摘要:
目的:观察神经调节蛋白-1(NRG-1)对急性心肌梗死(AMI)大鼠心室重构、心功能和循环肾素 血管紧张素系统(RAS)的影响.方法:将成年雄性SD大鼠随机分为假手术组、模型组、NRG-1组.模型组和NRG-1组结扎冠状动脉左前降支建立AMI大鼠模型,假手术组只开胸不结扎.造模成功后2h内,NRG-1组经尾静脉注射NRG-1(10 μg/kg),假手术组和模型组尾静脉注射等量生理盐水,连续7d.用MPA心功能分析系统测定左室收缩压(LVSP)、左室舒张末期压(LVEDP)、左室压力上升的最大变化速率(+dp/dtmax)、左室压力下降的最大变化速率(-dp/dtmax),苏木精-伊红(HE)染色和Masson染色观察心肌组织形态学改变,计算心肌胶原容积分数(CVF),酶联免疫吸附试验(ELISA)法检测大鼠血清血管紧张素(Ang)Ⅰ、AngⅡ水平.结果:与假手术组相比,模型组LVSP、-dp/dtmax降低,LVEDP升高,出现严重心肌纤维化及炎症程度评分、CVF和血清AngⅠ、AngⅡ浓度明显升高,差异均有统计学意义(P≥0.05或P<0.01).与模型组比较,NRG-1组大鼠LVSP、-dp/出dtmax显著升高(P<0.05或P<0.01),LVEDP显著降低(P≥0.01),心肌纤维化明显减轻,CVF、AngⅠ、AngⅡ浓度明显降低(P≥0.05或P<0.01).结论:NRG-1可通过抑制循环RAS活性抑制AMI大鼠心室重构,改善心功能.%Objective:To investigate the influence of neuregulin-1(NRG-1) on ventricular remolding,heart function and the main components of circulating renin-angiotensin-system(RAS) in a rat model of acute myocardial infarction(AMI).Methods:SD rats were randomly divided into the sham group,the model group and the NRG-1 group.Rat models of AMI were established by ligation of the left anterior descending coronary artery in all groups except for the sham group.After 2 hours of modeling,the rats in the NRG-1 group were injected with NRG-1(10 μg/kg) via caudal vein for 7 days,and rats in the sham group and the model group received equal volume of saline.The heart function of the rats was measured by MPA cardiac function analysis system.Myocardial morphology was observed by HE staining.The myocardial fibrosis and collagen volume fraction(CVF) were observed by Masson staining.Serum levels of angiotensin Ⅰ (Ang Ⅰ) and angiotensin Ⅱ (Ang Ⅱ) were detected by enzyme-linked immunosorbent assay(ELISA).Results:Compared with the sham group,the left ventricular systolic pressure(LVSP),and left ventricular pressure decrease maximum rate(-dp/dtmax) were markedly decreased in model group,while the left ventricular end diastolic pressure(LVEDP) was increased significantly(P≥0.01).The LVSP,and-dp/dtmax were elevated,while the LVEDP was declined notably by administrationof NRG-1(P<0.01).We noticed that model group rats exhibited more severe myocardial fibrosis and inflammatory cell infiltration by HE staining,but reversed by treatment of NRG-1.Moreover,the CVF and the serum levels of Ang Ⅰ and Ang Ⅱ in NRG-1 group were significantly lower than those in the model group (P <0.05).Conclusion:NRG-1 inhibited ventricular remodeling and improved heart function through suppressing the activity of RAS.