灯盏花素联合预适应对兔心肌缺血再灌注细胞凋亡的影响

Effect of Unified Breviscapine and Ischemic Preconditioning on Myocardial Cell Apoptosis during Myocardial Ischemia/Reperfusion in Rabbits

目的研究不同剂量灯盏花素联合缺血预适应对心肌缺血再灌注细胞凋亡的影响及其相关凋亡基因Bcl-2、Bax的表达。方法采用在体兔心肌缺血再灌注损伤模型,将48只新西兰大白兔随机分为4组。①假手术组(Sham组):左旋支结扎处只串线不结扎;②IR组:左旋支阻断40min,再灌注180min;③IP组:左旋支阻断5min,继灌注5min,再循环2次后,左旋支阻断40min,再灌注180min;④BI组:经左颈外静脉注入灯盏花素5mg·kg-1,10min后同IP组。每组12只,其中每组6只测定心肌梗死面积,取梗死危险区心肌进行免疫组化染色计算Bcl-2、Bax基因蛋白表达率。另6只取梗死危险区心肌组织利用AnnexinV-FITC/PI试剂盒行细胞流式术检测心肌早期细胞凋亡率和坏死细胞凋亡率。结果与IR组比较,IP、BI各组能够明显缩小缺血再灌注的心肌梗死面积(P<0.01);BI组较IP组疗效显著(P<0.01)。与IR组比较,IP组和BI组均能显著减少缺血再灌注引起的细胞凋亡和坏死细胞数(P<0.05);BI组较IP组能进一步明显减少早期细胞凋亡数和坏死细胞数(P<0.05)。与IR组比较,IP组、BI组Bcl-2蛋白表达增加(P<0.01)、Bax蛋白表达显著减少(P<0.01),BI组较IP组Bax蛋白表达减少明显(P<0.05)。结论灯盏花素联合预适应较单纯预适应能进一步加强对缺血再灌注损伤心肌的保护作用,其通过增加细胞内Bcl-2蛋白表达、抑制Bax蛋白表达,使Bcl-2/Bax比值增高从而抑制细胞凋亡。

Objective To explore the effects of breviscapine with ischemic preconditioning on myocardial apoptosis in the rabbit model of myocardial ischemia/reperfusion and the expression of Bcl-2 and Bax genes. Methods Myocardial ischemia/reperfusion model in rabbits were made and 48 New Zealand White rabbits were randomly divided into four groups. （1）Group Sham （n = 12） ： all rabbits were anesthetized and left circumflex coronary arteries were not obstructed. （1）Group IR （ischemia/reperfusion group, n = 12）; rabbits underwent 40 min of occlusion of the left circumflex coronary artery, and 180 min of reperfusion. （3）Group IP （ischemic preconditioning group, n = 12） ： rabbits underwent three cycles of 5 min of occlusion and reperfusion, followed by 40 min of occlusion and 180 min of reperfusion. （4）Group Bh rabbits received 5 mg＇KgI of Breviscapine for 10 min followed by experiment in Group IP. Area of myocardial infarct （AI） and ischemic risk zone （AR） were determined by computer morphometry. The expression of Bcl 2 and Bax protein were deter- mined by immunohistochemistry in half rabbits of each group. Rates of early apoptotic myocytes and infarct myocytes were detected by flow cytometry in remained rabbits. Results The myocardial infarct size （IS%） decreased significantly in Group IP and BI compared with Group IR （P〈0.01） ; IS% decreased significantly in Group B1 compared with Group IP （P〈0. 01 ）. The percentage of early apoptotic and necrosis myocytes reduced in Group IP and Group BI compared with Group IR （P〈0. 05）. The percentages of necrosis myocytes and apoptotic myocytes decreased in Group BI compared with Group IP （P〈0. 05）. The expression of Bcl-2 increased significantly and the expression of Bax decreased significantly in Group IP and BI （P〈0. 01） compared with Group IR. The expression of Bax decreased significantly in Group BI corn pared with Group IP （P〈0. 05）. Conclusion Combined breviscapine with ischemic preconditioning can strengthen the protect effect on myocardial ischemia-reperfusion injury, by modulating the expression of Bcl-2 and Bax genes and increas- ing Bcl-2/Bax to inhibit cell apoptosis.