心肌缺血/再灌注前处置时血浆一氧化氮的变化及意义

目的：在兔心肌缺血／再灌注前处置模型的基础上，了解NO在心肌缺血前处置中所起的作用及意义。方法：采用免麻醉后开胸结扎左冠状动脉降支，反复结扎（缺血）10分钟，放开（再灌）5分钟，最后结扎30分钟再灌20分钟造成缺血／再灌注前处置模型后，对比观察了各组动物血浆中NO、TXB2、6－K－PGF1α、SOD和MDA浓度的变化，以及各组动物球结膜微循环及心肌病理学的变化。结果：前处置组血浆NO、6－K－PGF1α、SOD浓度显著高于缺血／再灌注组，而MDA、TXB2浓度明显低于缺血／再灌注组。前处置组心肌超微结构损伤明显轻于缺血／再灌注组，球结膜微循环基本正常。结论：心肌缺血前处置可增加心血管内皮细胞合成NO，而NO具有减轻心肌缺血／再灌注损伤、改善微循环障碍的作用。     

β-受体阻滞剂对家兔心肌缺血再灌注后纤溶活性及血管活性物质含量的影响

探讨艾司洛尔、索他洛尔、美托洛尔和卡维地洛对家兔心肌缺血再灌注后纤溶活性、血管内皮活性物质含量的影响。新西兰大白兔 5 8只 ,随机分为 6组 ,Ⅰ组 :AMI组 ,Ⅱ组 :缺血 再灌注 (ischemicreperfusion ,IR)组 ,Ⅲ组 :IR +艾司洛尔组 ,Ⅳ组 :IR +索他洛尔组 ,Ⅴ组 :IR +美托洛尔组 ,Ⅵ组 :IR +卡维地洛组 ;制作IR动物模型 (除AMI组 ) ,缺血 6 0min后再灌注 2 4 0min ,分别于缺血前、再灌注前 ,再灌注 2 4 0min后取血测定t PA、PAI 1的活性和ET、NO浓度。结果显示 :冠脉结扎后 ,血浆ET、NO浓度和PAI 1活性显著高于结扎前 ,而t PA活性显著低于结扎前 (P <0 0 1) ,再灌注后 ,血浆ET、NO浓度和PAI 1活性进一步升高 ,t PA活性进一步下降 (P <0 0 1)。与IR组对比 ,各组NO的浓度再灌注后无显著性差异 ,艾司洛尔组再灌注后血ET浓度显著降低 (P <0 0 1) ,血t PA、PAI 1活性无明显的变化 ;索他洛尔、美托洛尔、卡维地洛均能显著的升高再灌注后t PA活性 ,降低血PAI 1活性和ET浓度 (P <0 0 1)。提示 :索他洛尔、美托洛尔、卡维地洛有改善缺血再灌注过程中纤溶活性、抑制内皮细胞释放ET的有益作用 ;艾司洛尔能抑制缺血再灌注过程中ET的释放 ,对纤溶活性无明显的影响     

延迟预适应减少大鼠心肌缺血再灌注的细胞凋亡

目的 以SMAC和XIAP的表达变化为着眼点,探讨心肌缺血延迟预适应抗心缺血再灌注（MI/R）后细胞凋亡的机制。方法 SD大鼠分为对照组、假手术组、缺血再灌注组、延迟缺血预处理组。缺血再灌注组采用经典大鼠冠脉结扎,缺血1h,再灌1h。延迟缺血预处理组采用缺血5 min,再灌5 min,反复循环3次,24 h后缺血1 h,再灌1 h。流式细胞仪测定心肌细胞凋亡率,检测caspase-3活性,Western blot分析胞质SMAC及XIAP的表达。结果 与对照组相比,缺血再灌注组细胞凋亡率、caspase-3的活性及SMAC的表达明显升高（P<0.01）,XIAP的表达明显下降（P <0.01）。延迟缺血预处理组细胞凋亡率、caspase-3的活性及SMAC的表达较缺血再灌注组明显下降（P<0.01）,XIAP的表达较缺血再灌注组升高（P <0.01）。结论 心肌缺血延迟预适应可以减少MI/R造成的细胞凋亡,机制与其阻碍SMAC自线粒体释放,从而保护XIAP对caspase家族的抑制密切相关。     

