延龄草皂苷通过抑制TGF-β/Smad3与Wnt/β-catenin信号通路改善大鼠肺纤维化

Trillium Saponins ameliorates pulmonary fibrosis in rats by inhibiting TGF-β/Smad3 and Wnt/β-catenin signaling pathways

目的探讨延龄草皂苷对肺间质纤维化大鼠的治疗作用及其可能机制。方法雄性SD大鼠50只,随机分为对照组,模型组,延龄草皂苷低、中、高剂量组[25 mg/(kg·d)、50 mg/(kg·d)和100 mg/(kg·d)],每组10只。除对照组外,其余各组采用气管插管注入博来霉素法(5 mg/kg)建立大鼠肺纤维化模型;次日开始连续给药28 d。处死大鼠后,取肺组织称重并计算肺系数;进行HE和Masson染色观察小鼠肺组织形态病理学变化;ELISA法检测大鼠白细胞介素-1β(IL-1β)、肿瘤坏死因子(TNF-α)、白细胞介素-6(IL-6)、丙二醛(MDA)和活性氧(ROS)的表达以及超氧化物歧化酶(SOD)的活性;Western blotting法检测大鼠肺组织中纤连蛋白(fibronectin)、胶原蛋白Ⅰ型(CollagenⅠ)、α-平滑肌肌动蛋白(α-SMA)、转化生长因子-β(TGF-β)、SMAD同源物3(Smad3)、Wnt3a、β-连环蛋白(β-catenin)和糖原合成酶激酶-3β(GSK-3β)的蛋白表达水平。结果与模型组比较,延龄草皂苷低、中、高剂量组的肺系数降低,大鼠肺组织炎性细胞浸润、胶原沉积和纤维化程度改善,大鼠IL-1β、TNF-α、IL-6、MDA和ROS的表达水平降低,SOD的活性升高,发挥抗炎、抗氧化作用;肺纤维化标志蛋白fibronectin,CollagenⅠ和α-SMA表达被抑制;大鼠肺组织TGF-β1、Smad3、Wnt3a、β-catenin和GSK-3β蛋白的表达水平降低,且治疗效果呈现剂量依赖性。结论延龄草皂苷可通过抗炎、抗氧化,抑制TGF-β/Smad3与Wnt/β-catenin信号通路激活,从而对肺纤维化产生保护作用。

Objective To investigate the treatment and mechanism of Trillium Saponins in rats with pulmonary interstitial fibrosis.Methods Fifty male SD rats were divided into 5 groups,namely the control group,the model group,and the low,medium,and high Trillium Saponins treatment groups,with 10 in each group.Except the control group,the other groups were injected with bleomycin 5 mg/kg through tracheal intubation.A rat model of pulmonary fibrosis was established.The treatment group was given 25,50 and 100 mg/(kg·d)Trillium Saponins by gavage the next day.After 28 days of treatment,the rats were sacrificed,and blood and lung tissues were taken.The lung tissue was weighed and the lung coefficient was calculated.HE staining and Masson staining were used to observe rat lung histopathology.The expressions of interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),malondialdehyde(MDA)and reactive oxygen species(ROS)and the activity of superoxide dismutase(SOD)were detected by ELISA kit.Western blotting experiment was employed to detect the protein expression levels of transforming growth factor-β(TGF-β)1,Smad3,Wnt3 a,β-catenin,glycogen synthase kinase-3β(GSK-3β),fibronectin,CollagenⅠandα-SMA in lung tissue.Results Compared with the model group,lung coefficient was decreased,inflammatory cell infiltration,collagen deposition and fibrocytosis were reduced,the expressions of IL-1β,TNF-α,IL-6,MDA and ROS levels were decrease,the activity of SOD was increased,the expressions of fibronectin,CollagenⅠ,α-SMA,TGFβ1,Smad3,Wnt3 a,β-catenin and GSK-3βproteins were inhibited in lung tissue of low,medium,and high Trillium Saponins treatment groups.Conclusion Trillium has anti-inflammatory and anti-oxidant properties,and can inhibit the activation of TGF-β/Smad3 and Wnt/β-catenin signaling pathways to protect against pulmonary fibrosis.