基于TGF-β1/Smad通路研究牛膝多糖对慢阻肺模型大鼠的作用机制

Study the Mechanism of Achyranthes Bidentata Polysaccharide on COPD Model Rats Based on TGF-β1/Smad Pathway

目的:基于TGF-β1/Smad通路研究牛膝多糖对慢阻肺模型大鼠的作用机制。方法:60只大鼠,随机选10只为对照组,其余大鼠采用向气管内滴注脂多糖加香烟熏的方法复制大鼠慢阻肺模型,将模型成功的大鼠随机分为模型组、地塞米松组(0.5 mg·kg^(-1))及牛膝多糖低、中、高剂量组(2 g·kg^(-1)、4 g·kg^(-1)、8 g·kg^(-1)),每只10只,连续给予相应的药物30 d。检测大鼠肺功能;ELISA法检测血清基质金属蛋白酶组织抑制因子-1(tissue inhibitor of matrix metalloproteinase-1,TIMP-1)、血管内皮细胞生长因子(vascular endothelial growth factor, VEGF)、骨桥蛋白(osteopontin, OPN)水平;HE染色观察大鼠对肺组织病理损伤变化;Western Blot法检测大鼠肺组织转化生长因子β1(transforming growth factorβ1,TGF-β1)、Smad2、Smad3蛋白表达;RT-PCR法检测大鼠肺组织TGF-β1 mRNA、Smad2 mRNA、Smad3 mRNA水平。结果:与模型组比较,牛膝多糖低、中、高剂量大鼠吸气阻力、呼气阻力明显降低,0.3秒用力呼出气量占用力肺活量百分比明显升高(P<0.05);明显降低大鼠血清TIMP-1、VEGF、OPN水平(P<0.05);明显下调大鼠肺组织TGF-β1蛋白表达,明显降低p-Smad2/Smad2、p-Smad3/Smad3水平(P<0.05);明显降低大鼠肺组织TGF-β1 mRNA、Smad2 mRNA、Smad3 mRNA水平(P<0.05),同时改善大鼠肺组织的病理损伤。结论:牛膝多糖可改善慢阻肺模型大鼠肺功能,减轻炎症反应,可能与调控TGF-β1/Smad通路有关。

Objective: To study the mechanism of achyranthes bidentata polysaccharide on chronic obstructive pulmonary disease(COPD) model rats based on TGF-β1/Smad pathway.Methods: 60 rats were randomly selected as the control group.The remaining rats used lipopolysaccharide instillation into the trachea and cigarette smoking to replicate the rat model of COPD.The successful rats were randomly divided into model group, dexamethasone group(0.5 mg·kg^(-1)) and achyranthes bidentata polysaccharide low, medium and high doses group(2 g·kg^(-1),4 g·kg^(-1),8 g·kg^(-1)) and given corresponding drugs for 30 days.The pulmonary function of rats was measured;the levels of tissue inhibitor of matrix metalloproteinase-1(TIMP-1),vascular endothelial growth factor(VEGF) and osteopontin(OPN) in serum were detected by ELISA;HE staining was used to observe the pathological changes of rat lung tissue, and Western Blot was used to detect transforming growth factor β1(TGF-β1),Smad2 and Smad3 protein expression;RT-PCR method was used to detect the levels of TGF-β1 mRNA,Smad2 mRNA and Smad3 mRNA in rat lung tissue.Results: Compared with the model group, the inspiratory resistance and expiratory resistance of rats with low, medium and high doses of achyranthes bidentata polysaccharide decreased significantly, and 0.3 second forced expiratory volume/forced vital capacity(FEV0.3/FVC) increased significantly(P<0.05).It can significantly reduce the levels of serum TIMP-1,VEGF and OPN in rats(P<0.05);it can significantly down-regulate the expression of TGF-β1 protein in rat lung tissue, and significantly reduce the levels of p-Smad2/Smad2,p-Smad3/Smad3(P<0.05);it can significantly reduce the levels of TGF-β1 mRNA,Smad2 mRNA and Smad3 mRNA in rat lung tissue(P<0.05);at the same time, it can improve the pathological damage of lung tissue.Conclusion: Achyranthes bidentata polysaccharide can improve pulmonary function and reduce inflammatory response in COPD model rats, which may be related to the regulation of TGF-β1/Smad pathway.