川芎嗪对实验性心肌缺血再灌注损伤中一氧化氮和内皮素的干预

目的:探讨一氧化氮(NO)和内皮素(ET)在心肌缺血再灌注损伤(MIRI)中的作用及川芎嗪对其的影响。方法:实验兔分为假手术对照组(n=10)、心肌缺血再灌注组(n=10)及心肌缺血再灌注+川芎嗪组(n=10);分别检测缺血前、缺血40min和再灌注20min3个时点的指标变化。检测血浆及心肌组织一氧化氮代谢产物(NOP)含量、测定ET水平、乳酸脱氢酶(LDH)活性,并行心肌电镜观察。结果:心肌缺血40min、再灌注20min血浆NOP明显低于、ET及LDH显著高于假手术对照组,尤以再灌注20min变化显著(均P＜0.01);心肌组织NOP和LDH明显低于、ET显著高于假手术对照组(P＜0.05和P＜0.01);心肌超微结构发生异常改变。川芎嗪可逆转上述指标的异常变化。结论:缺血再灌注导致血管内皮功能紊乱(即NO水平下降和ET水平升高),在MIRI发生发展中起介导作用;川芎嗪通过保护冠脉内皮,提高机体内NO水平和降低机体内ET水平,从而减轻MIRI。     

040 去甲肾上腺素预处理对缺血/再灌注大鼠心脏5'-核苷酸酶的保护作用

目的: 在在体大鼠模型上从生化和酶组化的角度观察比较了去甲肾上腺素预处理和经典缺血预处理对缺血/再灌注大鼠心脏的保护作用及5'-核苷酸酶(5'-NT)活性的影响, 以期为一种非创伤性预处理方式提供实验依据并探讨其机制. 方法: 将24只体重200～250 g的雄性SD大鼠分为4组, 即: Ⅰ组, 假手术组; Ⅱ组, 缺血/再灌注组, 左冠状动脉前降支结扎使心肌缺血30 min后恢复再灌20 min; Ⅲ组, 经典缺血预处理组, 按Murry法进行; Ⅳ组, 去甲肾上腺素预处理组, 在缺血前15 min开始由舌静脉在5 min内缓慢滴入NE 1.6 μg. 再灌结束后, 测血清肌酸激酶活性; 原位观察心肌细胞色素C氧化酶、 5'-核苷酸酶活性. 结果: 经典缺血预处理或去甲肾上腺素预处理后缺血/再灌注心肌心肌细胞色素C氧化酶损伤性反应明显减轻(P<0.05)、血清肌酸激酶漏出减少(P<0.01); 5'-核苷酸酶活性升高(P<0.05). 结论: 去甲肾上腺素预处理及经典缺血预处理均能保护缺血/再灌注大鼠心脏超微结构、减少心肌酶漏出, 具有相似的抗心肌缺血/再灌注损伤作用, 这种作用可能与保护5'-核苷酸酶活性, 使内源性腺苷增多有关.     

缺血预处理对缺血/再灌注大鼠心脏有关酶保护作用的研究

目的 :在在体大鼠模型上原位观察比较了经典缺血预处理对缺血 /再灌注大鼠心肌有关酶活性的影响 ,以期进一步探讨预处理保护作用的机制。方法 :将 2 4只体重 2 0 0～2 5 0 ｇ的雄性ＳＤ大鼠分为 4组 ,即 :Ⅰ组 ,假手术组 ;Ⅱ组 ,缺血 /再灌注组 ,左冠状动脉前降支结扎使心肌缺血 30ｍｉｎ后恢复再灌 2 0ｍｉｎ ;Ⅲ组 ,经典缺血预处理组 ,按Ｍｕｒ ｒｙ法进行 ;Ⅳ组 ,去甲肾上腺素预处理组 ,在缺血前 15ｍｉｎ开始由舌静脉在 5ｍｉｎ内缓慢滴入ＮＥ 1.6 μｇ。再灌结束后原位观察过氧化氢酶、5’ 核苷酸酶及Ｃａ2 ＡＴＰ酶活性及琥珀酸脱…     

