基于NGF-TrkA通路探讨肝肺同治法对哮喘模型小鼠神经源性炎症的影响

Immune imbalance and neurogenic inflammation are of the most difficult pathological basis of bronchial asthma, which in some degree are similar with the pathomechnism of coagulation of phlegm, stasis, and Qi in Chinese medicine theory. Currently researches in the field of neurogenic inflammation are at the starting stage, people found that NGF participates in multiple links in the pathological changes of asthma, and TrkA is the receptor with high affinity. Th1/Th2 cytokines imbalance may indirectly promote the induction of neurogenic inflammation by regulating the expression of NGF mRNA, meanwhile NGF may also participate in the Th1/Th2 immune balance by inducing Th1 to the Th2 deviation. .Our previous research has shown that the therapeutic method of phlegm and stasis resolving and asthma relieving have bilateral regulating action on Th1/Th2 balance of asthmatic mice model. In this study, we begin with the inter-relationship between neurogenic inflammation and the pathological status of the coagulation of phlegm, stasis and Qi caused by dysfunction of the liver in smoothing Qi-flow and failure of the lung in dispersion, aiming at exploring the intervention effect of phlegm and stasis resolving and liver soothing method on NGF-TrkA pathway and Th1/Th2 imbalance of asthmatic mice model, through observation on IL-13/IL-18, and NGF, TrkA, SP and their changes in airway and brain tissue, another objective is to focus on the best intervention time node, so as to analyze the inherent relevant information between intervention on neurogenic inflammation and Th1/Th2 imbalance. We also look forward to launch a preliminary investigation on the possibility of liver-based therapy theory on asthma.

免疫失衡与神经源性炎症是支气管哮喘两大难治病理环节，与中医理论中阴阳失衡导致痰、气、瘀互结的病机基础有相似性。目前有关神经源性炎症在哮喘发病机理中的作用及对策处于探索阶段。NGF参与哮喘发生的多个病理环节，TrkA是其高亲和力受体。Th1/Th2类细胞因子免疫失衡可能通过调控NGFmRNA表达间接促进其诱导神经源性炎症；NGF可能诱导Th1向Th2型免疫应答偏移而参与免疫失衡效应。.前期研究发现化痰祛瘀平喘法可双向调节哮喘Th1/Th2失衡。本研究拟从肝失条达、肺失宣肃所致痰、气、瘀互结与神经源性炎症的关系入手，提出"肝肺同治"假说，观察化痰祛瘀疏肝法对哮喘模型动物气道及脑组织IL-13/IL-18及NGF、TrkA的影响，研究其对哮喘NGF-TrkA信号转导通路及Th1/Th2失衡的干预作用，找出最佳干预时机及环节，分析其对哮喘两大难治环节干预机制的内在相关性，并探讨从肝论治哮喘的可能。

免疫失衡和神经源性炎症哮喘的两大病理环节，中医治肺法对前者作用确切。疏肝法是调节气机的有效手段。拟从肝失条达、肺失宣肃所致痰、气、瘀互结与神经源性炎症的潜在关系入手，提出“肝肺同治”假说，研究其对哮喘NGF-TrkA信号通路及Th1/Th2失衡的干预作用，找出最佳干预时机及环节，分析其对哮喘两大难治环节干预机制的相关性，探讨从肝论治哮喘的可能。.研究设发作前、全程、发作后三种干预方式，以肝肺同治法（SGPCF）进行干预，以治肺法（PCF）及地塞米松（DMX）为对照，以ELISA、RT-PCR、Western blot、IHC等方法观察不同干预时机各组小鼠BALF及肺、脑组织中IL-13、18、NGF、TrkA、SP、Akt等指标的改变， .结果显示，模型小鼠行为学表现、肺组织病理变化显著，BALF总IgE、EOS、IL-13、RORγt升高，IL-18、FOXp3降低，NGF、TrkA、SP、Akt升高；两中药组均可降低其升高的IL-13、RORγt，升高其降低的IL-18、FOXp3，与DXM相似；两中药组均可降低其升高的NGF、TrkA、SP、Akt，对NGF的降低在三种干预方式下均优于DXM；SGPCF全程和发作后干预作用优于其他两组。SGPCF对IL-13、18的最佳干预时机与PCF同，为全程干预；而对NGF、TrkA的最佳干预时机为全程及发作后。IL-13、IL-18、NGF、TrkA间密切相关，IL-18与其余各指标间呈负相关，其余各指标间呈正相关；经两中药治疗后，上述负相关消失。.上述发现提示：肝肺同治法对哮喘小鼠Th1/Th2免疫失衡、Treg/Th17细胞分化失衡及NGF、TrkA介导的神经源性炎症均有确切作用。其对免疫失衡作用与其他两组相近，对神经源性炎症作用优于其他两组，最佳时机为全程及发作后干预。哮喘免疫失衡与神经源性炎密切相关，肝肺同治法对后者作用更为明显，且发作后干预优势突出，对临床缩短疗程有积极意义，肝肺同治对哮喘神经-免疫病理的影响机制值得深入研究。.此外，哮喘小鼠肝脏不同程度与横隔粘连，外观脂肪样病变，肝小叶轮廓破坏，部分肝窦充血扩张，门脉和汇管区炎症细胞浸润；各处理组上述改变均有减轻；提示哮喘动物肝脏病理应得到重视；其结肠组织的SP、Akt明显升高，与肺组织中改变同步。提示“肺与大肠相表里”理论在哮喘防治中亦有重要前景。