title: The effects of hyperoxia on pulmonary clearance of Pseudomonas aeruginosa.
abstract: Among the toxic effects of hyperoxia may be impaired pulmonary clearance of gram-negative bacteria. To better define this effect, we exposed BALB/c mice to 100% O2 for 24, 48, or 72 hr and intrabronchially inoculated them with 10(6) Pseudomonas aeruginosa. Clearance was assessed 4 hr later by quantitative lung cultures of air- and O2-exposed mice. Clearance was first reduced at 48 and 72 hr in mice exposed to O2. To determine the mechanism responsible, we measured bronchoalveolar lavage neutrophil (PMN) counts and neutrophil chemotactic activity at 0, 2, and 4 hr after instillation of P. aeruginosa into mice first exposed to air or O2 for 48 hr. Air-exposed mice had more PMNs than did O2-exposed mice after challenge (13.3 +/- 2.1 X 10(5) vs. 4.4 +/- 0.6 X 10(5)). There was no difference in neutrophil chemotactic activity between air- and O2-exposed mice at any time, although chemotactic activity increased in both groups after challenge. Our data suggest that hyperoxia impairs pulmonary clearance of P. aeruginosa by decreasing the influx of PMNs and that this effect is not due to diminished chemotactic activity in bronchoalveolar lavage fluid.
authors.forename: M M
authors.initials: MM
authors.lastname: Dunn
authors.forename: L J
authors.initials: LJ
authors.lastname: Smith
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte; D007958:Leukocyte Count; D008168:Lung / Q000382:microbiology* / Q000473:pathology; D008171:Lung Diseases / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009504:Neutrophils / Q000276:immunology / Q000502:physiology*; D010100:Oxygen / Q000494:pharmacology*; D011552:Pseudomonas Infections / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D011550:Pseudomonas aeruginosa / Q000502:physiology*
chemical_list: D010100:Oxygen