微小RNA在心肌缺血再灌注损伤中的作用及机制

微小RNA（microRNA,miRNA）是一类在进化上高度保守的小分子非编码RNA,大约南19～25个核苷酸组成,具有转录后渊控蛋白质编码基因表达的功能,     

微小RNA参与心肌缺血再灌注损伤的作用机制及研究进展

心肌缺血再灌注损伤是影响冠心病尤其是急性心肌梗死血运重建治疗效果的重要原因之一,近年来,众多研究发现微小RNA在心肌缺血再灌注过程中发挥调控作用,上调或者下调靶微小RNA的表达可减轻心肌缺血再灌注损伤,为临床上心肌保护提供了新的治疗靶点,现将围绕微小RNA在心肌缺血再灌注损伤中的调控机制及临床应用等方面的新进展进行综述。     

卡维地洛对心肌缺血再灌注损伤的保护作用研究进展

心肌缺血——再灌注损伤是心血管专科临床实践中较为常见的问题,也被认为是心肌保护问题的关键。卡维地洛作为一种新型的第三代β受体阻滞剂,相比于传统的β受体阻滞剂,具有抗氧化、钙拮抗、抗凋亡、抑制炎症反应,扩血管、线粒体保护、抗心律失常等作用,决定其对于心肌的缺血——再灌注损伤具有一定的保护作用,本文现就此方面目前的研究进展作一综述。     

心肌缺血/再灌注损伤中炎症反应作用机制的研究进展

心肌缺血／再灌注（I／R）损伤是指心肌组织缺血后恢复血流,血液的再灌注不能使其功能恢复,反而加重其结构损伤和功能障碍的病理生理过程,最终可能导致心肌梗塞、纤维化、心肌肥厚和心力衰竭。心肌I／R损伤的发生发展机制复杂,涉及到多系统多环节的异常,而炎症反应伴随其全过程,其中钙超载、活性氧（ROS）产生、中性粒细胞浸润和补体激活均参与调节心肌I／R损伤的炎症反应。因此,进一步了解炎症因子和相关信号通路在心肌I／R损伤中的作用,对该病的防治具有十分重要的理论和应用价值。     

褪黑激素保护心肌缺血/再灌注损伤研究进展

褪黑激素是一类具有多种功能的激素,可通过结合特定受体,激活一系列复杂的信号通路,发挥心脏缺血/再灌注损伤的保护效应。本综述主要对褪黑激素受体、褪黑激素诱导心肌保护的可能作用机制、以及褪黑激素的药物应用和临床研究等进行简要概述。     

染料木素对心肌缺血再灌注损伤的保护作用及机制研究

目的研究染料木素（Gen）对大鼠心肌缺血再灌注损伤的保护作用,并进一步阐明其机制。方法 40只SD大鼠,随机分为模型组、阴性对照组和Gen高剂量组（10 mg/kg）、Gen中剂量组（5 mg/kg）、Gen低剂量组（2.5mg/kg）。持续观察各组标准Ⅱ导联心电图（ECG）T波幅度变化情况,测定血清中乳酸脱氢酶（LDH）,磷酸肌酸激酶（CK）,丙二醛（MDA）及超氧化物歧化酶（SOD）含量,确定心肌损伤程度。免疫组化法检测Bc l-2、Bax、Caspase-3蛋白的表达。结果 Gen能降低大鼠心肌冠脉结扎后T波幅度抬高,降低LDH、CK和MDA水平,升高SOD水平,抑制Bax、Caspase-3的表达而增强Bc l-2的表达,减少心肌细胞凋亡。结论 Gen对冠脉结扎诱发的大鼠心肌缺血再灌注损伤有保护作用,其作用机制可能与抑制脂质过氧化,减少自由基损伤,上调Bc l-2蛋白表达,下调Bax、Caspase-3蛋白表达,抑制心肌细胞凋亡有关。     

补体耗竭对心肌缺血再灌注的保护作用及机制

目的明确耗竭补体对心肌缺血再灌注的保护作用.方法12只小猪随机分为对照组和眼镜蛇毒因子(CVF)组,CVF组在结扎冠状动脉前6h按20U/kg注射CVF以耗竭补体.开胸结扎小猪左冠状动脉前降支60min,然后松扎5h.测定血流动力学、梗死面积、心肌组织髓过氧化物酶(MPO)等指标,并作免疫组织化学检查.结果(1)血流动力学两组左室内压上升最大速度(+ap/dtmax)在心肌缺血期间均有明显下降,再灌注5h后对照组回升至(326±42)kPa/s,而CVF组回升达(418±41)kPa/s(P<0.05);(2)心肌梗死面积(坏死区占左心室重量百分比)对照组为(13.2±4.0)%,CVF组仅为(7.6±2.8)%(P<0.05);(3)MPO活性(U/g)对照组坏死区为2.68±0.15,而CVF组为1.27±O.14(P<O.01);(4)免疫组化染色对照组坏死区心肌组织有明显Clq、C3、C5b-9的沉积.结论CVF耗竭补体对小猪心肌缺血再灌注有显著心肌保护作用,此可能与抑制粒细胞有关.     

