吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

目的 探讨吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响.方法 雄性SD大鼠,体重180～200 g,应用Langendorff体外灌流装置,采用全心停灌45 min、再灌注60 min的方法制备大鼠离体心脏缺血再灌注模型.取模型制备成功的心脏40个,随机分为5组(n=8):缺血再灌注组(IR组)、吗啡预处理组(M1组)、吗啡后处理组(M2组)、吗啡预处理-后处理组(M1+M2组)、5-羟葵酸(5-HD)混合吗啡后处理组(5-HD+M2组).M1组全心停灌前30 min灌注含3.0 μmol/L吗啡的K-H液20 min,随后灌注K-H液10 min.M2组再灌注即刻灌注含3.0 μmol/L吗啡的K-H液10 min,随后灌注正常K-H液50 min.5-HD+M1组再灌注即刻灌注含3.0 μmol/L吗啡+10-4nunol/L 5-HD的K-H液10 min,随后灌注正常K-H液50 min.于再灌注60 min时,测定心肌肌酸激酶(CK-MB)活性,计算心肌梗死区与缺血危险区的比值(IS/AAR).结果 与IR组相比,其余各组IS/AAR减少,CK-MB活性降低(P<0.05);与M2组比较,5-HD+M2组CK-MB活性及IS/AAR升高(P<0.05);M1组、M2组和M1+M2组上述指标比较差异无统计学意义(P>0.05).结论 吗啡预处理.后处理虽然可减轻大鼠离体心脏缺血冉灌注损伤,但是与单独应用时效果相似,其原因可能是两者单独应用减轻心脏缺血再灌注损伤的机制均与开放线粒体ATP敏感性钾通道有关.     

MicroRNA-1和microRNA-21在缺血预处理、后处理及远端预处理中的表达变化

目的 通过离体缺血-再灌注心脏模型,观察缺血预处理(IPC)、缺血后处理(IPO)和肢体远端预处理(RIPC)后心脏microRNA1(miRNA-1)和microRNA21 (miRNA-21)的表达变化,以及它们所调控靶蛋白热休克蛋白70 (HSP70)和程序性细胞死亡4(PDCD4)表达变化,期望从miRNA调控水平揭示心脏的内源性保护机制.方法 取Sprague-Dawley (SD)大鼠心脏,建立离体Langendorff心肌缺血-再灌注模型,随机分为4组(每组12只),对照组、IPC组、IPO组和RIPC组.检测各组血流动力学指标,蛋白印迹法(Western blotting)检测PpDCD4、HSP70、B细胞淋巴瘤/白血病-2(Bc1-2)和Bc1-2相关X蛋白(Bax)含量,taqman探针法检测miRNA-1和miRNA-21含量,末端脱氧核苷酸转移酶介导的原位缺口标记法(TUNEL)检测心肌细胞凋亡,2,3,5-氯化三苯基四氮唑(TTC)法检测心肌梗死面积. 结果 IPC组心肌的miRNA-1和miRNA-21表达明显高于对照组,但RIPC组和IPO组心肌的miRNA-1表达较对照组明显降低( P＜0.05).IPC组、RIPC组和IPO组心肌中HSP70、PDCD4和Bax蛋白含量较对照组明显减少(P＜ 0.05),Bc1-2蛋白含量各组间差异无统计学意义.IPC组、RIPC组和IPO组左室心肌梗死面积/左室总面积以及心肌细胞凋亡率明显低于对照组(P＜ 0.05). 结论 miRNA-1和miRNA-21在缺血预处理、缺血后处理和远端预处理后,表达变化是不同的,同时各处理组中miRNA与其靶蛋白并不都是负性调节关系.     

