Antigen challenge induces a supraglottic but not a subglottic edema in the rat larynx

Abstract

To examine the reaction of mast cells in the larynx of sensitized rats after allergen challenge and determine whether a type I hypersensitivity reaction can elicit a supraglottic and subglottic edema. Rats were sensitized with ovalbumin (OA) and challenged 3 weeks later by intravenous injection of either OA or NaCl and perfused with glutaraldehyde. The larynges were removed and processed for light and electron microscopy. Sections from the epiglottis and subglottic region were examined. In challenged animals, the connective tissue mast cells (CTMC) in the epiglottic submucosa, but not the mucosal mast cells (MMC) in epithelium, were significantly reduced compared with the case of controls, and the connective tissue was edematous. In the subglottic region, the number of both MMC and CTMC was reduced (albeit not significantly), and there was no edema in the lamina propria. Allergen challenge induces a marked edema in the epiglottis but not in the subglottic area. The results indicate that the supraglottic and subglottic regions react differently to allergen challenge.