Ginkgo Biloba Extract Provides Additive Cardioprotection Against Heart Ischemia/refusion Injury In Rabbit Postconditioning Animal Model

Objective:To observe if postconditioning(PC) together with ginkgo biloba extract(EGb) will synergically protect the myocardium from severe ischemia/reperfusion.We also observed the influence of PC on myocardium ultrastructure and on the expression of Heme oxygenase-1(H0-1) in both of heart and virgin kidney.Methods:48 Newsland rabbits were divided randomly into four groups(n=12), rabbits underwent 30min left coronary artery (LCA) occlusion followed by 3 h of reperfusion.(1) Untreated group(A), no intervention after LCA occlusion;(2)PC group(B), 3cir×10s handling initiated immdiately at the onset of reperfusion; (3)EGb group(C): pretreated with EGb (2ml/Kg.d) 3 dys before the experiment ,and no intervention after LCA occlusion.(4) PC+EGb group(D), pretreated with EGb(2ml/Kg.d) 3days before the experiment, and 3cir×10s handling initiated immdiately at the onset of reperfusion.We randomly extracted 6 rabbits of each group to record the arrhymia at the onset of reperfusion; measured area at risk and infarct size,plasma creatine kinase (CK) activity level at onset of the reperfusion, 1h,2h,3h of reperfusion,and MDA,MPO,SOD, NOS level at 3h of reperfusion. The others were observed the influence of PC on myocardium ultrastructure and on the expression of H0-1 in both of heart and virgin kidney.Results: 1.Index of I/R injury:(1)I/R arrhythmia score: Compared with A group,B,C,D could attenuated ventricular arrhythmias after reperfusion(P<0.01). the arrhythmia score of D was not different with B(P>0.05),but lower than C grope(P<0.05);(2) infarct size: Compared with A group,B,C,D could reduce the infarct size(P<0.01). D was lower than both of B and C(P<0.05) ;(3) plasma CK activity: Compared with A group,B,C,D could significantly degraded the plasma CK activity at the onset ,1h,2h,3h of reperfusion(P<0.01) . D was lower than both of B and C (P<0.01).2.Index of cardioprotection: Compared with A group,B,C,D could significantly degrad the plasma MPO, MDA activity and improve the plasma SOD,NOS activity at 3h of reperfusion(P<0.01),The plasma MPO, MDA activity of D waslower than B and C(P<0.05),While the plasma SOD,NOS activity was higher than B ,C(P<0.01).3. myocardial ultrastructure: B,C,D leaded to a significant improvement in myocardial ultrastructure compared with A, especially of D.4.The expression of HO-1 in both heart and kidney of B,C, D was higher than A(P<0.01). D is higher than B and C(P<0.01).Conclusion:1. PC and EGb could protect the heart against the I/R injury; 2. PC together with EGb could synergically protect the myocardium from severe I/R injury ; 3. Both PC and EGb could upregulate the expression of HO-1 in heart,We supposed that HO-1 involve in the cardioprotection mechanism of PC and EGb;4. PC could upregulate the expression of HO-1 in the virgin kidney, We supposed that induction HO-1 can enhance resistance of remote virgin organ to ischemic stimulation.