Development of an in vitro Batch-type Closed Gas Exposure Device with an Alveolar Epithelial Cell Line, A549, for Toxicity Evaluations of Gaseous Compounds

To simply evaluate toxicity for various types of exhaust-gas samples collected in various locations, we developed a small-scale (150 mL) batch-type completely closed gas exposure device incorporated with an air-liquid interface culture of a human alveolar epithelial cell line, A549. On the basis of cell viability tests using an acid phosphatase assay after 48 h of gas exposure, the developed device was able to measure clear dose-response relationships for volatile organic and inorganic compounds, such as benzene, trichloroethylene (TCE), acetone, SO(2) and NO(2) gases, but not CO gas. Although the 50% effective concentration values in the device were much higher than 50% lethal concentration values reported in animal experiments, the tendency of the toxic intensity observed in the former was roughly consistent with that of the acute toxicity in the latter. We further applied the device to evaluate the toxicity of cigarette smoke as an example of actual environmental gases, and successfully measured acute cell death from the gas after 48 h of exposure. The present small device is expected to be one of good tools not only in simultaneously assessing various gaseous chemicals or samples, but also in studying acute toxicity expression mechanisms in human lung epithelia.