异甜菊醇抗麻醉大鼠心肌缺血复灌损伤的作用机制

目的研究双萜类化合物异甜菊醇抗心肌缺血复灌损伤作用与线粒体ATP敏感性钾通道(m itoKATP)开放的关系。方法用经典的大鼠冠状动脉结扎30 m in,再通90 m in,形成心肌缺血复灌模型。造模前iv异甜菊醇1.0 m.gkg-1和/或选择性m itoKATP关闭剂5-羟基癸酸(5-HD)10 m.gkg-1预处理,以血流动力学、心肌梗死面积、血清乳酸脱氢酶和肌酸激酶的活性、心肌丙二醛含量、SOD、GSH-PX活性和心肌组织病理学检查,评价异甜菊醇抗心肌缺血复灌损伤的作用与m itoKATP的关系。结果异甜菊醇具有改善大鼠缺血复灌引起的心功能和组织损伤,降低心肌活性氧含量,但此作用可被预先给予的5-HD减弱。结论异甜菊醇抗心肌缺血复灌损伤的作用可能与m itoKATP的开放和活性氧减少有关。

The mechanism of the cardioprotective effect of isostevioside in anesthetized rats

OBJECTIVE To study on the relationship between the cardioprotective effect of isostevioside(ST-1) and mitochondrial ATP-sensitive potassium channels(mitoKATP) in vivo.METHODS The hemodynamics changes were determined during ischemia-reperfusion.The measures of myocardial area suffered from ischemia-reperfusion injury,activity of the serum LDH and CK,the SOD,GSH-PX activities and content of MDA of myocardium homogenate were determined at the end of the experiment.Myocardial structure was examined by microscope.RESULTS In 5-HD ST-1 group,the values of hemodynamics,the activities of SOD and GSH-PX were significantly less than those in ST-1 pretreated group.Myocardial infarct size,the activities of serum LDH and CK,the content of MDA in myocardium were higher than those in ST-1 pretreated group.The myocardial microstructures were worse than those in ST-1 pretreated group,but each index was better than those in IR group.CONCLUSION The result is suggested that the cardioprotective effect of ST-1 agaInst ischemia-reperfusion injury may be related to mitochondrial ATP-sensitive channels(mitoKATP) and reactive oxygen species.