Chronic bronchial allergic inflammation increases alveolar liquid clearance by TNF-alpha -dependent mechanism

1 Institut National de la Santé et de la Recherche Médicale U416, Institut Pasteur de Lille, 59019 Lille; 2 EA2689, Institut Fédératif de Recherche 22, Université de Lille II, 59024 Lille; 3 Service d'Anatomie et de Cytologie Pathologiques, Hôpital Saint-Louis, 75010 Paris, France; and 4 Departments of Anesthesia and Perioperative Care and Surgery, University of California-San Francisco, San Francisco, California 94143 Bronchial inflammation in allergic asthma is associated with active exudation from the bronchial tree into the interstitial space of both mucosa and submucosa. The aim of this study was to evaluate epithelial and endothelial permeability as well as alveolar fluid movement in a model of chronic allergic inflammation in Brown-Norway rats sensitized and challenged with ovalbumin (OA). Control groups were challenged with saline solution (C), and rats were immunized by OA but not challenged (Se). Lung sections showed a marked inflammatory infiltrate associated with perivascular and peribronchiolar edema in OA. To measure alveolar liquid clearance, a 5% bovine albumin solution with 1 µCi of 125 I-labeled human albumin was instilled into the air spaces. Alveolar-capillary barrier permeability was evaluated by intravascular injection of 1 µCi of 131 I-labeled albumin. Endothelial permeability was significantly increased in OA, from 0.08 ± 0.01 in the C group to 0.19 ± 0.03 in OA group ( P