肾交感神经去神经支配改善心肌梗死后左心室重构的可能机制。

Possible mechanism by which renal sympathetic denervation improves left ventricular remodelling after myocardial infarction.

作者信息

Zheng Xiao-Xin, Li Xiao-Yan, Lyu Yong-Nan, He Yi-Yu, Wan Wei-Guo, Zhu Hong-Ling, Jiang Xue-Jun

机构信息

Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China.

Cardiovascular Research Institute of Wuhan University, Wuhan, 430060, China.

出版信息

Exp Physiol. 2016 Feb;101(2):260-71. doi: 10.1113/EP085302. Epub 2015 Dec 16.

Abstract

What is the central question of this study? The enzyme system that is responsible for extracellular matrix (ECM) turnover is the matrix metalloproteinases (MMPs), which can be blocked by the tissue inhibitors of MMPs (TIMPs). Whether renal sympathetic denervation (RSD) is able to ameliorate post-myocardial infarction left ventricular remodelling through attenuation of ECM via regulation of MMP activity and/or the MMP-TIMP complex remains unknown. What is the main finding and its importance? Renal sympathetic denervation has therapeutic effects on post-myocardial infarction left ventricular remodelling, probably by attenuating the ECM through regulation of the MMP9-TIMP1 complex in the transforming growth factor-β1 (a profibrotic cytokine that accelerates ECM remodelling after ischaemia) signalling pathway. Whether renal sympathetic denervation (RSD) is able to ameliorate post-myocardial infarction (post-MI) left ventricular (LV) remodelling by attenuation of the extracellular matrix via regulation of matrix metalloproteinase (MMP) activity and/or the MMP-tissue inhibitor of matrix metalloproteinase (TIMP) complex remains unknown. Sixty-five Sprague-Dawley rats were randomly divided into the following four groups: normal (N, n = 15), RSD (RSD, n = 15), myocardial infarction (MI, n = 15) and RSD 3 days after MI (MI3d+RSD, n = 20). The bilateral renal nerves were surgically denervated 3 days after MI had been induced by coronary artery ligation. Left ventricular function was assessed using echocardiography and a Millar catheter at 6 weeks post-MI. Plasma noradrenaline, angiotensin II and aldosterone, collagen volume fraction, transforming growth factor-β1 (TGF-β1), MMP2, MMP9 and TIMP1 in heart tissue were measured 6 weeks after MI. In rats with MI3d+RSD compared with MI rats, RSD improved systolic and diastolic function, resulting in an improvement in ejection fraction (P < 0.05), fractional shortening (P < 0.05) and LV internal dimension in systole (P < 0.05) and diastole (P < 0.05). Additionally, RSD treatment decreased left ventricular end-diastolic pressure (P < 0.05) and increased LV systolic pressure (P < 0.05) and maximal and minimal rate of LV pressure (both P < 0.05). Meanwhile, RSD reduced collagen content (P < 0.01). TIMP1 was upregulated (P < 0.05), whereas MMP2, MMP9 and TGF-β1 were downregulated in the LV of RSD-treated animals (P < 0.05). Renal sympathetic denervation has therapeutic effects on post-MI LV remodelling, probably owing to effects on the extracellular matrix by regulation of the MMP9-TIMP1 balance in the TGF-β1 signalling pathway. Renal sympathetic denervation may be considered as a non-pharmacological approach for the improvement of post-MI cardiac dysfunction.

摘要

本研究的核心问题是什么?负责细胞外基质(ECM)周转的酶系统是基质金属蛋白酶(MMPs),其可被MMP组织抑制剂(TIMPs)阻断。肾交感神经去支配(RSD)是否能够通过调节MMP活性和/或MMP-TIMP复合物来减轻ECM,从而改善心肌梗死后左心室重构,目前尚不清楚。主要发现及其重要性是什么?肾交感神经去支配对心肌梗死后左心室重构具有治疗作用,可能是通过在转化生长因子-β1(一种促纤维化细胞因子,可加速缺血后ECM重构)信号通路中调节MMP9-TIMP1复合物来减轻ECM。肾交感神经去支配(RSD)是否能够通过调节基质金属蛋白酶(MMP)活性和/或MMP-基质金属蛋白酶组织抑制剂(TIMP)复合物来减轻细胞外基质,从而改善心肌梗死后(post-MI)左心室(LV)重构尚不清楚。65只Sprague-Dawley大鼠被随机分为以下四组:正常组(N,n = 15)、RSD组(RSD,n = 15)、心肌梗死组(MI,n = 15)和心肌梗死后3天RSD组(MI3d+RSD,n = 20)。在通过冠状动脉结扎诱导心肌梗死后3天,对双侧肾神经进行手术去支配。在心肌梗死后6周,使用超声心动图和Millar导管评估左心室功能。在心肌梗死后6周,测量心脏组织中的血浆去甲肾上腺素、血管紧张素II和醛固酮、胶原容积分数、转化生长因子-β1(TGF-β1)、MMP2、MMP9和TIMP1。与MI大鼠相比,MI3d+RSD大鼠的RSD改善了收缩和舒张功能,导致射血分数(P < 0.05)、缩短分数(P < 0.05)以及收缩期(P < 0.05)和舒张期(P < 0.05)左心室内径得到改善。此外,RSD治疗降低了左心室舒张末期压力(P < 0.05),增加了左心室收缩压(P < 0.05)以及左心室压力的最大和最小变化率(均P < 0.05)。同时,RSD降低了胶原含量(P < 0.01)。在接受RSD治疗的动物左心室中,TIMP1上调(P < 0.05),而MMP2、MMP9和TGF-β1下调(P < 0.05)。肾交感神经去支配对心肌梗死后左心室重构具有治疗作用,可能是由于在TGF-β1信号通路中调节MMP9-TIMP1平衡对细胞外基质产生了影响。肾交感神经去支配可被视为改善心肌梗死后心脏功能障碍的一种非药物方法。

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