Toxicology and applied pharmacology
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Toxicol. Appl. Pharmacol. · May 1996
Comparative StudyTime-dependent changes of inflammatory mediators in the lungs of humans exposed to 0.4 ppm ozone for 2 hr: a comparison of mediators found in bronchoalveolar lavage fluid 1 and 18 hr after exposure.
Acute exposure of humans to ozone results in reversible respiratory function decrements and cellular and biochemical changes leading to the production of substances which can mediate inflammation and acute lung injury. While pulmonary function decrements occur almost immediately after ozone exposure, it is not known how quickly the cellular and biochemical changes indicative of inflammation occur in humans. Increased bronchoalveolar lavage (BAL) fluid levels of neutrophils (PMNs) and prostaglandins (PGE2) have been reported in humans as early as 3 hr and as late as 18 hr after exposure. ⋯ A comparison of these changes with changes observed in an earlier study in which subjects underwent BAL 18 hr after an identical exposure regimen indicates that IL-6 and PGE2 levels were higher 1 hr after exposure than 18 hr after exposure, fibronectin and tissue-plasminogen activator levels were higher 18 hr after exposure, and that PMNs, protein, and C3a were present at essentially the same levels at both times. These results indicate that (i) several inflammatory mediators are already elevated 1 hr after exposure; (ii) some mediators achieve their maximal levels in BAL fluid at different times following exposure. These data suggest that the inflammatory response is complex, depending on a cascade of timed events, and that depending on the mediator of interest one must choose an appropriate sampling time.