银杏酮酯预处理对心肌缺血再灌注大鼠心肌细胞凋亡的影响

探讨银杏酮酯预处理对心肌缺血再灌注大鼠心肌细胞凋亡的影响及可能的作用机制。方法以36只雄性Wistar大鼠为研究对象,将实验动物随机分为3组:假手术组、心肌缺血再灌注模型组与银杏酮酯组。采用结扎大鼠冠状动脉左前降支的方法,建立大鼠心肌缺血再灌注损伤模型。假手术组穿线后不结扎,模型组于缺血前30 min腹腔注射生理盐水,银杏酮酯组大鼠于缺血前30 min腹腔注射银杏酮酯(100mg/kg)。造模24h后处死大鼠,TUNEL法检测心肌细胞凋亡, Western blot方法检测心肌组织Bax和caspase-3蛋白表达,实时PCR方法检测心肌组织Bax mRNA和caspase-3 mRNA的表达。结果银杏酮酯预处理可明显降低心肌缺血再灌注大鼠心肌细胞凋亡率,降低心肌缺血再灌注大鼠心肌组织Bax和caspase-3蛋白与mRNA表达水平。结论银杏酮酯预处理降低缺血再灌注大鼠心肌细胞凋亡率可能与抑制Bax和caspase-3表达相关。     

去甲肾上腺素预处理对缺血/再灌注大鼠心脏有关酶保护作用的研究

目的 :本实验在在体大鼠模型上原位观察比较了去甲肾上腺素预处理和经典缺血预处理对缺血 /再灌注大鼠心肌有关酶活性的影响 ,以期探讨一种非创伤性预处理保护作用的机制。方法 :将 2 4只体重2 0 0～ 2 50ｇ的雄性ＳＤ大鼠分为 4组 ,即 :Ⅰ组 ,假手术组 ;Ⅱ组 ,缺血 /再灌注组 ,左冠状动脉前降支结扎使心肌缺血 30ｍｉｎ后恢复再灌 2 0ｍｉｎ ;Ⅲ组 ,经典缺血预处理组 ,按Ｍｕｒｒｙ法进行 ;Ⅳ组 ,去甲肾上腺素预处理组 ,在缺血前 1 5ｍｉｎ开始由舌静脉在 5ｍｉｎ内缓慢滴入ＮＥ 1 6μｇ。再灌结束后测血清一氧化氮含量 ,原位观察过氧化氢…     

川芎嗪对缺血再灌注所致大鼠离体心脏损伤的保护作用

目的:观察川芎嗪对缺血再灌注所致大鼠离体心脏损伤的保护作用。方法:心脏缺血再灌注模型:大鼠离心脏Langen-dorff灌流,全心停灌20分钟后复灌40分钟造成缺血--再灌注损伤。将充水乳胶球囊通过左心房插入左心室,Medlab-u/81生物信号采集处理系统记录分析心功能指标LVP,±dp/dtmax,HR和CF,收集再灌5分钟时,冠脉流出液。用分光光度法测定肌酸激酶(CK)活性。结果:缺血再灌注能降低冠脉流量,LVP,±dp/dtmax值,减慢心率、增加CK释放量,两个浓度的川芎嗪(40与80mg·L-1)对离体大鼠心脏缺血再灌注损伤有保护作用,表现为改善心功能,增加冠脉流量,减少心肌细胞内酶CK的释放,川芎嗪与维拉帕米有相似的心肌保护作用。结论:川芎嗪对心脏缺血再灌注心功能损伤具有保护作用。     

