抄録
Aspiration of gastric contents induces not only severe pneumonitis but also large airway damages. This study is designed to elucidate which component of gastric juice is responsible for damage of the tracheal mucosa. Forin vivostudy, human gastric juice with bile (pH 4.0 and 1.5), human gastric juice without bile (pH 1.2), pepsin solution and hydrochloric acid were injected into the trachea of rats. Forin vitrostudy, the extracted tracheas were incubated in human gastric juice with or without bile, human duodenal juice and hydrochloric acid. After the treatment, the morphological changes were observed by scanning and transmission (ruthenium red staining) electron microscopy. The tracheal damage induced by injection of gastric juice with bile showed spotty desquamation of the epithelial cells, remaining the basement membrane. On the other hand, the trachea injected of gastric juice without bile showed only an increase of secretion and destruction of junctional complex and cell membrane. The effect induced by pepsin solution showed milder desquamation as compared with gastric juice with bile. However, hydrochloric acid caused no pathological change. These findings were well comparable to those of thein vitroexperiment.
As a result, pepsin and bile acids in the gastric juice are most responsible for the damage of the tracheal mucosa in rats.
