Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
Department of Vascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan Province, China.
J Mol Med (Berl). 2018 Aug;96(8):791-806. doi: 10.1007/s00109-018-1664-3. Epub 2018 Jun 29.
Trimetazidine (TMZ) has been demonstrated to have protective effects against myocardial ischemia/reperfusion (MI/R) injury. In the present study, we investigated the effects and the underlying mechanisms of TMZ on autophagy during MI/R in vivo and in vitro. In the in vivo study, an animal model of MI/R was induced by coronary occlusion. TMZ (20 mg/kg/day) protected the rat hearts from MI/R-induced heart failure by increasing ejection fraction and fractional shortening and decreasing end-systolic volume, end-diastolic volume, left ventricular (LV) internal diameter at systole, and LV internal diameter at diastole; it alleviated myocardial injury and oxidative stress by decreasing LDH, creatine kinase MB isoenzyme, ROS, and MDA levels and increasing SOD and glutathione peroxidase levels in plasma. TMZ also reduced myocardial infarct size and apoptosis. Moreover, TMZ markedly inhibited MI/R-induced autophagy by decreasing the protein and messenger RNA levels of LC3-II, Beclin1, ATG5, and ATG7 and the number of autophagosomes and by involving the AKT/mTOR pathway. Further, in the in vitro experiments, H9c2 cells were incubated with TMZ (40 μM) to explore the direct effects of TMZ following exposure to hypoxia and reoxygenation (H/R). TMZ increased cell viability and the concentration of intracellular SOD and inhibited H/R-induced cell apoptosis and ROS production. Moreover, TMZ decreased the number of autophagosomes and autophagy-related protein expression; it also upregulated p-AKT and p-mTOR expression. In addition, TMZ augmented Bcl-2 protein expression and diminished Bax protein expression, the Bax/Bcl-2 rate, and cleaved caspase-3 level. However, these effects on H9c2 cells were notably abolished by the PI3K inhibitor LY294002. In conclusion, our results showed that TMZ inhibited I/R-induced excessive autophagy and apoptosis, which was, at least partly, mediated by activating the AKT/mTOR pathway.
TMZ improved cardiac function, alleviated myocardial injury and oxidative stress, and reduced the myocardial infarct area and apoptosis. TMZ inhibited MI/R-induced myocardial autophagy, H/R-induced H9c2 cell apoptosis, and autophagy flux. The effect of TMZ on autophagy was repressed by LY294002. TMZ protected against MI/R injury by inhibiting excessive autophagy via activating the AKT/mTOR pathway.
曲美他嗪（TMZ）已被证明对心肌缺血/再灌注（MI/R）损伤具有保护作用。本研究旨在探讨 TMZ 在体内和体外 MI/R 过程中对自噬的影响及其潜在机制。
在体内研究中，通过冠状动脉阻塞诱导 MI/R 动物模型。TMZ（20mg/kg/天）通过增加射血分数和缩短分数，减少收缩末期容积、舒张末期容积、收缩期左心室（LV）内径和舒张期 LV 内径，减轻心肌损伤和氧化应激，降低血浆中乳酸脱氢酶、肌酸激酶 MB 同工酶、ROS 和 MDA 水平，增加 SOD 和谷胱甘肽过氧化物酶水平，从而保护大鼠心脏免受 MI/R 引起的心衰。TMZ 还减轻了心肌梗死面积和细胞凋亡。此外，TMZ 通过降低 LC3-II、Beclin1、ATG5 和 ATG7 的蛋白和信使 RNA 水平以及自噬体数量，并通过涉及 AKT/mTOR 途径，显著抑制 MI/R 诱导的自噬。此外，在体外实验中，用 TMZ（40μM）孵育 H9c2 细胞，以探讨 TMZ 在暴露于缺氧和再氧合（H/R）后对细胞的直接影响。TMZ 增加细胞活力和细胞内 SOD 浓度，抑制 H/R 诱导的细胞凋亡和 ROS 产生。此外，TMZ 减少自噬体和自噬相关蛋白的表达；它还上调了 p-AKT 和 p-mTOR 的表达。此外，TMZ 增加了 Bcl-2 蛋白的表达，减少了 Bax 蛋白的表达、Bax/Bcl-2 比率和 cleaved caspase-3 水平。然而，这些对 H9c2 细胞的影响被 PI3K 抑制剂 LY294002 显著消除。
我们的结果表明，TMZ 抑制 I/R 诱导的过度自噬和细胞凋亡，至少部分通过激活 AKT/mTOR 途径介导。
