Melatonin ameliorates myocardial injury by reducing apoptosis and autophagy of cardiomyocytes in a rat cardiopulmonary bypass model.
Melatonin ameliorates myocardial injury by reducing apoptosis and autophagy of cardiomyocytes in a rat cardiopulmonary bypass model.
复制标题
褪黑素通过减少大鼠体外循环模型中心肌细胞的凋亡和自噬来改善心肌损伤
作者：
Huang X;Hou J;Huang S;Feng K;Yue Y;Li H;Huang S;Liang M;Chen G;Wu Z
心肌损伤是体外循环心脏手术后常见的并发症。本研究的目的是在大鼠体外循环模型中验证褪黑素可以减轻心肌损伤的假设。方法雄性SD大鼠18只，随机分为假手术组（SO组）、体外循环组（CPB组）和褪黑素组（MT组），每组6只。SO组大鼠在不进行CPB的情况下进行插管，CPB组大鼠在CPB前每天腹腔注射等体积的溶剂，持续7天，褪黑素组大鼠在CPB前每天腹腔注射20 mg/kg的褪黑素溶液，持续7天。CPB 120 min后检测血浆白细胞介素（IL）-6、IL-1β、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、丙二醛（MDA）、肌酸激酶（CK）-MB和心肌肌钙蛋白T（cTnT）的表达水平。用二氢乙锭（DHE）法检测活性氧（ROS）。TUNEL法检测细胞凋亡。电镜观察线粒体损伤和自噬体。免疫荧光法检测细胞凋亡诱导因子（AIF）。Western blotting检测B细胞淋巴瘤/白血病2相关X（Bax）、B细胞淋巴瘤/白血病2（Bcl-2）、细胞色素C（Cyto-C）、切割型半胱天冬酶9（cleaved caspase-9）、AKT、p-AKT、信号转导和转录激活因子3（STAT 3）、p-STAT 3、LC 3、P62、雷帕霉素激酶的机制靶点（mTOR）、p-mTOR和甘油醛-3-磷酸脱氢酶（GAPDH）的表达。结果褪黑素能显著降低CPB后IL-1β、IL-6、MDA、CK-MB、cTnT水平，升高SOD、GSH-Px水平，并能改变CPB后上述指标。褪黑素可降低体外循环诱导的心肌细胞超氧化物歧化酶产生、凋亡指数和自噬。体外循环期间褪黑素激活AKT、STAT 3和mTOR信号通路。结论褪黑素可能通过抑制氧化损伤、细胞凋亡和细胞自噬而发挥心脏保护作用。AKT、STAT 3和mTOR信号通路参与了这一过程。
Background Myocardial injury is a frequent complication after cardiac surgery with cardiopulmonary bypass (CPB). This study aimed to test the hypothesis that melatonin could attenuate myocardial injury in a rat CPB model. Methods Eighteen male Sprague-Dawley rats were randomly divided into three groups, n = 6 for each group: the sham operation (SO) group, CPB group and melatonin group. Rats in the SO group underwent cannulation without CPB, rats in CPB group intraperitoneal injected an equal volume of vehicle daily for 7 days before being subjected to CPB and rats in melatonin group intraperitoneal injected 20 mg/kg of melatonin solution daily for 7 days before being subjected to CPB. After 120 min for CPB, the expression levels of plasma interleukin (IL) -6, IL-1β, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), creatine kinase (CK) -MB and cardiac troponin T (cTnT) were measured. Reactive oxygen species (ROS) were detected by dihydroethidium (DHE). Apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. Mitochondrial damage and autophagosomes were detected by electron microscopy. Apoptosis inducing factor (AIF) was detected by immunofluorescence. The expression of B cell lymphoma/leukemia2 associated X (Bax), B cell lymphoma/leukemia 2 (Bcl-2), cytochrome C (Cyto-C), cleaved caspase-9, AKT, p-AKT, signal transducer and activator of transcription 3 (STAT3), p-STAT3, LC3, P62, mechanistic target of rapamycin kinase (mTOR), p-mTOR and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were determined using western blotting. Results Melatonin significantly decreased the levels of IL-1β, IL-6, MDA, CK-MB and cTnT and increased the levels of SOD and GSH-Px, all of which were altered by CPB. Melatonin reduced cardiomyocyte superoxide production, the apoptosis index and autophagy in cardiomyocytes induced by CPB. The AKT, STAT3 and mTOR signaling pathways were activated by melatonin during CPB. Conclusion Melatonin may serve as a cardioprotective factor in CPB by inhibiting oxidative damage, apoptosis and autophagy. The AKT, STAT3 and mTOR signaling pathways were involved in this process.