钙敏感受体在大鼠心肌缺血/再灌注损伤的表达变化及与心肌损伤关系

目的： 观察钙敏感受体（CaSR）在大鼠心肌缺血/再灌注时的表达变化，揭示其与心肌缺血/再灌注损伤的关系。方法： Wistar大鼠随机分为5组：假手术组（sham组）、缺血再灌注1、2、4和6 h组（I/R 1 h、2 h、4 h、6 h组）。采用冠状动脉结扎和松结的方法，复制大鼠在体心肌缺血/再灌注损伤模型，记录左室收缩压（LVSP）和左室内压最大变化速率（±dp/dtmax），测定血清LDH、SOD活性和MDA含量，透射电镜观察心肌超微结构变化， RT-PCR法检测心肌组织中CaSR mRNA的表达变化。结果：LVSP、左室内压±dp/dtmax及SOD活性随再灌注时间延长而减低，LDH活性和MDA含量在再灌注2 h时最高；心肌超微结构损伤在再灌注1 h、2 h较重，随再灌注时间延长而减轻；大鼠心肌缺血/再灌注1 h、2 h心肌组织CaSR的mRNA表达升高，再灌注4 h、6 h后降低。结论： CaSR mRNA表达多时心肌损伤较重，CaSR可能参与了心肌缺血/再灌注损伤。     

Nicardipine augments local myocardial perfusion after coronary artery reperfusion in dogs

Nicardipine is a potent coronary and systemic vasodilator without depression of ventricular function. We investigated the changes in local myocardial perfusion (LMP) according to the nicardipine administration after coronary reperfusion in a beating canine model. A Doppler probe was placed around the left anterior descending coronary artery (LAD) and thermal diffusion microprobe was implanted in the myocardium perfused by the exposed LAD. To define the nicardipine effects, we compared the two groups (control group, n=7 vs nicardipine group, n=7). In nicardipine group, 5 microgram/kg/min nicardipine was infused continuously. After the release of the LAD occlusion, LAD blood flow were increased compared to the baseline of both groups. However, there was no difference between groups in the LAD blood flow. The LMP after LAD reperfusion did not recover to the baseline level until 30 min after LAD reperfusion in control group (74%, 52% and 70% at 10, 20 and 30 min after LAD reperfusion, respectively). In nicardipine group, however, the LMP recovered to the baseline level at 20 min (99%), and increased more than the baseline level at 30 min (141%) after LAD reperfusion. Our findings suggest that the nicardipine augments the LMP following the release of a coronary occlusion.     

顿抑心肌的微循环障碍机制研究

目的 :探讨顿抑心肌微循环改变及机制。方法 :制备左前降支冠脉(LAD)阻断不同时间 ( 15和 60min)后再灌注 2h犬心肌顿抑模型 ,在不同观察时间点行静脉心肌声学造影 (MCE) ,计算心肌视频密度峰值(PVI)、MCE曲线上升斜率 (α)和曲线早期下降斜率 ( β) ,分别代表心肌血流灌注量、灌注速度和排空速度。测定相应时间点冠状静脉窦血乳酸浓度。结果 :⑴心肌顿抑早期PVI显著增高 ,1h后恢复至结扎前水平 ;⑵再灌注期顿抑区与正常区PVI比值、α比值、β比值显著高于LAD结扎前 ,随着再灌注时间的延长比值逐渐回降 ;⑶再灌注期冠状静脉窦血乳酸浓度明显增高。结论 :心肌顿抑早期心肌微循环处于“高动力”状态 ,血流灌注增加与排空加快并存 ;顿抑心肌缺氧代谢加强 ;心肌内微循环短路可能是心肌顿抑微循环障碍的机制。     

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.     

