二甲双胍抑制哮喘模型大鼠气道重塑的研究

Effects of metformin on airway remodeling in rat asthma model

目的观察二甲双胍对哮喘气道重塑的影响及其可能作用机制。方法 28只B/N大鼠随机分为对照组、哮喘组、二甲双胍干预组和雷帕霉素干预组;制备哮喘模型,以二甲双胍、雷帕霉素进行干预;末次激发48小时后测定大鼠气道阻力及气道反应性,收集肺组织标本,采用组织病理学方法观察气道炎症细胞浸润、气道壁杯状细胞增生、气道壁纤维化和重塑情况以及气道平滑肌增殖情况,采用蛋白印迹法检测AMPK/mTOR通路相关蛋白的表达。结果与哮喘组相比,二甲双胍和雷帕霉素干预可显著降低乙酰胆碱气道反应性(P<0.05);减轻大鼠肺组织中炎细胞浸润以及气道壁结构的变化(P<0.05);减少气道上皮中杯状细胞增生、肺组织中胶原纤维沉积、支气管平滑肌增生(均P<0.05)。进一步研究发现,二甲双胍和雷帕霉素的作用与AMPK/mTOR通路相关,与哮喘组相比,二甲双胍和雷帕霉素干预可显著降低p-mTOR、p-p70s6k1、SKP2的表达,而p21蛋白表达明显增加(P<0.05)。两种干预措施具有相似效应(P>0.05)。结论二甲双胍可以通过激活AMPK、进而抑制mTOR通路来缓解气道高反应性和气道重塑,可能是治疗哮喘和预防气道重塑的潜在药物。

Objective To observe the effect of metformin on airway remodeling in asthma and its possible mechanism. Methods Twenty-eight B/N rats were randomly divided into control group, asthma group, metformin intervention group and rapamycin intervention group. After that, the asthma model was established and intervened with metformin and rapamycin. The airway resistance and airway reactivity were measured 48 hours after the last challenge,and then the lung tissue samples were collected. Histopathological examination was used to observe airway inflammatory cell infiltration, goblet cell proliferation, airway wall fibrosis and remodeling, as well as airway smooth muscle proliferation. The expression of AMPK/mTOR pathway related proteins was detected by Western blot. Results Compared with the asthma group, metformin and rapamycin significantly reduced the airway responsiveness induced by high concentration of acetylcholine(P<0.05), reduced the infiltration of inflammatory cells in lung tissue and the changes of airway wall structure(P<0.05), reduced goblet cell proliferation in airway epithelium, collagen fiber deposition in lung tissue and bronchial smooth muscle hyperplasia(P<0.05). Further studies showed that the effects of metformin and rapamycin were related to AMPK/mTOR pathway. Compared with the asthma group, metformin and rapamycin could significantly reduce the expression of p-mTOR, p-p70 s6 k1 and SKP2, while p21 protein expression was significantly increased(P<0.05). In addition, metformin and rapamycin had similar effects(P>0.05). Conclusion Metformin can alleviate airway hyperresponsiveness and airway remodeling by activating AMPK and then inhibiting mTOR pathway,which may be a potential drug for treating asthma and preventing airway remodeling.