不同七氟醚缺血处理方式对大鼠离体心脏缺血再灌注损伤的作用及其对基因表达谱的影响

目的：比较七氟醚缺血预处理（ SpreC）、七氟醚缺血后处理（ SpostC）及SpreC＋SpostC对大鼠离体心脏缺血再灌注损伤（ MIRI）的保护作用及其对心肌基因表达谱的影响。方法自主跳动的40只大鼠离体心脏经10 min平衡期灌注后,随机分为4组：对照（ CTRL）组、SpreC组、SpostC组和SpreC＋SpostC组。观察各组平衡期、缺血前及复灌15、60、120 min的血流动力学指标变化;各组缺血后复灌15 min,检测左室心肌烟酰胺腺嘌呤二核苷酸（ NAD＋）水平;平衡期和复灌120 min取各组冠状动脉流出液,检测乳酸脱氢酶（ LDH）和磷酸肌酸激酶（ CK-MB）水平;复灌120 min时测定心肌梗死面积及左室心肌取材行全基因芯片表达谱分析。结果与CTRL组比较,SpreC组、SpostC组和SpreC＋SpostC组心脏功能改善、梗死面积减小、LDH及CK-MB水平降低（P均＜0．05）,且SpreC＋SpostC的心肌保护效果优于单纯SpreC或SpostC（ P均＜0．05）。 SpreC组、SpostC组和SpreC＋SpostC组心脏NAD＋水平均高于CTRL组（P均＜0．05）,且SpreC＋SpostC组高于SpreC或SpostC组（P均＜0．05）。基因谱分析显示,仅有少数基因同时受SpreC、SpostC和SpreC＋SpostC同向调节。结论 SpreC和SpostC 能为大鼠离体心脏的MIRI提供程度相近的保护作用,二者联合应用效果更佳。不同七氟醚缺血处理方式对MIRI后心肌基因表达谱的影响不同。     

细胞外信号调节激酶通路在七氟醚后处理对抗大鼠离体心脏缺血再灌注损伤中的作用

目的研究活性氧（ROS）、细胞外信号调节激酶（ERK1/2）及线粒体通透性转换孔（mPTP）在七氟醚缺血后处理减轻离体大鼠心脏缺血-再灌注损伤中的作用。方法以K-H缓冲液灌注离体大鼠心脏,全心缺血30min后复灌60min建立缺血-再灌注损伤模型。七氟醚缺血后处理的心脏于缺血后复灌最初15min以3%七氟醚饱和的K-H缓冲液灌注。分别单独给予或与七氟醚同时给予ROS清除剂NAC（4mM）或ERK1/2阻断剂PD98059（20μM）,用以评价ROS及ERK1/2在七氟醚缺血后处理中的作用。比较各组间血流动力学、心肌梗死面积、冠脉流出液中乳酸脱氢酶（LDH）及肌酸肌酶-MB（CK-MB）水平。同时,测定各组缺血30min复灌60min后心肌丙二醛（MDA）含量以反映氧化应激损伤程度。Western blotting测定ERK1/2的磷酸化情况。测定心肌烟酰胺腺嘌呤二核苷酸（NAD＋）含量以反映mPTP的开放情况。结果与对照组相比,复灌之初给予3%七氟醚可显著改善心功能（增加左室发展压力、左室最大收缩/舒张速率、冠脉流量、心率,并降低左室舒张末期压力）、降低心肌梗死面积及减少LDH及CK-MB释放（P〈0.05）。七氟醚的心肌保护作用同样表现在降低缺血-再灌注损伤后心肌的MDA含量（P〈0.05）。然而,给予NAC或PD98059不仅可消除上述保护作用,而且可以抑制七氟醚增强ERK1/2磷酸化及抑制mPTP开放的保护作用（P〈0.05）。结论 3%七氟醚缺血后处理通过ROS-ERK1/2-mPTP信号通路可为健康大鼠离体心脏的缺血-再灌注损伤提供保护。     

