Alterations to the bronchial and bronchiolar surfaces of adult mice after exposure to high concentrations of oxygen.

We have studied the effects of inhalation of 95 to 100% oxygen on the surface morphology of the bronchi and bronchioles of adult mice, using scanning electron microscopy. Denudation of cilia and truncation of the remaining cilia were commonly observed during high oxygen exposure. Bleb formation, a "moth-eaten" appearance of the non-ciliated cell surface and desquamation of unidentified cells were present in the bronchus after 96 hours of oxygen exposure. Deformation of non-ciliated cells, denudation of cilia, and flattening of the luminal surface were also seen in the bronchiole. For studying the recovery process from acute oxygen damage, we returned mice to room air after four days of high oxygen inhalation and killed them four, seven and 15 days after. There were more variable and complex changes of surface morphology in individual mice during the recovery phase. We observed flattening of the epithelial surface in the bronchiole and bronchus, and noticed that deformation of non-ciliated cells were seen even after 15 days. High oxygen inhalation causes severe morphological changes in the bronchial and bronchiolar mucosa, and those morphological lesions remain for at least two weeks after cessation of oxygen inhalation.