乙酰胆碱对离体大鼠缺血/复灌心脏的保护作用及其机制

目的:探讨乙酰胆碱(ACh)预处理抗心肌缺血复灌(I/R)损伤作用及其与线粒体渗透性转换孔和/或线粒体ATP敏感性钾通道的关系。方法:采用离体大鼠心脏Langendorff灌流方法进行全心停灌30min,复灌120min复制I/R模型。测定心室力学指标和复灌各时间点冠脉流出液中乳酸脱氢酶(LDH)含量。实验结束测定心肌组织formazan含量的变化。结果:与单纯I/R组相比,ACh(0.1μmol/L,5min)预处理明显提高心肌细胞的formazan含量,降低复灌期间冠脉流出液中LDH含量,明显改善I/R所致的左室发展压、左心室内压最大上升和下降速率、心率与发展压乘积和左室舒张末压力的下降,缓解冠脉流量的减少。线粒体渗透性转换孔开放剂苍术苷(20μmol/L,复灌前给药20min)和线粒体ATP敏感性钾通道抑制剂5-羟基癸酸(100μmol/L,缺血前给药20min)能明显减弱ACh的保护作用。结论:在大鼠离体心脏灌流模型上,ACh预处理具有抗心脏缺血/复灌损伤的作用,这种保护作用可能与其抑制线粒体渗透性转换孔的开放和促进线粒体ATP敏感性钾通道的开放有关。     

降钙素基因相关肽在离体大鼠心肌缺血后处理中的作用

目的:观察降钙素基因相关肽(CGRP)在离体大鼠心肌缺血后处理保护中的作用。方法:采用离体大鼠全心停灌心肌缺血复灌模型。测定心室动力学指标、复灌各时间点冠脉流出液中乳酸脱氢酶(LDH)含量和心肌组织formazan含量的变化。结果:与缺血/复灌组相比,缺血后处理组明显增加心脏formazan含量,降低冠脉流出液中LDH含量,促进左室发展压、左室做功和冠脉流量的恢复。CGRP受体阻断剂CGRP-(8-37)和线粒体ATP敏感性钾通道阻断剂5-HD均减弱了缺血后处理的作用,且CGRP-(8-37)阻断了线粒体ATP敏感性钾通道开放剂Diaz的心肌保护作用。结论:缺血后处理可能通过促进线粒体ATP敏感性钾通道的开放,引起内源性降钙素基因相关肽的释放发挥心肌保护作用。     

δ-阿片受体在缺血后处理心肌保护中的作用

目的：探讨δ-阿片受体是否参与缺血后处理对抗心肌缺血/复灌（I/R）损伤和心肌细胞低氧/复氧（H/R）损伤作用及其机制。方法：采用离体大鼠心脏Langendorff灌流模型,全心停灌30 min、复灌120 min复制I/R模型。测定心室力学指标和复灌时冠脉流出液中乳酸脱氢酶（lactate dehydrogenase,LDH）活性,实验结束测定心肌组织formazan含量。酶解分离的心肌细胞采用低氧60min、复氧60min复制H/R模型,测定心肌细胞存活率。结果：在离体心脏模型上,与I/R组相比,缺血后处理组（停灌后复灌即刻立即给予6次全心停灌/复灌循环）心肌组织的formazan含量明显增高,复灌期间冠脉流出液中LDH明显降低,同时缺血后处理明显改善心室力学指标,缓解冠脉流量的减少 在分离心肌细胞模型上,低氧后处理明显提高心肌细胞存活率。δ-阿片受体阻断剂naltrindole（NTI）和线粒体钙激活钾通道（KCa）阻断剂paxilline（Pax）在离体大鼠心脏模型和分离心肌细胞模型上均能明显减弱缺血后处理的作用。在心肌细胞模型上,与H/R组相比,δ-阿片受体激动剂DADLE明显提高心肌细胞存活率,其作用可被paxilline所阻断。结论：缺血后处理具有抗心肌缺血/复灌损伤的作用,这种保护作用可能与其激活δ-阿片受体和开放KCa有关。     