糖尿病对离体大鼠缺血后适应心肌保护作用的影响

目的探讨糖尿病对离体大鼠缺血后适应心肌保护作用的影响。方法诱导2型糖尿病大鼠模型,采用Langendorff离体心脏灌流法,全心停灌30min,复灌60min,制成心肌缺血模型;全心停灌30min后,给予再灌注10s、停灌10s6次循环,然后再灌注至60min,制备缺血后适应模型。测定血流动力学指标和复灌20min冠状动脉流出液中乳酸脱氢酶(LDH)、肌酸激酶(CK)的含量。实验结束分离出左心室心肌并横切成5片,并测定心肌梗死面积。结果糖尿病大鼠缺血后适应血流动力学无明显改善,心肌酶释放量未减低,心肌梗死面积未显著减少(50.1%±3.7%比45.7%±4.8%,P0.05)。结论缺血后适应对糖尿病大鼠离体心脏无保护作用。     

谷氨酰胺对离体大鼠心脏缺血再灌注损伤的影响

目的研究谷氨酰胺对心肌缺血再灌注损伤时心功能和心肌酶的影响。方法30只sD大鼠取心脏建立Langendorff灌注模型,随机分为三组：（1）对照组（A组,正常灌注90min）;（2）缺血再灌注组（B组,全心缺血30min,复灌60min）;（3）谷氨酰胺组（c组,取心脏前3小时静脉注射谷氨酰胺0．75g/kg,全心缺血30min,复灌60min）。记录三组心脏的血流动力学水平,测定冠脉流出液肌钙蛋白I水平,测定复灌后心肌的热休克蛋白70水平。结果实与缺血再灌注组相比,谷氨酰胺组的左室发展压（LVDP）、左室内压上升/下降速率（±dp/dt）和心率明显增加,左室舒张末期压力（LVEDP）和肌钙蛋白I水平显著降低（P均〈0．05）,谷氨酰胺组热休克蛋白70表达水平显著增加（P〈0．05）。结论谷氨酰胺能改善缺血再灌注损伤大鼠心脏的血流动力学,减轻心肌损伤,这些作用可能与其诱导热休克蛋白70表达相关。     

七氟醚后处理对大鼠离体心肌缺血/再灌注时线粒体融合蛋白2表达及细胞凋亡的影响

目的探讨七氟醚后处理对大鼠离体心肌缺血/再灌注时线粒体融合蛋白2（Mfn2）表达及细胞凋亡的影响。方法健康成年雄性SD大鼠,体重220g~280g,采用随机数字表法,将其分为假手术组（S组）、缺血/再灌注组（I/R组）、七氟醚后处理组（Sev组）。采用Langendorff离体心脏灌流系统建立心肌缺血/再灌注损伤模型。K-H液平衡灌注30min后,S组继续灌注K-H液150min;I/R组停灌30min,复灌120min;Sev组停灌30min后灌注含3%七氟醚饱和的K-H液5min,再用K-H液冲洗10min,继续灌注K-H液,总灌注时间为120min。于再灌注结束时取心肌组织,采用免疫组化法测定Mfn2蛋白表达,TUNEL法测定心肌细胞凋亡,计算心肌细胞凋亡指数（AI）。电镜下观察心肌细胞及线粒体的超微结构。结果与S组比较,I/R组和Sev组Mfn2蛋白表达下调,AI增加（P〈0.05）;与I/R组比较,Sev组Mfn2蛋白表达上调,AI降低（P〈0.05）。电镜结果显示I/R组心肌细胞线粒体出现较重损伤,线粒体膜断裂,嵴不规则或消失。Sev组心肌细胞线粒体损伤较轻,线粒体形态完整。结论七氟醚后处理对大鼠离体心肌缺血/再灌注损伤具有保护作用,其机制可能与上调心肌组织Mfn2表达,保护线粒体形态完整,减少心肌细胞凋亡有关。     

