牡荆素抑制自噬和凋亡途径介导大鼠离体心脏缺血再灌注损伤的保护作用

Cardioprotective Effect of Vitexin-Mediated Autophagy and Apoptosis on Isolated Heart Ischemia-Reperfusion Injury in Rats

目的:探讨牡荆素在大鼠离体心脏缺血再灌注模型中对心脏的保护作用及潜在机制。方法:SD大鼠随机分为6组:正常对照组、缺血/再灌注(ischemia/reperfusion,I/R)组、牡荆素0. 43、1. 30、4. 32和12. 97μg/ml组,采用Langendorff法建立大鼠离体心脏I/R模型。利用生物机能实验系统检测各组大鼠离体心脏的血流动力学指标,如心率(HR)、冠脉流量(CF)、左室舒张末压(LVEDP)、左室收缩压(LVSP)、左室收缩压最大上升速率(+d P/dtmax)、左室舒张压最大下降速率(-d P/dtmin)以及心脏收缩张力,TTC染色法观察大鼠离体心脏的梗死面积,HE染色法观察各组大鼠心肌组织病理学变化。免疫印迹法检测P62、Beclin1、LC3BⅡ/Ⅰ、Cleaved caspase-3(CC-3)和Cleaved caspase-9(CC-9)的表达情况。结果:与对照组相比,I/R组大鼠离体心脏的CF、LVSP、+dP/dtmax、-dP/dtmin以及心脏收缩张力均显著降低,其HR、LVEDP值显著升高,心肌梗死面积增加,心肌组织病理性损伤显著,心肌组织中自噬相关蛋白LC3BⅡ/Ⅰ比值和Beclin 1的表达上调,P62蛋白下调;凋亡相关蛋白CC-3和CC-9的表达上调。与I/R组比较,牡荆素干预组可显著改善大鼠离体心脏血流动力学指标,减少心肌梗死面积,减轻心肌病理性损伤。Western Blot检测结果显示牡荆素干预各组显著下调自噬相关蛋白LC3BⅡ/Ⅰ和Beclin 1的表达,上调P62蛋白的表达,并显著抑制凋亡蛋白CC-3和CC-9的表达。结论:牡荆素可通过抑制缺血心肌的自噬和凋亡,对大鼠离体心脏缺血再灌注损伤起到保护作用。

Objective: To study the cardioprotective effect of vitexin-mediated autophagy and apoptosis on isolated heart ischemia-reperfusion injury in rats,and explore its mechanism Methods: SD rats were randomly divided into six groups: the control group,the model group (ischemia/reperfusion,I/R) and Vitexin (VT,0. 4323,1. 2969,4. 323 and 12. 969 μg/ml) groups. The isolated rat heart I/R model was established by Langendorff method. Biological function experimental system was used to observe the hemorheology indexes: Heart rate (HR),coronary flow (CF),left ventricular end-diastolic pressure (LVEDP),left ventricular systolic pressure (LVSP),Left ventricular systolic pressure maximum rate of rise (+ dP/dtmax),Left ventricular diastolic blood pressure maximum rate of decline(-dP/dtmin),and Cardiac contraction tension. The infarct size of heart was observed and detected by TTC staining. Pathological changes of the heart tissues were observed by HE staining. P62,Beclin1,CC-3,LC3 BⅡ/Ⅰ,and CC-9 protein expressions in ischemic myocardial tissues were measured by Western blotting.Results: Compared with the control group,CF,LVSP,+ dP/dtmax,-dP/dtmin,and Cardiac contraction tension in I/R model group were significantly reduced. HR and LVEDP were markedly increased and the infarct size of myocardial was increased after the isolated hearts ischemia reperfusion. Pathological damages in myocardium were increased. Expressions of LC3 BⅡ/Ⅰ,Beclin 1,CC-3 and CC-9 in ischemic myocardium were up-regulated significantly and expression of P62 was decreased in I/R model group. Compared with the model group,Vitexin significantly improved the hemodynamic parameters of isolated rat hearts,reduced myocardial infarct size,and improved myocardial pathological damages. Western blot analyses revealed that vitexin markedly down regulated the expressions of LC3 BⅡ/Ⅰand Beclin 1 and up regulated P62 expression. All doses of Vitexin also suppressed the expressions of CC-3 and CC-9 in I/R injury rats. Conclusions : The results indicate that vitexin protects isolated heart against myocardial I/R injury,its mechanism may be related to inhibiting autophagy and apoptosis signaling pathways.