Abstract： Objective To investigate the effects of calcium preconditioning (CP) on immature myocardial cell apoptosis and apoptosisregulated proteins. Methods The experiment was carried out from June 2000 to December 2001 in the Renmin Hospital of Wuhan University. Twelve rabbits with the age of 1421 d and the weight of 230300 g were divided into 2 groups with 6 in each group by random digital table. For rabbits in the ischemia/reperfusion group (I/R group), after Langendorff models were routinely set up, KrebsHenseleit (KH) solution was perfused for 20 minutes and reperfused for 120 minutes after 45 minutes of ischemia. For rabbits in the CP group, after Langendorff models were established, KH solution was perfused for20 minutes, and 45 seconds’ noncalcium KH solution perfusion and 5 minutes’ KH solution perfusion were repeated 3 times before 45 minutes of ischemia and 120 minutes of reperfusion of KH solution. In situ apoptosis identification and semiquantitative analysis were used to detect the myocardial cell apoptosis; agarose gel electrophoresis was used to detect the nucleosomal ladder of DNA fragments; and the expression of bcl-2, bax and fas were detected with Western blot method. Results The apoptosis rate for the CP group was lower than that of the I/R group (4.53%±1.22% vs. 12.30%±2.12%,t=7.780, P=0.000). Nucleosomal ladder of DNA fragments of the CP group was lower than that of the I/R group (OD value: 56 460±1 640 vs. 135 212±3 370,t=51.460,P=0.000). The expression of bcl-2 in the I/R group was lower than that of the CP group (OD value: 13 217±1 770 vs. 31 790±1 018,t=22.280, P=0.000). The expression of bax (OD value: 30 176±1 025 vs. 7 954±730, t=43.260, P=0.000) and fas (OD value: 29 197±1 233 vs. 8 140±867, t=34.220, P=0.000) in the I/R group was higher than that of the CP group. Conclusion CP can affect the expression of myocardial bcl-2, bax, and fas, and decrease immature myocardial cell apoptosis.
Objective To determine the protection effects and mechanisms for immature myocardium with limbs ischemic preconditioning (LIP). Methods Using the Langendorff perfusion apparatus to perfuse isolated hearts, we randomly divided 30 Japanese longeared white rabbits into 5 groups, each having 6 rabbits. For the I/R group，after the perfusion model was established, the isolated hearts underwent 15 min of perfusion with KH solution before working for another 15 min . Then perfusion was stopped to cause ischemia for 45 min before reperfusion for 15 min and working for another 30 min . For E1 group, the model was established by 3×LIP (double limbs obstructed for 5 min followed by 5 min reperfusion for 3 times) and then procedures of the I/R group were carried out. For E2 group, before procedures of the E1group were done, superoxide dismutase (SOD) was injected till LIP was completed. For E3 group, intravenous protein kinase C (PKC) polymyxin (PMB) was injected for 10 minutes before E1 procedures were repeated. For E4 group, intravenous mitochondrial ATPsensitive K+ channels (mitoKATP) blocker 5-hydroxydecanoate was injected for 10 min before E1 procedures were carried out. The left ventricular function recovery, myocardial water content (MWC), creatine kinase (CK) and lactate dehydrogenase (LDH) leakage, malondialdehyde (MDA) and ATP content, SOD activity and superoxygen negative ion (O2 ·-) content were tested. Results Left ventricular recovery in E1 group was better than other groups (Plt;0.05). ATP content and SOD activity in E1 group were also better than all other groups (Plt;0.05). MWC in E1 group was lower than other groups (Plt;0.05). MDA content, CK and LDH leakage in E1 group were also lower than other groups (Plt;0.05). There was no significant difference of the above indications among I/R,E2,E3 and E4 groups, while the difference of O2·- content in E1,E3 and E4 groups before and after preconditioning was significant. Conclusion LIP has obvious protective effects for immature myocardium and the mechanisms are probably through PKC stimulation and opening of mitoKATP.
