北五味子乙素对大鼠离体心肌缺血再灌注损伤的保护作用及分子机制

Protective Effect of Schisandrin B on the Isolated Rat Heart against Myocardial Ischemia/Reperfusion Injury and Its Molecular Mechanism

目的:观察北五味子乙素(schisandrin B,Sch B)对缺血再灌注(ischemia/reperfusion,I/R)大鼠离体心脏功能、梗死面积、乳酸脱氢酶及相关蛋白表达的影响,探讨其对I/R损伤的保护作用及分子机制。方法:Wistar大鼠50只,随机分为5组:空白对照组(CON)、缺血再灌注组(I/R)、Sch B预保护组(Sch B)、PI3K抑制剂组(I/R+Sch B+LY)、腺苷酸活化的蛋白激酶(AMP-activated protein kinase,AMPK)抑制剂组(I/R+Sch B+CC)。采用Langendorff法建立离体大鼠心脏I/R模型,心肌缺血2 h,再灌注5、15、30、60 min。观察I/R期间室内压最大上升速率(+dp/dtmax)、室内压最大下降速率(-dp/dtmax)、左心室舒张末压、冠脉流量和心率;测定心脏灌流液中乳酸脱氢酶(lactate dehydrogenase,LDH)含量,2,3,5-氯化三苯基四氮唑(2,3,5-triphenyltertrazolium chloride,TTC)染色测定各组心肌梗死面积;免疫印迹检测心肌中总蛋白激酶B(protein kinase B,PKB)、磷酸化Akt(p-Akt)、总糖原合成酶激酶-3β(glycogen synthease kinase-3β,GSK-3β)、磷酸化GSK-3β(p-GSK-3β)蛋白表达。结果:Sch B可显著改善I/R所致的心肌功能损伤,减少梗死面积,提高心肌中p-Akt和p-GSK-3β蛋白表达。结论:Sch B对大鼠离体心脏I/R损伤具有一定保护作用,其机制可能与激活AMPK和PI3K/Akt信号通路有关。

Objective： To observe the effect of schisandrin B （SchB） on cardiac function, infarct size, lactate dehydrogenaseand related protein expression in the isolated heart from rats with myocardial ischemia/reperfusion （I/R） injury andconsequently to explore its protective effect against I/R injury and the underlying molecular mechanism. Methods：Fifty Wistar rats were randomly divided into five groups： control group （Control）, ischemia/reperfusion group （I/R） andSchB preconditioning group （SchB）, PI3K inhibitor group （I/R ＋ SchB ＋ LY294002）, and AMPK inhibitor group （I/R ＋SchB ＋ Compound C）. The Langendorff method was used to establish the isolated rat heart model of I/R injury, ischemiafor 2 h, reperfusion for 5, 15, 30 and 60 min respectively. The ＋dp/dtmax, ？dp/dtmax, left ventricular end-diastolic pressure（LVEDP）, coronary flow （CF）, heart rate （HR） and LDH activity in perfusion fluids were observed during I/R period. Themyocardial infarct area was measured with TTC staining and myocardial total Akt, phosphorylation Akt, total GSK-3β andphosphorylation GSK-3β protein expression were evaluated by the Western blotting technique. Results： SchB significantlyimproved the myocardial damage caused by I/R injury, reduced infarct size, and increased the expression of p-Akt andp-GSK-3β. Conclusion： SchB has protective effects against I/R damage in isolated hearts from rats, which may be related tothe activation of the AMPK and PI3K/Akt signaling pathways.