| The change of antioxidant enzyme(superoxide dismutase, catalase, glutathione peroxidase) in the endotoxin infused rat lung. |
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Jeong Sup Song, Chi Hong Kim, Soon Seog Kwon, Young Kyoon Kim, Kwan Hyoung Kim, Ki Han Han, Hwa Sik Moon, Sung Hak Park |
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Department of lnternal Medicine, Catholic University Medical College, Seoul, Korea |
| 내독소 투여후 쥐의 폐조직내 Antioxidant (Superoxide Dismutase, Catalase, GSH-Peroxidase) 의 변화에 대한 연구 |
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| Abstract |
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.
Results
We observed the follo \V ing results. 1) The lung wet / dry weight ratio and albumin concentration in the BAL f1uids were increased to peak at 12 hours and neutrophil number in the BAL fluids were peak at 6 hours after endotoxin injection in the large dose group. 2) Cu, Zn SOD (I U/ mg protein) was significantly decreased after 6, 12 hours after endotoxin injection in the large dose group . 3) There were no singnificant change in the level of Mn SOD, catalase, GSH.Px after endotoxin injection in both groups.
Conclusion
Endotoxin in the large dose group produced the acute pulmonary edema and decreased the Cu, Zn SOD in the lung tissue after injecting endotoxin at 6 and 12 hours. These phenomenon may be due to the cell membrane damage by endotoxin. Further research would be necessary whether giving SOD by intratracheal route or method to increase the synthesis of SOD may lessen the acute lung injury by endotoxin.
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| Key Words:
Endotoxin, antioxidant enzyme. |
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