Effects of Roflumilast, Selective PDE4 Inhibitor, on Airway Reactivity in Ovalbumin-Sensitized Guinea Pigs

Background: Roflumilast as a phosphodiesterase 4 inhibitor has shown to increase lung functions and decrease the number of exacerbations in chronic obstructive lung disease. In this study, its ability to decrease the airway hyperresponsiveness in a model of eosinophil inflammation was evaluated. Methods: Healthy adult male guinea pigs were divided into groups as follows: the first group was considered as a healthy control group (without sensitization and therapy), animals in the second group were sensitized with ovalbumin, but left without further treatment, and the animals in the third group were sensitized with ovalbumin and treated with roflumilast perorally for 7 consecutive days. In vivo airway reactivity was evaluated using double-chamber whole body plethysmograph and measuring the specific airway resistance after nebulization of histamine aerosol. In vitro experiments were performed with tissue strips of trachea and lungs in organ bath, where their contractile responses to cumulative doses of acetylcholine and histamine were registered. The numbers of inflammatory cells in blood and bronchoalveolar lavage fluid were measured using standard staining. Results: Guinea pigs with roflumilast treatment showed decreased in vivo and in vitro airway reactivity associated with suppressed recruitment of inflammatory cells (especially eosinophils) in blood and bronchoalveolar lavage fluid. Conclusion: Roflumilast has demonstrated the therapeutic potential in the model of ovalbumin induced eosinophil inflammation typically present in patients with bronchial asthma.