Clinical Study Of Medicinal Preconditioning In The Ischemia-Reperfusion Injury Of Myocardium

Backgroud and objective Cardiopulmonary bypass(CPB)is applied in open heart operation to temporary block the blood circulation of the cardiac coronary artery. Myocardial ischemia/reperfusion injury(MI/RI)can be caused by CPB.The main presentations of MI/RI are arrhythmia,reversible contractile dysfunction(myocardial stunning),endothelium dysfunction and myocardial ultrastructure change,which play the important role to success in surgery.At present,MI/RI is a commonly occurred perioperative cardiac problem that hinders ischemic myocardium to acquire the best curative effect from the reperfusion therapy.The prevention or reduction of MI/RI has become an important subject. Recently,many research results show that MI/RI can be prevented by many drugs which suppressed the acute ischemic arrhythmia,hemorrhagic necrosis and the expansion of the infarcted area.But because of the adverse effects and the effects of drugs to the physiology,it is very difficult for the drugs to play a role.Therefore,most of the drugs are still in the stage of fundamental research.In order to get a better understanding of the effect of anesthetics,the improvement of energy metabolism of cells,the synthesis of the specific precursor of NO and the intervention of traditional Chinese herbs to the drugs of myocardial ischemia reperfusion(MIR),132 patients undergoing open heart surgery utilizing CPB were divided into four groups.Made intervention with Propofol,Ketamine,1, 6-diphosphate,L-arginine and tetramethylpyrazine and observed the expression of heat shock protein(HSP)72,myocardium induced nitric oxide synthase(iNOS), polymorphonuclear neutrophil(PMN)NF-κB,Bcl-2 and the change of serum cardiac troponin T(cTnT)for further understanding the protecting action and mechanism of different drugs to MI/RI.Methods A hundred and thirty-two patients undergoing open-heart-surgery by CPB were randomly divided into four groups.The first group(G1)has twenty-eight patients,which were randomly divided into two groups(n=14 each),control(C)and TMP groups(M).In group M,TMP 3 mg/kg were given for thirty minutes after anesthesia induction and 1 mg/kg were given in oxygenator during CPB.In group C,same volume 0.9%NaCl were given at same time.A piece of right atrium myocardium was obtained before and after aortic cross-cramping(ACC)during cardiopulmonary bypass to measure the levels of HSP72 mRNA by semi-quantitative RT-PCR.Peripheral levels of AST,LDH,CK and CK-MB were measured before the CPB and 30 minutes after opening of aorta clamp and 24 h after cardiosurgery as markers of heart damage.A piece of right auricle myocardium was obtained before the CPB and 30 min after opening aorta to observe myocardial ultrastructure and analyzing mitochondria semiquantatively according to Flameng method.The second group(G2)has thirty-six patients,which were randomly divided into three groups(n=12 each),control(C)and Ketamine interfered groups(K1 and K2). In group K1 and K2,Ketamine 0.5 mg/kg and 1.0 mg/kg were vein injected before sternum splitted at the time of aorta intubated and 5 minutes before aorta clamped off partly.A piece of right auricle myocardium was obtained at the time of right atria intubated(T1),30 minutes after aorta clamped on(T2)and 30 minutes after aorta clamped off(T3)to measured the levels of iNOSmRNA and HSP72mRNA by one step real time fluorescence quantitative RT-PCR(used SYBR Green 1 fluorescence inosculating method).Blood samples were drawn from superior vena at T1,T2,T3 and two hours after aorta clamped off(T4).The content of creatinekinase(CK)and creatinekinase isozyme(CK-MB)were detected.The third group(G3)has fourty patients,which were randomly divided into four groups(n=10 each),control(C),L-Arg(L),FDP(F)and L-Arg plus FDP groups(D). In group L,L-Arg 200mg/kg were infused after aorta clamped off.In group F,FDP 200mg/kg were infused before aorta clamped on.In group D,L-Arg 200mg/kg were infused after aorta clamped off and FDP 200mg/kg were infused before aorta clamped on.Blood samples were taken to measure the levels of cardiac Troponin T(cTnT), Lactate dehydrogenase(LDH),MB isoenzyme of creatine kinase(CK-MB), malondialdehyde(MDA)and the activity of superoxide dismutase(SOD)before aortic-clamping on and 30 minutes,2 hours and 6 hours after aorta clamped off.The fourth group(G4)has fourty patients,which were randomly divided into two groups(n=20 each),control(C)and propofol groups(P).There were no differences between two groups about medication during operation except that the propofol was used for anesthesia maintenance in group P.In group P,the plasma concentration of propofol was targeted and started from 2.5-3.4μg/ml by target-controlled infusion, then adjusted plasma concentration to depend on blood pressure and heart rate.Blood samples were taken from superior vena cava after anesthesia induction and before CPB(T1),30 minutes after aorta clamped on(T2),while aorta clamped off(T3),30 minutes after CPB(T4)and 90 minutes after CPB(T5)to measure following data, NF-kB and Bcl-2 in neutrophil,and plasma levels of tumour necrosis factor-α(TNF-α), interleukin-8(IL-8),interleukin-10(IL-10),malondiadilyde(MDA)and superoxide dismutase(SOD)activity.Results In the first group(G1),there were no significant differences between the two groups in sex,age,weight,ACC time,CPB time and cardioplegic solution.The expression of HSP72mRNA and the serum concentration of AST,LDH,CK and CK-MB