体外循环术中心肌缺血—再灌注损伤后肌浆网Cal^2＋调 …

目的研究体外循环术中心肌缺血－再灌注（Ｉ－Ｒ）损伤后肌浆网Ｃａ＾２＋调节蛋白ｍＲＮＡ表达。方法实验用犬１２只,主动脉阻断缺血６０ｍｉｎ、继之开放后再灌注６０ｍｉｎ,建立体外循环术中全心缺血－再灌注心肌损伤模型。于主动脉阻断期间,分组以冷晶体液停跳液间断灌注（ＩＣＣＣ）或温血停跳液持续灌注（ＣＷＢＣ）做心肌保护。采用ＲＴ－ＰＣＲ技术,测定ＳＲ Ｃａ＾２＋－ＡＴＰ酶、钙螯合蛋白的ｍＲＮＡ水平,观察心输     

常温体外循环温血心停搏液持续灌注心肌保护的实验研究

目的　为了探讨常温体外循环温血心停搏液持续灌注心肌保护的机理。方法　１５ 条犬随机分成三组,在体外循环下分别灌注三种不同的心停搏液,对三种不同的心肌保护方法进行对比观察。结果　温血心停搏液灌注液（Ｃ组） 的ＣＫ－ ＭＢ、ＬＤＨ、ＭＤＡ 及钙离子含量在心脏再灌注３０ｍｉｎ 时均明显低于冷晶体（Ａ 组） 及冷血心停搏液灌注组（Ｂ组）（ Ｐ＜ ０－０５）;而ＡＴＰ 含量则明显高于Ａ、Ｂ 两组（ Ｐ＜０－０５）。心肌超微结构检查也显示Ｃ组心肌无明显缺血损伤。结论　常温体外循环温血心停搏液持续灌注心肌保护的效果良好。     

镁对缺氧再给氧心肌保护作用的实验研究

实验研究心肌细胞缺氧－再给氧（ＡＯ－ＲＯ）时镁对细胞对脂质过氧化物（ＬＰＯ），Ｃａ＾２＋荧光强度及超微结构的影响，结果：心肌细胞ＡＯ－ＲＯ后，细胞线粒体肿胀，变性及排列紊乱，结果受损、细胞内ＬＰＯ、Ｃａ＾２＋荧光强度升高，低镁０．３ｍｍｏｌ／Ｌ＋ＡＯ－ＲＯ组比单纯ＡＯ－ＲＯ组再明显，Ｐ〈０．０１，镁２．０ｍｍｏｌ／Ｌ和０．８ｍｍｏｌ／Ｌ组，上述改变得到明显改善，这与镁具有抗ＬＰＯ保护细胞膜结构完整性及阻止Ｃａ＾２＋内流，减轻Ｃａ＾２＋超载从而降低心肌Ａ０－ＲＯ损伤等作用有关。     

细胞内外钙与氧自由基在脑缺血再灌注损伤中作用

目的用复制大鼠脑缺血再灌注动物模型,研究细胞内外钙平衡紊乱与氧自由基在脑缺血再灌注损伤中的作用。方法测定假手术组、缺血３０ｍｉｎ再灌注６０ｍｉｎ生理盐水（ＮＳ）处理组和单唾液酸四己糖神经节苷脂（ＧＭ１）处理组海马脑组织线粒体钙（ｍｉｔｏｃｈｏｈｄｒｉａｃａｌｃｉｕｍ,ＭＣａ）、钙调素（ｃａｌｍｏｄｕｌｉｎ,ＣａＭ）、丙二醛（ｍａｌｏｎｄｉａｌｄｅｈｙｄｅ,ＭＤＡ）含量变化。结果缺血３０ｍｉｎ再灌注６０ｍｉｎＮＳ处理组ＭＣａ、ＣａＭ、ＭＤＡ含量显著升高（Ｐ＜００１）,用ＧＭ１处理后则上述指标明显改善。结论急性脑缺血再灌注后有细胞内外钙平衡紊乱和氧自由基代谢障碍发生,且相互协同作用     

