基于心衰心肌中NGF/LIF平衡探索桂枝汤改善心脏交感神经支配失衡的作用和机制

Cardiac sympathetic nerve remodeling (CSNR) is one of the most important pathological mechanisms in the process of chronic heart failure (CHF), however, sustained suppression of sympathetic activity may be harmful to the patients’ condition when they develop to advance CHF. The up-regulation of nerve growth factor (NGF) leads to sympathetic autonomic hyperinnervation in early period of CHF, and then the down-regulation of NGF leads to sympathetic autonomic denervation in later period. Increased expression of leukemia inhibitory factor (LIF) in CHF leads to sympathetic rejuvenation and cholinergic differentiation, and causes sympathetic functional denervation. Therefore, we proposed the hypothesis that the expression of NGF and LIF as well as the NGF\LIF balance are important molecular mechanisms which determined the sympathetic innervations imbalance. Our previous studies showed that Guizhi decoction was effective in alleviating diabetic cardiac autonomic nerve remodeling, and has two-side effects on improving sympathetic nerve denervation and sympathetic sprouting. In the present study, we assume that Guizhi decoction has effects on improving sympathetic innervations imbalance via modulating the expression of NGF and LIF as well as the NGF/LIF. Firstly, we plan to observe the changes of sympathetic anatomical and functional innervations when modulating expression of NGF and LIF as well as the NGF\LIF balance through injection of adeno-associated virus 9 (VVA9). Secondly, Guizhi decoctions (with different proportion between Ramulus Cinnamomi and Radix Paeoniae Alba) will be administrated to the rats, and exploring the effects and molecular mechanism of Guizhi decoction on regulating the balance between anatomical and functional innervations of cardiac sympathetic nerve during CHF based on NGF\LIF balance. It may provide theoretical and experimental basis towards the therapy of cardiac sympathetic nerve remodeling in CHF .

心脏交感神经重塑是心衰的重要病理基础之一，临床中持续抑制交感神经活性对心衰晚期病情不利。心衰早期神经生长因子（NGF）升高导致交感神经解剖学高支配而晚期NGF降低致交感神经解剖学失支配。白血病抑制因子（LIF）在心衰中持续升高引起交感神经“再生幼稚化”和胆碱能转化，导致交感神经功能性失支配。因此，我们假设NGF和LIF表达及平衡关系可能是决定交感神经支配失衡的重要分子机制。我们前期证明桂枝汤可防治糖尿病自主神经病变，减轻去交感神经损伤和交感过度芽生。据此假设桂枝汤可通过调节心衰心肌NGF和LIF表达及其平衡来改善交感神经支配失衡。本项目利用腺相关病毒选择性改变NGF和LIF，观察其对心脏交感神经的解剖和功能学影响。从NGF和LIF表达及平衡关系探讨不同桂芍配伍比例的桂枝汤对心衰心脏交感神经支配的调节机制。这为开发新的治疗交感神经重塑的理想药物提供理论和实验依据。

心脏交感神经重塑是心衰的重要病理基础之一，临床中持续抑制交感神经对心衰病程进展不利。研究指出，白血病抑制因子（LIF）和神经生长因子（NGF）是影响交感神经功能学和解剖学支配的重要分子机制。LIF在心衰中持续升高可致交感神经“再生幼稚化”和“胆碱能性质转化”，诱导交感神经功能学失支配，而NGF与交感神经支配密度相关，其表达的高低可导致交感神经解剖学高支配或低支配。因此，我们假设LIF和NGF表达及平衡可能是决定心衰心脏交感神经支配失衡的重要分子机制。前期研究表明桂枝汤可防治糖尿病心脏自主神经病变，抑制交感过度芽生及减轻去交感神经损伤。据此我们假设桂枝汤可通过调节心衰心肌LIF和NGF表达以改善交感神经支配失衡。本研究结果显示：在心衰心肌肥厚期，LIF表达上调可诱导交感神经“再生幼稚化”，导致交感神经功能学低支配，NGF表达上调则导致交感神经支配密度增加，导致心脏交感神经解剖学高支配。由心肌肥厚期向代偿期再到失代偿期过程中，心肌LIF表达持续升高，诱导交感神经“胆碱能性质转化”，导致交感神经功能学支配，而NGF表达持续下调，导致交感神经出现解剖学失支配。通过腺相关病毒特异性的激活/干扰LIF表达，证明在心肌肥厚期上调LIF可促进交感神经“再生幼稚化”和“胆碱能性质转化”，导致交感神经功能学低支配，同时LIF上调，抑制了NGF表达，导致交感神经解剖学低支配，不利于心肌肥厚期；而下调LIF可减少NGF消耗，抑制交感神经解剖学失支配。相反，在心衰失代偿期，上调的LIF可加剧交感神经功能学低支配，对心衰晚期不利。在给予桂枝汤干预后，研究证明桂枝汤可调节LIF/NGF表达改善心脏交感神经功能学/解剖学支配，延缓心衰病程进展。本研究揭示了心衰交感神经重塑中的动态病理过程，阐释了经方桂枝汤改善心衰心脏交感神经支配失衡的作用机制，为中医药防治心衰心脏交感神经重塑提供了新思路和实验依据。