微小RNA-19a-3p对充血性心力衰竭模型大鼠心肌纤维化的影响及机制研究

Effect and mechanism of microRNA-19a-3p on myocardial fibrosis in rats with congestive heart failure

目的:探讨微小RNA-19a-3p(miR-19a-3p)对充血性心力衰竭(CHF)模型大鼠心肌纤维化的影响及机制。方法:将60只SD大鼠随机分为NC组、Model组、NC agomir组(尾静脉注射NC agomir)、miR-19a-3p agomir组(尾静脉注射miR-19a-3p agomir)、miR-19a-3p agomir+腺苷酸活化蛋白激酶(AMPK)抑制剂Compound C组(尾静脉注射miR-19a-3p agomir和250μg/kg Compound C),每组12只。NC组仅暴露腹主动脉而不结扎,其他组均构建CHF模型。给药结束后,比较各组大鼠血流动力学参数[左心室收缩压(LVSP)、左心室内压最大上升速率(+dp/dtmax)]和心脏功能指标[左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、室间隔厚度(IVS)、左心室功能(LVEF)]。Masson染色检测心肌纤维化情况。Western blot检测大鼠心肌组织Ⅰ型胶原蛋白(CollagenⅠ)、Ⅲ型胶原蛋白(CollagenⅢ)、转化生长因子-β(TGF-β)及通过调控AMPK/沉默信息调节因子1(SIRT1)/过氧化物酶体增殖物激活受体γ辅激活因子1α(PGC-1α)通路相关蛋白表达。实时荧光定量聚合酶链反应(RT-qPCR)检测大鼠心肌组织miR-19a-3p的相对表达量。结果:与NC组比较,Model组大鼠心肌纤维化程度加重,LVSP、+dp/dtmax、LVEF、miR-19a-3p表达水平及p-AMPK/AMPK、SIRT1、PGC-1α蛋白表达降低,LVESD、LVEDD、IVS及CollagenⅠ、CollagenⅢ、TGF-β蛋白表达升高(均P<0.05)。与Model组、NC agomir组比较,miR-19a-3p agomir组大鼠心肌纤维化程度改善,LVSP、+dp/dtmax、LVEF、miR-19a-3p表达水平及p-AMPK/AMPK、SIRT1、PGC-1α蛋白表达升高,LVESD、LVEDD、IVS及CollagenⅠ、CollagenⅢ、TGF-β蛋白表达降低(均P<0.05)。与miR-19a-3p agomir组比较,miR-19a-3p agomir+Compound C组大鼠心肌纤维化程度加重,LVSP、+dp/dtmax、LVEF及p-AMPK/AMPK、SIRT1、PGC-1α蛋白表达降低,LVESD、LVEDD、IVS及CollagenⅠ、CollagenⅢ、TGF-β蛋白表达升高(均P<0.05),而miR-19a-3p表达水平比较差异无统计学意义(P>0.05)。结论:过表达miR-19a-3p可能通过激活AMPK/SIRT1/PGC-1α通路抑制CHF大鼠心肌纤维化。

Objective:To explore the effect and mechanism of microRNA-19a-3p(miR-19a-3p)on myocardial fibrosis in rats with congestive heart failure(CHF).Methods:Sixty SD rats were randomly divided into NC group,Model group,NC agomir group(tail vein injection of NC agomir),miR-19a-3p agomir group(tail vein injection of miR-19a-3p agomir),miR-19a-3p agomir+Compound C(AMPK inhibitor)group(tail vein injection of miR-19a-3p agomir and 250μg/kg Compound C),with 12 rats in each group.In the NC group,only the abdominal aorta was exposed without ligation,and the CHF model was constructed in the form of abdominal aortic stenosis in the other groups.After the administration,the hemodynamic parameters LVSP and+dp/dtmax)and cardiac function indexes(LVEDD,LVESD,IVS and LVEF)were compared in each group.Masson staining was used to detect myocardial fibrosis.Western blot was used to detect the expression of CollagenⅠ,CollagenⅢ,TGF-βand AMPK/SIRT1/PGC-1αpathway related proteins in rat myocardial tissue.RT-qPCR was used to detect miR-19a-3p expression in rat myocardial tissue.Results:Compared with the NC group,the degree of myocardial fibrosis in the Model group increased,the LVSP,+dp/dtmax,LVEF,the expression level of miR-19a-3p,and the protein expressions of p-AMPK/AMPK,SIRT1 and PGC-1αwere significantly reduced,the LVEDD,LVESD,IVS,and CollagenⅠ,CollagenⅢ,and TGF-βprotein expressions were significantly increased(all P<0.05).Compared with the Model group and the NC agomir group,the degree of myocardial fibrosis in the miR-19a-3p agomir group was weakened,the LVSP,+dp/dtmax,LVEF,the expression level of miR-19a-3p,and the protein expressions of p-AMPK/AMPK,SIRT1 and PGC-1αwere significantly increased,the LVESD,LVEDD,IVS,and the protein expressions of CollagenⅠ,CollagenⅢand TGF-βwere significantly reduced(all P<0.05).Compared with the miR-19a-3p agomir group,the degree of myocardial fibrosis in the miR-19a-3p agomir+Compound C group was enhanced,the LVSP,+dp/dtmax,LVEF,and the protein expressions of p-AMPK/AMPK,SIRT1 and PGC-1αwere significantly reduced,the LVESD,LVEDD,IVS,and the protein expressions of CollagenⅠ,CollagenⅢand TGF-βwere significantly increased(all P<0.05),and there was no significant difference in the expression level of miR-19a-3p(P>0.05).Conclusion:Overexpression of miR-19a-3p may inhibit myocardial fibrosis in CHF rats by activating AMPK/SIRT1/PGC-1αpathway.