EXPERIMENTALLY-INDUCED POLYPS IN THE SINUS MUCOSA - A STRUCTURAL-ANALYSIS OF THE INITIAL-STAGES

To document polyp formation in the sinus mucosa, the authors of this s tudy subjected New Zealand white rabbits to different modes of manipul ation intended to induce inflammation of the maxillary sinus. These ma nipulations included a combination of bacterial infection and mechanic al trauma, the deposition of agarose into the sinus cavity, and the de position of N-formyl-methionyl-leucyl-phenylalanine, a chemotactic pep tide, into the sinus cavity. A majority of animals developed polyps, w hich were examined by light and electron microscopy. Polyp formation a ppears to involve epithelial disruption and the migration of immature branching epithelium, While part of the migrating epithelium eventuall y covers the mucosal defect, other branches spread into the underlying connective tissue, where intraepithelial microcavities with a differe ntiated, ciliated lining are formed. Fusing cavities separate the deve loping polyp body from the adjacent mucosa. With the described method, mucosal polyps can be induced with high reproducibility.