AMELIORATION OF ISCHEMIA-REPERFUSION INJURY BY HUMAN THIOREDOXIN IN RABBIT LUNG

Human thioredoxin is a polypeptide with thiol groups, possessing reduc ing activity, which is proved to have the ability to reduce active oxy gens, This study evaluated the effect of human thioredoxin on the isch emia-reperfusion lung injury and the roles of human thioredoxin on act ive oxygens by chemiluminescence examination, The left hilum of the lu ng of Japanese white rabbits was occluded for 110 minutes and then rep erfused for 90 minutes, Ten, 30, 60, and 90 minutes after reperfusion the right hilum was occluded for 5 minutes and the pulmonary functions of the left lung were examined, The animals were divided into four gr oups, three ischemia groups and a sham group (without occlusion; n = 6 ), The ischemia groups received human thioredoxin, 60 mg/kg (n = 10), N-acetylcysteine, 150 mg/kg (n = 7), or saline solution (control, n = 10) during reperfusion, Three rabbits in the human thioredoxin group a nd the control group were used to measure active oxygens with a cyprid ina luciferin analog, An additional group of reperfused lungs (n = 3) that were given superoxide dismutase after 110 minutes of ischemia was established to identify chemiluminescence examination, Compared with the sham group, reperfusion after 110 minutes of ischemia produced a s ignificant lung injury in the control group, Among the ischemia groups , the human thioredoxin group showed significantly higher arterial oxy gen tension at 30, 60, and 90 minutes after reperfusion than the contr ol group, although there was no significant difference between the N-a cetylcysteine and control groups. Histologically, intraalveolar exudat ion, interstitial thickening, and cellular infiltration were seen in t he control group, whereas in the thioredoxin group alveolar structure was well preserved. In the measurement of active oxygens the chemilumi nescence in the human thioredoxin group was less than that in the cont rol group and as little as that in the group administered superoxide d ismutase. We concluded human thioredoxin attenuated ischemia-reperfusi on injury by involving active oxygens in rabbit lungs.