卡托普利对缺血—再灌注心肌的保护作用

在大鼠心脏Ｌａｎｇｅｎｄｏｒｆｆ灌流模型上观察缺血－再灌注（Ｉ／Ｒ）时心肌局部血管紧张素ＩＩ（ＡＧＴＩＩ）的变化及卡托普利（ｃａｐｔｏｐｒｉｌ）对心肌保护作用。缺血３０ｍｉｎ后再灌注，心肌ＡＧＴＩＩ含量升高６０％，钙含量增加１．８倍，蛋白漏出明显增多，肌浆网（ＳＲ）的摄钙量减少５５％。ｃａｐｔｏｐｒｉｌ能有效抑制ＡＧＴＩＩ的生成，减轻心肌细胞损伤，并明显改善ＳＲ的摄钙功能，１０＾－９ｍｏｌ／Ｌ的Ａ     

缺血再灌注损伤心肌电镜细胞化学的定性与定量分析（二）──琥珀酸脱氢酶和细胞色素氧化酶

本研究选择心脏瓣膜病患者２０例，随机分为两组，每组１０例，在瓣膜置换术中，一组采用低温体外循环加冷晶体停跳液（Ｓｔ．Ｔｈｏｍａｓ医院液）间断灌注的心肌保护方法（简称低温组），另一组采用常温体外循环加温血停跳液持续灌注的心肌保护方法（简称常温组）。两组缺血期和再灌注期心肌琥珀酸脱氢酶（ＳＤＨ）和细胞色素氧化酶（ＣＣＯ）染色定性分析结果均为阳性，计算机图像分析结果表明，低温组再灌注期ＳＤＨ酶活力灰度值高于低温组缺血期（１４３．０７±１．３８，１１５．２５±０．１５，Ｐ＜０．０５）．两组再灌注期ＳＤＨ酶活力灰度值相差极为显著，低温组大于常温组（１４３．０７±１．３８，１２９．０６±４．６３，Ｐ＜０．０１）。常温组缺血期ＣＣＯ酶活力灰度值显著高于低温组缺血期（１４５．５４±６．９０，１２８．４０±５．４３，Ｐ＜０．０５），常温组再灌注期ＣＣＯ活力显著高于低温组再灌注期（１４８．６２±４．８２，１２３．６０＋４．８２，Ｐ＜０．０５）。表明低温组缺血期心肌线粒体酶系可发生代偿，低温组再灌注期心肌线粒体损伤较重，而常温组可减轻缺血再灌注损伤，无需代偿。同时也表明温血停跳液可提供ＣＣＯ以适宜的相对高氧代谢环境，在该代谢环节?     

心肌局部肾素－血管紧张素系统在心肌缺血及再灌注损伤时的激活及Losartan的保护作用

观察心肌局部肾素－血管紧张素系统（ＲＡＳ）在心肌缺血再灌注损伤时的激活情况及特异性非肽类血管紧张素Ⅱ１型受体（ＡＴ１）阻断剂Ｌｏｓａｒｔａｎ的保护效应。方法离体大鼠心脏灌流模型，心功能测定，放射免疫测定。结果心肌缺血４０ｍｉｎ后，心肌内ＡｎｇⅡ即明显增高（Ｐ＜０．０１），ＡｎｇⅠ增高尚不明显；再灌１０ｍｉｎ后，ＡｎｇⅠ、ＡｎｇⅡ均明显升高（Ｐ＜０．０１），Ｌｏｓａｒｔａｎ５μｍｏｌ／Ｌ不明显影响这种增高，但却能使缺血再灌注损伤后的心功能得到明显改善，减少心肌肌酸激酶（ＣＫ）的释放。结论一定时间的缺血和再灌注均能使心肌组织中ＲＡＳ有所激活，ＡｎｇⅡ增高可加重缺血心肌的损伤，Ｌｏｓａｒｔａｎ通过特异阻断ＡＴ１受体有减轻这种损伤的作用     

