Protective Effect Of Eleutherosid Preconditioning Against Ischemic Reperfusion Injury In Isolated Rat-heart

Objective: To investigate the protective effect of eleutherosid preconditioning against ischemic-reperfusion injury on isolated rat heart and the dose-effect relationship between eleutherosid preconditioning and the myocardium protection.Methods:(1) Setting up ischemic-reperfusion model by Langendorff isolated heart system Before the experiment, inject heparin 500U/kg into rat abdominal cavity for anticoagulation. 30 minutes later, inject 0.3% pentobarbital to anesthesia by way of peritoneal injection. First, openning the chest, take the heart out and washout it swiftly in the 4 0C Kerbs-Henseleit perfusate without calcium for 20seconds. Then suspend the isolated rat heart to the aortic cannulation of Langendorff system for retro-perfusion. Perfusion fluid is the saturate K-H liquid by 95%O2 + 5% CO2 .perfusion pressure is 75mmH2O, perfusion rate is 5-8ml/min, perfusion temperature is 37 0C. After the heart rebeating , inset a sacculus rotundus to the left ventricle and regulate ventricular pressure to 4～10mmHg. After perfusing steadly 15 minutes,stop perfusion to ischemia 25 minutes ,and then reperfuse 30 minutes. (2)Subgroup and treatment of experimental animals Adult male SD rats were randomized to one model control group and four preconditioning treatment groups (A,B,C,D,E group) .A group ( ischemic-reperfusion group ): After perfusing steadly with K-H perfusate , continue to perfuse 15 minutes and stop perfusing for 25 minutes , then reperfuse 30 minutes . B,C,D,E group : After perfusing steadly with K-H perfusate , the four preconditiong group were given different dose of eleutheroside(30mg/kg,40mg/kg,60mg/kg,80mg/kg )for 10 minutes with K-H perfusate at the same time. Then do as A group.(3)Experiment Index Take the arrhythmogenesis as index for cordies electric activity. Look LVEDP,LVDP,+dp/dtMax,-dp/dtMax as index for heart function. And also using coronary artery flow rate (CBF ) and cardiac creatase LDH,CK as experimental index. Results:(1)Before ischemia , values of cardiac creatase LDH and CK for each groups have no significant difference . After reperfusion , releases of LDH and CK in several points of each group have decreased more significantly compared with I/R group (P <0.01 ) . (2)Before ischemia , heart functional parameters of each group have no significant difference. After reperfusing 30 minutes ,compared with I/R group , 30mg/kg and 80mg/kg group have no effect on the contraction and relaxation of left ventricle . While 40mg/kg and 60mg/kg group may increase LVDP,+ dp/dtMax and -dp/dtMax more significantly(P <0.05,P <0.01 and P <0.05 respectively). (3)Before ischemia , base values of CBF in each group have no significant difference . At the time of reperfusing 5,10,15,20,30min , compared with I/R group , 30mg/kg and 80mg/kg group have no effect on CBF , While 40mg/kg and 60mg/kg group may raise CBF more significantly (P <0.01 ) .(4) Compared with I/R group , In the first 5 minutes of reperfusion , 30mg/kg and 80mg/kg group have no significant difference in the incidence rate of ventricular fibrillation(VF)and the arrhythmia score. While 40mg/kg and 60mg/kg group have lower incidence rate of VF and arrhythmia scorce (P <0.01 and P <0.05).Conclusions: 1.Eleutherosid has significant preconditional protection on ischemia-reperfusion injury of isolated rat heart. 2.As for the protection on ischemia-reperfusion injury of isolated rat heart , eleutheroside preconditioning has a dose-effect relationship from 30mg/kg to 80mg/kg group.