Protection Of Modified HTK Solution BCP For NHBD Pig Heart

Part I The study of normothermic ischemia time in NHBD pig heartObjective:To study the normothermic ischemia time in non heart beating donors(NHBD) pig heart through exsanguinate cardiac arrest without donors pretreatment.Methods:21 pair adult pigs(each pair contains 1 donor and 1 recipient) were divided into four groups. In S0 group (control group n=6), cardiac arrest was induced by Stanford solution(0?,1000 ml) perfusion, and donor heart was stored for 2h with Stanford solution at 4?; in S15 group (15 min-normothermic ischemia time group, n=6), 15 min-normothermic ischemia in situ after exsanguinate cardiac arrest, donor hearts were perfused and stored for 2 h with Stanford solution at 4?; in S30 group (30 min-normothermic ischemia group n=6),30 min-normothermic ischemia in situ after exanguinate cardiac arrest, donor hearts were perfused and stored at 4?for 2h with Stanford solution; in S45 group (45 min-normothermic ischemia group n=3),45 min-normothermic ischemia in situ after exanguinate cardiac arrest, donor hearts were perfused and stored at 4?for 2h with Stanford solution. Orthotopical transplantation was performed through the biatrial technique in each group. Hemodynamic changes, enzyme activities, ATP, cTn I, myocardial water content and ultrastructure were examined. Statistical Methods:All data are expressed as the mean±standard deviation (SD) of at least three independent experiments. Two-tailed, paired Student's t test and one-way ANOVA were used to determine the differences between the control and treatment groups (Analyze-It software for Microsoft Excel).Statistical analysis:Comparison of groups were performed with student t test, difference between multiple groups were studied with analysis of variance.Results:S0?S15?S30 group could wean from eardiopulmonary bypass successfully; and S45 failed. In S30 group, cardiac output descends obviously compared with So?S15 groups, with statistical variance(P<0.05). In S30 group, enzyme activities, cTn I, myocardial water content increased while ATP decreased compared with So and S15 group(P<0.05). In S45 Group, myocardial ultrastructures changed irreversiblely and could not reanimated while in the other three groups, still maintain integrities.Conclusions:1. Within 30 min, The NHBD pig heart of normothermic ischemia without pretreatment is fitable in heart transplantation.2. After 45 min, the NHBD pig heart of normothermic ischemia without pretreatment is unfitable in heart transplantation because of the irreversible damages of the cardiac muscle ultrastructures. Part?Protection of modified HTK solution BCP for NHBD pig heart.Objectives:To study the protective effect of modified HTK solution BCP (blood cardioplegia) in the NHBD pig heart of 30 min-normothermic ischemia in situ after exanguinate cardiac arrest.Methods:24 pair adult pigs (each pair contains 1 donor and 1 recipient) were divided into four groups. In So group (control group n=6), cardiac arrest was induced by Stanford solution(0?,1000 ml) perfusion, donor heart was stored for 2h with Stanford solution at 4?. In S30 group (Stanford solution group n=6),30 min-normothermic ischemia in situ after exanguinate cardiac arrest, donor hearts were perfused and stored at 4?for 2h with Stanford solution. In SH30 group (HTK group n=6),30 min-normothermic ischemia in situ after exanguinate cardiac arrest, donor hearts were perfused cold leukocyte-depleted BCP and stored at 4?for 2h with HTK solution. Before aortic unclamping, a second controlled reperfusion was performed with 500ml leukocyte-depleted blood. In SHO30 group (modified HTK group n=6), 30 min-normothermic ischemia in situ after exanguinate cardiac arrest, donor hearts were perfused cold leukocyte-depleted BCP (blood cardioplegia) and stored at 4?for 2h with modified HTK solution (include:HTK solution 1000ml, Heparin 5mg, thromboxane synthase inhibitor lOmg). Before aortic unclamping, a second controlled reperfusion was performed with 500ml leukocyte-depleted blood (Heparin 3mg, thromboxane synthase inhibitor 5mg).Then orthotopical transplantation was performed in a biatrial technique.. Hemodynamic changes, enzyme activities, ATP, cTn I, SOD, MDA, Myocardial apoptosis, Bcl-2, Bax, Caspase-3 protein and ultrastructure were examined.Statistical analysis:Comparison of groups were performed with student t test, difference between multiple groups were studied with analysis of varianceResults:In SH30?SHO30 group, all the observed indicators are better than S30 group (P<0.05).In SH30?SHO30 group, hemodynamic changes have no statistical variance.(P>0.05), other indicators are worse than So group. In SHO30 group, enzyme activities, ATP, cTn I, SOD and MDA were better in SH30 group. Myocardial apoptosis, Bax, Caspase-3 protein are higher than SH30, Bcl-2 protein is lower than SH30. Mycardial ultrastructure revealed there are no thrombus in SHO30 and So group, but many thrombus in S30.According ultrastructure of cardiac muscle, mitochondrial and microvascular endothelial cells, S0 group has the best integrity, SHO30 group the second, S30 group the worst.Conclusions: 1. Modified HTK solution BCP can reduce the ischemia reperfusion injuries of NHBD pig heart, which endured 30 min of normothermic ischemia after exanguinate cardiac arrest.2. Thromboxane synthase inhibitor combined with heparin can ameliorate the NHBD pig's myocardial microcirculation after reperfusion, and strengthen the protection of the NHBD heart which endured 30 min normothermic ischemia.3. Thromboxane synthase inhibitor can reduce apoptosis during the process of ischemia reperfusion injuries.