热休克蛋白在心肌缺血再灌注损伤中的保护作用

热休克蛋白是细胞受应激原刺激后诱导产牛的、有利于增强机体抵御恶劣环境的一组应激蛋白,心肌缺血再灌注可诱导生成热休克蛋自,并使之随心肌损伤的加重而增多,对心肌缺血冉灌注所致的损伤起到保护作用。热休克蛋白具有保护缺血心脏,减轻再灌注损害的作用,还可以作为监测指标,更好地估计心肌损伤程度,预测转归。本文通过阅读围内外文献对热休克蛋白在心肌缺血再灌注中的保护作用加以综述。     

褪黑素减轻心肌缺血/再灌注损伤的作用及机制

目的:探讨褪黑素（melatonin,Mel）在大鼠心肌缺血/再灌注（MI/R）损伤中的拮抗作用及其机制。方法:80只体质量200~250 g雄性SD大鼠随机分为4组:假手术（Sham）组、溶剂对照（MI/R+V）组、Mel治疗（MI/R+Mel）组、Mel+EX527（MI/R+Mel+EX）组。常规结扎左冠状动脉前降支行心肌缺血/再灌注手术,缺血30 min,再灌72 h后超声心动图法检测各组大鼠心功能,再灌6 h后ELISA法检测血清酶学指标,TUNEL法检测心肌细胞凋亡率,Evans blue-TTC双染法测定梗死面积,Western blot法检测沉默信息转录调控因子1（SIRT1）、乙酰化叉头转录因子1（Ac-Foxo1）及凋亡相关蛋白表达水平。结果:Mel治疗可显著改善MI/R损伤后心功能,降低血清肌酸激酶（CK）及乳酸脱氢酶（LDH）水平,降低凋亡率及梗死面积,上调SIRT1表达,下调Ac-Foxo1水平,降低凋亡相关蛋白表达。而使用EX527阻断SIRT1信号后逆转Mel的上述作用（均P<0.01）。结论:Mel可发挥抗凋亡作用减轻MI/R损伤并改善心功能,其作用机制可能与其激活SIRT1信号通路并降低Ac-Foxo1水平有关。     

丹参酮Ⅱ-A磺酸钠注射液在体外循环中对心肌缺血/再灌注损伤保护作用的研究

目的研究丹参酮Ⅱ-A磺酸钠注射液在体外循环中对心肌缺血／再灌损伤的保护作用。方法随机选取20例行心脏直视手术的患者,分为对照组和丹参酮Ⅱ-A磺酸钠注射液组。丹参酮Ⅱ-A磺酸钠组于转机前给予丹参酮Ⅱ-A磺酸钠注射液2mg／kg。分别于主动脉插管后（T1）、开放主动脉前1-3min（T2）、主动脉开放后30min（T3）、主动脉开放后120min（T4）,主动脉开放后720min（B）共5个时间点进行抽血,测定血清中超氧化物歧化酶（SOD）、丙二醛（MDA）含量;记录主动脉开放至心脏复跳所需时间,心律失常（室速／室颤）的发生率和持续时间。血清中超氧化物歧化酶、丙二醛采用分光光度法测定。结果两组患者围术期血清SOD浓度变化比较：对照组各时间点SOD的变化差异无统计学意义（P〉0．05）,丹参酮Ⅱ-A磺酸钠组SOD浓度逐渐上升,在T4时间点达最高值（P〈0．05）,T5时间点下降;组间比较,丹参酮Ⅱ-A磺酸钠组在T4时间点较对照组高（P〈0．05）。两组患者血清MDA浓度变化比较：对照组MDA浓度随时间点的推进逐步增高,于T4达最高值（P〈0．05）,丹参酮Ⅱ-A磺酸钠组MDA浓度也逐渐升高,在T4时间点达高峰,B时间点下降,两时间点与T1比较差异有统计学意义（P〈0．05）,组间比较,T4、L时间点差异有统计学意义（P〈0．05）,丹参酮Ⅱ-A磺酸钠组比对照组MDA的上升幅度小。两组患者心律失常的发生情况比较：对照组共出现室颤2例,占20％,室速1例,占10％,丹参酮Ⅱ-A磺酸钠组出现室颤1例,无室速发生;对照组室速室颤持续时间3min,电击除颤后转为窦性心律,丹参酮Ⅱ-A磺酸钠组室颤后36s自动转为窦性心律。主动脉开放至心脏复跳所需时间：对照组所需时间较丹参酮Ⅱ-A磺酸钠组明显较长,差异有统计学意义（P〈0．05）。结论在体外循环心脏直视手术中,临床剂量的丹参酮Ⅱ-A磺酸钠注射液能使患者血清中的SOD浓度升高,有效降低MDA的浓度,缩短主动脉开放至心脏复跳所需时间,减少心律失常的发生率并缩短其时间,提示丹参酮Ⅱ-A磺酸钠注射液对心肌缺血／再灌注损伤有保护作用。     

