Interference of methysergide, a specific 5-hydroxytryptamine receptor antagonist, with airway chronic allergic inflammation and remodelling in a murine model of asthma
Article first published online: 20 APR 2007
Clinical & Experimental Allergy
Volume 37, Issue 5, pages 723–734, May 2007
How to Cite
Lima, C., Souza, V. M. O., Soares, A. L., Macedo, M. S., Tavares-de-Lima, W. and Vargaftig, B. B. (2007), Interference of methysergide, a specific 5-hydroxytryptamine receptor antagonist, with airway chronic allergic inflammation and remodelling in a murine model of asthma. Clinical & Experimental Allergy, 37: 723–734. doi: 10.1111/j.1365-2222.2007.02700.x
- Issue published online: 20 APR 2007
- Article first published online: 20 APR 2007
- Submitted 16 June 2006; revised 26 December 2006; accepted 8 February 2007
- lung remodelling;
- prolonged allergen exposure
Background Airway remodelling encompasses the structural changes observed in asthmatic airways. Mast cells, through the release of histamine and 5-hydroxytryptamine (serotonin), are implicated in early asthmatic reactions, bronchoconstriction and mucosal oedema, and in the development of bronchial hyperresponsiveness. However, the association between serotonin and remodelling processes in murine model of airways inflammation remains to be elucidated.
Objective As serotonin is released by murine mast cells upon antigen challenge, we tested the hypothesis of its involvement in the development of inflammatory and remodelling processes in a murine model of chronic airway inflammation following prolonged allergen challenge.
Methods BALB/c mice were exposed to aerosolized ovalbumin for 20 min 2 days a week, for 4 consecutive weeks. Two hours before each challenge, they were treated with methysergide (intranasally, 40 μg/kg). Forty-eight hours after the last aerosol challenge, bronchoalveolar lavage (BAL) and lung tissue were collected for analysis.
Results Methysergide inhibited the allergen-induced increase in airway eosinophilia, reduced T helper type 2 (Th2) cytokines in lung, spleen or thoracic lymph nodes, and specific IgE levels. The extravasation of plasma and fibronectin production in the lung, and collagen deposition in the lung were also inhibited after methysergide treatment. Although methysergide treatment induced an increase in IFN-γ levels, experiments with neutralizing antibody suggest that this is not responsible for inhibition. In addition, instillation of serotonin to immunized mice induced eosinophil recruitment to BAL, Th2 cytokine production and fibronectin release in lung as well as collagen deposition.
Conclusion Serotonin may contribute to the development and maintenance of remodelling through the release of cytokines and of fibrogenic mediators. Serotonin should therefore be considered as relevant for the development and maintenance of airway remodelling.