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Consecutive allergen challenges resulted in decreased bronchial responsiveness
1Respiratory Department, Beijing Children's Hospital, Capital University of Medical Sciences, Beijing 100045, China.
Chinese Medical Journal
|March 1, 2003
Summary
Allergic airway inflammation in rats induced by ovalbumin (OVA) led to persistent bronchoconstriction. However, this airway hyper-responsiveness was reduced, showing a dissociation between inflammation and response.
Area of Science:
- Pulmonary immunology
- Respiratory physiology
- Allergic airway inflammation
Background:
- Allergic airway inflammation is a hallmark of asthma.
- Bronchial responsiveness to stimuli like acetylcholine is a key feature of asthma.
Purpose of the Study:
- To investigate bronchial responsiveness to acetylcholine in a rat model of allergic airway inflammation.
- To explore the relationship between airway inflammation and hyper-responsiveness.
Main Methods:
- SD rats were immunized and challenged with chicken ovalbumin (OVA) to induce allergic airway inflammation.
- Airway responsiveness was assessed by measuring the acetylcholine (Ach) provocation concentration (PC(200)).
- Bronchoalveolar lavage fluid (BALF) and lung tissue were analyzed to confirm inflammation.
Main Results:
- Rats exposed to OVA exhibited significantly higher baseline airway resistance compared to controls.
- Multiple OVA exposures resulted in a significant decrease in airway responsiveness to acetylcholine.
- Analysis confirmed the presence of airway allergic inflammation in the OVA-challenged group.
Conclusions:
- Multiple ovalbumin exposures induce persistent bronchoconstriction in rats.
- A dissociation exists between the bronchoconstrictor response and bronchial hyper-responsiveness.
- Airway hypo-responsiveness was observed despite the presence of allergic airway inflammation.