Sodium hydroxide-induced esophageal stricture via an endoscopic injection needle: a novel rabbit model of corrosive injury.

Benign strictures of the esophagus are commonly encountered in clinical practice and are difficult to manage conservatively. This study aimed to establish a novel animal model of benign esophageal stricture by using corrosive-induced injury in rabbits with an injection of sodium hydroxide (NaOH) via a self-made endoscopic injection needle. Corrosive injury of the esophagus was induced in 10 rabbits by administration of 1 mL of 1.5% NaOH using a laryngoscope with a self-made endoscopic injection needle. The self-made injection needle was fabricated by modification of the core of an endoscopic injection needle. The laryngoscope examination was performed at 2 weeks and 4 weeks after induction of corrosive injury; esophagography was also performed at 4 weeks to assess esophageal stricture. All animals were euthanized at the end of the fourth week; the esophagus was removed, and stained sections were examined microscopically. Laryngoscope examination at 2 weeks showed ulceration. At the end of fourth week, laryngoscopy, radiological, and gross examinations showed successful induction of esophageal stricture in all animals, without any complication. The mean stricture index at the end of fourth week was 49.54±3.61%; the mean length of stricture was 18 .0±2.5mm. Microscopic examination revealed focal ulceration and submucosal thickening secondary to fibrosis. Rabbit esophageal stricture induced using laryngoscopy with endoscopic injection of a small amount of low-concentration sodium hydroxide is a technically simple, safe, and reproducible method for creation of an animal model of esophageal stricture. This model can be useful for developing new treatment methods for esophageal stricture.