Complementary anti-inflammatory effects of a β-blocker and a corticosteroid in an asthma model

Glucocorticosteroids are the mainstay treatment for chronic asthma; however, adverse effects can limit their usefulness. We previously determined in experimental asthma that chronic administration of β 2 -adrenoceptor inverse agonists reduced airway hyperresponsiveness and indexes of inflammation. However, the effect of co-administration of glucocorticosteroids with β 2 -adrenoceptor inverse agonists is unknown. Therefore, we evaluated the anti-inflammatory effect of co-administration of dexamethasone, a glucocorticosteroid, and nadolol, a β 2 -inverse agonist, in a murine asthma model. We measured eosinophils and cytokines in bronchoalveolar lavage fluid and mucin content in epithelial cells after exposure to different concentrations of dexamethasone and nadolol. Dexamethasone was administered for 3 days and nadolol for 24 days prior to ovalbumin challenge. Both drugs were continued during five daily intranasal challenges with ovalbumin. Independent administration of dexamethasone (0.4 mg/kg/day) or nadolol (25 ppm) reduced bronchoalveolar lavage eosinophils by 58% and 36%, respectively ( P