and the scores of myocardial mitochondria were significantly increased after ACC as compared to before ACC in the two groups(P＜0.05 or P＜0.01).The expression of HSP72 mRNA were significantly higher after ACC in the group M than in the control group(P＜0.05).The serum concentration of AST,LDH,CK and CK-MB and the scores of myocardial mitochondria were significantly lower in the group M than in the control group(P＜0.05)after CPB.The myocardial ultrastructure in the group had milder alterations than in the control group after CPB(P＜0.05).In the second group(G2),there were no significant differences among the three groups in sex,age,weight and time of aorta clamped on and cardiopulmonary bypass (P＞0.05).The expression of iNOSmRNA and HSP72mRNA were significantly increased at T2 and T3 and the serum concentration of CK,CK-MB were significantly increased at T2,T3 and T4 as compared to at T1 in the three groups(P＜0.05 or P＜0.01).The expression of iNOSmRNA and HSP72mRNA were significantly increased at T3 and the serum concentration of CK and CK-MB were significantly increased at T3 and T4 as compared to at T2 in the three groups(P＜0.05 or P＜0.01). The serum concentration of CK and CK-MB were significantly increased at T4 as compared to at T3 in the three groups(P＜0.01).Compared to the control group,the expression of iNOSmRNA significantly decreased in the group K1 at T2 and in the group K2 at T2 and T3(P＜0.01),the serum concentration of CK and CK-MB were significantly lower in the groups K1 and K2 at T2,T3 and T4(P＜0.01),the expression of HSP72mRNA were significantly increased in the group K1 and K2 at T2 and T3.Compared to the group K1,the expression of iNOSmRNA significantly decreased in the group K2 at T2 and T3(P＜0.01),the serum concentration of CK and CK-MB were significantly lower in the group K2 at T2,T3 and T4(P＜0.05 or P＜0.01),the expression of HSP72mRNA were no significant differences in the group K2(P＞0.05).In the third group(G3),the plasma concentration of cTnT,LDH,CK-MB,MDA and SOD were significantly increased at T2,T3 and T4 as compared to at T1 in the four groups(P＜0.05 or P＜0.01).Compared to the control group,the plasma concentration of cTnT were significantly lower in the group L and F at T4 and in the group D at T3 and T4(P＜0.05),the plasma concentration of LDH were significantly lower in the group L at T3 and in the group D at T2,T3 and T4(P＜0.05 or P＜0.01), the plasma concentration of CK-MB and MDA were significantly lower in the group L,F and D at T2,T3 and T4(P＜0.05 or P＜0.01),the plasma concentration of SOD were significantly higher in the group L,F and D at T3.The plasma concentration of cTnT were significantly lower in the group D than in the group L at T3(P＜0.01)and in the group F at T3 and T4(P＜0.01).The plasma concentration of LDH were significantly lower in the group D than in the group F at T2(P＜0.05).In the fourth group(G4),there were no significant differences between two groups in sex,age,weight,ascending aorta clamping time,CPB time and operation time(P＞0.05).The expression of NF-kB and Bcl-2 and the count of neutrophil were significantly increased at T4 as compared to at Tl in the two groups(P＜0.01).The serum concentration of TNF-α,MDA and SOD were significantly increased at T2,T3, T4 and T5 as compared to at T1 in the two groups(P＜0.05 or P＜0.01).The serum concentration of IL-8 and L-10 were significantly increased at T3,T4 and T5 as compared to at T1 in the two groups(P＜0.05 or P＜0.01).Compared to the control group,the expression of NF-kB and Bcl-2 and the count of neutrophil were significantly decreased in the group P at T4(P＜0.01),the serum concentration of TNF-αand MDA were significantly lower in the group P at T2,T3,T4 and T5 (P＜0.05 or P＜0.01),the serum concentration of IL-8 were significantly lower in the group P at T3,T4 and T5(P＜0.05),the serum concentration of IL-10 were significantly higher in the group P at T3,T4 and T5(P＜0.05),the serum concentration of SOD were significantly higher in the group P at T2,T3,T4 and T5 (P＜0.05).Conclusion HSP72,iNOS,NF-kB and Bcl-2 take part in myocardial ischemia -reperfusion injury.HSP72 gene expression increase in myocardium of patients undergoing open heart surgery during CPB.TMP pre-conditioning can induce HSP72 gene expression and protect myocardial mitochondria from ischemia reperfusion injury and attenuates CPB-induced myocardial ischemia reperfusion injury through a self-protective mechanism.Ketamine in dose of anesthesia(1.0mg/kg)and subanaesthetic(0.5mg/kg)can decrease iNOSmRNA and increase HSP72mRNA expression in myocardium and reduce leakage of myocardium enzyme.Ketamine acts myocardial protection,and which in anesthesia dose is more effective than in subanaesthetic dose.The both of L-Arg and FDP can produce protective effects on myocardial ischemia reperfusion injury during open heart surgery with CPB through different protective mechanism.The combined use of L-Arg and FDP shows obvious synergistic effects on myocardial protection.Propofol is used to the patients undergoing open heart surgery during the CPB not only has the satisfactory actions of anesthesia and sedation but also has the actions of inhibiting Inflammatory reaction and abatement tissue injury by impact the function of neutrophil,the proinflammatory anti-inflammatory cytokines and oxygen free radicals etc.It has the prevention to MI/RI that was induced by infection or uninfection during cardiac surgery.So it has the clinic significance to use propofol in cardiac surgery anaesthesia.