MicroRNAs与心肌缺血/再灌注损伤关系的研究进展

MicroRNA(miRNA)是一类体内生成,长度介于17~25 nt的非编码小RNA。此类RNA在翻译后的水平对基因表达发挥负调控作用,广泛参与生物体的生长发育及各种病理生理过程。近年研究表明,miRNA在心肌缺血/再灌注损伤(MIRI)中发挥重要作用,其参与了与MIRI有关的心肌细胞凋亡、热休克蛋白、离子通道以及细胞生存信号通路的调控,并可作为某些药物的作用靶点,为MIRI的治疗提供了新的思路。     

Mediated protective effect of electroacupuncture pretreatment by miR-214 on myocardial ischemia/reperfusion injury

Background Electroacupuncture pretreatment plays a protective role in myocardial ischemia/reperfusion （I/R） injury and microRNAs （miRNAs） could act on various facets of cardiac function. However, the role of miRNAs in the cardioprotection by electroacupuncture pre-treatment on myocardial I/R injury remains unknown. The purpose of the study was to examine whether miR-214 was involved in cardio-protection by electroacupuncture. Methods Using rat myocardial I/R model, we examined the role of electroacupuncture pretreatment in myocardial I/R injury and analyzed the changes in the expression of miR-214. In addition, I/R was simulated in vitro by performing oxy-gen-glucose deprivation （OGD） on H9c2 cell cultures, and the effect of electroacupuncture pretreatment on I/R injury as well as expressional level of miR-214 were examined in vitro. Furthermore, the miR-214 mimic was transfected into OGD-treated H9c2 cells, we analyzed the cell apoptosis, lactate dehydrogenase （LDH） and creatine kinase （CK） activities, intracellular free Ca2＋concentration （[Ca2＋]i） as well as the relative protein levels of sodium/calcium exchanger 1（NCX1）, BCL2-like 11 （BIM）, calmodulin-dependent protein kinase IIδ（CaMKIIδ） and Cyclophilin D （CypD）. Results The in vivo results revealed that compared with the I/R group, the electroacupuncture pretreatment group showed significant decreased myocardial infarct size, as well as the increased indices of the cardiac function, including heart rate, mean arterial pressure, left ventricular systolic pressure and maximal rate for left ventricular pressure rising and declining （±dp/dt max）. In addition, electroacupuncture pretreatment could inhibit the elevation of LDH and CK activities induced by I/R injury. The quantitative PCR （qPCR） results demonstrated electroacupuncture pretreatment could provide cardioprotection against myocardial I/R injury in rats with miR-214 up-regulation. In the meanwhile, in vitro, electroacupuncture pretreatment protected     

促红细胞生成素与心肌缺血再灌注损伤

近年来促红细胞生成素(erythropoietin,EPO)的非造血生物作用逐渐引起关注。研究表明,EPO 可以减轻缺血缺氧时心肌细胞的损伤,减少心肌细胞的调亡,从而使其可能成为预防和治疗心肌缺血再灌注损伤的一条途径。     

硫氮酮对心肌缺血再灌注损伤内皮功能的保护作用

目的 :研究硫氮酮对心肌缺血再灌注 (MIR)损伤内皮功能的保护作用。方法 :将 4 8只大鼠制成心肌MIR模型 ,并随机分成假手术组、MIR组、硫氮酮组。各组分别于缺血前、缺血 30min、再灌注 90min、180min检测乳酸脱氢酶 (LDH) ,肌酸磷酸激酶同工酶 (CK MB) ,一氧化氮 (NO) ,丙二醛 (MDA)含量。结果 :①MIR组与假手术组相比 ,LDH、CK MB升高 ,NO下降 ,MDA上升。②硫氮酮组与MIR组相比 ,LDH、CK MB降低 (P <0 .0 5和P <0 .0 1) ,NO活性增加 (P <0 .0 5 ) ,MDA产生减少 (P <0 .0 5 )。结论 :硫氮酮能减轻脂质过氧化程度 ,改善内皮功能 ,保护心肌MIR损伤     

