The change of antioxidant enzyme(superoxide dismutase, catalase, glutathione peroxidase) in the endotoxin infused rat lung.

Background: Gram.negative bacterial endotoxin induced septicemia is known to be a leading cause in the development of adult respiratory distress syndrome(ARDS). The mechanism of endotoxin induced lung injury is mainly due to the activated neutrophils which injure the capillary endothelial cells by releasing oxidant radical and resulted in pulmonary edema . We studied the change of antioxidant enzyme in the case of large or small , intermittant dose of endotoxin infused rat lungs Methods: Endotoxin was given to the rat through the peritoneal cavity in the dose of 7 mg/ kg body weight in the large dose group and 1 mg/ kg for 10 days in the small dose group. Bronchoalveolar lavage (BAL) was done and rats were killed at 6, 12. 24 hours after single endotoxin injection in the large dose group and 3. 7. 10 days after daily endotoxin injection for 10 days in the small dose group. The lungs were perfused with normal saline through the pulmonary artery to remove the blood and were homogenized in 5 volume of 50 mM potassium phosphate buffer containing 0.1 mM EDT A. After centrifuging at 100,000 g for 60 minute, the supernatent was removed and stored at -70 'C until measuring for superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH.Px) and protein Resu1ts: We observed the follo \V ing results.