卡托普利对缺血－再灌注心肌的保护作用

在大鼠心脏Ｌａｎｇｅｎｄｏｒｆｆ灌流模型上观察缺血。再灌注（Ｉ／Ｒ）时心肌局部血管紧张素ＩＩ（ＡＧＴＩＩ）的变化及卡托普利（ｃａｐｔｏｐｒｉｌ）对心肌保护作用。缺血３０ｍｉｎ后再灌注，心肌ＡＧＴＩＩ含量升高６０％，钙含量增加１．８倍，蛋白漏出明显增多；肌浆网（ＳＲ）的摄钙量减少５５％。ｃａｐｔｏｐｒｉｌ能有效抑制ＡＧＴＩＩ的生成，减轻心肌细胞损伤，并明显改善ＳＲ的摄钙功能。１０－９ｍｏｌ／Ｌ的ＡＧＴＩＩ与正常ＳＲ温育，使ＳＲ的摄钙量降低４１％。这提示：Ｉ／Ｒ过程中，心肌局部ＡＧＴＩＩ生成增加是参与再灌注损伤的重要因素；而ＡＧＴＩＩ对ＳＲ钙转运功能的直接抑制可能是Ｉ／Ｒ后ＳＲ功能障碍的原因之一。     

心肌缺血再灌注损伤肌浆网Ca^2＋—ATPase活性变化电镜酶细胞化学观察

心肌缺血再灌注损伤肌浆网Ｃａ２＋－ＡＴＰａｓｅ活性变化电镜酶细胞化学观察（摘要）谷天祥肖德绵张显清谷春久石玉秀李厚文姜桂娥王天骄应用电镜酶细胞化学技术观测大鼠离体缺血再灌注心肌细胞肌浆网、细胞膜原位Ｃａ２＋－ＡＴＰａｓｅ活性变化，旨在探讨心肌缺血再灌...     

缺氧预处理对乳兔心肌细胞缺氧复氧损伤的保护研究

目的：观察预处理（ＰＣ）对乳兔心肌细胞缺氧复氧（Ａ－Ｒ）损伤的影响。方法：采用心肌细胞Ａ－Ｒ模型，用短暂缺氧进行预处理。结果：缺氧预处理能提高Ａ－Ｒ后心肌细胞存活率（７７．２１±３．１０ＶＳＡ－Ｒ组５９．８３±２．１０．Ｐ＜０．０１）．减少ＭＤＡ产生（０．７５±０．０２ＶＳＡ－Ｒ组１．６１±０．０８ｎｍｏｌ／ｍｇｐｒ，Ｐ＜０．０１）及乳酸脱氢酶的漏出（Ｐ＜０．０１）。结论：离体乳兔心肌细胞存在ＰＣ保护现象。     

Leukocyte-depleted secondary blood cardioplegia attenuates reperfusion injury after myocardial ischemia

BACKGROUND: Activated neutrophils have been implicated in reperfusion injury of the myocardium; leukocyte depletion at the time of reperfusion may contribute to better myocardial protection after cardiac surgery. In the present study, we examined whether leukocyte depletion as an adjunct to terminal blood cardioplegia attenuates reperfusion injury. METHODS: Porcine hearts that had undergone 60 minutes of normothermic ischemia with cardioplegia and 60 minutes of reperfusion under cardiopulmonary bypass were divided into four groups according to the methods of 15 min of controlled initial reperfusion: whole blood reperfusion (n = 6), leukocyte-depleted reperfusion (n = 6), secondary blood cardioplegia (n = 6) and leukocyte-depleted secondary blood cardioplegia (n = 6). At 60 min of reperfusion, hemodynamic recovery, release of malondialdehyde (MDA) as a marker for free oxygen radicals, CK-MB-isoenzyme from the coronary sinus, recovery of adenosine triphosphate, and myocardial water content were evaluated. RESULTS: The group with leukocyte-depleted secondary blood cardioplegia showed the best hemodynamic recovery (Emax and total dp/dt), lowest levels of MDA, CK-MB and myocardial water content, and highest adenosine triphosphate recovery. CONCLUSIONS: These results suggest that controlled reperfusion with leukocyte-depleted secondary blood cardioplegia attenuated severe damage of the myocardium as compared to whole blood reperfusion.     

