基于上皮间充质转化和细胞外基质沉积研究人参皂甙Rg1对COPD发生发展的作用及机制

Airway remodeling is the prominent pathophysiological feature of COPD. However, the related mechanisms have not been completely elucidated, effective approaches to the control of airway remodeling are urgently needed. Ginseng has been shown used as a medicinal herb to improve symptoms of COPD. However, the chemopreventive effects of Ginsenoside Rg1 in COPD have not been tested. Recently, we have revealed the fact that Ginseng has the chemoprevention activity in a mouse lung squamous cell carcinoma through pathways involving ERK and Smads. Ginsenoside Rg1 restrains airway epithelial to myofibroblast transition in vitro induced by TGF-β1. All of these evidences suggest that Ginsenoside Rg1 could suppress lung fibrogenesis via inhibition the couse of epithelial mesenchymal transition and deposition of extracellular matrix. To test this idea, airway epithelial cells, fibroblasts and COPD rat-models were chosen for our study. This project is designed for the following purposes: first, to investigate the effects of Ginsenoside Rg1 on the lung function and pathological features of COPD rat-models, second, to evaluate the effects of Ginsenoside Rg1 on epithelial mesenchymal transition and deposition of extracellular matrix in vivo and in vitro, third, to reveal the mechanisms from the views of ERK and Smads pathways. From the stand points of epithelial mesenchymal transition and deposition of extracellular matrix, the project will set up an academic foundation for finding compounds to inhibit, delay, or reverse the process of airway remodeling.

气道重建是COPD发生发展中突出的病理生理基础，其机制尚未完全阐明，亟待寻找可有效抑制COPD气道重建的药物。人参制剂已用于改善COPD症状，但人参皂甙对COPD的化学预防作用及机制仍知之甚少。前期研究显示，人参可预防肺鳞癌的发生，其作用与ERK通路及Smads通路相关；同时观察到人参皂甙Rg1可抑制由TGF-β1诱导的气道上皮间充质转化。据此提出假说：人参皂甙Rg1通过抑制上皮间充质转化及细胞外基质沉积影响气道重建，最终有效抑制吸烟相关COPD的发生和发展。为验证这一假说，利用气道上皮细胞、肺间质成纤维细胞及COPD大鼠模型，观察人参皂甙Rg1对大鼠肺功能及组织形态的影响，体内及体外明确药物对上皮间充质转化及细胞外基质沉积的作用，从Smads、ERK两条通路初步探讨其作用机制。本项目从上皮间充质转化及细胞外基质沉积两方面，为研究疗效明确，可抑制、减轻或延缓气道重建的药物奠定理论基础。

研究人参皂甙Rg1对慢性阻塞性肺疾病上皮间充质转化和细胞外基质沉积的影响，并探讨其相关机制，为人参皂甙Rg1治疗COPD小气道纤维化提供理论依据。.通过烟熏法建立COPD大鼠模型，灌胃法进行人参皂甙Rg1干预。进行肺功能测定。检测肺组织E-cad和α-SMA的表达，观察人参皂甙Rg1对肺内EMT的影响。检测大鼠肺内胶原沉积情况，肺组织MMP-9和TIMP-1蛋白表达。检测血清和肺泡灌洗液中TGF-β1含量，肺组织TGF-β1表达。体外培养人支气管上皮细胞，研究人参皂甙Rg1对香烟烟雾提取物诱导的小气道上皮细胞EMT的影响及机制。人参皂甙Rg1对CSE诱导的人支气管上皮细胞EMT的影响。人参皂甙Rg1对调控EMT的TGF-β1/Smad通路的影响。体外培养人胚肺成纤维细胞（MRC-5细胞），研究人参皂甙Rg1对CSE诱导的成纤维细胞/肌成纤维细胞转化和细胞外基质沉积的影响和机制。人参皂甙Rg1对CSE诱导的MRC-5细胞向肌成纤维细胞转化和细胞外基质沉积的影响。研究表明人参皂甙Rg1可以减轻烟熏大鼠的肺结构破坏，改善肺功能，降低肺内EMT和细胞外基质沉积，降低血清、肺泡灌洗液和肺内TGF-β1水平；人参皂甙Rg1通过抑制Smad2/3磷酸化，改善CSE诱导的支气管上皮细胞EMT；人参皂甙Rg1通过抑制Smad2/3磷酸化，改善CSE诱导的肺成纤维细胞/肌成纤维细胞转化和细胞外基质沉积。我们的研究表明人参皂甙Rg1通过抑制EMT和细胞外基质沉积来改善COPD小气道纤维化，这一作用可能是通过TGF-β1/Smad通路完成的。