缺血后适应对大鼠心肌缺血再灌注后血流动力学改善的影响

目的 研究缺血后适应(ischemic postconditioning,IPO)对正常离体大鼠心肌再灌注后血流动力学的改善作用.方法 采用正常离体大鼠心脏Langendorff灌流方法,全心停灌30 min,复灌60 min复制成心肌缺血的再灌注损伤(I/R)模型,测定血流动力学指标和再灌30 min冠脉流出液中乳酸脱氢酶(LDH)、肌酸激酶(CK)含量.实验结束后分离出左心室心肌并横切成5片,置入TTC中测定心梗面积.结果 离体大鼠心肌缺血后适应干预后可显著改善再灌注后左室收缩压(LVSP)以及左心室内压最大上升速率(+dP/dtmax)等血流变学指标,并显著减少了再灌注后LDH与CK的释放量及室性心律失常的发生;同时后适应干预减少了心肌梗死面积(47.3%,29.5%).结论 缺血后适应处理对离体大鼠缺血再灌注后的血流动力学指标损伤有明确的改善作用,预防了心肌缺血再灌注损伤.     

盐酸法舒地尔预处理联合缺血后处理对离体大鼠心肌缺血/再灌注的影响

目的 探讨Rho激酶抑制剂盐酸法舒地尔预处理联合缺血后处理对离体大鼠心肌缺血/再灌注的影响.方法 60只雄性Wistar大鼠,取出心脏,随机分为对照（Control）组、缺血后处理（IPO）组、小剂量法舒地尔预处理（LF）组、大剂量法舒地尔预处理（HF）组、小剂量法舒地尔预处理联合缺血后处理（LF＋ IPO）组、大剂量法舒地尔预处理联合缺血后处理（HF＋ IPO）组,各10只.采用Langendorff离体心脏流灌装置,行缺血30 min,再灌注120min,制备心肌缺血/再灌注模型.缺血后处理采用6×10s的再灌注/缺血循环,法舒地尔预处理于缺血前15 min分别以含有1 μmol/L、10 μmol/L的法舒地尔KH液灌注.记录各组血流动力学指标,测定心肌梗死面积,测定冠状动脉（冠脉）灌流液中超氧化物歧化酶（SOD）、丙二醛（MDA）含量.结果 LF＋ IPO组和HF＋ IPO组缺血后心功能明显改善、心肌梗死范围缩小、SOD活性升高、MDA含量降低,与Control组相比,P均＜0.01;HF＋ IPO组的上述各指标与IPO组和HF组相比,P均＜0.05.结论 法舒地尔预处理联合缺血后处理可减轻离体大鼠心脏缺血/再灌注损伤,同时大剂量法舒地尔预处理与缺血后处理两者联合应用时对缺血再灌注心肌有协同保护作用,其作用机制可能与两者提高机体抗氧化应激损伤的能力有关.     

钙调节蛋白对七氟烷处理再灌注心律失常的影响

目的：七氟烷对离体大鼠心脏再灌注心律失常的影响的探究。方法：在血流动力学稳定30min后，缺血20min，再灌注60min，建立缺血再灌注损伤模型。参考相关发表大鼠动物模型文献[1-2]将50只大鼠随机分成以下5组，每组10只：时间对照组（TC）：用95%氧合KH液恒流在离体心脏内灌流110 min；缺血/再灌注组（I/RI）：连续灌流95%氧合KH液30min后停止20min，恢复灌流60min；七氟烷预处理组（sevofluranepreconditioning,Sevo PC）：离体心脏用95%氧合KH液灌流20 min，用95%氧合的3%七氟烷饱和KH混合液灌流10 min，停止20 min，恢复灌流60 min；七氟烷后处理组（sevofluranepostconditioning,Sevo Po C）：离体心脏用95%氧合KH液灌流30 min，停止20 min，用95%氧合的3%七氟烷饱和KH混合液灌流10 min，恢复灌流50 min；七氟烷联合处理组（sevofluranepreconditioning and postconditioning,PCPO）：离体心脏用...     

