Abstract
This study was conducted to establish a novel model of airway mucous cell hyperplasia and mucous hypersecretion suitable for both morphological and physico-biochemical examinations, using a xenotransplanted in vivo culture system. Tracheal epithelial cells of rabbits were cultured in de-epith-elialized rat tracheal grafts transplanted to nude mice. At four weeks, human neutrophil elastase (300μg/graft) or saline was injected into the graft lumina. Three weeks later, intratracheal mucus was collected from the retrieved tracheas, and the grafts were examined histologically.
The percentage of mucous cells in the elastase-treated tracheas was significantly increased compared to the control level (25.5±0.8% vs. 12.9±0.9%, p<0.001). Histochemically, mucous cells containing acidic glycoprotein were more abundant in the elastase-treated tracheas. The volume of mucus did not differ in the untreated and treated tracheas. The acidity of the mucus in the control and the elastasetreated tracheas was pH 7.7±0.2 and 6.3±0.1, respectively (p<0.001). Amounts of protein, N-acetyl-neuraminic acid, and fucose were all significantly higher in the elastase-treated tracheas.
These results indicate that elastase induced mucous cell hyperplasia and the hypersecretion of acidic mucus. This culture model will be useful for studying the role played by elastase in the development of this pathological condition.
