[Experimental study on injury of the rat nasal mucosa by distilled water irrigation, and its regeneration].
Injuries caused by distilled water and the regeneration process in the nasal mucosa in the respiratory region of the rat were examined electron microscopically and immunohistochemically by light microscopy. The mucosal injury was observed as exfoliation and desquamation of ciliated cells and goblet cells almost everywhere. The basal cells and basal membrane were intact. The regeneration process was completed by the migration, proliferation and differentiation of basal cells. The numbers of nuclear mitotic figures started to increase in a group of rats observed 6 hours after treatment (6-hour group), peaked at 48 hours, and returned to the baseline state after day 4. The BrdU labeling index, on the other hand, started to increase after 6 hours, peaked at 36 hours, and returned to the baseline state after day 4. The goblet cells were predominant even in the 21-day group, compared to the control group. Nuclear mitotic figures and secretory granules were observed together in one cell in the 36-hour group.