Drp1和自噬在七氟醚后处理大鼠心肌保护中的作用

目的探究动力相关蛋白1(Drp1)和自噬在七氟醚后处理心肌保护中的作用。方法健康成年雄性SD大鼠45只,体重200~230g,采用随机数字表法分为假手术组(Sham组)、缺血再灌注组(I/R组)和七氟醚后处理组(SpostC组),各15只。采用左冠状动脉结扎30min、松开扎线120min的方法制备大鼠心肌缺血再灌注模型,Sham组只穿线不结扎,SpostC组于再灌注前吸入2.5%七氟醚5min。以TTC染色法测量大鼠心肌梗死面积(IS),以Western-blot法测定Drp1及自噬相关蛋白微血管相关蛋白轻链3-Ⅱ(LC3-Ⅱ)的表达,以苏木精-伊红(HE)染色法观察心肌损伤变化。结果Sham组存在Drp1及LC3-Ⅱ蛋白低表达;与Sham组比较,I/R组Drp1及LC3-Ⅱ蛋白表达上调,IS值增加(P<0.05),HE染色结果示心肌损伤加重;与I/R组比较,SpostC组Drp1及LC3-Ⅱ蛋白表达下降,IS值减小(P<0.05),HE染色结果示心肌损伤减轻。结论正常心肌细胞中存在低水平自噬,Drp1介导的自噬在七氟醚后处理心肌保护中具有重要作用。     

锌对缺血后适应预防糖尿病大鼠心肌缺血再灌注损伤的影响

目的探讨锌对离体糖尿病(DM)大鼠缺血后适应预防心肌缺血再灌注损伤作用的影响。方法高脂饮食联合链脲佐菌素(STZ)诱导建成2型DM(T2DM)大鼠模型,将40只雄性Wistar大鼠随机平均分为正常大鼠缺血再灌注组(A组:N+I/R),正常大鼠缺血后适应组(B组),DM大鼠后适应组(C组),锌干预DM大鼠后适应组(D组)。四组均采用离体大鼠心脏灌流模型方法,全心停灌30 min,复灌60 min,制成心肌缺血再灌注模型,对B、C、D三组在再灌注初始时,均先给予再灌注10 s,全心停灌10 s,共6次循环的缺血后适应干预。测定左室收缩压(LVSP)和再灌30 min冠状动脉流出液中乳酸脱氢酶(LDH)和肌酸激酶(CK)的含量。分离左室心肌并测定心肌梗死面积,对心肌进行免疫组织化学染色测定磷酸化蛋白激酶B(P-Akt)和磷酸化糖原合成酶激酶(GSK-3β)的表达。结果 D组与C组相比,锌干预的离体DM大鼠心脏缺血后适应可显著改善再灌注后LVSP以及左心室内压最大上升速率(+d P/dtmax)等血流动力学指标,并显著减少了再灌注后LDH与CK的释放量;同时缺血后适应干预减少了心肌梗死的面积,P-Akt及P-GSK-3β的表达增加。C组与A组相比,对DM大鼠给予缺血后适应处理后,其血流动力学无明显改善,且心肌酶释放量未减低,同时也没有显著减少心梗面积,P-Akt,P-GSK-3β的表达减少。结论锌干预的离体大鼠心脏恢复或增强了缺血后适应对DM大鼠心肌再灌注损伤的保护作用,其机制与锌使DM大鼠心肌细胞内P-Akt及P-GSK-3β增强,进而使缺血后心肌梗死面积减小和心肌酶释放量减少有关。     

七氟烷预处理改善离体大鼠心脏的再灌注心律失常

目的在Langendorff离体灌注模型研究七氟烷预处理对再灌注心律失常的影响。方法取SD大鼠心脏建立Langendorff灌注模型,随机分入以下三组：（1）对照组;（2）缺血再灌注组;（3）七氟烷预处理组（3％七氟烷预处理15分钟）。记录各组的血流动力学、心电图,测量冠脉流出液肌钙蛋白I水平,测定细胞内钙离子和活性氧水平。结果七氟烷预处理能显著增加缺血再灌注损伤后左室发展压,左室内压上升／下降速率和心率,降低左室舒张末期压力,减少冠脉流出液肌钙蛋白I水平（P均〈O．05）。在再灌注心律失常方面,与缺血再灌注组相比,七氟烷预处理能显著减少室性早搏个数[从182（133）次／分降至83（52）次／分],缩短室速[41（45）s降至20（22）s]和室颤[从22（43）s降至0（0）s]的发作时程,减少室颤发生率（从80％降至10％）,并降低再灌注心律失常评分[从4（0）降至2（O）]（P均〈0.05）。七氟烷预处理还能降低心肌细胞内钙离子和活性氧水平（P均〈0.05）。结论七氟烷预处理对缺血再灌注损伤心脏起保护作用,能改善离体大鼠心脏的再灌注心律失常。     