线粒体钙单向转运体参予肿瘤坏死因子α抗心肌缺血/复灌损伤的研究

目的：探讨肿瘤坏死因子α（TNFα）诱导的抗心肌缺血／复灌损伤的保护作用是否与线粒体钙单向转运体以及相关成分有关。方法：采用离体大鼠心脏灌流方法,结扎冠状动脉左前降支30min和复灌120min复制局部缺血／复灌损伤模型,测定心肌梗死面积、冠脉流量和冠脉流出液中乳酸脱氢酶（LDH）含量。提取大鼠心肌线粒体,分光光度法测啶,520nm吸光度。结果：与单纯缺血／复灌组相比,10U／ml TNFα预处理明显降低心脏缺血／复灌后的梗死面积和复灌期冠脉流出液中LDH含量,促进冠脉流量的恢复;复灌开始用线粒体钙单向转运体激动剂精胺（20μmol／L）灌流10min减弱了TNFα降低梗死面积和LDH含量的作用。10u／ml TNFα预处理离体大鼠心脏后分离线粒体,520nm处吸光度的下降明显低于对照组;精胺（50μmol／L）减弱了TNFα对520nm处吸光度的影响。结论：TNFα诱导的抗心肌缺血／复灌损伤的保护作用可能与其抑制线粒体钙单向转运体的开放和抑制线粒体通透性转变孔道开放有关。     

一氧化氮和线粒体ATP敏感性钾通道介导血管紧张素转换酶抑制剂加强阈下预处理的作用

实验采用离体大鼠心脏Langendorff灌流模型,观察含巯基（卡托普利）和不含巯基（培哚普利拉）的两种血管紧张素转换酶抑制剂（angiotensin-converting enzyme inhibitors,ACEI）对抗心肌缺血的作用,并探讨一氧化氮（nitric oxide,NO）和线粒体ATP敏感性钾通道（mimchondrial ATP-sensitive potassium channel,mitoKATP channel）是否参与ACEI的心肌保护作用。结果表明：（1）给予大鼠心脏2min全心停灌和10min复灌作为闽下缺血预处理（subthreshold preconditioning,sPC）、卡托普利或培哚普利拉单独使用,均不能改善长时间缺血复灌（缺血30min＋复灌120min）引起的心肌损伤。（2）当两种ACEI分别和sPC联合使用时,与sPC组相比,缺血心脏在长时间缺血后的复灌期问左室舒张末压（left ventricular end-diastolic pressure,LVEDP）明显降低,左宦发展压（left ventricular developed pressure,LVDP）和冠脉流量明显增高,乳酸脱氢酶（lactate dehydrogenase,LDH）的释放量和心肌梗死面积明显低于sPC组。（3）利用NOS抑制剂L-NAME和mitoKATP通道的抑制剂5-HD灌流10min后,可明显抑制卡托普利／培哚普利拉和sPC联合使用引起的LVEDP降低,并使LVDP和冠脉流量降低,LDH的释放量和心肌梗死面积明显增高（P〈0．05）。（4）sPC、卡托普利或培哚普利拉单独使用,心脏NO的产生增加。ACEI和sPC联合使用,与三者单独使用相比NO的浓度亦明显增高（P〈0．05）。结果提示：含与不含巯基的ACEI与闽下缺血预处理联合使用均可使大鼠心脏功能明显改善,其心肌保护作用的机制可能通过NO途径,并和mitoKATP通道的激活有关。     

线粒体钾通道参与葛根素抗心肌细胞缺氧/复氧损伤的作用

目的:探讨线粒体ATP敏感性钾通道和线粒体钙激活钾通道在葛根素预处理抗心肌细胞缺氧/复氧损伤中的作用。方法:采用酶解分离大鼠心肌细胞复制心肌细胞缺氧/复氧模型,台盼蓝拒染法测定心肌细胞存活率;四甲基罗丹明乙酯(TMRE)孵育测定线粒体膜电位值;分离线粒体测定线粒体渗透性转换孔开放程度。结果:与缺氧/复氧组相比,葛根素(0.24mmol/L)预处理5min可明显增加心肌细胞的存活率,线粒体ATP敏感性钾通道抑制剂5-羟基癸酸(100μmol/L,预处理20min)或线粒体钙激活钾通道阻断剂paxilline(1μmol/L,预处理5min)均可拮抗葛根素的作用。葛根素预处理可明显减弱缺氧引起的线粒体膜电位的耗损,5-羟基癸酸和paxilline都能明显拮抗其作用。在分离心肌线粒体模型上,葛根素显著减弱CaCl2诱导的线粒体在A520处吸光度降低,其作用与单独应用线粒体渗透性转换孔抑制剂环孢菌素A相似;5-羟基癸酸和paxilline可拮抗葛根素的保护作用。结论:在大鼠分离心肌细胞模型或分离线粒体模型上,葛根素预处理具有抗缺氧/复氧损伤的作用,这种保护作用可能与其促进线粒体ATP敏感性钾通道和线粒体钙激活钾通道的开放,进而稳定线粒体膜电位,抑制线粒体渗透性转换孔开放有关。     

