糖尿病、氧化应激与AS教材分析.ppt

* * * 体内自由基的产生和清除应是平衡的，人体才能保持健康。正常情况下，自由基反应对于机体防御机制是必要的，自由基的产生与清除保持平衡。但在某些病理情况下，如果自由基产生过多或清除自由基的抗氧化防御系统能力下降，体内就会有多余的自由基（特别是氧自由基），会损伤细胞成分，导致疾病和衰老的发生。 氧化应激是指机体在遭受各种有害刺激时．机体或细胞内自由基的产生和抗氧化防御之间严重失衡，或外源性氧化物质的过量摄入，导致活性氧在机体或细胞内蓄积而引起的细胞毒性，从而导致组织损伤过程。 * * * * angina * Matrix metabolism and integrity of the plaques fibrous cap This slide depicts the current understanding of the dynamics of the plaques stability and thrombogenicity. The inflammatory cells can send molecular messages to the smooth muscle cells (interferon-g) that inhibit the ability of this cell type to synthesize new collagen to strengthen the plaques fibrous cap. In addition, the inflammatory cells can release proteolytic enzymes capable of degrading collagen and other structurally important constituents of the plaques fibrous cap. Thus, when there is inflammation in the intima, the collagen responsible for the integrity of the plaques fibrous cap is under double attack, subject to both decreased synthesis and increased degradation. This sets the stage for plaque disruption. The inflammatory cells also are responsible for signaling and producing increased quantities of tissue factor, a potent procoagulant deemed responsible for thrombosis of ruptured plaques. ? Reference: Libby P. Molecular bases of the acute coronary syndromes. Circulation 1995;91:2844-2850. ? * * * * * * MMPs的水平和活性主要受四个因素的调控：ox-LDL, ROS, TNF-α以及IL-1。而研究表明TNF-α和IL-1的表达和释放都可以受ox-LDL的影响。 * * 将人冠状动脉内皮细胞分别与浓度分别为10，20，40和80 ug/ml的ox-LDL共同孵育24小时。凝胶电泳法及western法检测MMP1和MMP3蛋白表达的变化。 结果表明，ox-LDL诱导人冠状动脉内皮细胞MMPs的表达，且呈剂量依赖性。 * * 基质金属蛋白酶的水平对于不稳定心绞痛的诊断及预后预测具有重要的临床意义。 采用酶联免疫吸附试验（ELISA法）测定不稳定心绞痛患者及正常对照者血清MMP-9水平，结果发现不稳定心绞痛组患者入院时MMP-9水平明显高于健康对照组，待病情稳定后，其MMP-9水平较入院时明显降低。 研究表明，MMP-9水平对不稳定心绞痛的诊断及预后预测具有一定的参考价值。 * Pleiotropic atheroprotective vascular effects of nitric oxide (NO). NO not only is a potent vasodilator, but it also inhibits the interaction between platelets and the endothelium, it inhibits leukocyte adhesion, smooth muscle cell proliferation, an