Continuous tepid blood cardioplegia can preserve coronary endothelium and ameliorate the occurrence of cardiomyocyte apoptosis

OBJECTIVE: In modern cardiac surgery, crystalloid or blood cardioplegic solutions have been used widely for myocardial protection; however, ischemia does occur during protection with intermittent infusion of cold crystalloid or blood cardioplegic solutions. The present study was designed to evaluate the effect of different cardioplegic methods on myocardial apoptosis and coronary endothelial injury after global ischemia, cardiopulmonary bypass (CPB), and reperfusion in anesthetized open-chest dogs. METHODS: The dogs were classified into five groups to identify the injury of myocardium and coronary endothelium: group 1, normothermic CPB without cardiac arrest; group 2, hypothermic CPB with continuous tepid blood cardioplegia, and with cardiac arrest; group 3, hypothermic CPB with intermittent cold blood cardioplegia, and with cardiac arrest; group 4, hypothermic CPB with intermittent cold crystalloid cardioplegia, and with cardiac arrest; and group 5, sham-operated control group. During CPB, cardiac arrest was achieved with different cardioplegia solutions for 60 min, followed by reperfusion for 4 h before the myocardium and coronary arteries were harvested. Coronary arteries were harvested immediately and analyzed by scanning electron microscopy. Cardiomyocytic apoptosis was detected using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling, Western blot, and DNA ladder methods. RESULTS: Regardless of the detection method used, significantly higher percentages of apoptotic cardiomyocytes were found in group 3 and group 4 than in other groups. Expression of caspase-3 correlated with increased apoptosis. Scanning electron microscopy revealed severe endothelial injury of coronary arteries in group 3 and group 4. CONCLUSION: These results point to an important explanation for the difference in cardiac recovery after hypothermic ischemia and arrest with various cardioplegic solutions.     

犬肺缺血预处理对体外循环心肌的影响

目的探讨肺缺血预处理对体外循环心肌的保护作用及机制。方法12只健康杂种犬,体重12～15kg,随机分为实验组和对照组,每组6只。对照组为单纯体外循环组;实验组为缺血预处理组,在主动脉阻断前行左肺门阻断5min,再灌注5min,重复一次,然后同对照组行体外循环,两组体外循环均持续1h。于体外循环前、再灌注120min后采集心肌标本,测定心肌含水量、MDA、SOD活性及病理改变。结果体外循环后心肌含水量和MDA实验组低于对照组;心肌SOD活性实验组高于对照组;实验组心肌标本炎症水肿程度明显较对照组轻。结论犬肺缺血预处理对体外循环心肌缺血再灌注损伤有保护作用,其机制可能是减轻了心肌缺血再灌注损伤。     

Controlled oxygen reperfusion protects the lung against early ischemia-reperfusion injury in cardiopulmonary bypasses by downregulating high mobility group box 1

Restricting oxygen delivery during the reperfusion phase of cardiopulmonary bypass (CPB) protects the heart, but effects on lung ischemia reperfusion (IR) in CPB are unknown. We examined whether extracellular high mobility group box 1 (HMGB1) mediated inflammation during early lung IR injury in CPB. Fourteen healthy canines received CPB with 60 minutes of aortic clamping and cardioplegic arrest, followed by 90 minutes reperfusion. Following surgery, the animals were randomized into control (n = 7) or test (n = 7) groups. Control animals received a constant level of 80% FiO(2) during the entire procedure, and the test group received a gradual increase in FiO(2) during the first 25 minutes of reperfusion. In the test group, the FiO(2) was initiated at 40% and increased by 10% every 5 minutes, to 80%. Histology, lung injury variables, HMGB1 expression, and inflammatory responses were assessed at baseline (T1) and at 25 minutes (T2) and 90 minutes (T3) after starting reperfusion. Treatment with controlled oxygen significantly suppressed lung pathologies, lung injury variables, and inflammatory responses (all P < .001). After lung IR injury, HMGB1 mRNA and protein expressions were significantly decreased in the controlled oxygen group (all P < .001). Controlled oxygen reperfusion is protective in the early stages of lung IR injury in a canine CPB model, and this protection is linked to HMGB1 downregulation.     

