title: Hyperpnea with dry air causes time-dependent alterations in mucosal morphology and bronchovascular permeability.
abstract: This study examines the morphological and physiological changes that occur in canine peripheral airways after hyperpnea with dry air. Peripheral airways were exposed to a 5-min 2,000 ml/min dry air challenge (DAC) at 24, 6, 2, or 1 h before or 60 s after (0 h) the injection of colloidal carbon. After recording the dry air-induced increase in peripheral airway resistance, the lungs were removed and prepared for morphometric analysis (n = 5). Light microscopy revealed that 50% of the airway perimeter appeared damaged at 0, 1, and 2 h after DAC, and repair was evident 6-24 h after the challenge. The average goblet-to-ciliated cell ratio decreased from 0.34 before DAC to 0.15 after DAC and recovered within 24 h. Dry air-induced bronchovascular leakage occurred immediately after DAC and persisted for > or = 24 h. DAC decreased mast cell number only in regions where the mucosa was damaged, and this decrease was inversely correlated with bronchovascular leakage. Finally, leukocyte infiltration was evident 1-2 h after DAC and continued throughout the 24-h period. We conclude that hyperpnea with dry air causes mucosal injury, inflammation, and microvascular leakage and that these dry air-induced effects persist for > or = 24 h after DAC.
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland 21205, USA.
authors.forename: C
authors.initials: C
authors.lastname: Omori
authors.forename: B H
authors.initials: BH
authors.lastname: Schofield
authors.forename: W
authors.initials: W
authors.lastname: Mitzner
authors.forename: A N
authors.initials: AN
authors.lastname: Freed
mesh_terms: D000388:Air; D000818:Animals; D001980:Bronchi / Q000098:blood supply* / Q000473:pathology*; D002199:Capillary Permeability; D002452:Cell Count; D002465:Cell Movement; D004285:Dogs; D006813:Humidity; D006985:Hyperventilation / Q000473:pathology* / Q000503:physiopathology*; D007962:Leukocytes / Q000502:physiology; D008297:Male; D008407:Mast Cells / Q000473:pathology; D008833:Microcirculation; D009092:Mucous Membrane / Q000473:pathology; D013997:Time Factors