伊贝沙坦抑制兔心肌缺血/再灌注ICAM-1和VCAM-1的表达

 目的：探讨伊贝沙坦对兔心肌急性缺血/再灌注损伤和缺血/再灌注区细胞间粘附分子-1（ICAM-1）、血管内皮细胞粘附分子-1（VCAM-1）表达的影响。 方法： 假手术组，左冠状动脉前降支近端穿线，但不结扎；缺血再灌注组（IR组），缺血60 min再灌360 min和伊贝沙坦防治组。处死动物后，从再灌注区取组织、HE染色后，光镜下检查；用免疫组化SP方法检测ICAM-1、VCAM-1在标本组织中的表达。 结果： 与假手术组相比，IR组的组织损伤和中性粒细胞渗出程度明显重于假手术组（P<0.01）；再灌注区的ICAM-1、VCAM-1表达明显上调（P<0.01）。伊贝沙坦显著缓解上述变化（P<0.01）。 结论： 心肌急性缺血/再灌注诱导再灌注区ICAM-1、VCAM-1表达上调，伊贝沙坦能明显缓解心肌缺血/再灌注损伤。     

外源性ATP诱导PC12细胞的膜孔形成

 目的：探讨外源性三磷酸腺苷(ATP)诱导PC12细胞的膜孔形成及关键分子靶标。方法：用不同浓度的ATP处理培养的PC12细胞,采用倒置相差显微镜观察形态,CCK-8法检测细胞存活率,YO-PRO-1染色检测细胞膜通透性,Western blotting和real-time PCR检测P2X7 受体和pannexin 1（Panx1）表达的变化。结果：（1）ATP（1 mmol/L、3 mmol/L、5 mmol/L）作用3 h,可见随着ATP浓度升高,PC12细胞变圆,脱壁细胞增多;当ATP浓度为3 mmol/L或5 mmol/L时,PC12细胞活力较对照组显著下降（P<0.05）。（2）不同浓度的ATP（0、1、3、5 mmol/L）作用1 h,PC12细胞摄入YO-PRO-1的荧光强度随着浓度增加而增加;同一浓度的ATP作用不同时间（15、30、60 min）,随着时间的增加,胞内的荧光强度也增加。（3）亮蓝G（P2X7受体的抑制剂）预处理可明显拮抗ATP引起的细胞活力下降和胞内荧光强度增强（P<0.05）,而生胃酮（Panx1的抑制剂）预处理不改变细胞活力和胞内的荧光强度（P>0.05）。（4）ATP作用3 h使PC12细胞 P2X7受体的mRNA和蛋白表达明显升高（P<0.05）,而Panx1 mRNA和蛋白表达变化不大（P>0.05）。结论：胞外高浓度ATP引起PC12细胞的膜孔形成可能主要与P2X7受体的表达和激活有关。     

热休克蛋白70在大鼠心肌缺血再灌注过程中的表达及其意义

目的 :探讨热休克蛋白 70 (HSP70 )在心肌缺血再灌注损伤中的表达及其意义。方法 :结扎 /松解SD大鼠左冠状动脉前降支 ,建立大鼠缺血 0min、3 0min ,再灌注 60min、12 0min动物模型。免疫组化技术和图像分析技术检测心肌细胞内HSP70、Bcl 2 /Bax基因的蛋白表达 ,硫代巴比妥酸 (thiobarbituricacid ,TBA)法测心肌组织丙二醛 (MDA)含量 ,优化紫外分光光度法测血清肌酸激酶 (CK)活性。结果 :( 1)HSP70于缺血 0min即有表达 ,再灌注 60min达高峰 ,之后下降。 ( 2 )Bcl 2蛋白再灌注组表达较缺血组明显降低 (P <0 .0 5 )。( 3 )Bax蛋白表达、MDA含量、CK活性于缺血 3 0min开始升高直至再灌注 12 0min。结论 :HSP70的异常表达与心肌缺血再灌注损伤的发生有关 ,且可能是缺血再灌注损伤细胞发展、恶化的重要标志。     

