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目的:研究细胞穿透肽PEP-1携带过氧化氢酶(CAT)穿透大鼠离体心肌的能力,并探讨PEP-1-CAT融合蛋白预处理对大鼠离体心肌缺血-再灌注损伤的保护作用及其机制。方法:建立大鼠离体心脏Langendorff灌流模型,随机分为5组(n=10):缺血-再灌注组(I/R组)行平衡30 min、停灌30 min与再灌注60 min,CAT组、PEP-1-CAT融合蛋白预处理组(A、B、C、D组)在平衡15 min后依次以10,5,10,20μmol/L的融合蛋白预处理15 min,停灌、复灌与I/R组相同。记录各组左室舒张末压(LVEDP)、左室收缩压(LVSP)、左室内压最大变化速率(±dp/dtmax)及冠脉流量(CF)变化,测定平衡15 min时、再灌注15 min时冠脉流出液乳酸脱氢(LDH)活性。测定再灌注60 min时心肌丙二醛(MDA)含量。结果:PEP-1-CAT融合蛋白能高效转导入离体心肌组织并呈现剂量依赖性。在平衡15 min末,各组LVEDP、LVSP、±dp/dt max以及LDH活性比较差异无统计学差异(P>0.05)。与I/R组比较,B、C、D组在再灌注后各时间点LVEDP降低(P<0.01),LVSP、±dp/dt max以及CF升高(P<0.01),灌注15 min时冠脉流出液LDH活性降低(P<0.01),再灌注后60 min心肌MDA含量降低(P<0.01)。CAT处理组所有结果和对照组相比无统计学意义(P>0.05)。结论:PEP-1-CAT融合蛋白能高效转导入离体心肌织并对大鼠离体心肌缺血-再灌注损伤具有明显的保护作用,将为其治疗心肌缺血再灌注损伤奠定坚实的实验基础。
AIM: To investigate the ability of cell penetrating peptide PEP-1 to carry catalase (CAT) in isolated rat myocardium and to investigate the effect of PEP-1-CAT fusion protein pretreatment on isolated rat myocardial ischemia-reperfusion Injury protection and its mechanism. Methods: Langendorff perfusion model of isolated rat heart was established and randomly divided into 5 groups (n = 10): ischemia / reperfusion group (I / R group) for 30 min, reperfusion for 30 min and reperfusion for 60 min, CAT group and PEP-1-CAT fusion protein pretreatment group (A, B, C and D) were pretreated with 10, 5, 10 and 20 μmol / L fusion protein for 15 min after balancing for 15 min, Reperfusion and I / R group the same. The changes of left ventricular end diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), maximal rate of change of left ventricular pressure (± dp / dtmax) and coronary flow (CF) were recorded. Coronary effluent lactate dehydrogenation (LDH) activity at min. The content of malondialdehyde (MDA) in myocardium was measured 60 min after reperfusion. RESULTS: The PEP-1-CAT fusion protein was transduced into isolated myocardium efficiently and in a dose-dependent manner. There was no significant difference in LVEDP, LVSP, ± dp / dt max and LDH activity between groups at the end of 15 min of equilibration (P> 0.05). Compared with I / R group, LVEDP, LVSP, ± dp / dt max and CF were significantly increased in groups B, C and D at each time point after reperfusion (P <0.01) The activity of LDH in the effluent decreased (P <0.01), and the content of MDA in myocardium decreased 60 min after reperfusion (P <0.01). All the results of CAT treatment group compared with the control group had no statistical significance (P> 0.05). CONCLUSION: PEP-1-CAT fusion protein can efficiently transduce into isolated cardiac muscle tissue and has obvious protective effect on isolated rat myocardial ischemia-reperfusion injury. It will lay a solid foundation for its treatment of myocardial ischemia-reperfusion injury basis.