrograms/ml by means of short-term bioassays using mammalian cell culture systems. Cytotoxicity is demonstrated by a strong dose-dependent reduction of cloning efficiency after treatment of V79 cells with EPM. Employing the dye exclusion test with erythrosin B, no considerable loss of cell viability was observed. Using the same cell system, EPM revealed a highly increased number of aberrant mitoses, whereby the occurrence of C mitoses and metaphases with chromosome clusters was especially pronounced. This effect led to mitotic arrest as shown by a highly increased mitotic index at 5 and 10 micrograms/ml EPM. The results indicate disturbances of the mitotic spindle in a way similar to the known spindle poison colcemid. As a consequence of spindle disturbances, EPM produced numerical chromosome alterations such as aneuploidy and polyploidy. Cytogenetic analyses using human lymphocyte cultures treated with EPM revealed a slight increase of chromosomal aberrations at 10 micrograms/ml and a dose-dependent induction of sister chromatid exchanges in the range 2.5-10 micrograms/ml. At least, EPM showed a dose-dependent increase in the cell transformation assay using SV 40-infected Syrian hamster kidney cultures. The great variety of cytotoxic and genotoxic effects found with EPM suggests a potential health hazard to human populations exposed to gasoline engine exhaust. The possible contribution to cytotoxic and genotoxic activity by organolead compounds derived from antiknock additives is discussed.