Effects of hyperoxia on the activity of rat pulmonary macrophages.
Castranova-V; Ma-JYC; Barger-MW; Pailes-WH; Dedhia-HV; Dalal-NS; Billie-M; Vallyathan-V
Toxicologist 1992 Feb; 12(1):291
This study characterized the activity of pulmonary macrophages after in vivo exposure of rats to 95% oxygen for 64 hrs. Zymosan-induced hydrogen peroxide (H2O2) production was decreased by 41% in phagocytes obtained from O2-exposed rats. Similarly, zymosan-stimulated oxygen radical generation monitored by electron spin resonance was decreased by 53% in phagocytes from hyperoxic rats. This decline in activity could not be accounted for fully by decreased viability, since membrane integrity of exposed cells declined by only 12%. In contrast, zymosan-stimulated chemiluminescence (CL) rose by 540% after O2-exposure. This high CL could not be explained by lower antioxidant levels (reduced and oxidized glutathione) in O2-exposed cells. Further, there was no difference in the proportion of CL generated by superoxide, H2O2, cyclooxygenase, or lypoxygenase metabolites in O2- exposed vs control macrophages. Lipid peroxidation of lavaged pneumocytes was elevated by 118% after O2 treatment. Therefore, high CL may be due to the production of reactive lipids by O2-exposed pneumocytes. In conclusion, in vivo exposure of rats to hyperoxic conditions results in lipid peroxidation, decreased membrane integrity, and depressed ability of phagocytes to release reactive oxygen species in response to particles.
Animal-studies; Animals; Pulmonary-function; Oxidation; Oxidative-processes; Laboratory-animals; Free-radicals; Free-radical-generation
The Toxicologist. Society of Toxicology 31st Annual Meeting, February 23-27,1992, Seattle, Washingtion