经胸廓内动脉置泵对急性心肌缺血犬t-PA和PAI的影响

Changes in tissue plasminogen activator and plasminogen activator inhibitor during administration of nitroglycerine into internal thoracic artery in dogs with acute myocardial ischemia

目的 通过建立经胸廓内动脉置泵治疗犬急性心肌缺血的动物模型 ,观察介入组和对照组组织型纤溶酶原激活物及其抑制物 ( t PA、PAI)的变化。方法 6 0条健康杂种犬 ,随机分为介入组和对照组 ,每组 30条。在静脉麻醉下开胸 ,结扎左冠状动脉前降支 ,建立急性心肌缺血动物模型。介入组分离胸廓内动脉后远端结扎 ,在近端置管 ,外接输液加压泵 ,通过胸廓内动脉加压滴注硝酸甘油 ;对照组通过外周静脉滴注硝酸甘油。于冠状动脉结扎前、结扎后 0 .5 h、以及给予硝酸甘油 2 h和 6 h后股静脉采血测定 t PA和 PAI。结果 在冠状动脉结扎后 0 .5 h两组 t PA均升高 ,对照组在 2 h和 6 h逐渐下降 ,而介入组无明显变化 ;两组在结扎后 6 h差异有统计学意义 ( P<0 .0 5 )。冠状动脉结扎后两组 PAI逐渐上升 ,对照组在结扎后 6 h最高 ,而介入组在结扎后 2 h最高 ;两组 PAI在结扎后 6 h差异有统计学意义 ( P<0 .0 5 )。结论 经胸廓内动脉置泵介入治疗犬急性心肌缺血可促进血管内皮释放 t PA、抑制 PAI分泌 。

Objective To study the changes in tissue plasminogen activator(tPA) and plasminogen activator inhibitor(PAI) in a model of acute myocardial infarction reproduced in the dog with administration of nitroglycerin into internal thoracic artery under pressure. Methods Sixty healthy crossbreed dogs were randomly divided into experimental and control group with 30 dogs in each group. The animal model of acute myocardial ischemia was reproduced by ligating the left anterior descending coronary artery. Internal thoracic artery in the experimental group was ligated, and a tube was introduced into the proximal end. Nitroglycerine was infused under pressure into the internal thoracic artery in experimental group. The drug was given intravenously in control group. tPA and PAI were measured before anterior coronary artery ligation and at 0 5, 2 and 6 hours after cononary artery ligation. Results The tPA levels in two groups were increased at 0 5 hour after coronary artery ligation, and gradually declined in control group, while no obvious change was found in experimental group. There was significant difference between experimental group and control group at 6 hours after coronary artery ligation( P <0 05). PAI levels were increased after coronary artery ligation, peaking at 6 and 2 hours after coronary artery ligation in both groups. Significant difference in PAI level was observed between two groups at 6 hours after coronary artery ligation( P <0 05). Conclusion Introduction of nitroglycerine through internal thoracic artery under pressure is effective to accelerate release of tPA from the endothelium while inhibit secretion of PAI, therefore it is useful to modulate the balance of fibrinolysis.