The Study Of Protective Effects Of Treatment With Ulinastatin On Ischemia-reperfusion Injury During Rabbit Non-heart-beating Donors Lung Transplantation

Objective: To investigate the protective effects of treatment with ulinastatin (UTI) on ischemia-reperfusion during rabbit non-heart-beating donors lung-transplant, and explore the possible mechanism.Methods: Thirty rabbits were divided randomly into three groups: group A as control group, group B as UTI flushing group and group C as UTI preconditioning plus flushing group. In group A donors were exsanguinated to maintain hypotension for 30 minutes before intravenous injection of potassium chloride to make heart arrest. After a period of 1 hour warm ischemia in situ,topical cooling was executed. Meanwhile, the donor lungs were antegradely flushed through pulmonary arteries with low-postassium-dextron(LPD) solution at 4℃.After flushing in situ, lung-heart blocks were harvested and store at 4℃for another 5h, then perfused for 90 minutes in isolated, ventilated, blood-perfused rabbit lung models. Pulmonary venous blood samples were collected for blood gas analysis at 1, 15, 30, 60, and 90, minutes after initiation of reperfusion. At the same time, pAwP was recorded respectively. The serum TNF-αlevel was measured after reperfusion, lung samples were obtained at the end of reperfusion. The pulmonary water index (W/D), tissue myeloperoxidase(MPO) activity, tissue malondialdehyde(MDA) content, mRNA expression of IL-8 and ICAM-1 were measured. Microscopic examination of donor lungs were conducted.In group B,the same procedures were conducted as in group A except for adding addition UTI (500,000u/L) to LPD solution. In group C, except that a bolus of UTI(50,000u/kg) was given to donors intravenously during hypotension, the same procedures were conducted as in group B.Results: (1) In all three groups, there were same tendencies of gradually decreasing of PO₂ levels; and compared with B and C groups, PO₂ levels in group A showed significently lower inclination. Similar results could be observed in pAwP values, but the tendency was increasing. (2) The level of W/D, MPO, MDA, the mRNA expression of IL-8 and ICAM-1 in group B and C decreased more evidently than in group A(.P<0.05). So did in serum level of TNF-α. (3 )The microscopic change of donor lung tissues in group A is damaged more severely than in group B and C. (4) There also were significent differences between group C and group B except for four observing subjects: PO₂ , pAwP, IL-8 and ICAM-1 mRNA(p > 0.05), but they showed a tendency of improvement in group C too.Conclusion: (1) This study showed this isolated, ventilated, blood-perfused rabbit NHBDs lung model(warm ischemic time 60 minutes) had imitated the clinical situation of NHBDs lung transplantation,and may play a important role in the research of NHBDs lung transplantation. (2)A big dose of UTI flushing pulmonary artery had a protective effect of graft fuction by attenuating ischemia-reperfusion injury. UTI preconditioning during hypotension can further attenuate IRI, partly by decreasing the level of oxygen free radicals,and partly by inhibiting macrophage's releasing TNF-α, decreasing the expression of mRNA of IL-8 and ICAM-1 in lung tissues, and inhibiting the activating of PMN to alleviating the ischemia-reperfusion induced inflammation.