Trypan blue method for the identification of areas of damage to airway epithelium due to mechanical trauma.

A method has been developed for locating the regions of pulmonary epithelial damage due to mechanical trauma, based on the inability of the injured cells to exclude vital stains such as trypan blue. Scanning electron microscopy was used to confirm the sites, as well as the specific type of mechanical damage. The damaged area on rabbit tracheal epithelium due to gentle stroking was characterized by denudation of the ciliated epithelial cells, leaving only a layer of flat, non-ciliated cells. Repeated gentle stroking of the epithelial surface removed all the epithelial cells, exposing the underlying connective tissue layer. The trypan blue method provides a fast and sensitive means of locating damaged airway epithelium due to mechanical trauma. Because the dye is non-toxic, the repair process of the epithelium can also be studied, following the initial assessment of the extent of epithelial damage.