IRAK-4活性在脂多糖预处理减轻肝脏缺血再灌注损害中作用的实验研究

目的:观察脂多糖(LPS)预处理后白细胞介素-1受体相关激酶-4（IRAK-4）表达水平在大鼠肝脏缺血再灌注(I/R)早期的变化，探讨LPS预处理减轻肝脏缺血再灌注损害(I/RI)的相关机制。 方法:雄性SD大鼠，随机分为正常对照组，缺血再灌注组(I/R组)和LPS预处理组（LPS组）。正常对照组未予任何处理；LPS组第 1 d 经尾静脉给予脂多糖0.1mg·kg-1，第2、3、4、5 d给予0.5 mg·kg-1；I/R组给予等体积0.5 mL无菌PBS液。第 8 d，建立肝脏缺血再灌注模型。再灌注后0 min、60 min及180 min, 蛋白免疫印记法及逆转录-聚合酶链式反应测定肝组织的IRAK-4蛋白和mRNA表达水平；酶连免疫吸附法检测肝组织NF-κB活性及血清TNF-α含量。 结果:再灌注0 min, IRAK-4蛋白与mRNA表达水平依次为LPS组>I/R组>正常对照组(P<0.01), NF-κB活性以及TNF-α含量LPS组与I/R组差异无显著(P>0.05)，但均高于正常对照组(P<0.01)；再灌注后60 min及180 min，LPS组的IRAK-4蛋白与mRNA表达水平，NF-κB活性以及TNF-α含量却明显低于I/R组（P<0.01）。 结论:抑制IRAK-4表达是LPS预处理减轻肝脏I/RI的重要机制之一。     

脂质胞壁酸延迟预适应对大鼠供心停搏/复灌性损伤的影响

目的：探讨脂质胞壁酸（LTA）诱导的延迟预适应对大鼠供体心脏停搏/复灌性损伤的影响。 方法： 采用心脏Langendorff灌流模型，腹腔注射LTA后24 h，观察心脏停搏保存4 h后再灌注30 min及60 min时心脏功能及再灌注末灌流液中心肌型肌酸激酶同功酶（CK-MB）、乳酸脱氢酶（LDH）及一氧化氮（NO）含量，并用dUTP缺口末端标记（TUNEL）法检测左室心肌细胞凋亡。 结果： LTA预适应组再灌注30 min和60 min时心脏的冠脉流量，左室发展压及压力最大上升和下降速率等参数值显著大于对照组（均P<0.01）。LTA预适应组灌流液中NO含量明显大于对照组（P<0.01），而CK-MB和LDH的水平和心肌凋亡指数小于对照组（均P<0.01）。一氧化氮合酶抑制剂L-NG-硝基精氨酸甲酯（L-NAME）能取消LTA预适应的保护效应。 结论： LTA预适应能显著改善供体心脏停搏/再灌注后的心功能，减少心肌坏死和细胞凋亡，内源性NO在介导LTA预适应中发挥关键作用。     

Attenuation of oxidant damage in the postconditioned heart involves non-enzymatic response and partial catalytic protection

Oxidant stress, among other effectors, is implicated in the sequel of myocardial reperfusion injury. It is generally accepted that maintaining the balance between oxidant and antioxidant signalling within the cell provides protection against reperfusion damage. The cardioprotective strategy of postconditioning (PC) reduces reperfusion injury through complex mechanisms; however, the contribution of the antioxidant system has not been fully investigated. In this study, isolated rat hearts were subjected to PC after 30 min global ischaemia, and then to 5 min (IR5) or 60 min of reperfusion (IR60). Postconditioning significantly increased the left ventricular developed pressure and the double product (heart rate × left ventricular developed pressure) for both early (PC5) and prolonged reperfusion (PC60, PC before 60 min of reperfusion). Necrotic tissue diminished to 10.8% in PC60 hearts, compared with 49% of infarct size measured in IR60 hearts (P < 0.05 versus IR60). Also, protein carbonylation and malondialdehyde levels decreased and were correlated with a significant augmentation in CuZn superoxide dismutase activity (P < 0.05, PC60 versus IR60) and increased glutathione redox state (GSH:GSSG ratio; P < 0.05, PC60 versus IR60). Diethylthiocarbamate, a non-selective superoxide dismutase inhibitor, significantly diminished the protection afforded by PC when administered throughout the protocol. However, administration of this inhibitor only during reperfusion had no effect on PC-induced cardioprotection. These results indicate that non-enzymatic antioxidants account for the protective effect of PC, modifying the oxidant stress caused by ischaemic reperfusion in rats. The contribution of CuZn superoxide dismutase activity in the observed cardioprotective effect is less clear, and could be relevant if acting in concert with other PC-activated mechanisms.     

