Establishment of surgically induced chronic acid reflux esophagitis in rats

Background: The purpose of the study was to establish an animal model of ch ronic acid reflux esophagitis which could be used for further investigation s of the pathophysiology of reflux esophagitis. Methods: Esophagitis was pr oduced 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 histologi c features of the esophagus were examined, and the survival rate of these a nimals was investigated. Moreover, the effects of lansoprazole on this mode l was studied. Results: The 3-week survival rate was 90%, and esophagitis w as noted in all rats. Esophagitis was found 2 or 3 cm above the esophagogas tric junction in most cases and at 4.0 +/- 2.3 sites per animal. Histopatho logically, there were increased thickness of the esophageal epithelium, elo ngation of the lamina propria papillae, which extended upward into the epit helium, marked inflammatory cell infiltration, interruption of the lamina m uscularis mucosae, and increase of collagen fibers in the lamina propria an d submucosa. These signs were in accord with the histologic features of typ ical chronic esophagitis. No signs of esophagitis were observed, except in one animal, in the rats given 1 mg/kg/day of lansoprazole. Conclusions: Thi s experimental rat model is considered useful as a model of chronic acid-ty pe esophagitis for the evaluation of the pathophysiology of reflux esophagi tis and the evaluation of drug efficacy.