Effect of disodium cromoglycate on airway mucus secretion during antigen-induced late asthmatic responses in a murine model of asthma

Background: Disodium cromoglycate (DSCG) is known to inhibit both immediate and late asthmatic responses (IAR and LAR). However, its effect on mucus hypersecretion is unknown. Using a murine model of asthma, we aimed to determine whether mucus secretion increased during IAR and LAR. We also studied the potency of DSCG in inhibiting mucus secretion and on airway eosinophilia. Methods: Mice were subjected to initial intraperitoneal sensitization and airway challenge to ovalbumin ( OVA) and then provoked by additional exposure to OVA. Some mice were pretreated with aerosolized DSCG ( 20 mg/ml) 1 h before the provocation with OVA. After serial measurements of enhanced pause ( Penh), an indicator of airflow obstruction, serum samples and bronchoalveolar lavage fluids (BALF) were collected. Then, the lungs were excised and a morphometric analysis for mucus hypersecretion was performed. Results: A biphasic increase in Penh ( IAR and LAR) was observed in sensitized animals after provocation with OVA. Airway eosinophilia was observed during both responses. Intraluminal mucus significantly increased during LAR, but not during IAR. DSCG significantly attenuated both IAR and LAR, and significantly inhibited the increase in intraluminal mucus during LAR, but had no effect on eosinophilia in BALF. Conclusion: Our results suggest that airway hypersecretion may be involved as a component of airflow obstruction during LAR, and that this is unlikely during IAR. DSCG may be effective in reducing excessive airway mucus caused by exposure to allergens. Copyright (C) 2005 S. Karger AG, Basel.