[The production of the oxygen-derived free radicals after heart-lung transplantation]

Some effectiveness of free radical scavengers for the prevention of reperfusion injury are reported, however those scavengers do not perfectly repel the reperfusion injury and do not widely used to avoid that insult. This study was undertaken to assess why free radical scavengers do not be so effective to prevent the reperfusion injury. The heart-lung transplantation was performed according to the method of Schäfers. Explanted heart-lung block was immersed and preserved in the University of Wisconsin solution excluding allopurinol for just 4 hours at 4 degrees C. The recipients were divided into three groups: group I (n = 8), mimetic group with lactated Ringer's solution, group II (n = 7), animals treated with allopurinol, and group III (n = 7), animals treated with superoxide dismutase (SOD) and catalase (CAT). All scavengers were administered during preservation and reperfusion process. Graft function was evaluated by max dp/dt and partial pressure of oxygen in pulmonary venous blood. Free radicals generated in the plasma obtained from the pulmonary vein and coronary sinus were measured, using electron spin resonance (ESR) spectrometry and the production of free radicals from the neutrophils obtained from the pulmonary vein was measured by chemiluminescence. In group II and III, the grafts got significantly better restore than in group I in cardiac and respiratory function until 30 min after reperfusion, but the graft's function in group I gradually detenorated at 60 min after reperfusion. ESR spectra were deteriorated and indicated a hyperfine splitting constant of aN = 1.55 mT, aH beta = 0.28 mT suggesting the presence of PBN-OH, ESR signals were significantly higher and showed a marked increase in group I than in group II after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)