Establishment of surgically induced chronic acid reflux esophagitis in rats

Background: The purpose of the study was to establish an animal model of chronic acid reflux esophagitis which could be used for further investigations of the pathophysiology of reflux esophagitis. Methods: Esophagitis was produced by ligating the transitional region between the forestomach and the glandular portion with a 2-0 silk thread and covering the duodenum near the pylorus ring with a small piece of an 18Fr Nelaton catheter. The histologic features of the esophagus were examined, and the survival rate of these animals was investigated. Moreover, the effects of lansoprazole on this model was studied. Results: The 3-week survival rate was 90%, and esophagitis was noted in all rats. Esophagitis was found 2 or 3 cm above the esophagogastric junction in most cases and at 4.0 +/- 2.3 sites per animal. Histopathologically, there were increased thickness of the esophageal epithelium, elongation of the lamina propria papillae, which extended upward into the epithelium, marked inflammatory cell infiltration, interruption of the lamina muscularis mucosae, and increase of collagen fibers in the lamina propria and submucosa. These signs were in accord with the histologic features of typical chronic esophagitis. No signs of esophagitis were observed, except in one animal, in the rats given 1 mg/kg/day of lansoprazole. Conclusions: This experimental rat model is considered useful as a model of chronic acid-type esophagitis for the evaluation of the pathophysiology of reflux esophagitis and the evaluation of drug efficacy.