Pediatr Allergy Respir Dis.  2003 Sep;13(3):162-170.

Effect of Dexamethasone on Airway Hyperresponsiveness and Airway Inflammation in Ovalbumin-induced Murine Asthma Model

• Lee DK

Abstract

PURPOSE
Glucocorticoids is the most effective therapy in the long-term control of asthma. It appears to reduce inflammation in asthmatic airways largely by inhibiting the action of transcription factors that regulate abnormal gene expression. But, the effect of the glucocorticoids on the bronchial hyperresponsiveness (BHR) is still controversial. The aim of this study is to investigate the effect of dexamethasone (DEX) on airway hyperresponsiveness and airway inflammation in Ovalbumin (OVA) -induced murine asthma model. METHODS: Female BALB/c mice were immunized with OVA and alum on day 0 and challenged intratracheally on days 8, 15, 18 and 21 with OVA. DEX, 1.5 mg/kg. And, they were administered 30 min after OVA challenges on day 15, 18 and 21 by intraperitoneal injection. BHR to methacholine measured 24 hours later after last OVA challenge and number of total leukocytes and eosinophils in the bronchoalveolar lavage fluid (BALF) was counted. Lung histomorphometry and measurement of total IgE concentration in the BALF were performed. RESULTS: Dexamethasone treatment did not change BHR to methacholine in this model. But it significantly reduced recruitment of leukocytes and eosinophils in the BALF. Eosinophilic inflammation and mucus plugging in lung tissues were significantly attenuated in the dexamethasone treated mice. Total IgE level in the BALF decreased by dexamethasone treatment. CONCLUSION: Dexamethasone treatment attenuates the eosinophilic inflammation but not the BHR in the murine asthma model. This study demonstrates the dissociation between airway eosinophilia and BHR by dexamethasone treatment.

Keyword

Asthma; Dexamethasone; Mice; Bronchial hyperresponsiveness

MeSH Terms

Animals
Asthma*
Bronchoalveolar Lavage Fluid
Dexamethasone*
Eosinophilia
Eosinophils
Female
Gene Expression
Glucocorticoids
Humans
Immunoglobulin E
Inflammation*
Injections, Intraperitoneal
Leukocytes
Lung
Methacholine Chloride
Mice
Mucus
Ovalbumin
Ovum
Transcription Factors
Dexamethasone
Glucocorticoids
Immunoglobulin E
Methacholine Chloride
Ovalbumin
Transcription Factors