Esophageal stricture induced by an ultraslim upper endoscope in a novel rabbit model of corrosive injury

Abstract

Objective. Benign esophageal strictures are regularly encountered problems in clinical practice. The management of refractory benign esophageal stricture, which fails to establish adequate food passage despite multiple dilatation sessions, has been considered challenging. Experimental animal models are essential for the development of effective treatment methods. The aim of this study was to establish a new animal model of benign esophageal stricture using rabbits. Material and methods. Corrosive injury of the esophagus was induced by administration of 1 ml of 1.5% sodium hydroxide in eight rabbits using an ultraslim upper endoscope equipped with a 5-Fr polytetrafluoroethylene tube and 5-Fr balloon catheter. Two weeks after corrosive injury, endoscopic examination was performed to confirm the state of the injury site. Four weeks after corrosive injury, the esophageal stricture was assessed by endoscopy and esophagography. All animals were then euthanized. Results. Two weeks after corrosive injury, endoscopic examination showed that ulceration had been induced. Four weeks after corrosive injury, endoscopic, radiologic and gross examinations showed that esophageal stricture had been induced without complications in all animals. The esophageal lumen diameter was reduced by an average of 51.8% (range, 48.3%–57.2%), and the mean stricture length was 25.7 mm (range, 20.1–29.3 mm). Microscopic examination revealed focal ulceration and submucosal thickening secondary to fibrosis. Conclusions.Rabbit esophageal stricture induced by endoscopic delivery of a small amount of low-concentration sodium hydroxide is a relatively simple, safe, and reproducible animal model. This model may be useful in the development of new treatment methods for esophageal stricture.