Liguzinediol调控心肌细胞线粒体动力学和自噬改善心肌梗死后大鼠心功能的机制

Mechanism of liguzinediol regulating mitochondrial dynamics and mitophagy to improve cardiac function in rats after myocardial infarction

目的:观察川芎嗪衍生物2,5-二羟甲基-3,6-二甲基吡嗪(liguzinediol,Lig)对左冠状动脉前降支结扎致心肌梗死大鼠的心功能改善作用及其潜在机制。方法:结扎大鼠心脏左冠状动脉前降支复制大鼠心肌梗死模型,给予不同剂量Lig(5、10、20 mg/kg)及阳性药地高辛(0.0332 mg/kg)治疗12周。超声心动图检测心功能;试剂盒检测心肌损伤标志物脑钠肽(brain natriuretic peptides,BNP)、乳酸脱氢酶(lactate dehydrogenase,LDH)和三磷酸腺苷(adenosine triphosphate,ATP)含量;HE染色观察心肌形态;电镜检测线粒体形态;Western blot检测线粒体动力学相关蛋白的表达水平;免疫组织化学染色检测线粒体自噬相关蛋白的表达水平。复制氧糖剥夺(oxygen glucose deprivation,OGD)H9C2细胞模型。使用Lig干预细胞,并将自噬激动剂和抑制剂与Lig结合使用。Western blot检测线粒体自噬相关蛋白的表达;转染LC3B腺病毒检测自噬水平;荧光标记检测线粒体膜电位、活性氧(reactive oxygen species,ROS)水平和细胞凋亡。结果:Lig各个剂量均能显著升高心肌梗死模型大鼠射血分数(ejection fraction,EF)、左室短轴缩短率(fractional shortening,FS),减小左室收缩末期内径(left ventricular dimension in systole,LVIDs)。Lig可显著降低心肌梗死模型大鼠血清BNP、LDH,并增加大鼠心脏中ATP水平。Lig改善心肌梗死大鼠心肌细胞及线粒体形态,调节心肌梗死大鼠心脏中线粒体动力学相关蛋白表达并促进自噬。在体外,Lig减少OGD模型H9C2细胞的ROS含量,促进线粒体自噬和融合,保护线粒体膜电位,减少H9C2细胞凋亡。自噬激动剂与Lig的合用部分增加了Lig对OGD模型H9C2细胞的保护作用,自噬抑制剂则可改变Lig对OGD模型H9C2细胞线粒体的调节作用及对凋亡的抑制作用。结论:Lig可促进线粒体自噬和融合,维持线粒体形态和功能完整,减少心肌细胞凋亡,改善心肌梗死大鼠的心功能。

Objective:This study aims to explore the effect and mechanism of liguzinediol(Lig)on cardiac function in myocardial infarction rats.Methods:The model of heart failure after myocardial infarction was established by ligating the left anterior descending coronary artery of rats.Different doses of Lig(5,10,20 mg/kg)and digoxin(0.0332 mg/kg)were used for the treatment of the rats for12 weeks.Cardiac function was detected by echocardiography.Serum myocardial injury markers of brain natriuretic peptides(BNP),lactate dehydrogenase(LDH)and myocardial tissue adenosine triphosphate(ATP)were detected by the detection kit;HE staining was used for observing myocardial morphology;electron microscopy was used to detect mitochondrial morphology;the expressions of mitochondrial dynamics and autophagy related proteins were detected by Western blot;and immunohistochemical staining was used to detect the expression of mitophagy related proteins.The cardiomyocyte model was replicated by oxygen and glucose deprivation(OGD).The expression of mitophagy-related proteins was detected by Western blot,and mitophagy levels were detected by LC3B adenovirus transfection.Mitochondrial membrane potential,reactive oxygen species(ROS)level and apoptosis were detected by fluorescence labeling.Results:Lig significantly increased ejection fraction(EF),fractional shortening(FS),and decreased left ventricular dimension in systole(LVIDs)in myocardial infarction rats.Lig significantly reduced serum BNP and LDH in myocardial infarction model rats,and increased the level of ATP in the heart of myocardial infarction rats.Lig improved the morphology of cardiomyocytes and mitochondria in the hearts of myocardial infarction rats,regulated the expression of mitochondrial dynamics-related proteins and promoted autophagy in the hearts of myocardial infarction rats.In vitro,Lig reduced ROS content in OGD model of H9C2 cells,promoted mitophagy and fusion,protected mitochondrial membrane potential,and reduced H9C2 cell apoptosis.The combined use of autophagy agonist and Lig partially increased the protective effect of Lig on OGD model of H9C2 cells,while autophagy inhibitor completely abolished the regulatory effect of Lig on mitochondria of OGD model of H9C2 cells and canceled its inhibitory effect on apoptosis of OGD model of H9C2 cells.Conclusion:Lig can promote mitochondrial autophagy and fusion,maintain mitochondrial morphology and function integrity,reduce cardiomyocyte apoptosis,and improve cardiac function in myocardial infarction rats.