Clinical experience of coenzyme Q10 to enhance intraoperative myocardial protection in coronary artery revascularization

Seventy-eight patients undergoing coronary artery bypass grafting (CABG) were compared retrospectively to evaluate whether pretreatment with coenzyme Q₁₀ (CoQ) is effective in preventing left ventricular depression in early reperfusion following CABG. CoQ (5 mg/kg, intravenously) was given to 60 patients, 2 hours prior to the onset of cardiopulmonary bypass (CPB). CABG was performed using saphenous vein under CPB associated with cold cardioplegia in the standard fashion. Heart rate, mean arterial pressure, and cardiac index showed no significant difference between the CoQ and control groups. However, left ventricular stroke work index was significantly elevated at 6 and 10 hours of reperfusion following CABG in the CoQ-treated group compared with the controls. Serum MB-CK was lower at 0 and 6 hours of reperfusion in the CoQ group compared with the controls. These results suggest that pretreatment with intravenous CoQ is effective in preventing left ventricular depression in early reperfusion and in minimizing myocardial cellular injury during CABG followed by reperfusion.     

Myocardial protective effect of deep hypothermic cardiac arrest without aortic cross clamp in neonatal hearts: Comparison with cardioplegic arrest in a rabbit model

Summary Using an isolated perfusion model of neonatal rabbit hearts aged 3 to 6 days, cardioplegic arrest (CPA) using crystalloid cold cardioplegia with aortic cross clamp (AXC: 60min,n = 15) and continuous deep hypothermic perfusion (DHP) at 15°C without AXC (n = 15) were compared. The hearts were divided into two subgroups: intact hearts (n = 18) and with preceding 40min warm ischemia (stressed hearts,n = 22). In the intact hearts, there were no significant differences between the CPA and DHP groups in left ventricular function, myocardial water content, and myocardial mitochondrial score after reperfusion. In the stressed hearts, recovery of cardiac output and left ventricular work was significantly higher in the DHP group than in the CPA group. The postreperfusion myocardial mitochondrial score was significantly better in the DHP group than in the CPA group. These results suggest that non-AXC DHP may be advantageous in the setting of stressed hearts with preceding ischemic injury where conventional CPA cannot provide adequate myocardial protection.     

LOX-1 abrogation reduces myocardial ischemia-reperfusion injury in mice

LOX-1 is a newly described lectin-like receptor for oxidized-LDL (ox-LDL), which is over-expressed in the ischemic myocardium. To examine the pathogenic role of LOX-1 in the determination of ischemia-reperfusion (I-R) injury to the heart, we developed LOX-1 knockout (KO) mice, and subjected these mice to 60 min of left coronary artery occlusion followed by 60 min of reperfusion. I-R in the LOX-1 KO mice resulted in a significant reduction in myocardial injury as well as in accumulation of inflammatory cells in the I-R myocardium and lipid peroxidation (P < 0.01 vs. wild-type mice). Concomitantly, there was significant preservation of cardiac function in the LOX-1 KO mice despite I-R (P < 0.01 vs. the wild-type mice). The phosphorylation of oxidative stress-sensitive mitogen-activated protein kinase (p38MAPK) and protein kinase B/Akt-1, expression of nitrotyrosine and inducible nitric oxide synthase (iNOS), and superoxide dismutase activity were enhanced during I-R in the wild-type mice. These alterations in p38MAPK, Akt-1 and iNOS were much less pronounced in the LOX-1 KO mice. The superoxide dismutase activity increased further in the LOX-1 KO mice. These observations provide compelling evidence that LOX-1 may be a key modulator of myocardial I-R injury, and its effect is mediated by pro-oxidant signals. LOX-1 may be a potential target for therapy of myocardial ischemic injury.     