去甲肾上腺素预处理对缺血/再灌注大鼠心脏5’-核苷酸酶的保护作用

目的 :在在体大鼠模型上从生化和酶组化的角度观察比较了去甲肾上腺素预处理和经典缺血预处理对缺血 /再灌注大鼠心脏的保护作用及 5’ 核苷酸酶 (5’ ＮＴ)活性的影响 ,以期为一种非创伤性预处理方式提供实验依据并探讨其机制。方法 :将 2 4只体重 2 0 0～ 2 5 0ｇ的雄性ＳＤ大鼠分为 4组 ,即 :Ⅰ组 ,假手术组 ;Ⅱ组 ,缺血 /再灌注组 ,左冠状动脉前降支结扎使心肌缺血 30ｍｉｎ后恢复再灌 2 0ｍｉｎ ;Ⅲ组 ,经典缺血预处理组 ,按Ｍｕｒｒｙ法进行 ;Ⅳ组 ,去甲肾上腺素预处理组 ,在缺血前 15ｍｉｎ开始由舌静脉在 5ｍｉｎ内缓慢滴入ＮＥ 1.6…     

Batroxobin对狗心脏缺血／再灌注损伤中内皮素的影响

本工作研究Batroxobin对狗心脏I／R损伤过程中ET水平的.针狗左冠状动脉前降支结扎30min,恢复血流90min,造成I／R模,于缺血前或缺血后15min静注Batroxobin（1U／kg),测定血浆,心肌ET浓度以及血浆CK和LDH活性。结果表明,I／R组心肌组织及血浆ET水平明显升高,心肌组织明显损伤Batroxobin能够显著降低再灌期血浆及心肌ET水平,降低CK及LDH活性,减轻心肌组织I／R损伤。     

绞股蓝总皂甙对大鼠心肌缺血再灌注损伤的保护作用

结扎大鼠冠状动脉40分钟,解除结扎恢复血流再灌注20分钟,复制大鼠心肌缺血/再灌注损伤模型,观察绞股蓝总皂甙(GP)对心肌缺血/再灌注损伤的影响。结果,GP明显提高心肌组织GSH-Px活性,降低心肌MDA含量,使降低的线粒体膜流动性恢复,减轻再灌注导致心肌超微结构损伤。提示,GP对大鼠心肌缺血/再灌注损伤有保护作用,作用机理与抗氧化作用有关。     

Protective effect of sauchinone against regional myocardial ischemia/reperfusion injury: inhibition of p38 MAPK and JNK death signaling pathways

Sauchinone has been known to have anti-inflammatory and antioxidant effects. We determined whether sauchinone is beneficial in regional myocardial ischemia/reperfusion (I/R) injury. Rats were subjected to 20 min occlusion of the left anterior descending coronary artery, followed by 2 hr reperfusion. Sauchinone (10 mg/kg) was administered intraperitoneally 30 min before the onset of ischemia. The infarct size was measured 2 hr after resuming the perfusion. The expression of cell death kinases (p38 and JNK) and reperfusion injury salvage kinases (phosphatidylinositol-3-OH kinases-Akt, extra-cellular signal-regulated kinases [ERK1/2])/glycogen synthase kinase (GSK)-3β was determined 5 min after resuming the perfusion. Sauchinone significantly reduced the infarct size (29.0% ± 5.3% in the sauchinone group vs 44.4% ± 6.1% in the control, P < 0.05). Accordingly, the phosphorylation of JNK and p38 was significantly attenuated, while that of ERK1/2, Akt and GSK-3β was not affected. It is suggested that sauchinone protects against regional myocardial I/R injury through inhibition of phosphorylation of p38 and JNK death signaling pathways.     

