Abstract
Male albino rats were exposed to 81, 86, 90 or 99% oxygen until death. Rats were also administered methyl prednisolone (MP) 10–60 mg/kg/day intraperitoneally. MP-treated rats survived significantly less than controls: 53.5 ± 4.7 vs. 65.2 ± 8.2 h, p < 0.001 in 99% O2, 74.4 ± 9.4 vs. 120 ± 39.8 h, p < 0.02 in 86% O2 and 113.7 ± 21.4 vs. 162 ± 17.9 h, p < 0.03 in 81 % O2. Rats were exposed to 99% O2 for 10,30 and 50 h and the activity of superoxide dismutase (SOD) and catalase in their lungs was monitored. MP-treated rats showed less increase in pulmonary SOD after 10h (111 vs. 171%, p < 0.03) but no effect on SOD activity thereafter. MP had no effect on the response of catalase to O2. No effect of MP on lung morphology could be found under the light microscope.