【作者】 张毅；

【导师】 叶章群； 潘铁成；

【作者基本信息】 华中科技大学 ， 外科学， 2010， 博士

【摘要】 目的：冠状动脉粥样硬化性心脏病(coronary heart disease, CAD),简称冠心病,是严重威胁人类健康,常导致患者猝死的常见疾病,随着冠状动脉搭桥术(coronary artery bypass graft, CABG)、溶栓疗法、体外循环、心脏移植、药物洗脱支架(drug eluting stent,DES)及经皮冠状动脉成形术(percutaneous transcoronary angioplasty, PTCA)的广泛开展,急性心肌梗死的死亡率和预后有了明显的改善,然而冠心病发作和治疗中因为缺血再灌注(Ischemia/Reperfusion, I/R)造成的心肌损伤使严重影响了冠脉血运重建后即时的生存率和远期心功能的恢复。落新妇苷(Astilbin)是从土茯苓的乙醇提取液中分离得到的3个二氢黄酮醇甙之具有抗炎症、抗氧化功能。我院心胸外科高思海教授2003年使用从赤土茯苓提取落新妇苷首次在离体心脏模型发现其对心肌缺血再灌注损伤有抑制作用。本研究以此为基础,进一步从细胞、器官和整体水平全面研究落新妇苷对冠心病心肌缺血再灌注损伤的保护作用机制。方法：以Balb/c小鼠为研究对象,将小鼠随机分成4组：非缺血正常对照组(Control group,C组)、缺血再灌注阳性对照组(Ischemia reperfusion group,I组)、落新妇苷低剂量治疗组(Low dosage Astilbin treatment group, L组)和落新妇苷高剂量治疗组(High dosage Astilbin treatment group, H组),分别取其乳鼠培养心肌细胞、小鼠心脏体外灌流和小鼠冠状动脉左前降支主干(LAD)结扎心肌梗塞模型,按标准心肌缺血再灌注进行处理,分别检测心肌细胞病理改变、氧化应激水平：ROS、MDA、SOD;炎症反应：NF-κB转录活性(EMSA)、TNF-α、IL-6的mRNA和蛋白水平；心肌细胞凋亡(TUNEL)。结果：缺血再灌注处理后出现典型心肌细胞损伤病理改变、氧化应激、炎症反应和心肌细胞凋亡。落新妇苷治疗组上述改变均有减轻及改善,有剂量依赖关系。结论：落新妇苷能够有效减轻心肌缺血再灌注损伤,其保护作用可能与抑制心肌缺血再灌注后氧化应激、减少炎症细胞因子分泌,从而减少心肌细胞凋亡有关。说明落新妇苷有抗氧化、抗炎症作用。更多还原

【Abstract】 Backgroud:Coronary heart disease become the first killer for adult. Myocardial ischemia and acute infarction arise secondary to atherosclerosis, followed by plaque rupture and thrombosis. Current treatments aim to terminate ischemiaby re-establishing blood flow as soon as possible. However, reperfusion may cause new damage, reperfusion injury, Several mechanisms have been proposed, such as rapid entry of sodium ions and water into myocardial cells producing intracellular edema during ischemia. Rapid entry of calcium ions produces the contraction bands and mitochondrial granules. Loss of vascular integrity results in hemorrhage into the infarct. Finally, the production of reactive oxygen species (ROS) is responsible for the peroxidation of membrane lipids and disruption of membrane integrity. Further, ischemia and reperfusion may alter the myocardial redox status and therefore the ability to detoxify ROS. Also, ROS can stimulate inflammation system,active NF-κB and produce pro inflammation cytokines such as IL-2、IL-6、TNF-α、INF-y, which can contribute to the server reperfusion damage.The drug which suppress ROS and inflammation is hopfully to prevent ischemia-reperfusion injury.OBJECTIVE:To investigate the protective effects of astilbin on heart ischemia-reperfusion (IR) injury in mice.from-3 levels:in vitro myocardial cell culture、ex vivo langendorff heart perfusion、in vivo LAD ligation in mice.METHODS:C57BL/6 mice were randomly allocated into 4 groups:no ischemia control group, C; Ischemia reperfusion group, I; Low dosage Astilbin treatment group,L; High dosage Astilbin treatment group, H。After ischemia reperfusion, the myocardial cells or heart from each group were studied. histological changes of the cardiac tissues were detected to evaluate injury. the level of ROS、MDA、SOD of the sample were measured by kit, TNF-a measured by RT-PCR and immunohistochemistry,NF-κB measured by EMSA.serum IL-6 level measued by ELISA, cardiac myocyte apoptosis tested by TUNELRESULTS:Compared with the untreated ischemia group, activities of SOD were diminished and ROS、MDA level increased obviously in IR group, whereas pretreatment with Astilbin significantly blunted the decrease of SOD activity, less ROS production and lower MDA level. and similar results were also found in histological examination. The NF-κB activity、expression of TNF-a mRNA and protein of cardial tissues in the astilbin group were lower than those in the untreated ischemia reperfusion group. The serum contents of IL-6 were decreased in the astilbin group as compared with the untreated ischemia reperfusion group (P<0.01).CONCLUSION:It has been well known that oxidative stress and inflammation are two major mechanismsinvolved in the development of CAD ischemia reperfusion injury, Oxidative stress is represented as increased activity of oxidant enzymes and/or reduced activity of antioxidant enzymes. ROS produced by oxidant enzymes participates in the progression of myocardial ischemia reperfusion damage in two ways:one is the direct oxidation to the membrane、mitochondria、enzyme of cardiac myocytes; the other is as an intracellular second messenger to induce expression of pro inflammation cytokines(IL-6、TNF-α), which lead to Caspase cascade and cardiac myocytes apoptosis. Astilbin can ameliorate cardiac myocytes ischemia reperfusion injury by 2 ways:1 eliminate ROS、MDA and recover SOD, rebalance the redox state; 2 inhibiting the production of pro inflammation cytokines IL-6 and TNF-a, prohibite the activity of NF-KB. Astilbin is a safe and effective medicine for anti-ischemia reperfusion injury.更多还原