Morphine postconditioning protects against reperfusion injury in the isolated rat hearts

BACKGROUND: Postconditioning is a novel strategy of attaining cardioprotection. Previous studies have suggested morphine mimics the effects of ischemic preconditioning. Whether it is also capable of producing postconditioning or not is still unclear. The purpose of this study was to determine (1) whether morphine postconditioning (MPostcond) would protect the heart against reperfusion injury and the subtype(s) of opioid receptors (OR) involved, (2) whether combining MPostcond with morphine preconditioning (MPC) would afford additive cardioprotection, and (3) to evaluate the role mitochondrial adenosine triphosphate-sensitive potassium (mito-K atp) channel played in MPostcond. MATERIALS AND METHODS: Isolated perfused rat hearts were subjected to 45 min of ischemia followed by 1 h of reperfusion. First, three morphine concentrations (0.3, 3.0 and 30 microM) were used to study the protective effect of MPostcond. Second, the effect of blockade of OR subtypes by three antagonists (nonselective OR antagonist naloxone, kappa-OR antagonist nor-binaltorphimine, and delta-OR antagonist naltrindole) on MPostcond was investigated. Third, the protective effects of MPC, MPostcond and the combining MPC with MPostcond on reperfusion injury were compared. Last, the effect of blockade of mito-K atp by 5-hydroxydecanoate on MPostcond was studied. MPostcond was induced by a 10-min perfusion of morphine in Krebs-Ringer's solution performed at the onset of reperfusion, and MPC was produced by a 20-min perfusion of morphine 10 min before ischemia. Infarct size (IS/AAR, as a percentage of the area at risk) was determined by 2,3,5-triphenyltetrazolium staining. RESULTS: IS/AAR was significantly reduced after MPostcond from 58% +/- 8% (control) to 37% +/- 6% (morphine 3.0 microM, P < 0.01). This effect was abolished by coadministering naloxone (58% +/- 7%), nor-binaltorphimine (52% +/- 5%), but not naltrindole (34% +/- 5%). MPC and MPostcond had similar extent of protective effect on IS/AAR, and combining MPC with MPostcond did not afford further cardiprotection. 5-Hydroxydecanoate also abolished the cardioprotection of MPostcond. Unexpectedly, all three OR antagonists and 5-hydroxydecanoate themselves also afforded some extent of cardioprotection. CONCLUSIONS: MPost confers cardioprotection via activating kappa-OR but not delta-OR and opening mito-K atp channels. MPost and MPC have no additive protection. kappa-OR and mito-K atp channel may play a dual role in protecting ischemia-reperfusion injury.     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

吗啡预处理-后处理对大鼠离体心脏缺血再灌注损伤的影响

Objective To evaluate the effects of morphine preconditioning-postconditioning on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Male SD rats weighing 180-200 g were killed after intraperitoneal injection of heparin 500 U/kg. The hearts were immediately removed and perfused in a Langendorff apparatus with K-H solution gassed with 95%O2-5%CO2 .HR and left ventricular systolic pressure (LVSP) were measured from a fluid-filled latex balloon in the left ventricle. Global myocardial ischemia was induced by interrupting perfusion for 45 min followed by 60 min reperfusion. Forty isolated rat hearts were randomly divided into 5 groups (n = 8 each): group 1 (I/R); group II morphine preconditioning (M1 ); group Ⅲ morphine postconditioning (M2); group IV M1 + M2; group V 5-hydroxydecanoate (5-HD) + M2. Group M1 was perfused with K-H solution containing morphine 3.0 μmol/L for 20 min 30 min before ischemia followed by 10 min normal K-H solution perfusion. Group M2 was perfused with K-H solution containing morphine 3.0 μmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Group 5-HD + M2 was perfused with K-H solution containing morphine 3.0 μmol/L+ 5-HD 10-4 mmol/L for 10 min at the beginning of reperfusion followed by 50 min normal K-H solution perfusion. Myocardial CK-MB activity was measured and myocardial infarct size (IS/AAR) detennined (by 2,3,5-triphenyl tetrazolium staining) at the end of 60 min reperfusion. Results The preconditioning, postconditioning and combination of preconditioning and postconditioning with morphine 3.0 μmol/L perfusion for 10 min all provided cardio-protective effects in terms of IS/AAR and myocardial activation of CK-MB. Conclusion Although the combination of morphine preconditioning and postconditioning can protect the heart against I/R injury, the effects are similar to those of either of them alone, and the reason may be that either of them alone protects the heart against I/R injury via activating mitoKATP .     