S-烯丙基-L-半胱氨酸对抗离体大鼠心肌缺血/再灌损伤作用的研究

目的：探讨S-烯丙基-L-半胱氨酸（SAC）预处理对心肌缺血/再灌（I/R）损伤的保护作用及其机制。方法：采用离体大鼠心脏Langendorff灌流模型,全心停灌30 min,再灌120 min建立I/R模型。测定血流动力学指标和再灌各时间点冠脉流出液中乳酸脱氢酶（LDH）含量。实验结束测心肌组织中甲月赞（formazan）,超氧歧化酶（SOD）及活性氧（ROS）量的变化。结果：与对照组比,SAC明显改善左室血流动力学指标,提高心肌组织的formazan含量,降低再灌期间冠脉流出液中LDH含量,提高心肌组织中SOD的活性,降低心肌组织中ROS的水平。苏氨酸明显减弱SAC的保护作用。结论：SAC对离体大鼠I/R心肌损伤有保护作用,其机制可能与SAC通过心肌细胞膜上的氨基酸转运体ASCT-1进入心肌细胞,增加心肌SOD活性,减少活性氧的损伤有关。     

黑木耳多糖对抗离体心脏缺血/再灌注损伤的研究

目的:探讨黑木耳多糖(AAP)对离体大鼠心脏缺血/再灌注(I/R)损伤的防护作用及其机制。方法:健康雄性SD大鼠灌胃黑木耳多糖(50,100,200mg/(kg.d))4周后,采用离体心脏Langendorff灌流方法,全心停灌30min,复灌120min建立I/R模型。测定左心室动力学指标和再灌注各时间点冠脉流出液中乳酸脱氢酶(LDH)含量;实验结束测定心肌组织甲月赞(formazan)、丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性的变化。结果:与单纯I/R组相比,AAP预处理明显提高心肌细胞的formazan含量,降低再灌注期间冠脉流出液中LDH含量,明显增强左室发展压、左心室内压最大上升速率和心率与发展压乘积的恢复,缓解冠脉流量的减少;高剂量AAP改善I/R心肌功能的作用要好于丹参预处理(4ml/(kg.d),gastricperfusion)组。中剂量AAP(100mg/(kg.d))预处理4周后明显抑制I/R心肌MDA的增加和SOD活性的减弱(P0.01),其效果要好于丹参阳性对照组。结论:在大鼠离体心脏灌流模型上,黑木耳多糖预处理具有抗心脏I/R损伤的作用,这种保护作用可能与其增加心肌SOD活性,减少脂质过氧化损伤有关。     

葛根素抗心肌细胞过氧化氢损伤的线粒体相关机制

目的:探讨葛根素(puerarin,Pue)预处理抗过氧化氢(H2O2)应激损伤的作用是否与线粒体渗透性转换孔和/或线粒体钙激活钾通道有关。方法:采用酶解分离大鼠心肌细胞模型,台盼蓝拒染法测定心肌细胞存活率;Rhodamine123孵育测定线粒体膜电位值,分离线粒体测定mPTP孔开放程度。结果:与H2O2应激组相比,Pue(0.24mmol/L)预处理5min可明显对抗H2O2应激引起的心肌细胞存活率的降低,线粒体钙激活钾通道阻断剂paxilline(Pax,1μmol/L,预处理30min)、线粒体渗透性转换孔开放剂atractyloside(20μmol/L,预处理20min)或PKC抑制剂chelerythrine(5μmol/L,预处理30min)可拮抗Pue的作用。Pue预处理或钙激活钾通道开放剂NS1619(10μmol/L,10min)都明显减弱H2O2应激引起的线粒体膜电位的去极化,线粒体渗透性转换孔开放剂atractyloside能明显减弱Pue的作用。在分离心肌线粒体模型上,Pue(0.24mmol/L,5min)显著减弱CaCl2诱导的线粒体在A520处吸光度降低,Pax(1μmol/L,5min)可拮抗Pue的作用。结论:在大鼠分离心肌细胞模型或分离线粒体模型上,Pue预处理具有抗过氧化氢应激损伤的作用,这种保护作用可能与其抑制线粒体渗透性转换孔的开放和促进线粒体钙激活钾通道的开放有关。     

