A novel external esophageal perfusion model for reflux-associated respiratory symptoms.

BACKGROUND AND OBJECTIVE Gastroesophageal reflux disease (GERD) has been linked to a number of extra-esophageal symptoms and disorders, primarily in the respiratory tract. Current animal models of reflux esophagitis are adapted to diseases of the digestive system, rather than to reflux-associated respiratory symptoms. The aim of this study was to evaluate a novel external esophageal perfusion model to induce esophageal, tracheal and pneumonic histological injury similar to that associated with GERD. METHODS Twenty guinea pigs were randomized to the acid-treated or PBS-treated group. Esophageal catheters were used to perfuse the esophageal lumen of guinea pigs with hydrochloric acid containing 1 g/l pepsin or PBS for 14 days. The total cell number and cell differential counts in bronchoalveolar lavage fluid (BALF) were determined 24 h after the last perfusion. Histological changes in the esophageal, tracheal and pneumonic tissues were observed by hematoxylin-eosin staining. RESULTS The numbers of lymphocytes, eosinophils and total inflammatory cells in the BALF were significantly higher in acid-perfused than PBS-perfused animals. Histological evidence suggested esophageal and pneumonic inflammations were prominent in acid-treated animals. CONCLUSION Repetitive, acid-perfused, esophageal events copied the animal models of reflux esophagitis, and elicited inflammatory responses in the airways and lungs of guinea pigs.