Hyperoxia inhibits stimulated superoxide release by rat alveolar macrophages
Factors responsible for the loss of respiratory burst capacity (stimulated extracellular O2-. release) of alveolar macrophages (AM) exposed to prolonged hyperoxia were assessed. Specific pathogen-free rats were exposed to 1 ATA O2 for 24-72 h, and lungs of survivors lavaged. Release of O2-. by cells...
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Published in | Journal of applied physiology: respiratory, environmental and exercise physiology Vol. 53; no. 3; p. 685 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.09.1982
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Subjects | |
Online Access | Get more information |
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Summary: | Factors responsible for the loss of respiratory burst capacity (stimulated extracellular O2-. release) of alveolar macrophages (AM) exposed to prolonged hyperoxia were assessed. Specific pathogen-free rats were exposed to 1 ATA O2 for 24-72 h, and lungs of survivors lavaged. Release of O2-. by cells after addition of concanavalin A, which stimulated AM but not polymorphonuclear leukocytes (PMN), or digitonin, which stimulated both cell types, was measured using cytochrome c reduction +/- superoxide dismutase. O2-. release by AM declined 47.2% (P less than 0.05) after 24 h of hyperoxia and 100% after 60 h. Percent PMN in the lavage was less than 3% at 0-36 h but increased to 16% at 48 h and to 44% at 72 h. Although addition of PMN to AM in vitro caused inhibition of AM O2-. release, the percent PMN required for inhibition was not reached in vivo until after a significant decline in AM O2-.-releasing capacity had already occurred. Cell-free lavage fluid from either control or hyperoxic rats did not affect AM O2-. release. AM in culture for 24 h in hyperoxia lost 76.7% (P less than 0.005) of O2-.-releasing capacity vs. cells incubated in 20% O2, although dye exclusion was unaffected. The results indicate that the major cause of loss of AM O2-. release by hyperoxia is a direct effect of O2 on the cells. |
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ISSN: | 0161-7567 |
DOI: | 10.1152/jappl.1982.53.3.685 |