نبذة مختصرة : In vitro exposures to air pollutants could, in theory, facilitate a rapid and detailed assessment of molecular mechanisms of toxicity. However, it is difficult to ensure that the dose of a gaseous pollutant to cells in tissue culture is similar to that of the same cells during in vivo exposure of a living person. The goal of the present study was to compare the dose and effect of O 3 in airway cells of humans exposed in vivo to that of human cells exposed in vitro . Ten subjects breathed labeled O 3 (18O 3 , 0.3 ppm, 2 h) while exercising intermittently. Bronchial brush biopsies and lung lavage fluids were collected 1 h post exposure for in vivo data whereas in vitro data were obtained from primary cultures of human bronchial epithelial cells exposed to 0.25–1.0 ppm 18O 3 for 2 h. The O 3 dose to the cells was defined as the level of 18O incorporation and the O 3 effect as the fold increase in expression of inflammatory marker genes (IL-8 and COX-2). Dose and effect in cells removed from in vivo exposed subjects were lower than in cells exposed to the same 18O 3 concentration in vitro suggesting upper airway O 3 scrubbing in vivo. Cells collected by lavage as well as previous studies in monkeys show that cells deeper in the lung receive a higher O 3 dose than cells in the bronchus. We conclude that the methods used herein show promise for replicating and comparing the in vivo dose and effect of O 3 in an in vitro system.
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