Ultrastructure of Mucociliary Transport System

Abstract

Fine structures of cilia of airways in rats and mice, including the microtubular organization, crown, basal body and rootlet, were outlined. Fixation from behind the walls of airways reserved the surface film covering the mucous membrane and the trachea was shown to be covered with two layers; all cilia were underneath a thin top layer of fine fibrillar material and the tips were sticked into the underside. On the other hand, the bottom layer where the main body of a cilium was located, was lucent. In small airways, all cilia were embedded in a single layer of fine granular material. In addition, changes in tracheal mucous membrane in rats which received a single dose of porcine pancreatic elastase intratracheally were reported. The principal finding seen 12 hours after elastase instillation was the nonciliated cells covering almost totally the surface of the trachea. Ciliogenesis was a very frequent finding and distinct increment of ciliated cells was seen by 72 hours. These findings were compared with those seen in the mucus membrane of the bronchial walls in patients with chronic bronchitis.