The Protective Effect Of Ischemic Postconditioning On Non-heart-beating Donor In Rat Lung Transplantation

Objective:To establish animal model of non-heart-beating donor in rat lungtransplantation and to observe the protective effect of various protectivemeasures on cadaver lung; to study the protective effect and mechanismof ischemic postconditioning on ischemic reperfusion injury in rat NHBDlung transplantation.Methods:PartⅠ: sixty four Sprague-Dawley rats were randomly divided intofour groups, heart-beating donor group (HBD group), non-heart-beatingdonor group without protective measure on cadaver lung (NHBD-Ngroup), non-heart-beating donor group with continuous mechanicalventilation on cadaver lung (NHBD-V group), and non-heart-beatingdonor group with topical cooling on cadaver lung by ice saline (NHBD-Igroup); PartⅡ: forty Sprague-Dawley rats were randomly divided intofour groups, namely control group (NHBD-C group) and ischemicpostconditioning group (NHBD-S group) with 5 cycles of 1 min'reperfusion and 1 min' reocclusion. Surviving rate in the observationperiod of 2 hour after transplantation, lung compliance, blood gas check, the wet/dry ratio of lung after transplantation, and pathological changeswere analyzed and compared among groups in PartⅠand PartⅡ.Besides, in PartⅠ, the amount of ATP,ADP and AMP in lung tissueafter transplantation were checked by high-performance liquidchromatography(HPLC), and the sum of adenylic nucleotides werecomputerized and compared among each group; in PartⅡ, the amount ofSOD and MDA, the expression of cell apoptosis and ICAM-1mRNA inlung tissue after transplantation were assessed, and ultramicroscopicstructural changes also observed in PartⅡ.Results: (in PartⅠand PartⅡ)1. Surviving rate: in PartⅠand PartⅡ, each group had highsurviving rate and there were no difference between each group.2. Lung compliance: in PartⅠ, the lung compliance in NHBD-Ngroup was much worse than that in HBD group, and there wereno significant difference among HBD group,NHBD-V groupand NHBD-I group; in PartⅡ, the lung compliance in NHBD-Sgroup was much better that in control group.3. Blood gas check: in PartⅠ, there were no significant differencebetween each group; in PartⅡ, the PaO2 and OI were higher inNHBD-S group compared with NHBD-C group.4. The wet/dry ratio of lung: in PartⅠ, the wet/dry ratio of lung inNHBD-N group was much higher than that in other groups, there were no significant difference among HBD group,NHBD-Vgroup and NHBD-I group; in PartⅡ, the wet/dry ratio of lung inNHBD-S group was much lower than that in NHBD-C group (p＜0.01).5. The amount of ATP,ADP and AMP: in PartⅠ, the amount ofATP,ADP and AMP and TAN in HBD group＞that in NHBD-Igroup＞that in NHBD-V group＞that in NHBD-N group.6. Pathological changes: in PartⅠ, the lung histologicalexamination showed that pathological changes in NHBD-Ngroup and in NHBD-V group were more serious than that inHBD group, and the pathological changes in NHBD-I group wasclose to that in HBD group; in PartⅡ, the pathological changesin NHBD-C group were more serious than that in NHBD-Sgroup.7. The expression of cell apoptosis: in PartⅡ, the expression of cellapoptosis in NHBD-C group were much higher than that inNHBD-S group.8. The amount of SOD and MDA: in PartⅡ, the amount of SOD inlung tissue after transplantation in NHBD-S group was muchhigher than that in NHBD-C group; the amount of MDA in lungtissue after transplantation in NHBD-S group was much lowerthan that in NHBD-C group. 9. The expression of ICAM-1mRNA: assessed by RT-PCR, theexpression of ICAM-1mRNA in lung tissue after transplantationin NHBD-S group was obviously down-regulated compared withNHBD-C group.10.Ultramicroscopic structural changes: Under electronicmicroscope, the ultramicroscopic structural changes in NHBD-Cgroup was more serious than that in NHBD-S group.Conclusion:1. Establishing animal model of non-heart-beating donor in rat lungtransplantation with two-cuff-one-stent technique is a simple andeffective method, which is fit for studying early problems inNHBD lung transplantation.2. The NHBD lung with 30 min of WIT is suitable for lungtransplantation in rats; and routine heparinization in donor andreceptor is not necessary.3. Excellent protective effect on cadaver lung can be reached bycontinuous ventilation or topical cooling, and the latter is a litterbetter than the former.4. Ischemic postconditioning has protective effect on NHBD lungtransplantation, it may decrease ischemic reperfusion injury afterlung transplantation and preserve the structure and function oflung. 5. The mechanism of ischemic postconditioning includes: increasethe amount of SOD and decrease the amount of MDA; inhibit theexpression of cell apoptosis after transplantation; down-regulatethe expression of ICAM-1mRNA of lung tissue aftertransplantation.