目的 探讨原儿茶酸（PCA）对心肌缺血再灌注损伤（MIRI）大鼠及缺氧/复氧H9c2细胞的影响及作用机制。方法 将心肌细胞H9c2分为对照组、模型组和PCA（1.562、3.125、6.250 μmol·L^-1）组，预给药24 h后，除对照组外厌氧箱缺氧4 h、复氧12 h在体外构建H9c2细胞损伤模型； CCK8法检测细胞存活率； JC-1染色检测细胞内线粒体膜电位； DCFHDA荧光探针检测细胞中活性氧（ROS）； Calcein AM荧光探针检测线粒体通透性转换孔（mPTP）开放程度；试剂盒法检测腺嘌呤核苷三磷酸（ATP）水平； FerroOrange荧光探针检测Fe²⁺水平检测。SD大鼠随机分为假手术组、单给PCA（100 mg·kg^-1）组、模型组、阿司匹林（100 mg·kg^-1）组和PCA低、中、高剂量（25、50、100 mg·kg^-1）组，假手术组和模型组ig给予0.5%羟甲基纤维素钠溶液，其余组ig给药，每天1次，连续2周，末次给药24 h后，除假手术组和单给PCA组外，采用冠状动脉左前降支结扎手术结扎30 min制备MIRI大鼠模型；通过2，3，5-氯化三苯基四氮唑（TTC）染色分析心肌梗死面积；苏木精-伊红（HE）染色分析各组心肌组织结构变化；心脏超声评估射血分数（EF）和左室短轴缩短率（FS）；通过ELISA法检测血清肌酸激酶同工酶（CK-MB）、乳酸脱氢酶（LDH）、天冬氨酸氨基转移酶（AST）、丙二醛（MDA）和谷胱甘肽（GSH）水平； Western blotting检测心脏组织中谷胱甘肽过氧化物酶4 （GPX4）和溶质载体家族7成员11 （SLC7A11）蛋白表达情况。结果 细胞实验结果表明，与模型组比较，PCA显著升高H9c2细胞存活率（P＜0.01），升高线粒体膜电位（P＜0.01），抑制异常mPTP开放和ROS的大量产生（P＜0.01），改善线粒体ATP合成受损（P＜0.01）；明显降低细胞内Fe²⁺水平；动物实验结果表明，与模型组比较，PCA组心肌梗死率显著降低（P＜0.01），心肌组织结构得到改善，EF和FS显著升高（P＜0.01），心肌损伤标志物CK-MB、LDH、AST、MDA水平显著降低（P＜0.01），GSH水平和GPX4、SLC7A11蛋白表达水平显著升高（P＜0.01）。结论 PCA可以改善MIRI，减轻心肌组织病理损伤，调节体内铁死亡，可能与升高GPX4、SLC7A11表达有关。

Objective To explore the effects and mechanisms of protocatechuic acid (PCA) on myocardial ischemia-reperfusion injury (MIRI) in rats and hypoxia/reoxygenation H9c2 cells. Methods H9c2 cells were divided into the control group, model group, and PCA (1.562, 3.125, and 6.250 μmol·L^-1) groups. After 24 h of pretreatment, except for the control group, the cells were subjected to 4 h of hypoxia and 12 h of reoxygenation in an anaerobic chamber to establish the H9c2 cell injury model in vitro. Cell viability was detected by CCK-8 assay; mitochondrial membrane potential was detected by JC-1 staining; Reactive oxygen species (ROS) in cells were detected by DCFH-DA fluorescence probe; The opening degree of mitochondrial permeability transition pore (mPTP) was detected by Calcein AM fluorescence probe; Adenine nucleoside triphosphate (ATP) levels were detected by kit method; Fe²⁺ levels were detected by FerroOrange fluorescence probe. SD rats were randomly divided into sham operation group, single PCA (100 mg·kg^-1) group, model group, aspirin (100 mg·kg^-1) group, and PCA low, medium, and high dose (25, 50, 100 mg·kg^-1) groups. The sham operation group and model control group were ig administered 0.5% sodium carboxymethyl cellulose solution, and the other groups were ig administered drugs once a day for two weeks. 24 h after the last administration, except for the sham operation group, the MIRI rat model was established by ligating the left anterior descending coronary artery for 30 min. Myocardial infarction area was analyzed by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining; Myocardial tissue structure changes were analyzed by hematoxylin-eosin (HE) staining; Left ventricular ejection fraction (EF) and fractional shortening (FS) were evaluated by cardiac ultrasound; Serum creatine kinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), malondialdehyde (MDA), and glutathione (GSH) levels were detected by ELISA; The expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) proteins in cardiac tissue was detected by Western blotting. Results The cell experiment results showed that compared with the model group, PCA significantly increased the survival rate of H9c2 cells (P<0.01), increased mitochondrial membrane potential (P<0.01), inhibited abnormal mPTP opening and excessive ROS production (P<0.01), improved mitochondrial ATP synthesis impairment (P<0.01), and significantly reduced intracellular Fe²⁺ levels. The animal experiment results showed that compared with the model group, the myocardial infarction rate in the PCA group was significantly reduced (P<0.01), myocardial tissue structure was improved, EF and FS were significantly increased (P<0.01), myocardial injury markers CK-MB, LDH, AST, and MDA levels were significantly decreased (P<0.01), and GSH levels and GPX4 and SLC7A11 protein expression levels were significantly increased (P<0.01). Conclusion PCA ameliorates myocardial reperfusion injury, attenuates myocardial histopathological damage, and regulates iron death in vivo, which may be related to the inhibition of GPX4 and SLC7A11 expression.

R285.5

中国医学科学院医学与健康科技创新工程项目（2021-I2M-1-071）