Histological changes of the pharynx and larynx in rats with chronic acid reflux esophagitis.

Conclusions: The histological changes of the pharynx and the larynx associated with surgically induced chronic acid reflux esophagitis were observed in rats. Chronic inflammatory change due to gastric acid reflux was found microscopically in the pharynx and larynx. This indicated that inflammatory changes due to gastric acid reflux are associated with the pathogenesis of laryngopharyngeal reflux disease (LPRD).

Objective: To clarify the pathological mechanism of LPRD by studying the histological changes of the pharynx and the larynx in rats with chronic acid reflux esophagitis.

Materials And Methods: An experimental rat model of chronic acid reflux esophagitis was created surgically. The pharynx, larynx, trachea, lung, and esophagus of these rats were observed histologically every 2 weeks until 20 weeks after the operation.

Results: At 8 weeks after the operation, mucosal thickening and inflammatory cell infiltration were observed in the hypopharynx of the rat model. Moreover, chronic inflammation with proliferation of fibroblasts, deposition of collagen fibers, and proliferation and dilatation of the capillaries were found as time progressed. However, little macroscopic change was observed in the hypopharyngeal mucosa. In addition, at 16 weeks post-operation, inflammatory cell infiltration was identified in the nerve cells around the thoracic esophagus, the arytenoid region, and the lung.