Effects of nifedipine and niludipine on ultrastructural changes induced by coronary occlusion in dog hearts

The effects of nifedipine and niludipine on the ultrastructural changes of myocardium induced by occlusion of the left anterior descending coronary artery (LAD) were investigated in dogs anesthetized with pentobarbital. The ultrastructural changes were graded to slight, moderate, severe, and irreversible ischemic injury. Subendocardial changes were usually severe compared to subepicardial changes. Nifedipine or niludipine was injected or infused intravenously. Complete occlusion of LAD for 60 or 90 min produced severe and irreversible ischemic injury, which was not prevented by nifedipine (30 μg/kg) or niludipine (30 μg/kg) injected 5 min after occlusion. Partial occlusion of LAD (about 67% occlusion) for 90 min did not produce constant ischemic changes, and therefore the effect of drugs could not be evaluated in this ischemic model. A bolus injection (10 μg/kg, 10 min before complete LAD occlusion) followed by a constant infusion (90 μg/kg/70 min for 70 min) of nifedipine (therefore a total dose of 100 μg/kg) inhibited the degree of ischemic injury produced by the complete LAD occlusion (60 min) in the subendocardium, but not in the subepicardium. However, niludipine in the same dose (100 μg/kg) did not improve the ischemic injury induced by complete LAD occlusion in both subendo- and subepicardium.     

Impact of delayed reperfusion of myocardial hibernation on myocardial ultrastructure and function and their recoveries after reperfusion in a pig model of myocardial hibernation.

This study examined the effect of delayed reperfusion of myocardial hibernation from 24 hours to 7 days on myocardial ultrastructural and functional changes and their recoveries after reperfusion. Background: We have previously shown in pigs that after reperfusion the functional and structural alterations in short-term myocardial hibernation which was reperfused in 24 hours can recover in 7 days. The effect of delayed reperfusion of hibernating myocardium on the extent and severity of cellular and extracellular structural changes of hibernating myocardium, and their recoveries after reperfusion is not known. Methods and Results: A severe LAD stenosis was created in 27 pigs, reducing resting flow by 30-40% immediately after placement of the stenosis and producing acute ischemia as evidenced by regional lactate production, a decrease in regional coronary venous pH, reduced regional wall thickening (from 38.5 +/- 5.1% to 10.4 +/- 8.0%) and a 33% reduction of regional oxygen consumption. The stenosis was maintained either for 24 hours in 9 pigs (group 1) with LAD flow of 0.65 +/- 0.13 ml/min/g (38% reduction), or for 7 days in 17 pigs (group 2) with LAD flow of 0.67 +/- 0.14 ml/min/g (36% reduction). There were no differences (p = NS) in the reduction of wall thickening, rate-pressure product, lactate production, or regional oxygen consumption between group 1 and group 2. Quantitative morphometric evaluation of the ultrastructure on electromicrographs revealed a greater decrease in sarcomere volume and a higher incidence of myocytes with reduced sarcomere volume in 7-day than in 24-hour hibernating regions (53 +/- 19% versus 33 +/- 14%, p < 0.05). Patchy myocardial necrosis with replacement fibrosis was common, but 6 of the 18 pigs had no myocardial necrosis or replacement fibrosis in the 7-day hibernating group, and 4 of 9 pigs had no patchy myocyte necrosis in the 24 hour hibernating group. In 6 pigs in group 1 in which the stenosis was then released and hibernating myocardium reperfused in 24 hours, regional wall thickening recovered to 30 +/- 6% (p = NS compared to baseline) after one week of reperfusion. In 12 pigs in group 2 in which the stenosis was released and hibernating myocardium reperfused in 7 days, regional wall thickening recovered slowly, from 10.1 +/- 7.2% to 18.1 +/- 8.3% at one week (n = 5) and to 28.0 +/- 3.6% at 3-4 weeks of reperfusion (n = 7, p < 0.05 compared to baseline). Similarly, the sarcomere volume or myofilament recovered significantly (p < 0.01) and was not different compared to the normal region (p = NS) in the 24-hour hibernating region of group 1, but the recovery was much slower and was incomplete at 4 weeks (p < 0.01) compared to baseline in the 7-day hibernating region of group 2. Recovery of regional wall thickening correlated with ultrstructural recovery (p < 0.01). By multivariate stepwise regression analysis, the degree of LAD flow reduction, the extent of fibrosis, and myofilament loss were independent predictors of the extent of functional recovery. Conclusions: In a porcine model of myocardial hibernation with myocardial hypoperfusion, systolic dysfunction, and metabolic adaptations, a longer period of myocardial hibernation with delayed reperfusion was associated with more severe abnormalities of myocytes. an increasing interstitial fibrosis, and more protracted myofibrillar and functional recoveries after reperfusion. The extent of functional recovery is related to the degree of coronary flow reduction, the severity of the ultrastructural changes, and the extent of interstitial fibrosis.     

