阿托伐他汀对大鼠心肌缺血再灌注后无复流的影响

The effects of atorvastatin on myocardial no-reflow after ischemia/reperfusion in rats

目的观察阿托伐他汀对大鼠心肌缺血再灌注后无复流的影响,探讨其可能机制。方法 56只雄性SD大鼠随机分为4组:(1)假手术组,左前降支冠脉(LAD)穿线不结扎180 min;(2)缺血再灌注组,结扎LAD60 min后再灌注120 min;(3)阿托伐他汀组,结扎LAD前给予阿托伐他汀20 mg/(kg.d)灌胃3 d;(4)阿托伐他汀+L-硝基精氨酸(L-NNA)组,L-NNA 15 mg/kg结扎LAD前15 min尾静脉注入,阿托伐他汀处理同上,后两组缺血再灌注处理同缺血再灌注组。实验结束后测血清CK-MB及心肌一氧化氮(NO)水平;心肌染色法区分缺血区、无复流区及梗死区;免疫组化法检测心肌及血管中eNOS、iNOS含量;电镜下观察微血管及心肌线粒体等超微结构改变。结果与假手术组比较,缺血再灌注组心肌及血管iNOS表达增加,eNOS表达无变化,心肌NO水平下降,微血管及心肌线粒体损伤明显;与缺血再灌注组比较,阿托伐他汀能抑制iNOS表达,诱导eNOS表达,增加NO水平,减轻微血管及心肌线粒体损伤,减少心肌梗死及无复流。一氧化氮合酶抑制剂L-NNA可阻断阿托伐他汀上述作用。结论阿托伐他汀通过eNOS/iNOS—NO途径,激活线粒体ATP敏感钾通道和减轻微血管损伤,减少心肌梗死及无复流。

Objective To evaluate the effects of atorvastatin on myocardial no-reflow after ischemia/reperfusion in rats,and to investigate the possible mechanisms.Methods Fifty-six male SD rats were randomly assigned to four groups： shame group,ischemia and reperfusion group,atorvastatin group and atorvastatin＋L-NNA group.Pretreatment of gastric lavage with atorvastatin [20 mg/（kg·d）] were given to subjects in atorvastatin group for 3 days.L-NNA（15 mg/kg） intravenous administration 15 minutes before ischemia plus atorvastatin pretreatment was given to subjects in atorvastatin＋L-NNA group.All rats,except for those in shame group,received occlusion of left anterior descending artery（LAD） for 60 minutes followed by 120 minutes of reperfusion.Serum CK-MB and myocardial NO were detected after experiment.Different myocardium regions of ischemia,no-reflow and infarction were recognized and assessed according to Evans blue dye,thioflavin S fluorescent dye and triphenyltetrazolium chloride（TTC） staining techniques,respectively.Electronic microscope was applied to observe ultramicrostructures of capillary endothelial cells and myocardial mitochondria.Results Atorvastatin significantly elevated the myocardial NO,reduced CK-MB activity,relieved the microcirculation and myocardial mitochondrial injury,and reduced the no-reflow and necrosis areas（P0.05）.However,these effects were reversed by L-NNA.Conclusion Atorvastatin can reduce the area of myocardial no-reflow after ischemia-reperfusion.This beneficial effect is dependant on NO by up-regulating eNOS expression,which activates mitochondrial K-ATP channel and reduces microvascular injury.