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Updated: Apr 7, 2026
A Reversible, Non-invasive Method for Airway Resistance Measurements and Bronchoalveolar Lavage Fluid Sampling in Mice
Published on: April 13, 2010
Suppression of heme oxygenase-1 activity reduces airway hyperresponsiveness and inflammation in a mouse model of
Kozo Kuribayashi1, Shin-ichiro Iida, Yasuhiro Nakajima
1a Department of Respiratory Medicine , Hyogo College of Medicine , Nishinomiya , Hyogo , Japan .
Objective:
Carbon monoxide (CO) levels in expired gas are higher in patients with bronchial asthma than in healthy individuals. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that catalyzes the degradation of heme to yield biliverdin, CO and free iron. Thus, HO-1 is implicated in the pathogenesis of bronchial asthma. However, whether HO-1 expression and activity in lung tissue are related to allergic airway inflammation remains unclear. We investigated whether expression of HO-1 is related to allergic airway inflammation in lungs and whether HO-1 could influence airway hyperresponsiveness and eosinophilia in mice sensitized to ovalbumin (OVA).
Methods:
C57BL/6 mice immunized with OVA were challenged thrice with an aerosol of OVA every second day for 8 days. HO-1-positive cells were identified by immunostaining in lung tissue, and zinc protoporphyrin (Zn-PP), a competitive inhibitor of HO-1, was administered intraperitoneally to OVA-immunized C57BL/6 mice on day 23 (day before inhalation of OVA) and immediately before inhalation on the subsequent 4 days (total five doses). Mice were analyzed for effects of HO-1 on AHR, inflammatory cell infiltration and cytokine levels in lung tissue. Ethical approval was obtained from the concerned institutional review board.
Results:
Number of HO-1-positive cells increased in the subepithelium of the bronchi after OVA challenge, and HO-1 localized to alveolar macrophages. Zn-PP clearly inhibited AHR, pulmonary eosinophilia and IL-5 and IL-13 expression in the lung tissue.
Conclusion:
Expression of HO-1 is induced in lung tissue during attacks of allergic bronchial asthma, and its activity likely amplifies and prolongs allergic airway inflammation.
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