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甘草苷调控TXNIP/TRX信号通路改善大鼠急性心肌梗死后心室重构的机制研究

Mechanism of liquiritin in the improvement of ventricular remodeling after acute myocardial infarction via regulating the TXNIP/TRX signaling pathway

  • 摘要: 探究甘草苷(LQ)对改善急性心肌梗死(AMI)后心室重构(VR)的作用机制。分子对接预测甘草苷与硫氧还蛋白相互作用蛋白(TXNIP)的结合作用。冠状动脉左前降支结扎构建急性心肌梗死模型大鼠,造模2周后,将造模成功的大鼠随机分为模型组、低剂量甘草苷组(20 mg/kg)和高剂量甘草苷组(40 mg/kg)。甘草苷每天灌胃给药1次,假手术组和模型组给予等体积的0.5%羧甲基纤维素钠(CMC-Na)溶液,均连续干预4周。超声心动图检测大鼠心脏功能,HE染色观察心脏病理变化,ELISA法检测大鼠血清肌酸激酶同工酶(CK-MB)活性,比色法检测大鼠血清丙二醛(MDA)、总超氧化物歧化酶(T-SOD)和过氧化氢酶(CAT)的活性。RT-qRCR法检测大鼠心肌组织中TXNIP、硫氧还蛋白(TRX)、NOD样受体热蛋白结构域相关蛋白3(NLRP3)的基因表达水平;Western blot法检测大鼠心肌组织中TXNIP、TRX和NLRP3蛋白表达水平。分子对接结果显示,甘草苷与TXNIP靶点的结合较好。20、40 mg/kg甘草苷干预后,可明显升高射血分数(EF)和缩短分数(FS)水平(P<0.01),降低左心室收缩末期内径(LVIDs)、左心室舒张末期内径(LVIDd)、左心室收缩末期容积(LVESV)、左心室舒张末期容积(LVEDV)水平(P<0.01);心肌结构改善显著,细胞排列趋于规则,炎性细胞浸润和坏死面积缩小;显著降低了心肌酶CK-MB水平(P<0.01);减少了血清中MDA活性,提高了CAT和T-SOD活性(P<0.01)。甘草苷有效抑制了AMI大鼠心肌组织中TXNIP和NLRP3的基因和蛋白的过度表达,同时促进了TRX基因和蛋白表达(P<0.01)。综上所述,甘草苷对TXNIP/TRX信号通路具有调控作用,抑制NLRP3炎症小体的激活,有效改善AMI后VR。

     

    Abstract: This study aimed to investigate the mechanism of liquiritin (LQ) in the improvement of ventricular remodeling (VR) after acute myocardial infarction (AMI). Molecular docking was used to predict the binding affinity of liquiritin to thioredoxin-interacting protein (TXNIP). After 2 weeks of modeling, the rats were randomly divided into a model group, a low-dose liquiritin group (20 mg/kg LQ), and a high-dose liquiritin group (40 mg/kg LQ). Liquiritin was administered by gavage once a day, and the sham group and model group were given the same volume of 0.5% sodium carboxymethylcellulose (CMC-Na), with intervention of 4 consecutive weeks. Echocardiography was employed to detect the cardiac function, HE staining was used to observe cardiological changes, ELISA was used to detect the activity of serum creatine kinase-MB (CK-MB) activity, and the colorimetric method was adopted to detect serum malondialdehyde (MDA), total superoxide dismutase (T-SOD) and catalase (CAT) activities. RT-qPCR was used to detect the gene expressions of TXNIP, thioredoxin (TRX) and NACHT, LRR, and PYD domains-containing protein 3(NLRP3). Western blot was used to detect the protein expressions of TXNIP, TRX and NLRP3 in rat myocardial tissue. Molecular docking results showed that liquiritin had a good binding affinity to TNXIP target. After 20 and 40 mg/kg liquiritin intervention, the levels of ejection fraction (EF) and fractional shortening (FS) were significantly increased (P<0.01), and the levels of LVIDs, LVIDd, LVESV, and LVEDV were decreased (P<0.01). The myocardial structure was significantly improved, the cell arrangement tended to be regular, and the area of inflammatory cell infiltration and necrosis was reduced. Liquiritin significantly reduced the level of CK-MB (P<0.01), decreased the activity of MDA, and increased the activities of CAT and T-SOD (P<0.01). Liquiritin effectively inhibited the overexpression of TXNIP and NLRP3 genes and proteins, and enhanced the expression of TRX genes and proteins in the myocardial tissues of AMI rats. In conclusion, liquiritin has a regulatory effect on the TXNIP/TRX signaling pathway, inhibits the activation of the NLRP3 inflammasome, and thus improves ventricular remodeling after acute myocardial infarction.

     

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