海州香薷总黄酮对大鼠离体心脏缺血/再灌注损伤的保护作用

目的：探讨海州香薷总黄酮（TrES）预处理对大鼠离体心脏缺血/再灌注损伤的保护作用及其可能机制。方法：应用Lgendorff心脏灌流系统建立离体大鼠心脏缺血/再灌注模型,采用全心停灌的处理方法,平衡后,停止灌流30min,再灌注120min作为缺sk/再灌注过程。设立正常对照组,模型对照组,药物预处理组（1,10,100tμg/mlTrES）,利用RM6240BD型多道生理信号采集处理系统实时监测左心室血流动力学各项指标,用TIE染色法测定心肌梗死面积,测定再灌注期间冠脉流出液中乳酸脱氢酶（LDH）含量,以及在520mm处测定由200pmol/LCaC12引起心肌线粒体渗透性转换孔的开放情况。结果：海州香薷总黄酮预处理可以明显改善缺血/再灌注后所引起的左心室收缩功能下降、心肌梗死面积增加的现象、降低复灌期间冠脉流出液中LDH的含量以及能够明显降低由CaC12引起的线粒体在520am处吸光度值,且上述作用具有剂量依赖性。结论：海州香薷总黄酮能够对抗大鼠心肌缺血再灌注损伤,且具有剂量依赖性,其心脏保护机制与抑制线粒体渗透性转换孔（MPTP）的开放有关。     

Advances in the mechanism and treatment of mitochondrial quality control involved in myocardial infarction

Mitochondria are important organelles in eukaryotic cells. Normal mitochondrial homeostasis is subject to a strict mitochondrial quality control system, including the strict regulation of mitochondrial production, fission/fusion and mitophagy. The strict and accurate modulation of the mitochondrial quality control system, comprising the mitochondrial fission/fusion, mitophagy and other processes, can ameliorate the myocardial injury of myocardial ischaemia and ischaemia-reperfusion after myocardial infarction, which plays an important role in myocardial protection after myocardial infarction. Further research into the mechanism will help identify new therapeutic targets and drugs for the treatment of myocardial infarction. This article aims to summarize the recent research regarding the mitochondrial quality control system and its molecular mechanism involved in myocardial infarction, as well as the potential therapeutic targets in the future.     

线粒体转录终止因子蛋白家族研究进展

线粒体转录终止因子蛋白的作用是与线粒体DNA的特异位点结合,导致线粒体基因转录停止。近年来,随着人们对线粒体基因转录机制和人线粒体疾病的深入研究,线粒体转录终止因子的功能开始受到人们的关注。本文介绍了线粒体转录终止因子及其家族成员的研究进展和有待解决的一些问题。     

Mitochondrial quality control in stroke: From the mechanisms to therapeutic potentials

Mitochondrial damage is a critical contributor to stroke‐induced injury, and mitochondrial quality control (MQC) is the cornerstone of restoring mitochondrial homeostasis and plays an indispensable role in alleviating pathological process of stroke. Mitochondria quality control promotes neuronal survival via various adaptive responses for preserving mitochondria structure, morphology, quantity and function. The processes of mitochondrial fission and fusion allow for damaged mitochondria to be segregated and facilitate the equilibration of mitochondrial components such as DNA, proteins and metabolites. The process of mitophagy is responsible for the degradation and recycling of damaged mitochondria. This review aims to offer a synopsis of the molecular mechanisms involved in MQC for recapitulating our current understanding of the complex role that MQC plays in the progression of stroke. Speculating on the prospect that targeted manipulation of MQC mechanisms may be exploited for the rationale design of novel therapeutic interventions in the ischaemic stroke and haemorrhagic stroke. In the review, we highlight the potential of MQC as therapeutic targets for stroke treatment and provide valuable insights for clinical strategies.     