Emulsified isoflurane postconditioning produces cardioprotection against myocardial ischemia–reperfusion injury in rats

Emulsified isoflurane (EIso) preconditioning can induce cardioprotection. We investigated whether EIso application after ischemia protects hearts against reperfusion injury and whether it is mediated by the inhibition of apoptosis. Rats were subjected to 30-min coronary occlusion followed by 180-min reperfusion. At the onset of reperfusion, rats were intravenously administered saline (sham, control group), 30 % intralipid (IL group) or 2 ml kg^?1 EIso (EIso group) for 30 min. After reperfusion, infarct sizes, myocardial apoptosis and expression of Bcl-2, Bax and caspase-3 proteins were determined. Hemodynamic parameters were not different among groups. Compared with control and intralipid group, EIso limited infarct size, inhibited apoptosis, increased the expression of Bcl-2, decreased the expression of Bax, cleaved caspase-3, and enhanced Bcl-2/Bax ratio. EIso protects hearts against reperfusion injury when administered at the onset of reperfusion, which may be mediated by the inhibition of apoptosis via modulation of the expression of pro- and anti-apoptotic proteins.     

阿魏酸川芎嗪对缺血再灌注大鼠心肌细胞凋亡及凋亡相关蛋白表达的影响

 目的：观察阿魏酸川芎嗪对缺血再灌注损伤大鼠心肌细胞凋亡的影响,并探讨其可能机制。方法：将60只雄性SD大鼠随机分成5组：（1）假手术组;（2）缺血再灌注组;（3）川芎嗪(4 mg/kg)组;（4）阿魏酸川芎嗪低剂量(4 mg/kg)组;（5）阿魏酸川芎嗪高剂量(8 mg/kg)组。采用结扎左冠状动脉前降支30 min、再灌注120 min的方法复制大鼠心肌缺血再灌注模型;各组大鼠于再灌注前10 min分别颈静脉注射给药,于再灌注结束后,进行血清生化及心肌组织学检测。结果：阿魏酸川芎嗪能显著降低心肌缺血再灌注损伤大鼠血清中肌酸激酶同功酶、乳酸脱氢酶、心肌钙蛋白I和丙二醛的水平,提高总超氧化物歧化酶活性,增加心肌Bcl-2蛋白的表达,减少心肌Bax蛋白的表达, 提高Bcl-2/Bax 的比值和降低心肌细胞凋亡指数,与缺血再灌注组比较,差异有统计学意义（P＜0.01）。阿魏酸川芎嗪各项指标优于川芎嗪（P＜0.05或P＜0.01）。结论：阿魏酸川芎嗪能减轻大鼠心肌缺血再灌注损伤;其抗缺血再灌注诱导的心肌细胞凋亡的机制可能与其上调Bcl-2蛋白和下调Bax蛋白表达有关。     

Cardiac sodium/calcium exchanger preconditioning promotes anti-arrhythmic and cardioprotective effects through mitochondrial calcium-activated potassium channel

Background: Reverse-mode of the Na⁺/Ca²⁺ exchanger (NCX) stimulation provides cardioprotective effects for the ischemic/reperfused heart during ischemic preconditioning (IP). This study was designed to test the hypothesis that pretreatment with an inhibitor of cardiac delayed-rectifying K⁺ channel (I_Kr), E4031, increases reverse-mode of NCX activity, and triggers preconditioning against infarct size (IS) and arrhythmias caused by ischemia/reperfusion injury through mitoK_Ca channels. Materials and methods: In the isolated perfused rat heart, myocardial ischemia/reperfusion injury was created by occlusion of the left anterior descending coronary artery for 30 min followed by 120 min reperfusion. Two cycles of coronary occlusion for 5 min and reperfusion were performed, or pretreatment with E4031 or sevoflurane (Sevo) before the 30 min occlusion with the reversed-mode of NCX inhibitor (KB-R7943) or not. Results: E4031 or Sevo preconditioning not only markedly decreased IS but also reduced arrhythmias, which was significantly blunted by KB-R7943. Furthermore, these effects of E4031 preconditioning on IS and arrhythmias were abolished by inhibition of the mitoK_Ca channels. Similarly, pretreatment with NS1619, an opener of the mitoK_Ca channels, for 10 min before occlusion reduced both the infarct size and arrhythmias caused by ischemia/reperfusion. However, these effects weren’t affected by blockade of the NCX with KB-R7943. Conclusion: Taken together, these preliminary results conclude that pretreatment with E4031 reduces infarct size and produces anti-arrhythmic effect via stimulating the reverse-mode NCX, and that the mitoK_Ca channels mediate the protective effects.     

