Laryngeal granuloma in experimental rats with gastroesophageal reflux disease and mechanically injured vocal cord mucosa.

OBJECTIVE

This study was undertaken to elucidate the mechanisms underlying laryngeal granuloma formation in a rat model of gastroesophageal reflux disease (GERD) with mechanically injured vocal cord mucosa.

METHODS

The rat model of GERD was surgically created by tying the pyloric sphincter and ligating the transitional region between the forestomach and the glandular portion (limiting ridge). The control rats received only a midline incision. In all the animals, a plastic bar was inserted into the trachea, and moved vertically thrice in 3 seconds to cause mechanical injury of the vocal cord mucosa. The rats were sacrificed 2 weeks postsurgically, and their pharynx and larynx were observed histologically.

RESULTS

Granulomas were observed in the vocal cord mucosa of the GERD group (3 of 5 animals); they presented a similar pathological structure to that of human laryngeal granulomas. In contrast, only abrasions and blisters were observed on the vocal cord mucosa in the control group (all 5 animals).

CONCLUSIONS

The development of laryngeal granuloma may involve both mechanical injury and gastric acid reflux.