[Establishment and application of an in vitro model for dynamic direct exposure of lung epithelial cells (A549) to airborne compounds].

ABSTRACT

OBJECTIVE: To establish and apply a dynamic in vitro model for direct exposure of human cells to gaseous contaminants to investigate the cellular responses to airborne chemical exposures. METHODS: Nitrogen dioxide (NO2) was selected as a model gas compound. Standard test atmospheres were generated (5.1 - 20.7 mg/m3), using clean air dilution method. A549 pulmonary type II-like epithelial cell lines and skin fibroblasts were grown on porous membranes. Human cells on transwell inserts were placed in horizontal diffusion chambers and exposed to various airborne concentrations of NO2 directly at the air- liquid interface for 1 h at 37 degrees C, 15 ml/min. The gasoline exhuast at different load (idle with cold start, 50% and 100% load) collected in Tedlar air bag directly exposed A549 cell for 15 min at 37 degrees C, 10 ml/min. Cytotoxicity of the test gas was investigated using the MTT, NRU (neutral red uptake) and CCK-8 assays. RESULTS: Dose-dependent effects of NO2 were observed in human cells tested which resulted in a significant reduction of cell viability at different concentrations of NO2 (MTT estimated curvegamma(MTT) = 0.989 - 0.021 chi (NO(2)) R2 = 0.84, P < 0.01; NUR estimated curvegamma(NUR) = 1.032 - 0.026 chi (NO(2)) R2 = 0.88, P < 0.01). Gasoline exhaust exposure at different load resulted in a decreased cell viability (significantly CCK-8 and MTT levels reduction than air exposure group). CONCLUSION: The dynamic direct exposure method can be used for in vitro inhalational and dermal toxicity studies and potentially as an new technology for biomonitoring of airborne contaminants in future occupational and environmental toxicity assessments.