Exposure of human lung cells to native diesel motor exhaust--development of an optimized in vitro test strategy.

To investigate the effects of native diesel motor exhaust on human lung cells in vitro, a new experimental concept was developed using an exposure device on the base of the cell cultivation system CULTEX (Patent No. DE19801763.PCT/EP99/00295) to handle the cells during a 1-h exposure period independent of an incubator and next to an engine test rig. The final experimental set-up allows the investigation of native (chemically and physically unmodified) diesel exhaust using short distances for the transportation of the gas to the target cells. The analysis of several atmospheric compounds as well as the particle concentration of the exhaust was performed by online monitoring in parallel. To validate the complete system we concentrated on the measurement of two distinct viability parameters after exposure to air and undiluted, diluted and filtered diesel motor exhaust generated under different engine operating conditions. Cell viability was not influenced by the exposure to clean air, whereas dose-dependent cytotoxicity was found contingent on the dosage of exhaust. Additionally, the quality of exhaust, represented by two engine operating conditions (idling, higher load), also showed well-distinguishable cytotoxicity. In summary, the experimental set-up allows research on biological effects of native engine emissions using short exposure times.