黄芩苷对冠心病大鼠缺血再灌注损伤的治疗作用及机制

Therapeutic effect and mechanism of baicalin on ischemia-reperfusion injury in rats with coronary heart disease

目的观察黄芩苷对冠心病大鼠缺血再灌注损伤的治疗作用,并探讨其作用机制。方法 25只SD大鼠随机分为对照组、模型组及10、25、50 mg/kg黄芩苷组各5只。除对照组外其他各组建立大鼠冠心病模型。10、25、50 mg/kg黄芩苷组分别给予10、25、50 mg/kg黄芩苷灌胃,模型组、对照组给予等量蒸馏水灌胃,均1次/d,连续2周。除对照组外其他各组均腹腔内注射垂体后叶素30 U/kg建立冠心病心肌缺血模型。制备大鼠血清样本,用心电图检测各组心功能指标,用生物信号处理系统记录左室收缩压、左室舒张压、最大收缩期内的压力变化速率(+dp/dtmax)和最大舒张末期的压力变化速率(-dp/dtmax);用硝基四氮唑蓝染色法测算大鼠心肌梗死面积百分比;用缺口末端标记法测算大鼠心肌细胞凋亡率;用Western blotting法检测大鼠心肌组织中分子伴侣蛋白葡萄糖调节蛋白78(GRP78)、感受器蛋白肌醇酶1(IRE1)、蛋白激酶R样内质网激酶(PERK)及活化转录因子6(ATF6)蛋白表达;用qRT-PCR法检测大鼠血清中GRP78、IREI、PERK、ATF6 mRNA表达。结果与对照组比较,模型组缺血30 min的波形变化、缺血再灌注120 min T波变化和左室舒张压、梗死面积百分比和心肌细胞凋亡率高(P均<0. 05),左室收缩压、+dp/dtmax和-dp/dtmax低(P均<0. 05),心肌组织或血清中GRP78、IREI、PERK和ATF6蛋白或mRNA表达高(P均<0. 05)。与模型组比较,10、25、50 mg/kg黄芩苷组缺血30 min的波形变化、缺血再灌注120 min T波变化和左室舒张末压、梗死面积百分比和心肌细胞凋亡率低(P均<0. 05),左室收缩压、+dp/dtmax、-dp/dtmax高(P均<0. 05),心肌组织或血清中GRP78、IREI、PERK和ATF6蛋白或mRNA表达低(P均<0. 05),且以上指标变化呈剂量依赖性。结论黄芩苷可改善冠心病大鼠缺血再灌注损伤后心功能,抑制心肌细胞凋亡;该作用可能与其降低内质网应激因子GRP78、IREI、PERK、ATF6的表达有关。

Objective To investigate the therapeutic effect of baicalin on ischemia-reperfusion injury in rats with coronary heart disease and to explore its mechanism.Methods Twenty-five male Sprague-Dawley rats aged 1 month and(200±50)g were randomly divided into 5 groups(n=5):control group,model group,10 mg/kg baicalin group,25 mg/kg baicalin group,and 50 mg/kg baicalin group.Coronary heart disease rat models were established in all groups except the control group.The 10,25,and 50 mg/kg baicalin groups were given 10,25,and 50 mg/kg baicalin,and the model group and the control group were given the same amount of distilled water for 2 weeks.Two weeks later,rat serum samples were prepared,and the cardiac function indexes of each group were detected by electrocardiogram.The carotid arterial intubation method and biosignal processing system were used to record the left ventricular systolic pressure,left ventricular end-diastolic pressure,+dp/dtmax,and-dp/dtmax in each group.The percentage of myocardial infarct size was measured by nitrotetrazolium blue staining after the rat myocardial tissue was obtained.The apoptosis rate of rat myocardial cells was measured by nick end labeling method.Western blotting and qRT-PCR were used to detect the expression of GRP78,IREI,PERK and ATF6 in myocardium and serum of 5 groups,respectively.Results Compared with the control group,the relative protein and mRNA expression of GRP78,IREI,PERK and ATF6,the waveform change after ischemia of 30 minutes,T wave change after ischemia-reperfusion of 120 minutes,the left ventricular end diastolic pressure,infarct size and cardiomyocyte apoptosis rate significantly increased,and the left ventricular systolic pressure,+dp/dtmax and-dp/dtmax significantly decreased in the myocardial tissues and serum of the model group(all P<0.05).Compared with the model group,the relative protein and mRNA expression levels of GRP78,IREI,PERK,and ATF6,the waveform change after ischemia of 30 minutes,T wave change after ischemia-reperfusion of 120 minutes,the left ventricular end diastolic pressure,infarct size and cardiomyocyte apoptosis rate significantly decreased,but the left ventricular systolic pressure,+dp/dtmax and-dp/dtmax significantly increased,and the left ventricular systolic pressure,+dp/dtmax and-dp/dtmax significantly decreased in the 10 mg/kg,25 mg/kg and 50 mg/kg baicalin groups(all P<0.05).In addition,the change of the above indicators was in a dose-dependent manner(all P<0.05).Conclusion Baicalin can improve the cardiac function and inhibit cardiomyocyte apoptosis after ischemia-reperfusion injury in rats with coronary heart disease,and this effect may be related to the decrease of endoplasmic reticulum stress factors GRP78,IIRE,PERK and ATF6.