ABSTRACT
BACKGROUND: Continuous oxygen inhalation of high concentration may improve antioxidase and simultaneously injure the lung in rats.OBJECTIVE: To observe the effect of intermittent high concentration oxygen on antioxidase activity and pulmonary tissue in rats.DESIGN: Complete randomized control experiment.SETTING: Department of Geriatric Cardiology and Department of Biochemistry, General Hospital of Chinese PLA. MATERIALS: The experiment was performed in Department of Hyperbaric Oxygen of Navy General Hospital and Department of Biochemistry of General Hospital of Chinese PLA from January 2002 to May 2002, in which, 10 healthy Wister rats were employed, mass weighted varied from 200 to 250 g, of either sex and randomized into two groups, 5 rats in each.METHODS: In the control, the rats were bred in the room environment for 7 days. In hyperoxic preconditioning (HP) group, the rats were placed in hyperbaric oxygen chamber and inhaled oxygen of 80％ to 85％ (101. 325 kPa) everyday for 6 hours, continuously for 7 days. At the end of experiment, the lung was collected to measure lung wet mass. 0.4 g pulmonary tissue was collected to prepare homogenate in freezing bath and its upper clear solution was collected to determine the activities of superoxide dismutase (SOD), glutathione peroxidase (GTTP) and catalase with chemiluminescence method successively. Pulmonary tissue was fixed with 30 g/L glutaradldehyde and prepared into sections to be observed the microstructure of lung under electron microscope.MAIN OUTCOME MEASURES: ① Comparison of lung wet mass and activities of SOD, glutathione peroxidase and catalase in pulmonary tissue in two groups. ② Alternation on microstructure of pulmonary tissue.RESULTS: Ten rats were all entered result analysis. ① Activities of SOD,GTTP and catalase in pulmonary tissue: Those in HP group were all higher remarkably than the control [(185.10±1.92) ％/g, (90.50±4.17) nkat/g,(4.38±0.18) k/g; (95.15±1.43) ％/g, (20.17±2.17) nkat/g, (1.10±0.19) K/g,t= -84.016, -33.488, -28.023, P ＜ 0.01]. ② Lung wet mass: That in HP group was near to the control [(1.32±0.07), (1.30±0.03) g, P ＞ 0.05], explaining that the fluid in the lung of HP group was not increased. ③ Microstructure of pulmonary tissue: In HP group, the basement membrane of pulmonary tissue was integrative and thickness was even, vascular endothelial cell was integrative and Ⅰ-type epithelial cell was not destroyed.CONCLUSION: Intermittent high concentration oxygen improves antioxidase activity in the lung of rat and does not injure the lung obviously.