Abstract： Objective To investigate the mechanism of protein kinase C(PKC) in immature myocardial ischemic preconditioning in order to further its clinical applicability. Methods Langendorff perfusion heart models of 24 rabbits were set up and they were randomly divided into 4 groups: ischemic reperfusion group (I/R group), myocardial ischemic preconditioning group (MIP group), chelerythrine group (CLT group) and protein kinase C group (PKC group). The emodynamics, biochemistry and myocardial ultrastructure were observed. Results The heart function recovery and myocardial water content in the MIP and the PKC groups were better than those of the I/R and the CLT groups (Plt;0.01). The adenosine triphosphate (ATP) content, superoxide dismutase activity, mitochondrial Ca2+-ATPase activity and synthesizing ATP activity of mitochondria in the MIP and the PKC groups were significantly higher than those of the I/R and the CLT groups (Plt;0.01). The dehydrogenase and creatine kinase leakage, malondialdehyde content, myocardial cell Ca2+ content and mitochondrial Ca2+ content in the MIP and the PKC groups were significantly lower than those of the I/R and the CLT groups (Plt;0.01). The myocardial ultrastructure injuries in the MIP and the PKC groups were less than that of the I/R and the CLT groups. Conclusion Myocardial ischemic preconditioning plays an important role in protecting immature myocardium, which is probably realized by the activation of PKC.
Objective To investigate the role of mitochondrial adenosine triphosphatesensitive potassium channel(mitoKATP) in immature myocardial ischemic preconditioning, and to provide evidence for immature myocardial protection. Methods Langendorff isolated heart infused model was used in the experiment. Twentyfour rabbits (aged from 14 to 21 days) were randomly divided into 4 groups：ischemiareperfusion group（I/R group）, myocardial ischemic preconditioning group(E1 group), 5hydroxydecanoate(5-HD) group (E2 group) and Diazoxide (Diaz) group(E3 group). Hemodynamics recovery rate, myocardial water content(MWC), the leakage rates of serum creatine kinase and lactate dehydrogenase, adenosine triphosphate content, superoxide dismutase activity, malondialdehyde content, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content, myocardial mitochondrial Ca2+-ATPase activity, the adenosine triphosphate(ATP) synthesizing ability of myocardial mitochondria were tested, and myocardial ultrastructure was observed via electron microscopy. Results The hemodynamics recovery rate, myocardial water content(P＜0.05), adenosine triphosphate content, superoxide dismutase activity, myocardial mitochondrial Ca2+-adenosine triphosphyatase(ATPase) activity and the ATP synthesizing ability of myocardial mitochondria of the rabbits in E1 and E3 group were significantly better than that in I/R group and E2 group(P＜0.05). Malondialdehyde content, the leakage rates of serum creatine kinase and lactate dehydrogenase, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content of the rabbits in E1 group and E3 group were significantly lower than that in I/R group and E2 group (P＜0.05). The myocardial ultrastructure injury in E1 and E3 group were significantly reduced compared with that in I/R and E2 group. Conclusion Myocardial ischemic preconditioning has significant protective effects on immature myocardium. Its mechanism may be related to the activation of mitoKATP.
Objective To investigate the immature myocardial protection effects with renal ischemic preconditioning. Methods 18 neonatal rabbits were randomly divided into three groups. Ischemic/reperfusion(I/R) group underwent 45 min ischemia followed with 45 min reperfusion after Langendorff model performed. Cardiac ischemic preconditioning(CIP) group underwent 45 min ischemia followed with 45 min reperfusion after 5 min ischemia and then 5 min reperfusion for two times. Renal ischemic preconditioning(RIP) group underwent 45 min ischemia followed with 45 min reperfusion after renal artery obstruction for 5 min and 5 min reperfusion for three times.The left ventricular function recovery,myocardial water content(MWC), lactate dehydrogenase (LDH) and creatine kinase(CK) leakage, malondialdehyde(MDA) content,adenosine triphosphate(ATP) content, superoxide dismutase(SOD) activity, myocardial cell Ca2+ ［Ca2+］c content,mitochondrial Ca 2+ content ［Ca2+］m,synthesizing ATP activity of mitochondria ［ATP］m and Ca2+ATPase activity of mitochondria ［Ca2+ATPase］m were tested. Results The recovery of postischemic heart function in RIP group and CIP group were higher than that I/R group(Plt;0.01). There were no significant difference of HR, AF in three groups （Pgt;0.05）. There were significant difference of CF，CO，LVSP and LVEDP in RIP group and CIP group than those I/R group（Plt;0.01）. There were significant difference of MWC, CK, LDH, ATP content, MDA, SOD activity, ［Ca2+］c content, ［Ca2+ATPase］m， ［Ca2+］m and ［ATP］m in RIP group than those I/R group（Plt;0.01). There were no significant difference between RIP group and CIP group upon every index (Pgt;0.05). Conclusion RIP has the same cardioprotection to immature myocardium as ischemic preconditioning.
