紫杉醇预防心肌细胞线粒体缺血再灌注损伤的机制研究

Study on mechanism of taxol preventing from mitochondrial damage during myocardial ischemia/reperfusion

目的探讨紫杉醇能否预防心肌细胞线粒体缺血再灌注损伤,并对其机制进行初步探讨。方法将离体大鼠心脏分为对照组、缺血组、缺血+0.1μmol/L紫杉醇组、缺血+0.3μmol/L紫杉醇组和缺血+1μmol/L紫杉醇组(n=15)。每组先给予15 min平衡后,对照组继续给予150 min常氧灌注;缺血组给予30 min缺血处理(Langendorff灌流,结扎左前降支30 min)+120 min常氧再灌注;缺血+0.1μmol/L(或0.3μmol/L、1μmol/L)紫杉醇组给予30 min缺血处理+120 min常氧再灌注,整个过程中均给予0.1μmol/L(或0.3μmol/L、1μmol/L)紫杉醇灌流。灌流结束后,左心室心肌进行冰冻切片。采用免疫组织化学方法观察微管;DCFH-DA试剂盒用来检测活性氧物种的数量,同时通过荧光光度计和分光光度计检测氧化酶活性。结果 10.1μmol/L紫杉醇灌流能明显降低微管断裂评分。20.1μmol/L,0.3μmol/L和1μmol/L紫杉醇减少氧自由基水平分别为33%、46%和51%(P<0.05)。30.3μmol/L和1μmol/L紫杉醇增加线粒体电子传递链复合体Ⅰ的活性,而0.1μmol/L,0.3μmol/L和1μmol/L紫杉醇均增加线粒体电子传递链复合物Ⅲ的活性。结论紫杉醇能预防心肌细胞线粒体缺血再灌注损伤。减少氧自由基生成、增加线粒体电子传递链复合体Ⅰ、Ⅲ的活性或许是其作用机制之一。

Objective To study the role of taxol in preventing mitochondrial damage during myocardial ischemia / reperfusion and its underlying mechanism. Methods The ischemic ventricular arrhythmia model was established and divided into five groups（ 15 in each group） ： control group,ischemic group,ischemic ＋ taxol（0.1μmol/L） group,ischemic ＋ taxol （0.3 μmol/L） group and ischemic ＋ taxol（ 1 μmol/L） group. After a 15-min equilibration period,the hearts were treated as follows： in the control group, 150 min normoxic superfusion;in ischemia group,30 min ischemia, 120 min normoxic superfusion ; in Taxol group,30 min ischemia, 120 min normoxic superfusion, with Taxol at a concentration of 0.1 （0.3 and 1 μmol/L,respectively） throughout the entire 150-min superfusion period. After the perfusion,left ventricular muscle was taken to make frozen sections. The microtubules were observed by immunohistochemical methods. The quantity of reactive oxygen species were detected by DCFH-DA Kits. The oxidase activity was tested by fluorescence photometer and spectro- photometer. Results ①Taxol（0.1 μmol/L） significantly reduced the infarct size as compared with control（P 〈 0.05 ）. 0.1,0.3 and 1 μmol/L Taxol reduced the level of ROS by 33% ,46% and 51%, respectively （P 〈 0.05 ）. ②0.3 and 1 μmol/L Taxol increased the activity of mitochondrial electron transport ehain complex I,whereas 0.1,0.3 and 1 μmol/L Taxol increased that of mitochondrial electron transport chain complex Ⅲ. Conclusion Taxol can prevent the mitochondrial damage during myocardial ischemia/reperfusion. The reduction of ROS production and the increase of the activity of mitochondrial electron transport chain complex Ⅰ and Ⅲ may be one of its mechanisms.