低浓度11,12-EET预干预对大鼠心肌缺血/再灌注损伤的影响

目的:观察外源性低浓度 11,12-EET预干预对大鼠在体心肌缺血/再灌注损伤的影响。方法:雄性Wistar大鼠,开胸,结扎和松开冠状动脉左前降支,复制心肌缺血/再灌注模型;采用缺血 5min/再灌注 5min两次造成缺血预处置。实验分 3组:对照组;缺血预处置组;外源性 11,12-EET预干预组。每组再分为A、B 2小组:A组动物心肌缺血 10min/再灌注 10min,主要观察缺血/再灌注各时程之心律失常;B组动物缺血 6 0min/再灌注 30min,主要观察缺血期心律失常、心功能的变化及再灌注后心肌梗死范围。结果:缺血预处置和 11,12-EET(6 2 4× 10^-8mol/L)预干预均可减轻缺血/再灌注心律失常及心功能的变化,降低心肌梗死范围。结论:11,12-EET预干预具有类缺血预处置样的心肌保护作用.     

High afterload during 10 min of regional ischaemia affects diastolic creep but not systolic function in reperfused (stunned) myocardium

The effect of afterload during regional ischaemia on myocardial stunning was studied in 15 pentobarbital anaesthetized cats. 10 min occlusion of the left anterior descending artery (LAD) was followed by 60 min of reperfusion. Afterload was decreased by intravenous infusion of nitroglycerine 3–8 μg kg^-1 min^-1 in group I (n=8); left ventricular peak systolic pressure (LVSP) 84±4 mmHg (mean±SEM) during coronary artery occlusion. In group II (n=7) LVSP was increased to 188±10 mmHg by inflating an intraaortic balloon during coronary artery occlusion. Regional function in the LAD perfused region was evaluated by cross-oriented sonomicrometry. Myocardial tissue blood flow was evaluated by radio-labelled microspheres. Afterload alterations did not affect regional systolic shortening (10.8±2.0% vs. 11.0±1.5% in group I and II, respectively, after 60 min of reperfusion). However, increased end-diastolic dimensions (diastolic creep) in both the circumferential and longitudinal segments were markedly more pronounced in the high afterload group (group II). Also important, the markedly increased myocardial tissue blood flow during reperfusion in group II as compared with group I (2.30±0.18 vs.  1.34±0.08 mL min^-1 g^-1 and 2.58±0.23 vs. 1.49±0.07 mL min^-1 g^-1 in subepicardial and subendocardial layers in the LAD perfused region) suggests that increased diastolic creep increased metabolic demands. This study indicates that passive stretching of the ischaemic area during coronary artery occlusion is an important mechanism behind diastolic creep.     

Myocardial tissue salvage by coronary thrombolysis with rt-PA: Absence of occlusion/reperfusion injury

