Acetylcysteine and its derivatives: functional and morphological effects on tracheal mucosa in vitro.

The effect of acetylcysteine and its derivatives on the mucociliary activity was investigated using a rabbit tracheal in vitro model system. High concentrations of N-acetyl-L-cysteine (Mucomyst), acetylcysteine, cysteine and glutathione significantly reduced the mucociliary activity. Application of Mucomyst (50 and 100 mg/ml) caused (within 1 h) marked changes in the ultrastructure of the ciliated epithelium of the rabbit trachea: compound cilia were commonly found and the epithelial cells showed signs of autolysis and were eventually shed. Although these lesions were obtained with higher concentrations than those generally present after inhalation or instillation, our results indicate the need of long-term in vivo studies of this drug.