The role of leukocyte-depleted reperfusion in cardiac surgery

Recent interest has been focused on the role of neutrophils in reperfusion injury as one of the mediating factors of inflammatory reactions. Several studies have reported the efficacy of leukocyte depletion in reperfusion using a leukocyte removal filter to attenuate reperfusion injury during cardiac surgery. For clinical application, we have introduced leukocyte-depleted terminal blood cardioplegia (LDTC) in patients with non-compromised or compromised hearts. The results of elective surgery in non-compromised LDTC did not significantly alter the results in terms of leakage of CK-MB, production of malondialdehyde from myocardium and the dopamine dose required at the weaning from cardiopulmonary bypass compared with the whole blood reperfusion or with terminal cardioplegia alone. In contrast, the results in emergency CABG patients differed significantly between the LDTC group and the other 2 groups. Leukocyte-depleted reperfusion was also effective in a similar fashion for patients with severe left ventricular hypertrophy caused by chronic aortic valve disease. Thus, leukocyte-depleted reperfusion may be beneficial as an adjunct to terminal cardioplegia during cardiac surgery to attenuate reperfusion injury in patients with compromised hearts, such as those with preoperative ischaemic insults or severe left ventricular hypertrophy.     

舒芬太尼对大鼠心肌缺血再灌注室性心律失常的影响

目的观察舒芬太尼预处理对大鼠心肌缺血再灌注室性心律失常的影响。方法72只大鼠随机分为假手术组(sham组)、缺血再灌注对照组(I-R组)、缺血预处理组(IPC组)和舒芬太尼不同剂量预处理组(SPC1、SPC2、SPC3组)。舒芬太尼不同预处理组分别以0.25,1,5μg/kg静脉泵注5min,停止5min,重复进行3次。于缺血前30min、缺血30min、再灌注90min时记录心电图,观察测定左室发展压(LVDP)、左室舒张末压(LVEDP),并记录缺血30min、再灌注40min内心律失常评分。并取右室心肌组织行超氧化物歧化酶(SOD)、丙二醛(MDA)测定。结果与sham组比较,I-R组LVDP、SOD降低,LVEDP、MDA升高,心律失常评分升高(P<0.05或0.01);与I-R组比较,IPC组以及SPC1、SPC2、SPC3组LVDP、SOD升高,LVEDP、MDA降低,心律失常评分降低(P<0.05或0.01)。结论舒芬太尼可模拟心脏缺血预处理作用,可降低心肌缺血再灌注室性心律失常的发生。     

异丙酚对婴幼儿体外循环心脏手术血细胞因子、心肌NF—κB、ICAM-1表达的影响

目的：观察异丙酚对婴幼儿体外循环心脏手术血细胞因子、心肌核转录因子（NF）-κB）和细胞间粘附分子（ICAM）-1表达的影响并试图说明其临床意义。方法：20例年龄1～9岁的先天性心脏病体外循环下行房、室间隔缺损矫正术的患儿,随机分为对照组（Ⅰ组,10例）和异丙酚麻醉组（Ⅱ组．10例）。麻醉诱导：咪唑安定,芬太尼,泮库溴铵。麻醉维持：Ⅰ组,吸入0．25％～2％安氟醚,Ⅱ组,持续输注异丙酚15～20mg／kg·h。两组分别于全麻诱导气管插管和动静脉穿刺完成后稳定10min（T0）,体外循环前（T1）、主动脉阻断25min（T2）、主动脉开放后30min（T3）、停止体外循环2h（T4）采集血液标本检测肿瘤坏死因子（TNF）-α、白细胞介素（IL）-6。右房插管和缺血再灌注30min取右房心耳组织标本,观察NF-κB和ICAM-1的表达。结果：两组患儿TNF—α在术中和术后无显著差异,IL-6于术中和术后均升高,且Ⅰ组的明显高于Ⅱ组（P〈0．05）。再灌注30min后Ⅰ组心肌组织NF—κB和ICAM-1的表达明显高于Ⅱ组（P〈0．05）。结论：婴幼儿体外循环心脏手术期间,全身炎症反应被激活,心肌细胞NF—κB和ICAM—1过度表达;异丙酚能减轻其炎症反应,抑制心肌NF-κB和ICAM-1的表达。