In vivo effects of caffeic acid phenethyl ester on myocardial ischemia-reperfusion injury and apoptotic changes in rats

Ischemia/reperfusion (I/R) has been reported to induce apoptotic cellular death in myocardium. This study tested the hypothesis that caffeic acid phenethyl ester (CAPE), one of the active components of propolis, may ameliorate myocardial apoptosis and oxidative myocardial injury. Wistar rats were divided into 4 groups: (i) sham operated, (ii) I/R, (iii) I/R+CAPE, and (iv) I/R+glutathione (GSH). CAPE (10 micromol/kg) was infused iv 10 min before occlusion of the left anterior descending coronary artery (30 min) followed by reperfusion (120 min). GSH (5 mg/kg) was infused iv after the occlusion and immediately before reperfusion. The TdT-mediated in situ nick end-labeling (TUNEL) method was used to evaluate apoptotic activity. I/R resulted in myocardial apoptosis, alterations of antioxidant status, elevation of serum creatine kinase (CK) and aspartate aminotransferase (AST) activities, evidence of lipid peroxidation, and elevated nitric oxide levels, compared to the sham-operation group. No apoptotic cells were found in the myocardial tissue of sham-operated rats. The TUNEL-positive myocardial cells averaged 60%, 30%, and 40% in the I/R, I/R+CAPE, and I/R+GSH groups, respectively. This study demonstrates that pretreatment with CAPE provides cardio-protection from I/R injury. The I/R+CAPE group showed reduced apoptosis, attenuated NO production, elevated myocardial superoxide dismutase (SOD) activity, and diminished serum CK and AST activities, compared to the I/R group.     

Does nitric oxide generation contribute to the mechanism of remote ischemic preconditioning?

The protective effect of local or remote ischemic preconditioning (IPC) on subsequent 40-min ischemic and 120-min reperfusion myocardial damage was investigated. Preconditioned rats underwent one cycle of myocardial ischemia/reperfusion consisting of 5-min ischemia produced as a left coronary artery (LCA) occlusion and 5 min of reperfusion. Remote IPC was produced as 15 min of small intestinal ischemia with 15 min of reperfusion as well as 30 min of limb ischemia with 15 min of reperfusion. A marked protective action was afforded by both IPC protocols with a more significant effect of local (classic) ischemic preconditioning. Since the protective effect of remote IPC was not abolished by nitric oxide (NO) synthase inhibition with Nω-nitro- -arginine ( -NNA) it is concluded that NO generation may not be involved in the mechanism of remote IPC.     

尼可地尔激活RISK通路减轻高胆固醇大鼠心肌缺血/再灌注损伤

目的探讨尼可地尔对高胆固醇大鼠心肌缺血/再灌注损伤的影响及其可能机制。方法应用高胆固醇饮食喂养健康雄性Wistar大鼠8周建立高胆固醇大鼠模型,应用Langendorff灌流装置采用全心缺血30min和再灌注120min建立离体心脏缺血/再灌注(I/R)模型。在缺血前或再灌注即刻灌注含有尼可地尔的KH液10min以制备尼可地尔药物预处理(NIC-pre)与后处理(NIC-post)模型。通过TTC染色测量心肌梗死面积、TUNEL染色检测心肌细胞凋亡率,Western blot检测RISK通路p-Akt和p-Erk1/2蛋白表达水平。结果与I/R对照组相比,NIC-30pre组与NIC-30post组均可降低心肌梗死面积和心肌细胞凋亡率,并显著上调p-Akt和pErk1/2的表达水平。结论尼可地尔减轻高胆固醇大鼠心肌缺血/再灌注损伤,与其激活RISK通路相关。