Characterization of precision-cut rat lung slices in a biphasic gas/liquidexposure system: Effect of O-2

Influence of oxygen on lung cell differentiation has been studied in precis ion-cut rat lung slice cultures. Rat lung slices were positioned on rolling inserts placed into vials with opened caps to allow free access to the gas eous phase. This system was placed into a continuous-flow rotating chamber with controlled pO(2), pCO(2) and hygrometry. Slices were cultured in a ser um-free medium up to 3 days under an atmosphere of 21 or 70% oxygen. Cellul ar antioxidant markers demonstrated an oxygen concentration-dependent respo nse. Slices cultured with 70% oxygen exhibited the highest specific activit y of catalase, NADPH cytochrome c reductase and gamma-glutamyl transpeptida se (GGT) as well as the highest levels of intracellular glutathione after 4 8 or 72 hours of incubation. Moreover, hyperoxic exposure altered the expre ssion of lung manganese-containing superoxide dismutase mRNA. Hyperoxia had little or no effect on intracellular ATP levels, which remained high in lu ng slices compared with freshly isolated tissue. The study of the pulmonary specific functions allowed to confirm maintenance of the in vitro cellular differentiation of lung slices incubated with 21% oxygen: (i) polyamine tr ansport is preserved and exhibited kinetic properties similar to those obse rved in lung in vivo; (ii) ATP levels remained constant throughout the time course of incubation. This in vitro model proves to be a useful tool to st udy mechanisms involved after oxygen exposure and will probably be useful f or the study of other environmental gaseous contaminants. Further developme nts in this method are under development. (C) 1999 Elsevier Science Ltd. Al l rights reserved.