Background Asthmatic inflammation is mediated by a network of cytokines, chemokines and adhesion molecules. Corticosteroids are the only effective agents available to control asthmatic inflammation. We investigated the effect of high-dose montelukast (MK), a selective cysteinyl leukotriene receptor 1 antagonist, on mediators of airway inflammation.
Objective The aim of this study was to determine the effect of a 3-day course of high-dose MK on mediators of airway inflammation induced by a single allergen challenge in sensitized mice.
Methods Ovalbumin (OVA)-sensitized BALB/c mice were treated with 25 mg/kg of MK or saline intravenously for 3 days. On the third day, a single inhalation challenge with OVA was given. Cellular infiltration was assessed in the bronchoalveolar lavage (BAL) and in the lung. Expression of IL-4, IL-5, IL-13 and eotaxin in the BAL, and the lung was determined. Serum IL-5 and total IgE was measured. IL-5 and eotaxin mRNA expression in the lung was determined. Finally, eotaxin and VACM-1 expression in the lung was assessed by immunohistochemistry.
Results MK reduced the number of eosinophils in the BAL by > 90%. There was also significant reduction in IL-5 in the BAL, lung and the serum, and IL-5 mRNA expression in the lung. IL-4 level in the lung and BAL, and IL-13 level in the lung also significantly decreased. Serum IgE level and lung VCAM-1 expression was also significantly lower in treated animals, but eotaxin protein and mRNA expression in the lung remained unchanged.
Conclusion MK exerts its anti-inflammatory effect through the suppression of T helper type-2 (Th2) cytokines. The use of high-dose MK as an anti-inflammatory agent in acute asthma should be further explored.