The effect of maimendongtang on airway clearance and secretion.

We investigated the effect of Maimendongtang on airway clearance and secretion in anaesthetized quails. The oral application of 1 g/kg of Maimendongtang significantly increased tracheal mucociliary transport velocity (MCTV), whereas 100 or 300 mg/kg of Maimendongtang failed to do so. Moreover, 300 mg/kg or 1 g/kg of Maimendongtang markedly attenuated human neutrophil elastase (HNE) or DNA-induced decrease in MCTV although 100 mg/kg of Maimendongtang had little effect. Furthermore, we found that Maimendongtang significantly restored HNE-induced increases in DNA, fucose and protein contents of airway surface fluid (ASF), whereas only Maimendongtang itself significantly decreased the protein content. These results indicate that Maimendongtang increases MCTV and the increase may be, at least in part, ascribed to the amelioration of ASF in the trachea.