神经胶质细胞生长因子-1β对慢性心衰大鼠心功能及促血管生成素、大麻素受体、蛋白激酶C表达的影响

摘要

目的分析神经胶质细胞生长因子-1β(neuregulin-1β)对慢性心衰大鼠心功能及促血管生成素(Ang2)、大麻素受体(CB1)、蛋白激酶C(PKC)表达的影响.方法将30只雄性SD大鼠随机分成正常组、模型组、neuregulin-1β干预组(each n=10).采用尾静脉注射阿霉素(20 mg/kg)的方法建立慢性心衰大鼠模型,并通过心脏超声确定模型成功.干预组于建模成功后连续1周每天尾静脉给予neuregulin-1β(10μg/kg·d),正常组给予与模型组等体积的生理盐水.三组大鼠均于实验第9周行大鼠心脏超声及血流动力学检测,取心肌组织进行HE染色进行病理学检测,采用Western blotting法检测三组大鼠心肌组织中PKC蛋白量,采用免疫组织化学法检测三组大鼠心肌组织中Ang2、CB1蛋白相对表达量.结果模型组和neuregulin-1β干预组在第8周心脏超声指标均显示慢性心衰大鼠模型建立成功.neuregulin-1β干预1周后,与模型组比较,干预组的心脏超声指标左心室舒张末期内径、左心室收缩末期内径均显著性降低(P＜0.05),左室缩短率与左室射血分数均显著性升高(P＜0.05);血流动力学指标左心室收缩压(LVSP)、左心室内压最大上升速率、左心室内压最大下降速率均显著性升高(P＜0.05),左心室舒张末期压显著性降低(P＜0.05);PKC相对蛋白量显著减少(P＜0.05);Ang2和CB1阳性区域评分明显降低(P＜0.05);同时病理结果显示,neuregulin-1β干预组较模型组心肌病变较轻,除部分心肌水肿外,未见明显的心肌细胞坏死、炎证浸润及明显的血管充血扩张.结论neuregulin-1β的干预显著改善大鼠心肌细胞的病变情况,其作用机制可能与下调PKC蛋白及Ang2、CB1的表达有关.%Objective To analyze the influence of neuregulin-1βon heart function and expressions of angiopoietin 2(Ang2), cannabinoid receptor 1(CB1) and protein kinase C (PKC) in rats with chronic heart failure (CHF).Methods Male SD rats (n=30) were randomly divided into normal group, model group and neuregulin-1βgroup (each n=10).The rat model of CHF was established by injection of doxorubicin (20 mg/kg) in caudal vein, and cardiac ultrasonography was used to confirm the model.After success modeling, neuregulin-1βgroup was given neuregulin-1β (10μg/kg·d) in caudal vein for 1 week, and normal group and model group were given isometric normal saline.All groups were given examinations of echocardiography and hemodynamics on the 9th week, and myocardial tissue samples were collected for pathological detection after HE staining.The content of PKC was detected by using Western blotting assay, and relative expressions of Ang2 and CB1 were detected by using immunohistochemistry technique in 3 groups.Results The indexes of echocardiography showed that rat model of CHF was successfully established in model group and neuregulin-1βgroup on the 8th week.The indexes of echocardiography of LVEDd and LVESd decreased significantly (P＜0.05), and LVFS and LVEF increased significantly (P＜0.05) in neuregulin-1βgroup compared with model group after intervention for 1 week.The hemodynamic indexes of LVSP, +dp/dtmax and-dp/dtmax increased significantly (P＜0.05), and LVEDP decreased significantly (P＜0.05) in neuregulin-1βgroup.The relative content of PKC decreased significantly (P＜0.05), and scores of positive regions of Ang2 and CB1 decreased significantly (P＜0.05).Meanwhile the pathological results showed that myocardial lesions were milder in neuregulin-1βgroup compared with model group, except of some myocardial edema, no significant myocardial necrosis, inflammatory infiltration and obvious vascular congestion and dilatation were observed.Conclusion The intervention of neuregulin-1βcan significantly ameliorate myocardial lesions in rats, and the mechanism may be related to the down-regulation of PKC, Ang2 and CB1 expressions.