Canine subglottic stenosis as a model for excessive fibrosis: a pilot histologic and immunohistochemical analysis

We propose that the canine subglottic stenosis model can be used to investigate the pathophysiologic characteristics of excessive fibrosis. Submucosal and cartilaginous subglottic laser injuries in 22 dogs were created to compare normal wound healing with canine subglottic stenosis formation, human subglottic stenosis, and human hypertrophic scars. Tissues were evaluated for the content of proliferating cell nuclear antigen, collagen, and elastic fibers. Compared with normal mucosal healing, subglottic stenosis formation showed intensified and prolonged inflammation, delayed epithelialization, more mitotic activity, and greater collagen deposition. The model has several useful features. Stenoses can be produced predictably in dogs, with each animal serving as its own control. Endoscopic harvesting of subglottic scar can be performed repeatedly because restenosis occurs. Also, canine subglottic stenosis shares histologic characteristics with human subglottic stenosis and, perhaps, human hypertrophic scars. Future experimentation with this model should facilitate the understanding of excessive fibrosis.