丹酚酸B对大鼠心肌缺血再灌注损伤内皮素及TXA2/PGI2系统的影响

目的　探讨丹酚酸 B(Sal B)对大鼠心肌缺血再灌注损伤 (MIRI)内皮素释放 (ET)及血栓素 /前列环素 (TXA2 / PGI2 )系统的影响。方法　大鼠心肌缺血 30 min后再灌注 1 2 0 min造成大鼠心肌缺血再灌注损伤模型 ,放免法测定给药前后血浆中 ET、TXB2 及 6- Keto- PGF1α的含量 ,观察 Sal B对 MIRI心肌的保护作用。结果　 Sal B可以减少 ET及 TXB2 的释放 ,提高 PGI2 的含量。结论　 Sal B可以减轻 MIRI,可能通过减少 ET的释放 ,改善 TXA2 / PGI2 系统的平衡状态 ,减轻心肌细胞的损伤。     

心肌缺血再灌注损伤研究进展

急性心肌梗死是主要的致死致残原因,再灌注治疗是其标准的治疗方案,然而再灌注治疗伴随着再灌注损伤,再灌注损伤的机理目前还未完全清楚,分子、细胞、组织上的改变均与参与再灌注损伤,本文就心肌缺血再灌注损伤的研究进展作一综述。     

Protective effects of ginsenosides in myocardial ischemia and reperfusion injury

To verify whether ginsenosides will attenuate the myocardial ischemia and reperfusion injury, the left anterior descending coronary artery (LAD) was snared for 2 hours in 23 dogs and then the ischemic myocardium was reperfused. 45 minutes after ischemia, the animals were randomly divided into a ginsenosides group (n = 11, receiving a slow IV bolus of ginsenosides 10 mg/kg and then a continuous infusion of 80 micrograms/kg/min) and a saline solution group (n = 12 receiving equal amount of glucose in saline). The treatment was started 45 minutes after coronary occlusion and stopped one hour after reperfusion. 24 hours later, the dogs were killed and the extent of myocardial necrosis was determined histologically. The LVEDP, arterial pressure and heart rate were markedly lower in the ginsenosides group. Electrocardiographic findings of myocardial ischemia were significantly improved in the ginsenosides group. 8 controls developed malignant arrhythmia after reperfusion, but none in ginsenosides group. The myocardial ultrastructure can be protected by ginsenosides during the period of ischemia and reperfusion. The infarct size in saline group was 22.7 +/- 3.2% while in the ginsenosides group it was 5.2 +/- 1.3% (P less than 0.05). These results show that ginsenosides can protect the ischemic myocardium and reperfusion injury of myocardium.     

Protective effects of melatonin on myocardial ischemia/reperfusion injury in vivo

The production of oxygen free radicals has been strongly implicated as an important pathophysiological mechanism mediating myocardial ischemia/reperfusion (I/R) injury. Various antioxidants have cardioprotective effects. Melatonin, an indoleamine synthesized by the pineal gland, is a potent antioxidant and a direct free radical scavenger. This is the first in vivo study to evaluate the effect of melatonin (0.5, 1.0, and 5.0 mg/kg, i.v. bolus) on myocardial I/R injury in anesthetized Sprague-Dawley rats. Results demonstrate that pretreatment with intermediate or high doses of melatonin (1.0 and 5.0 mg/kg) at 10 min before left coronary artery occlusion markedly suppressed ventricular tachycardia (VT) and ventricular fibrillation (VF), while reducing the total number of premature ventricular contractions and total duration of VT and VF that occurred during the 45-min ischemic period. Pretreatment with melatonin dramatically improved survival rate of rats when compared with the I/R-only group. After 1-hr reperfusion, melatonin caused a significant reduction in infarct size when compared with I/R-only group. Meanwhile, pretreatment with melatonin (1.0 mg/kg) significantly reduced superoxide anion production and myeloperoxidase activity; the latter is an index of neutrophil infiltration in the ischemic myocardium. Additionally, pretreatment with melatonin (1.0 and 5.0 mg/kg) significantly attenuated ventricular arrhythmias and mortality elicited by reperfusion following 5-min ischemia. In conclusion, melatonin suppresses ischemia- and reperfusion-induced ventricular arrhythmias and reduces infarct size resulting from I/R injury. The pronounced cardioprotective activity of melatonin may be mediated by its antioxidant activity and by its capacity for neutrophil inhibition in myocardial I/R.