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Mucosal injury and eicosanoid kinetics during hyperventilation-induced bronchoconstriction.
A N Freed1, Y Wang, S McCulloch
1Department of Environmental Health Sciences, The Johns Hopkins University, Baltimore, Maryland 21205, USA. afreed@jhsph.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|November 24, 1999
Summary
Hyperventilation causes airway injury and constriction in dogs, linked to mediator release. Dry air challenges increased epithelial cells and mediators, correlating with bronchoconstriction.
Area of Science:
- Respiratory Physiology
- Pulmonary Medicine
- Cellular Biology
Background:
- Hyperventilation can trigger airway responses.
- The mechanisms linking hyperventilation to bronchoconstriction are not fully understood.
- Investigating airway injury and mediator release is crucial for understanding these responses.
Purpose of the Study:
- To test if hyperventilation-induced mucosal injury stimulates mediator production.
- To determine if mucosal damage correlates with hyperventilation-induced bronchoconstriction.
Main Methods:
- Bronchoalveolar lavage (BAL) was performed on canine peripheral airways after dry air challenges (DAC) of varying durations.
- BAL fluid (BALF) was analyzed for cell counts and mediator concentrations.
- Airway obstruction was measured to assess bronchoconstriction.
Main Results:
- Epithelial cells increased in BALF immediately after 2- and 5-min DAC.
- Prostaglandins and thromboxane B(2) increased after 5-min DAC; leukotrienes increased after 5-min DAC.
- Warm, moist air did not alter BALF cells or mediators and caused less, earlier airway obstruction.
- BALF epithelial cells correlated with mediator release, which correlated with bronchoconstriction.
Conclusions:
- Hyperventilation-induced mucosal damage likely initiates peripheral airway constriction.
- The release of biochemical mediators plays a key role in this process.
- Dry air challenges are more potent in inducing these responses than warm, moist air.