Development of a new in vitro system for continuous in vitro exposure of lung tissue to complex atmospheres: Application to diesel exhaust toxicology

The purpose of this study was the development of a new incubation system th at can allow continuous exposure of lung tissue to complex atmospheres as a tool for the assessment of aerial environmental lung toxicology. To assess the pertinence of this new exposure system, we studied the impact of diese l engine exhausts as a complex atmosphere containing both gaseous and parti culate fractions and have been able to discriminate between the toxicologic al impacts of the gaseous phase and particulate matter from diesel exhausts . Continuous flow-through rotating chambers with controlled pO(2), pCO(2), and hygrometry have been designed in which lung slices are positioned in ro lling inserts that allow free access of atmosphere to the exposed lung tiss ue. Under control conditions, cell viability was preserved for at least 48 h as assessed by intracellular ATP, GSH, and K+ levels and slice O-2 consum ption levels. Short-term exposure (1 h) to diesel whole exhausts did not af fect intracellular potassium or slice O-2 consumption, while intracellular ATP and GSH levels were markedly decreased. Exposure to filtered exhausts s howed less marked effects on both ATP and GSH levels. Superoxide dismutase activity was decreased in a similar way by both total and filtered exhausts while Se+-dependent glutathione peroxidase activity was induced by filtere d exhausts to a larger extent than after total exhaust exposure, showing di fferent response patterns of lung tissue after exposure to whole or filtere d exhausts. In conclusion, this newly designed model opens a promising area in in vitro environmental lung toxicology testing.