黄芪甲苷诱导NO生成并激活PKCε对大鼠心肌缺血再灌注损伤的保护作用

Effect of astragaloside Ⅳ on myocardial ischemia-reperfusion injury in rats via NO production and PKCε promotion

目的:研究黄芪甲苷(AsⅣ)对大鼠心肌缺血再灌注损伤的保护作用,阐明其作用机制。方法:30只雄性Wistar大鼠随机分为假手术组、再灌注模型组、阳性药尼可地尔(10mg.kg-1)组、AsⅣ(5mg.kg-1)组及AsⅣ+氯化白屈莱赤碱(CHE)(3mg.kg-1)组,每组6只,结扎左冠状动脉前降支30min,松扎再灌注120min制备大鼠心肌缺血再灌注损伤模型,检测AsⅣ对其血清中LDH、MDA和SOD以及NO的影响,同时光镜下观察心肌细胞病理组织形态学变化,Western blotting法检测心肌细胞胞浆及胞膜PKCε蛋白表达。结果:AsⅣ组与模型组比较,LDH漏出量降低(P<0.05),MDA含量明显降低(P<0.01),SOD活力增强(P<0.01),NO含量增加(P<0.01)。HE染色组织形态学观察,与模型组比较,AsⅣ组心肌细胞形态有明显的改善,炎细胞浸润也有减轻。Western blotting法检测,AsⅣ组心肌细胞胞膜PKCε表达量高于模型组(P<0.05)。CHE减弱了ASⅣ的这种保护作用;与AsⅣ组比较,AsⅣ+CHE组LDH漏出量升高(P<0.05),MDA含量升高(P<0.01),SOD活力降低(P<0.01),PKCε胞膜表达量降低(P<0.05),心肌细胞水肿明显、胞质着色较浅。结论:AsⅣ通过诱导NO的生成对大鼠心肌缺血再灌注损伤产生保护作用,PKCε的激活可能是AsⅣ保护心肌细胞信号传导通路的组成部分。

Objective To study the effect of astragaloside Ⅳ（AsⅣ） on myocardial ischemia-reperfuion injury in rats and clarify its mechanism.Methods The models of myocardial ischemia-reperfusion injury in rats were established.30 male Wistar rats were divided into sham-operation group,ischemia-reperfusion model group,positive drug NIC group,AsⅣ group（5 mg·kg^-1,10 min before ischemia）,AsⅣ＋chelerythrine chloride（CHE） group（3 mg·kg^-1）.The activities of serum LDH and SOD and contents of serum MDA and NO in rats were measured.The morphological changes of cardiocytes in rats were observed by light microscopy.The protein expression of PKCε was analyzed by Western blotting.Results The LDH activity and MDA content in AsⅣ group were lower than those in model group（P〈0.05 or P〈0.01）,and the SOD activity and NO content were higher in AsⅣ group than those in model group（P〈0.01）.HE staining results confirmed that AsⅣ could obviously ameliorate cell structure and reduce inflammatory cell infiltration.AsⅣ could increase the protein expression of PKCε in membrane.CHE abolished the protective effect of AsⅣ partly,compared with AsⅣ group,the LDH activity and MDA content were increased（P〈0.05）,the SOD activity was decreased（P〈0.05）,the protein expression of PKCε in membrane was decreased（P〈0.05）,the cardiocytes had serious edema and the cytoplasm was stained slightly in AsⅣ＋CHE group.Conclusion AsⅣ possesses an obviously protective effect on myocardial ischemia-reperfusion injury in rats by increasing NO content.PKCε may be the down stream of NO which is involved in the transduction of AsⅣ.