Roles of mitochondrial dynamics modulators in cardiac ischaemia/reperfusion injury

The current therapeutic strategy for the management of acute myocardial infarction (AMI) is to return blood flow into the occluded coronary artery of the heart, a process defined as reperfusion. However, reperfusion itself can increase mortality rates in AMI patients because of cardiac tissue damage and dysfunction, which is termed ‘ischaemia/reperfusion (I/R) injury’. Mitochondria play an important role in myocardial I/R injury as disturbance of mitochondrial dynamics, especially excessive mitochondrial fission, is a predominant cause of cardiac dysfunction. Therefore, pharmacological intervention and therapeutic strategies which modulate the mitochondrial dynamics balance during I/R injury could exert great beneficial effects to the I/R heart. This review comprehensively summarizes and discusses the effects of mitochondrial fission inhibitors as well as mitochondrial fusion promoters on cardiac and mitochondrial function during myocardial I/R injury. The comparison of the effects of both compounds given at different time‐points during the course of I/R injury (i.e. prior to ischaemia, during ischaemia and at the reperfusion period) are also summarized and discussed. Finally, this review also details important information which may contribute to clinical practices using these drugs to improve the quality of life in AMI patients.     

线粒体质量控制失调与恶性肿瘤发生和发展相关性的研究进展

线粒体活性氧增多、线粒体DNA突变和拷贝数改变、Ca~(2+)超载、凋亡异常等功能障碍与肿瘤发生、生长、侵袭、转移密切相关.随着研究的逐渐深入,人们认识到线粒体是个动态的细胞器,在生理、病理因素刺激下,经线粒体融合/分裂、线粒体自噬、线粒体生物合成以及线粒体分子伴侣和线粒体未折叠蛋白反应的协同调控,在细胞器和分子水平达到对线粒体及其蛋白质的质量控制,限制和延缓功能受损线粒体的积累和过度增多,维持线粒体数量、形态、功能和蛋白质量的动态平衡,保证细胞正常生命活动的进行,使其更好地适应环境.若线粒体及其蛋白的稳态调节能力下降或失衡,会导致受损线粒体的积累并引发细胞内环境的紊乱,影响线粒体功能的正常发挥,从而诱导正常细胞的恶性转化.     

Reactive oxygen species, mitochondria, apoptosis and aging

In this paper, we shall review various antioxygen defense systems of the cell paying particular attention to those that prevent superoxide formation rather than scavenge already formed superoxide and its products. The role of uncoupled, decoupled and non-coupled respiration, mitochondrial pore, mitochondrion-linked apoptosis will be considered. Mitochondrial theory of aging will be regarded in context of reactive oxygen species-induced damage of mitochondrial DNA. (Mol Cell Biochem 174: 305–319, 1997)     

Unusual mitochondrial genome structures throughout the Euglenozoa

Mitochondrial DNA of Kinetoplastea is composed of different chromosomes, the maxicircle (bearing 'regular' genes) and numerous minicircles (specifying guide RNAs involved in RNA editing). In trypanosomes [Kinetoplastea], DNA circles are compacted into a single dense body, the kinetoplast. This report addresses the question whether multi-chromosome mitochondrial genomes and compacted chromosome organization are restricted to Kinetoplastea or rather occur throughout Euglenozoa, i.e., Kinetoplastea, Euglenida and Diplonemea. To this end, we investigated the diplonemid Rhynchopus euleeides and the euglenids Petalomonas cantuscygni, Peranema trichophorum and Entosiphon sulcatum, using light and electron microscopy and molecular techniques. Our findings together with previously published data show that multi-chromosome mitochondrial genomes prevail across Euglenozoa, while kinetoplast-like mtDNA packaging is confined to trypanosomes.     

A peep into mitochondrial disorder:multifaceted from mitochondrial DNAmutations to nuclear gene modulation

Mitochondrial genome is responsible for multiple human diseases in a maternal inherited pattern, yet phenotypes of patients in a same pedigree frequently vary largely. Genes involving in epigenetic modification, RNA processing, and other biological pathways, rather than “threshold effect” and environmental factors, provide more specific explanation to the aberrant phenotype. Thus, the double hit theory, mutations both in mitochondrial DNA and modifying genes aggravating the symptom, throws new light on mitochondrial dysfunction processes. In addition, mitochondrial retrograde signaling pathway that leads to reconfiguration of cell metabolism to adapt defects in mitochondria may as well play an active role. Here we review selected examples of modifier genes and mitochondrial retrograde signaling in mitochondrial disorders, which refine our understanding and will guide the rational design of clinical therapies.