Postischemic infusion of 17-beta-estradiol protects myocardial function and viability

BACKGROUND: Females demonstrate improved cardiac recovery after ischemia/reperfusion injury compared with males. Attenuation of myocardial dysfunction with preischemic estradiol suggests that estrogen may be an important mediator of this cardioprotection. However, it remains unclear whether post-injury estradiol may have clinical potential in the treatment of acute myocardial infarction. We hypothesize that postischemic administration of 17beta-estradiol will decrease myocardial ischemia/reperfusion injury and improve left ventricular cardiac function. MATERIALS AND METHODS: Adult male Sprague Dawley rat hearts (n = 20) (Harlan, Indianapolis, IN) were isolated, perfused with Krebs-Henseleit solution via Langendorff model, and subjected to 15 min of equilibration, 25 min of warm ischemia, and 40 min reperfusion. Experimental hearts received postischemic 17beta-estradiol infusion, 1 nm (n = 4), 10 nm (n = 4), 25 nm (n = 4), or 50 nm (n = 4), throughout reperfusion. Control hearts (n = 4) were infused with perfusate vehicle. RESULTS: Postischemic recovery of left ventricular developed pressure was significantly greater with 1 nm (51.6% +/- 7.4%) and 10 nm estradiol (47.7% +/- 8.6%) than with vehicle (37.8% +/- 9.7%) at end reperfusion. There was also greater recovery of the end diastolic pressure with 1 nm (47.8 +/- 4.0 mmHg) and 10 nm estradiol (54.0 +/- 4.0) compared with vehicle (75.3 +/- 7.5). Further, 1 nm and 10 nm estrogen preserved coronary flow after ischemia and decreased coronary effluent lactated dehydrogenase compared with controls. Estrogen at 25 nm and 50 nm did not provide additional benefit in terms of functional recovery. Estrogen at all concentrations increased extracellular signal-regulated protein kinase phosphorylation. CONCLUSIONS: Postischemic infusion of 17beta-estradiol protects myocardial function and viability. The attractive potential for the clinical application of postischemic estrogen therapy warrants further study to elucidate the mechanistic pathways and differences between males and females.     

缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响

目的 评价缺血预处理.后处理对大鼠肠缺血再灌注损伤的影响.方法 清洁级成年雄性SD大鼠40只.体重225～275 g,随机分为5组(n=8):假手术组(S组)仅分离肠系膜上动脉(SMA),不夹闭;肠缺血再灌注组(IIR组)采用夹闭SMA 60 min,再灌注60 min的方法制备肠缺血再灌注损伤模型;缺血预处理组(IPr组)夹闭SMA 10 min,再灌注10 min,余同IIR组;缺血后处理组(IPo 组)夹闭SMA 60 min后,再灌注30 s,缺血30 s,反复3次,再灌注60 min;缺血预处理.后处理组(IPr-IPo组)先行缺血预处理,再行缺血后处理,操作过程同IPr组和IPo组.于再灌注60 min时各组取肠粘膜组织,观察肠粘膜形态并行Chiu评分,检测丙二醛(MDA)含量,超氧化物歧化酶(SOD)及髓过氧化物酶(MPO)活性,同时采集动脉血样检测血浆肿瘤坏死因子α(TNF-α)及白细胞介素6(IL-6)浓度.结果 与S组比较,其余各组Chiu评分、MDA含量、MPO活性、血浆TNF-α与IL-6浓度升高,SOD活性降低(P<0.05).与IIR组比较,IPr组、IPo组及IPr-IPo组Chiu评分、MDA含量、MPO活性、血浆TNF-α和IL-6浓度降低.SOD活性升高(P<0.01).与IPr组和IPo组比较,IPr-IPo组Chiu评分和MDA含量降低,SOD活性升高(P<0.05).IPr组与IPo组各指标比较差异无统计学意义(P>0.05).结论 缺血预处理-后处理可减轻大鼠肠缺血再灌注损伤,较单独应用时效果好.     

