Effects of acute in vitro exposure of murine precision-cut lung slices to gaseous nitrogen dioxide and ozone in an air–liquid interface (ALI) culture

The aim of this study was to establish an air–liquid interface (ALI) culture of precision-cut lung slices (PCLS) for direct exposure of lung cells to gaseous contaminants. Nitrogen dioxide (NO2) and ozone (O3) were selected as model gas compounds. Acute pro-inflammatory and toxic effects of NO2 and O3 on live lung tissue were investigated. Murine PCLS were exposed to different flow rates (3–30 mL/min) of synthetic air, O3 (3.5–8.5 ppm), or NO2 (1–80 ppm). Tissue survived ex vivo in ALI culture and resisted exposure to NO2 (1–10 ppm) and O3 (3.5–8.5 ppm) for 1 h. Longer exposure to NO2 resulted in a clear loss of viability, whereas exposure to O3 was less effective. Exposure to NO2 dose-dependently induced release of the pro-inflammatory IL-1α (40%), whereas RANTES, IL-12, and eotaxin remained unchanged. Early secretion of IL-1α (80%), RANTES (>800%), MIP-1β (44%), and MCP-1 (60%) was already detected after 1 h of exposure to O3. The obtained data showed that direct exposure to O3 and NO2 induced cytotoxicity and pro-inflammatory responses in PCLS with ALI culture. This provides a model that more closely resembles in vivo exposure of airborne contaminants, and thus should be appropriate for toxicity testing.