中药川贝对哮喘模型小鼠气道重塑及TGF-β1/Smad信号通路的影响

The effects of Bulbus Fritillariae Cirrhosae on airway remodeling and TGF-β1/Smad signal pathway in mouse asthmatic model

目的:观察中药川贝对哮喘模型小鼠气道重塑及转化生长因子-β1(TGF-β1)/Smad信号通路的影响,探讨其治疗哮喘的作用机制。方法:BALB/c小鼠,随机分为正常组、模型组、高剂量组、低剂量组、阳性对照组。除正常组外,其他各组用卵蛋白(OVA)建立小鼠哮喘模型。造模成功后高剂量组和低剂量组分别按18.0mg·kg^(-1)和9.0mg·kg^(-1)剂量给予中药川贝灌胃;阳性对照组雾化吸入0.5mg·kg^(-1)地塞米松;正常组和模型组等量生理盐水灌胃,每天1次,连续28d。观察各组小鼠支气管管壁厚度和平滑肌厚度的变化以及支气管肺泡灌洗液(BALF)中嗜酸性粒细胞(EOS)计数的变化;酶联免疫吸附剂测定(ELISA)检测BALF和血清中TGF-β1浓度;蛋白印记分析(Western-blot)检测肺组织TGF-β1、磷酸化Smad2(p-Smad2)、Smad2、磷酸化Smad3(p-Smad3)、Smad3的表达;实时荧光定量PCR(Real Time-PCR)检测肺组织TGF-β1 mRNA、Smad2mRNA、Smad3mRNA的表达。结果:模型组小鼠支气管管壁厚度和平滑肌厚度,BALF中EOS计数,BALF和血清中TGF-β1浓度,肺组织TGF-β1、p-Smad2、Smad2、p-Smad3、Smad3的表达,肺组织TGF-β1mRNA、Smad2mRNA、Smad3mRNA的表达均明显高于对照组(P<0.01),高剂量组,低剂量组和阳性对照组上述指标则明显低于模型组(P<0.05或P<0.01)。结论:中药川贝可改善哮喘模型小鼠气道重塑状态,其机制可能与其抑制TGF-β1/Smad信号通路有关。

OBJECTIVE To investigate the effect of Bulbus Fritillariae Cirrhosae on airway remodeling and the expressions of transforming growth factor-β1（TGF-β1）/Smad signal pathway in lung tissues in mouse asthmatic models to explore its mechanism in treatment of asthma.METHODS BALB/c mice were randomly divided into normal group,model group,high dose group and low dose group,positive control group.Except for normal group,animals in other groups were sensitized and challenged with ovalbumin（OVA）to establish asthma murine models.Mice in high dose group and low dose group were orally administered with Bulbus Fritillariae Cirrhosae powder at the doses of 18.0 mg·kg^（-1） and 9.0 mg·kg^（-1）,respectively.Mice in positive control group were given dexamethasone by aerosol inhalation at the dose of 0.5 mg·kg^（-1）,while animals in normal group and model group were orally administered saline.All the drugs were given to mice per day for 28 days consecutively.The variations of thicknesses of bronchial wall and airway smooth muscle and the eosinophil（EOS）counts in bronchoalveolar lavage fluid（BALF）were observed.The concentrations of TGF-β1 in BALF and serum were measured by enzyme linked immunosorbent assay（ELISA）.The expressions of TGF-β1,phosphorylated Smad2（p-Smad2）,Smad2,phosphorylated Smad3（pSmad3）and Smad3 in lung tissues were detected by Western blot.The expressions of TGF-β1 mRNA,Smad2 mRNA and Smad3 mRNA in lung tissues were detected by real time PCR.RESULTS Compared with normal group,the variations of thicknesses of bronchial wall and airway smooth muscle,the EOS counts in BALF,the concentrations of TGF-β1 in BALF and serum,the expressions of TGF-β1,p-Smad2,Smad2,p-Smad3,Smad3 and TGF-β1 mRNA,Smad2 mRNA,Smad3 mRNA in lung tissues were increased significantly in model group（P0.01）.All of these parameters were reversed by the treatment of high dose,low dose and positive control（P0.05 or P0.01）.CONCLUSION Bulbus Fritillariae Cirrhosae can improve airway remodeling in a murine asthma model,and its mechanisms may be related to reduction of TGF-β1/Smad signal pathway.