Induction of Unscheduled Dna Synthesis in V79 Cells by Diesel Emission Particles Dispersed in Simulated Pulmonary Surfactant

Diesel emission particles (DEP) from an engine operating on the Federal Test Procedure UDC were dispersed in an aqueous mixture of dipalmitoyl lecithin (DPL), a major component of pulmonary surfactant and saline and were tested for genotoxicity using the unscheduled DNA synthesis (UDS) assay with autoradiography techniques in cultured Chinese hamster lung cells. A DEP sample from the same source was dispersed in dimethyl sulphoxide (DMSO) and subjected to the same assay. Both dispersions (in DPL and DMSO) were found to induce UDS in a dose-related manner. After separation of the sample into supernatant and sediment fractions, the activity of the DEP sample was found to reside in the supernatant fraction for the DMSO-dispersed sample; and in the sedimentary fraction for the surfactant-dispersed sample. These findings further indicate that genotoxic activity associated with DEP inhaled into the lung may become bioavailable through the dispersion properties of pulmonary surfactant components.