Establishment of a reflux esophago-laryngitis model in rats

To investigate the pathophysiology of reflux laryngitis, an experimental model is required.

The aim of this study is to establish an animal model of reflux esophago-laryngitis, modifying our previously reported model of chronic acid reflux esophagitis.

The modified chronic acid reflux esophagitis (m-RE) group (n = 10), in which the duodenum was wrapped with 2.5 mm of Nelaton catheter, was not treated with any drugs. Also postoperatively, two treatment groups (n = 10 in each) received different dosages of rabeprazole (RPZ): 1.0 mg/kg/day (RPZ 1.0 group) or 10.0 mg/kg/day (RPZ 10.0 group). As a control group (n = 5), other rats underwent sham operation. The esophagus and larynx were resected on day 14 after the operation, and ulcer score of the esophagus was assessed. The epithelial thickness and leukocyte infiltration of the supraglottic and subglottic laryngeal mucosae were investigated. The number of interleukin (IL)-1β-positive cells was also counted and defined as the IL-1β labeling index.

In the m-RE group, the epithelial thickness, leukocyte infiltration, and IL-1β labeling index of the supraglottic and subglottic laryngeal mucosae were increased compared with controls (P < 0.01). In the RPZ groups, not only the ulcer score of esophagus but also the epithelial thickness, leukocyte infiltration, and IL-1β labeling index of both the supraglottic and subglottic laryngeal mucosae were decreased dose-dependently relative to the m-RE group (P < 0.05).

Our modified chronic acid reflux esophagitis model proved useful in establishing a rat reflux esophago-laryngitis model, with both pathological laryngeal findings and reflux esophagitis shown to be improved by administration of a proton pump inhibitor.