Postconditioning is an effective strategy to reduce renal ischaemia/reperfusion injury

Background. Several recent studies have shown that a brief ischaemiaapplied during the onset of reperfusion (postconditioning) iscardioprotective in different animal models. The potential applicationof postconditioning to organs different from the heart, i.e.kidney, is not available and is investigated in the presentstudy. We also tested the hypothesis that mitochondria playa central role in renal protection during reperfusion. Methods. Wistar rats were subjected to left nephrectomy and90-min right kidney occlusion. In controls, the blood flow wasrestored without intervention. In postconditioned rats, completereperfusion was preceded by 3 min, 6 min and 12 min of reperfusionin a consecutive sequence, each separated by 5 min of reocclusion.Animals were studied for 48 h. Mitochondrial respiratory chainfunction, rate of hydroperoxide production and carbonyl proteinswere measured at the end of postconditioning and 24 h and 48h after reperfusion. Results. BUN and creatinine significantly decreased in the postconditioninggroup as compared to control rats. Mitochondrial respiratoryfunction was significantly impaired in control rats, mainlyat the level of Complex II. Postconditioning significantly reducedthis mitochondria impairment. The rate of mitochondrial peroxideproduction was higher in the control group than in the protectedgroup at the end of postconditioning reperfusion. Moreover,mitochondrial protein oxidation was significantly higher incontrol rats than in the postconditioning group at the end ofreperfusion. Conclusions. In the present study, postconditioning reducedrenal functional injury and reduces mitochondria respiratorychain impairment, mitochondria peroxide production and proteindamage.     

缺血预处理联合后处理对大鼠肾缺血再灌注损伤的影响

目的 评价缺血预处理联合后处理对大鼠肾缺血再灌注损伤的影响.方法 健康雄性SD大鼠30只,体重250～280 g,随机分为5组(n=6):假手术组(S组)、缺血再灌注组(I/R组)、缺血预处理组(IP组)、缺血后处理组(IPo组)和缺血预处理联合后处理组(IP+IPo组).S组仅开腹,游离双侧肾脏,分离双侧肾蒂但不夹闭.采用夹闭双侧肾蒂45 min、再灌注6 h的方法 制备肾缺血再灌注模型.IP组夹闭双侧肾蒂5 min,再灌注5 min,反复3次,余操作同I/R组;IPo组夹闭双侧肾蒂45 min后,再灌注10 8,缺血10 s,反复3次,再灌注6 h.于再灌注6 h时,经心脏抽血后迅速处死大鼠取肾,测定血清肌酐(Cr)和尿素氮(BUN)的浓度;采用硫代巴比妥酸法测定肾组织丙二醛(MDA)含量,采用黄嘌呤氧化酶法测定肾组织超氧化物歧化酶(SOD)活性;光镜下观察肾组织病理学结果 ;TUNEL法检测肾组织凋亡细胞,计算凋亡指数(AJ).结果 与S组比较,其余各组血清Cr和BUN的浓度升高,肾组织SOD活性降低,MDA含量和AI升高(P<0.05);与I/R组比较,IP组、IPo组和IP+IPo组血清Cr和BUN的浓度降低,肾组织SOD活性升高,MDA含量和AJ降低(P<0.05),肾损伤减轻;与IP组和IPo组比较,IP+IPo组肾组织SOD活性升高,AI降低(P<0.05),肾损伤减轻.结论 缺血预处理联合后处理可减轻大鼠肾缺血再灌注损伤,较单独应用时效果好.     

缺血后处理在小儿室间隔缺损修补术中的心肌保护作用

目的 探讨缺血后处理对小儿室间隔缺损患者的心肌保护作用.方法 40例患者随机分为缺血后处理组和对照组.缺血后处理组给予3个周期的缺血后处理,对照组按常规进行手术.分别于手术前、主动脉开放后6h和20h测定心肌肌钙蛋白Ⅰ.结果 开放主动脉后6h和20h后处理组的cTnⅠ均较对照组低,差异有统计学意义（P〈0.05）.结论 缺血后处理对行室缺修补手术小儿患者的心肌具有保护作用.