甲基莲心碱对自发性高血压大鼠心脏重构影响及其机制研究

Effect of neferine on cardiac remodeling in spontaneously hypertensive rats and its mechanism

目的观察甲基莲心碱(neferine,NE)对自发性高血压大鼠(spontaneous hypertension rats,SHRs)心脏重构的影响,并探讨其对活化转录因子6(activating transcription factor 6,ATF6)-C/EBP同源蛋白(CCAAT/Enhancer-binding Protein(C/EBP)Homologous Protein,CHOP)内质网应激(endoplasmic reticulum,ERs)信号通路的影响。方法48只大鼠喂养6个月后,然后随机分为4组:魏-凯二氏大鼠(Wistar-Kyoto,WKYs)+溶媒、SHRs+溶媒、WKYs+NE和SHRs+NE(n=12)。WKYs+NE和SHRs+NE组用NE治疗,剂量为25 mg·kg^(-1)·d^(-1);WKYs+溶媒、SHR+溶媒组用溶媒治疗。持续治疗5个月后,通过超声心动图和组织学分析评估心功能和纤维化。采用实时定量PCR和免疫印迹法检测ATF6、CHOP基因和蛋白表达水平。采用TUNEL法检测心肌细胞凋亡。结果与SHRs+vehicle组相比,NE治疗SHRs的血压升高逐渐降低,并且NE治疗SHRs可显著逆转心脏收缩和舒张功能不全(EF、FS和E/A比值降低)、心肌肥厚(心脏大小和HW/BW比值增加)、心肌细胞横截面积和心肌胶原沉积。qPCR和Western blot分析显示,NE治疗SHRs可显著减弱心脏组织中ATF6、CHOP mRNA水平以及蛋白水平。此外,与WKYs组相比,SHRs组大鼠心肌组织TUNEL阳性细胞明显增多,NE治疗SHRs可显著减弱心脏组织中TUNEL阳性细胞。结论NE可显著减轻SHRs心肌细胞凋亡和ERs,并改善SHRs的心脏重构,支持其作为高血压慢性治疗药物。

Objective To evaluate the effects of neferine(NE)on cardiac remodeling in spontaneously hypertensive rats(SHRs),and explore its impacts on the activating transcription factor 6(ATF6)-C/EBP homologous protein(CHOP)ER stress signaling pathway.Methods After feeding for 6 months,48 rats were randomly divided into 4 groups:WKYs+vehicle,SHRs+vehicle,WKYs+NE and SHRs+NE(n=12 per group).WKYs+NE and SHRs+NE groups were treated with NE at a dose of 25 mg·kg^(-1)·d^(-1);WKYs+vehicle and SHRs+vehicle groups were treated with vehicle.After 5 months of treatment,cardiac function,and fibrosis were evaluated by echocardiography and histological analysis.Protein and gene of ATF6,CHOP expression levels were analyzed by quantitative real-time PCR and immunoblotting.TUNEL method was used to detect cardiomyocyte apoptosis.Results The elevation in blood pressure decreased progressively in NE-treated SHRs compared with the vehicle controls.Moreover,the treatment of SHRs with NE significantly reversed cardiac systolic and diastolic dysfunction(decreased EF,FS,and E/A ratio),cardiac hypertrophy(increase of heart size,HW/BW ratios)and myocardial fibrosis compared with those in vehicle-treated SHRs.QPCR and Western blot analysis showed that NE treatment significantly reduced the levels of ATF6 and CHOP mRNA and protein in cardiac tissue.In addition,compared with WKYs group,the number of TUNEL positive cells in SHRs group was significantly increased.The treatment of SHRs with NE could significantly reduce the TUNEL positive cells in cardiac tissue compared with those in vehicle-treated SHRs.Conclusion NE can improve cardiac remodeling in SHR rats by inhibiting ERs and suppressing cardiomyocyte apoptosis,which supports it as a chronic hypertensive drug.