改良构建兔心肌缺血再灌注模型的体会

目的 探讨制作兔心肌缺血再灌注模型的改进方法.方法 20只新西兰大白兔,“六线六结”改良法开胸后,随机以“双线双结”法结扎兔冠状动脉左前降支（常规组,10只）和左室支（观察组,10只）30 min,松结实施再灌注2h后,取心测梗死面积.术前及再灌注2h后,检测血肌钙蛋白Ⅰ.结果 两组制模成功率均为70％;两组手术后肌钙蛋白Ⅰ较术前均明显升高,左室支结扎组升高更明显;观察组造成的心肌梗死面积明显大于常规组（P＜0.05）,且变异小.结论 改良法可有效地提高兔心肌缺血再灌注模型构建的成功率.     

瑞芬太尼预处理对缺血再灌注心肌线粒体功能的影响及机制

目的观察瑞芬太尼预处理对大鼠离体心脏缺血再灌注时心肌线粒体功能的影响,并探讨其机制。方法成年雄性SD大鼠36只,随机分为I／R组、RPC组、5HD＋RPC组,各12只。建立Langendorfff离体心脏灌注模型,用K－H液平衡20min。I／R组缺血前用K-H灌注液灌注45min;RPC组缺血前用含瑞芬太尼的灌注液灌注5min,再用K—H液冲洗5min,共3次;5HD＋RPC组用含有5-HD线粒体KATP通道阻断剂与瑞芬太尼的混合液灌注,共计45min。缺血30min和再灌注60min时测定各组心肌梗死面积、线粒体酶活性及线粒体膜电位（MMP）。结果与I／R组比较,RPC组再灌注60min时,梗死面积减少（P〈0．05）,而5-HD＋RPC组和I／R组相比差异无统计学意义。与K-H液平衡末比较,各组再灌注60min心肌线粒体酶活性及MMP降低（P〈0．01）。再灌注60min后,RPC组上述指标高于I／R组（P〈0．05）。结论瑞芬太尼预处理明显改善大鼠离体心脏缺血再灌注时心肌线粒体功能,其机制与开放线粒体ATP敏感性钾通道有关。     

Ischemic postconditioning protects remodeled myocardium via the PI3K-PKB/Akt reperfusion injury salvage kinase pathway

OBJECTIVE: We tested whether ischemic postconditioning (IPostC) is protective in remodeled myocardium. METHODS: Post-myocardial infarct (MI)-remodeled hearts after permanent coronary artery ligation and one kidney one clip (1K1C) hypertensive hearts of male Wistar rats were exposed to 40 min of ischemia followed by 90 min of reperfusion. IPostC was induced by six cycles of 10 s reperfusion interspersed by 10 s of no-flow ischemia. Activation of reperfusion injury salvage kinases was measured using Western blotting and in vitro kinase activity assays. RESULTS: IPostC prevented myocardial damage in both MI-remodeled and 1K1C hearts, as measured by decreased infarct size and lactate dehydrogenase release, and improved function. The reduction in infarct size and the recovery of left ventricular contractility achieved by IPostC was less in 1K1C hearts, but was unchanged in MI-remodeled hearts when compared to healthy hearts. In contrast, the recovery of inotropy was unaffected in 1K1C hearts, but was less in MI-remodeled hearts. Inhibition of the phosphatidylinositol 3-kinase (PI3K) pathway with LY294002 abolished the protective effects of IPostC on both disease models and healthy hearts. Western blot analysis in conjunction with in vitro kinase activity assays identified protein kinase B (PKB)/Akt but not p42/p44 extracellular-signal regulated kinase 1/2 (ERK1/2) as the predominant kinase in IPostC-mediated cardioprotection in remodeled hearts. IPostC increased phosphorylation of the PKB/Akt downstream targets eNOS, GSK3beta, and p70S6K in remodeled hearts. CONCLUSION: Our results offer evidence that IPostC mediates cardioprotection in the remodeled rat myocardium primarily via activation of the PI3K-PKB/Akt reperfusion injury salvage kinase pathway.     