Objective To investigate the protective effects of metallothionein （MT） for immature myocardium and myocardial interstitium.Methods Twenty-four rabbits （aged 14-21 days） were divided into 4 groups with random number table, 6 each group. Distilled water was injected intraperitoneally in control group and 3.6% ZnSO4 （1.5 ml/kg） was injected intraperitoneally in group 1, group 2 and group 3. Control group, group 1, group 2 and group 3 isolated working rabbit heart model were used in 24h, 12h, 24h and 48h after intraperitoneally respectively. The MT content, recovery of hemodynamics, biochemistry and myocardial ultrastructure were tested. Results The MT content, hemodynamics recovery, adenosine triphosphate （ATP） content, superoxide dismutase activity, Ca2＋-ATPase activity, synthesizing ATP activity of mitochondria, hydroxyproline in group 2 and group 3 were higher than those in control group and group 1 （P 〈 0. 01）. The myocardial watery content, creatine kinase and dehydrogenase leakage, malondialdehyde content, endothelin, mitochondrial Ca2＋ content in group 2 and group 3 were lower than those in control group and group 1（P〈0.01）. The myocardial ultrastructure injuries were less in group 2 and group 3 than that in control group and group l. Conclusion This study demonstrates that myocardial MT prolonged expression can be induced by ZnSO4 and the ischemia-reperfusion injury of immature myocardium and myocardial interstitium could be reduced by MT.
Objective To investigate the protection effects of different pH N 2 hydroxyethyl piperazine N′ 2 ethanesulfonic acid (HEPES) Krebs Henseleit (KH) reperfusate solutions on immature myocardium and myocardial interstitium. Methods Isolated perfused Langendorff model from immature rabbit hearts were performed. Twenty four rabbits were divided into control group, ischemia reperfusion group and acidic reperfusate group. The left ventricular function recovery, myocardial water content(MWC), lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, malondialdehyde(MDA) and adenosine triphosphate (ATP) content, superoxide dismutase(SOD) activity , hydroxyproline(HP) and endothelin(ET) content were tested. Results The left ventricular functional recovery, ATP content, SOD activity and HP content in acidic reperfusate group were higher than those of ischemia reperfusion group( P lt;0.05).MWC, MDA content, CK and LDH leakage, and ET content in acidic reperfusate group were lower than those of ischemia reperfusion group( P lt;0.05). Conclusion These results suggest pH paradox might be one of important mechanisms for immature myocardium and myocardial interstitium ischemia reperfusion injury,and acidic perfusate, at the beginning of reperfusion ,might attenuate pH paradox and ameliorate functional recovery in isolated perfused immature rabbit hearts.
目的 分析75岁以上高龄冠心病患者行冠状动脉旁路移植术（CABG）的治疗效果和临床经验。 方法回顾性分析山东省潍坊市人民医院和青岛市市立医院自2005年1月至2014年1月109例75岁以上行CABG术患者的临床资料。其中，男63例、女46例，平均年龄（78.1±4.2）岁，均为多支血管病变。术前心功能分级（NYHA） Ⅳ级23例、Ⅲ级57例、Ⅱ级29例。术中行非体外循环CABG （OPCABG） 92例，体外循环下行CABG （on pump CABG）术9例，体外循环辅助心脏不停跳下CABG （on pump beating heart CABG） 术8例。 结果 平均移植血管（2.5±1.4）支，围术期死亡4例，死亡率3.7%。其中，低心排血量综合征死亡1例，心律失常心室颤动死亡1例，肾衰和胃肠道并发症导致多器官衰竭死亡2例。术后主要并发症为心律失常、低心排血量综合征和肺部感染。105例生存患者95例获得随访，随访6～90 （45±26）个月，随访率90.5%。随访期间心源性死亡1例，非心源性死亡4例。患者心功能分级（NYHA）Ⅰ级81例，Ⅱ级18例，Ⅲ级2例，心绞痛消失。 结论 75岁以上冠心病患者行冠状动脉旁路移植术可改善患者症状，缓解心绞痛，提高生活质量，具有良好的近中期效果。