The effect of recombinant tissue-type plasminogen activator (rt-PA) on myocardial infarct size was studied in a coronary thrombosis model in open-chested, anaesthetised beagle dogs. Myocardial ischaemia was produced by localised thrombosis via endothelial injury and instillation of thrombin and fresh blood into the left anterior descending coronary artery (LAD). Myocardial infarct size and the area at risk were determined histochemically after 24 h of reperfusion by ex vivo staining of the LAD bed with 1.5% triphenyltetrazolium chloride (TTC). In non-reperfused animals the persistance of a coronary thrombus resulted in 50.7 ± 5.0% of the area at risk developing an infarct. Intravenous administration of rt-PA at a rate of 12 500 IU/kg/min delivered for 60 min resulted in recanalisation of the thrombosed artery within 16.1 ± 4.1 min in animals in which the thrombus was in place for 75 min and within 19.0 ± 2.8 min after 165 min of stable thrombosis. Lysis of the coronary thrombus and subsequent reperfusion was not accompanied by reactive hyperaemia nor ventricular arrhythmias. Infarct size was reduced to 1.5 ± 1.2% and 6.3 ± 4.1% of the area at risk in the animals whose coronary thrombi were lysed with rt-PA after 1.5 and 3 h of ischaemia, respectively. In contrast, mechanical reperfusion after 1.5 h of ischaemia induced by ligation resulted in an infarct of 35.1 ± 4.5% of the area at risk. These results suggest that rt-PA has an additional cardioprotective effect independent of lysis of the thrombosed coronary artery.     

TMLR对缺血心肌乳酸代谢及线粒体的影响

目的:探讨激光心肌血运重建术(TMLR)对急性心肌缺血(AMI)的作用与机制。方法: 将18条犬随机等分为假手术组、AMI组和TMLR组,采用连续型Nd:YAG激光行TMLR术。测动脉和冠状窦血乳酸含量(A.Lat 和CS.Lat),心肌乳酸代谢速率(MLR)和心肌乳酸吸收分数(MLE);超微电镜结合生物体视学原理定量观察心肌细胞线粒体形态和数量。结果: 结扎左前降支冠状动脉(LAD)后60 min,AMI组和TMLR组CS.Lat分别为(7.63±4.27)mmol/L和(5.78±3.98)mmol/L,P<0.05;MLR分别为(0.03±0.01)mmol·100 g心肌^-1·min^-1和(0.06±0.02)mmol·100 g心肌^-1·min^-1,P<0.05;MLE分别为(12.04±3.04)% 和(21.84±8.49)%,P<0.05。LAD结扎后4 h,AMI组和TMLR组线粒体体密度分别为(27.51±7.93)% 和(31.26±3.85)%,P>0.05;面密度分别为(1.25±0.18)μm^-1和(1.64±0.28)μm^-1,P<0.01;数密度分别为(0.10±0.03)μm^-3和(0.18±0.05)μm^-3,P<0.01;平均体积分别为(5.27±2.85)μm³和(2.80±0.54)μm³,P<0.05;平均外径分别为(2.06±0.36)μm和(1.78±0.12)μm,P<0.05。结论: TMLR可纠正急性心肌缺血犬的心肌乳酸代谢障碍和减轻心肌细胞损伤。     

咪唑安定保护家兔心肌缺血再灌注损伤机制的研究

目的 :观察咪唑安定对家兔心肌缺血 /再灌注期血清和心肌TNF α、IL 6的影响 ,探讨其保护作用机制。方法 :利用结扎 /开放左冠状动脉左前降支 ,结扎 30min/开放 1 80min建立心肌缺血 /再灌注模型。 2 4只家兔随机分为三组 (每组 8只 ) :假手术对照组 (A组 ) ,未予心肌缺血处理 ;缺血再灌注组 (B组 )于缺血前 5min(I0 )、缺血 30min(I1 )、再灌注 1h(R1 )和 3h(R2 )取颈内静脉血 ,并于实验结束后取心肌组织匀浆 ,分别测定IL 6和TNF α浓度 ;咪唑安定组(C组 )缺血前 2 0min静脉注射咪唑安定 0 .75mg/kg(人等效剂量 ) ,以每小时 0 .4mg/kg持续泵入 ,取血样时点和检测指标均同B组。结果 :C组血清TNF α在I1 和R1 时升高 ,R2 时降低 ,IL 6在R2 时升高 ,但在各时点均较B组相应值低 (P <0 .0 1或 0 .0 5 ) ,心肌组织TNF α、IL 6水平亦低于B组 (P <0 .0 5 ) ,但较A组明显升高 (P <0 .0 1 ) ;B组TNF α在I1 时点显著升高 ,IL 6在R1 和R2 时点持续升高 ,心肌组织中TNF α和IL 6含量明显增加 ,同A组和C组比差异有高度显著性。结论 :在心肌缺血再灌注损伤中 ,咪唑安定通过抑制心肌组织和血清TNF α和IL 6的合成或释放 ,从而对心肌组织有保护作用。     