Mitochondrial permeability transition pore and postconditioning

Postconditioning has recently been described as a powerful cardioprotection that prevents lethal reperfusion injury. Growing evidence suggests that mitochondrial permeability transition may be a key event in postconditioning. This proposition arises from the complementary observations that: (1) conditions for the mitochondrial permeability transition pore (mPTP) opening are built up during early reperfusion, (2) mPTP opens at the time of reperfusion, (3) transgenic structural alteration of mPTP modifies its opening probability following ischemia-reperfusion, (4) mPTP plays a role in preconditioning, and (5) postconditioning attenuates lethal reperfusion injury. We review in this article current evidence for an important role of the mitochondrial transition pore in postconditioning.     

Postconditioning with glucagon like peptide-2 reduces ischemia/reperfusion injury in isolated rat hearts: role of survival kinases and mitochondrial KATP channels

We recently reported that heart expresses functional receptors for the anorexigenic glucagon-like peptide (GLP)-2. Activation of these cardiac receptors affected basal heart performance through extracellular regulated kinase (ERK1/2) activation. Since ERK1/2 is considered one of the prosurvival kinases of postconditioning cardioprotective pathways, we hypothesized that GLP-2 directly protects the heart against ischemia/reperfusion (I/R) injury via prosurvival kinases. Wistar rat hearts were retrogradely perfused on a Langendorff perfusion apparatus. After 40-min stabilization, hearts underwent 30-min global ischemia and 120-min reperfusion (I/R group). In GLP-2 group, the hearts received 20-min GLP-2 (10(-7)?M) infusion at the beginning of the 120-min reperfusion. Perfusion pressure and left ventricular pressure (LVP) were monitored. Infarct size was evaluated by nitroblue-tetrazolium staining. Compared with the I/R group, GLP-2-treated hearts showed a significant reduction of infarct size and of postischemic diastolic LVP (index of contracture), together with a sharp improvement of developed LVP recovery (index of contractility). The protective effects were abolished by co-infusion with phosphatidylinositol 3-kinase inhibitor, Wortmannin (WT), the ERK1/2 inhibitor, PD98059, or the mitochondrial K(ATP) channel blocker, 5-hydroxydecanoate. GLP-2 effects were accompanied by increased phosphorylation of protein kinase B (PKB/Akt), ERK1/2 and glycogen synthase kinase (GSK3β). After 7-min reperfusion, WT blocked Akt and GSK3β phosphorylation. After 30-min reperfusion, WT inhibited phosphorylation of all kinases. In conclusion, the data suggest that GLP-2, given in early reperfusion, as postconditioning, protects against myocardial I/R injury, limiting infarct size, and improving post-ischemic mechanical recovery. It seems that the GLP-2-protection of rat heart involves multiple prosurvival kinases and mitochondrial K(ATP) channels.     

芬太尼后处理联合缺血后适应对兔心肌缺血再灌注损伤心肌坏死标志物的影响

目的 观察芬太尼后处理联合缺血后适应对兔心肌缺血再灌注损伤心肌坏死标志物及心肌梗死面积的变化,探讨其对心肌缺血再灌注损伤的保护作用.方法 32只日本大耳白兔,采用结扎左冠状动脉前降支30 min、复灌120 min建立心肌缺血再灌注损伤模型.按“随机数字表法”随机分为4组,每组8只：假手术组,动脉下仅穿线不结扎;缺血再灌注组,直接恢复再灌注;缺血后适应组,缺血后适应后恢复再灌注;芬太尼后处理＋缺血后适应组,缺血28 min给予芬太尼5μg· kg-1后处理,30 min予以缺血后适应.测定各组心肌坏死标志物（心肌肌钙蛋白Ⅰ浓度与肌酸激酶同工酶蛋白活力浓度）、计算心肌梗死面积及观察室性心律失常发生率.结果 芬太尼后处理＋缺血后适应组较缺血后适应组、缺血再灌注组外周血心肌肌钙蛋白Ⅰ浓度、肌酸激酶同工酶酶蛋白活力浓度降低,心肌梗死面积减小,差异均有统计学意义（P＜0.05）.缺血后适应组较缺血再灌注组外周血心肌肌钙蛋白Ⅰ浓度、肌酸激酶同工酶酶蛋白活力浓度降低,心肌梗死面积减小,差异均有统计学意义（P＜0.05）.芬太尼后处理＋缺血后适应组、缺血后适应组较缺血再灌注组室性心律失常发生率降低[0 vs.50％（4/4）,P＜0.05;12.5％（1/7）vs.50％（4/4）,P＜0.05],差异均有统计学意义（P＜0.05）.结论 芬太尼后处理联合心肌缺血后适应显著降低兔心肌缺血再灌注心肌肌钙蛋白Ⅰ浓度、肌酸激酶同工酶酶蛋白活力浓度,减少心肌梗死面积,降低室性心律失常发生率,可减轻心肌缺血再灌注损伤.     

