The effects of radical scavengers and leukocyte-depleted blood on reperfusion injury of extirpated rabbit lung.

Oxygen radicals produced by polymorphonuclear leukocytes were considered primarily responsible for reperfusion injury in lung transplantation. Using the extirpated rabbit lungs as a transplant model, we measured lung water volume, the oxygen radicals of lung tissue using a direct method (electron spin resonance) and an indirect method (measurement of peroxide lipids). The effects of free radical scavengers, human superoxide dismutase (h-SOD) and catalase (CAT), and leukocyte-depleted blood on reperfusion injury were evaluated in three experimental groups. Group I (n = 8, control): Lung reperfusion was performed with blood from other rabbits. Group II (n = 7): Immediately before reperfusion, h-SOD (1,500 u/ml) and CAT (3,000 u/ml) were added to the blood. Group III (n = 7): Reperfusion was performed with the leukocyte-depleted blood. Severe pulmonary edema and an elevation of malondialdehyde (MDA) occurred in Group I. In Group II, addition of radical scavengers to the reperfusion blood produced only mild pulmonary edema, but an elevation of MDA occurred as in Group I. In Group III, pulmonary edema and MDA elevation were almost completely suppressed.