Changes in catecholamine, angiotensin converting enzyme and adenosine triphosphatase in ischemic preconditioning rat hearts

Changes in catecholamine ,angiotensin converting enzy me and adenosine triphosphatase in ischemic preconditioning rat hearts     

预适应和后适应对缺血/再灌注损伤大鼠心肌组织炎症因子的影响

目的:观察缺血预适应(IPC)、缺血后适应(IPOC)对大鼠心肌组织缺血/再灌注(I/R)损伤后Toll样受体(TLR)及下游炎症因子的影响。方法:SD大鼠60只,通过SPSS软件随机分为假手术组(冠状动脉前降支下置线不结扎,n=15);I/R组(冠状动脉前降支结扎30min,再灌注60min,n=15);IPC组(冠状动脉前降支3次3min/5min的缺血/再灌注循环,然后结扎30min后,再持续灌注60min,n=15);IPOC组(冠状动脉前降支结扎30min,3次10s的缺血/再灌注循环,再持续灌注60min,n=15)。实验结束后测定大鼠血清肌酸激酶同工酶(CK-MB)和肌钙蛋白T(cTNT)水平;氯化硝基四氮唑兰(NBT)染色测定大鼠左室心肌梗死面积;免疫组织化学法测定心肌组织TLR-2、4的表达;酶联免疫吸附法测定心肌组织白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、单核细胞趋化蛋白-1(MCP-1)和肿瘤坏死因子-α(TNF-α)的含量。结果:与I/R组比较,IPC组、IPOC组大鼠血清CK-MB和cTNT水平显著降低(P<0.01),心肌梗死面积显著减小(P<0.01),心肌组织TLR-2、4表达和炎症因子IL-6、IL-1β、MCP-1、TNF-α含量显著下降(P<0.05,P<0.01);与IPC组比较,IPOC组减小I/R大鼠心肌梗死面积,降低血清CK-MB及心肌组织IL-6等作用和IPC组无显著差异(P>0.05)。结论:IPOC与IPC同样具有减轻心肌I/R损伤程度和缩小心肌梗死范围等作用,抑制TLR-2、4的表达可能是其保护I/R心肌的一个重要途径。     

Pretreatment with tyrosine kinase inhibitor attenuates the reduction of apoptosis 24 h after ischemic preconditioning

We investigated whether ischemic preconditioning (PC) attenuates ischemia/reperfusion-induced injury in part by decreasing apoptosis and whether tyrosine kinase (TK) can regulate the signaling pathway leading to apoptosis in delayed cardioprotection. Six groups of rabbits were studied in the early phase (EP) and in the delayed phase (DP): (1) sham-operated control animals were received vehicle only (Veh-sham); (2) rabbits that received I.V. genistein (a nonspecific TK inhibitor) 10 min before ischemia (Gen-sham); (3) rabbits that received I.V. daidzein (an inactive structural analog of genistein) 10 min before ischemia (Dzn-sham); (4) rabbits preconditioned with 4 cycles of 5-min occlusion of left anterior descending coronary artery (LAD) and 10-min reperfusion (PC); (5) rabbits that received I.V. genistein, 10 min before PC (Gen-PC); (6) rabbits that received I.V. daidzein 10 min before PC (Dzn-PC). All rabbits underwent 30-min ischemia followed by 180-min reperfusion. Infarct size in the PC, Gen-PC, and Dzn-PC groups in the EP was significantly (p < 0.0001) reduced relative to controls Gen and Dzn. Delayed cardioprotection was blocked significantly (p < 0.0001) by genistein. In the EP, apoptosis was significantly (p < 0.0001) decreased in PC, Gen-PC, and Dzn-PC groups relative to controls Gen and Dzn. In the DP, a reduction of apoptosis was not seen in the Gen-PC group. This study suggests that PC reduces ischemic injury in part by decreasing apoptosis after ischemia/reperfusion and also that TK phosphorylation is involved in the signal transduction cascade leading to the decline of apoptosis in the DP.