ERK通路在缺血后处理保护缺血再灌注大鼠心肌间质中的作用

目的探讨细胞外信号调节激酶1／2（ERK1／2）通路在缺血后处理减轻大鼠缺血／再灌注心肌间质损伤中的作用。方法32只健康雄性SD大鼠随机分为4组,假手术组（SC组）、缺血再灌注组（1／R组）、缺血后处理组（IPTC组）、ERK1／2抑制剂PD98059组（PD组）。记求各组在室血流动力学变化,观察心肌胶原含量,测定血浆中肌酸激酶（CK）和乳酸脱氧酶（LDH）浓度。以Western blot法测定心肌组织中ERK1／2、p-ERK1／2和心肌基质金属蛋白酶-2（MMP-2）蛋白表达水平,以RT—PCR法从转录水平检测MMP-2的表达水平。结果与I／R组相比,IPTC组心肌p-ERK1／2水平、心肌胶原含量和左室舒缩功能明显升高,而心肌MMP-2蛋白表达及mRNA水平、血浆CK、LDH活力明显降低;使用ERK1／2抑制剂PD98059后,心肌p-ERK1／2表达水平下降,同时心肌MMP－2蛋白及表达、血浆CK、LDH活力明显增高,心肌胶原含量、左室舒缩功能明显降低。结论缺血后处理通过激活ERK1／2信号通路、改变MMP－2活性发挥保护缺血再灌注心肌间质的作用。     

Hypercholesterolemia blocked sevoflurane-induced cardioprotection against ischemia–reperfusion injury by alteration of the MG53/RISK/GSK3β signaling

Background

Recent studies have demonstrated that volatile anesthetic preconditioning confers myocardial protection against ischemia–reperfusion (IR) injury through activation of the reperfusion injury salvage kinase (RISK) pathway. As RISK has been shown to be impaired in hypercholesterolemia, we investigate whether anesthetic-induced cardiac protection was maintained in hypercholesterolemic rats.

Methods

Normocholesteolemic or hypercholesterolemic rat hearts were subjected to 30 min of ischemia and 2 h of reperfusion. Animals received 2.4% sevoflurane during three 5 min periods with and without PI3K antagonist wortmannin (10 μg/kg, Wort) or the ERK inhibitor PD 98059 (1 mg/kg, PD). The infarct size, apoptosis, p-Akt, p-ERK1/2, p-GSK3β were determined.

Results

Two hundred and six rats were analyzed in the study. In the healthy rats, sevoflurane significantly reduced infarct size by 42%, a phenomenon completely reversed by wortmannin and PD98059 and increased the phosphorylation of Akt, ERK1/2 and their downstream target of GSK3β. In the hypercholesterolemic rats, sevoflurane failed to reduce infarct size and increase the phosphorylated Akt, ERK1/2 and GSK3β. In contrast, GSK inhibitor SB216763 conferred cardioprotection against IR injury in healthy and hypercholesterolemic hearts.

Conclusions

Hyperchoesterolemia abrogated sevoflurane-induced cardioprotection against IR injury by alteration of upstream signaling of GSK3β and acute GSK inhibition may provide a novel therapeutic strategy to protect hypercholesterolemic hearts against IR injury.