Ozone-induced acute tracheobronchial epithelial injury: relationship to granulocyte emigration in the lung.
Hyde-DM; Hubbard-WC; Wong-V; Wu-R; Pinkerton-K; Plopper-CG
Am J Respir Cell Mol Biol 1992 May; 6(5):481-497
Ozone (10028156) (O3) induced acute tracheobronchial epithelial injury and its relationship to granulocyte emigration were studied in monkeys. Male rhesus-monkeys were exposed to 0.96 parts per million O3 for 8 hours and maintained for up to 168 hours after exposure. Monkeys maintained for 12 to 168 hours were infused with indium-111-tropolonate labeled neutrophils 4 hours before death. At death, the lungs were removed and lavaged. The lavage fluid was analyzed for cellularity, labeled neutrophils, and prostaglandins. The tracheobronchial epithelium in the upper right lung lobe was examined for histological changes. Epithelial necrosis was seen in the trachea, bronchi, and respiratory bronchioles 1 hour after O3 exposure. The number of ciliated cells in these areas was sharply decreased. The total number of lavaged cells and neutrophils were significantly increased as were the levels of prostaglandin-F2alpha, prostaglandin-D2, and prostaglandin-E2. Twelve hours after exposure, the area of intercellular gaps in the tracheal epithelium was markedly increased and severe bronchial inflammation was also seen. The number of labeled neutrophils recovered in the lavage fluid and present in the epithelium and interstitium was significantly increased. Repair of the epithelium was seen 24 hours after exposure; however, bronchial inflammation and epithelial necrosis were more pronounced than at 12 hours. Total cell and neutrophil counts in the lavagate were still significantly elevated, but the proportion of labeled neutrophils was similar to the control value. Repair of the bronchial epithelium was evident 72 hours after exposure. Neutrophils were still present in the interstitium but in smaller numbers than at 24 or 12 hours. Lavage fluid cellularity was still increased, but the increase was due to alveolar macrophages. All epithelial tissues appeared normal 168 hours after O3 exposure, although eosinophil numbers in the tracheal interstitium and bronchial epithelium and interstitium were significantly increased. The authors conclude that emigration of granulocytic cells contribute to injury and repair of the tracheobronchial epithelium after short term O3 exposure.
Irritant-gases; In-vivo-studies; Lung-irritants; Histology; Laboratory-animals; Inhalation-studies; Lung-cells; Immune-reaction
American Journal of Respiratory Cell and Molecular Biology
University of California - Davis