阿魏酸对大气PM2.5诱导哮喘大鼠氧化损伤和TGF-β1/Smads信号通路改变的拮抗及机制研究

Mechanism of ferulic acid antagonizing oxidative damage and TGF-β1/Smads signaling pathway induced by atmospheric PM2.5 in asthmatic rats

目的探讨阿魏酸(ferulic acid)对大气细颗粒物(PM2.5)加重哮喘大鼠呼吸道损伤的干预作用及干预机制。方法SPF级12周龄的雄性SD大鼠随机分为阴性对照组、哮喘模型组、PM2.5染毒组(6.0 mg/kg)、阳性对照组(6.0 mg/kg PM2.5+0.1mg/kg地塞米松)、PM2.5+阿魏酸低剂量组(19.4mg/kg)、PM2.5+阿魏酸中剂量组(38.8 mg/kg)、PM2.5+阿魏酸高剂量组(77.6mg/kg),以卵清蛋白(OVA)皮下注射建模,气管滴注PM2.5,阿魏酸或地塞米松灌胃,OVA雾化,实验连续34 d,以比色法检测血清中超氧化物歧化酶(SOD)活力、丙二醛(MDA)的含量,以ELISA法检测肺组织中转化生长因子β1(TGF-β1)、Smad3、Smad2和Smad7含量,同时观察肺组织病理损伤。结果与阴性对照组相比,模型组血清的MDA含量增加,SOD活力降低(P<0.05);与模型组相比,PM2.5染毒组血清的MDA含量增加,SOD活力降低(P<0.05);与PM2.5染毒组相比,阳性对照组和PM2.5+阿魏酸低、中剂量干预组血清MDA含量降低(P<0.05),SOD活力升高;PM2.5+阿魏酸低、中剂量干预组血清MDA含量均低于PM2.5+阿魏酸高剂量组,PM2.5+阿魏酸中剂量组血清SOD活力高于PM2.5+阿魏酸高剂量组(P<0.05)。与阴性对照组相比,模型组肺组织TGF-β1、Smad2、Smad3含量增加(P<0.05),而Smad7含量显著降低(P<0.05);与模型组相比,PM2.5染毒组肺组织TGF-β1、Smad3含量增加(P<0.05);与PM2.5染毒组相比,阳性对照组和PM2.5+阿魏酸低、中剂量组肺组织TGF-β1、Smad2、Smad3含量降低(P<0.05),Smad7含量增加(P<0.05);PM2.5+阿魏酸低、中剂量组肺组织Smad7含量均高于PM2.5+阿魏酸高剂量组(P<0.05)。结论表明一定浓度的阿魏酸能够有效拮抗PM2.5对哮喘大鼠呼吸道损伤作用,可以通过减轻氧化损伤,重新调节TGF-β1/Smads信号通路发挥保护作用。

Objective To explore the protective effects and mechanism of ferulic acid(FA)on the respiratory tract injury aggravated by PM2.5 in asthmatic rats.Methods Male SPF-grade SD rats were randomly divided into the following seven groups,control group(normal saline),asthma model(OVA)group,PM2.5(OVA+6.0 mg/kg PM2.5)group,PM2.5+FA low dose group(OVA+6.0 mg/kg PM2.5+19.4 mg/kg FA),PM2.5+FA moderate dose group(OVA+6.0 mg/kg PM2.5+38.8 mg/kg FA),PM2.5+FA high dose group(OVA+6.0 mg/kg PM2.5+77.6 mg/kg FA)and positive control group(OVA+6.0 mg/kg PM2.5+dexamethasone),eight rats each group.OVA-sensitized rats were used to build the asthmatic rat models.Ferulic acid was given by oral administration.The rats was exposed to PM2.5 by tracheal instillation,then OVA was given by ultrasonic atomizing inhalation.The activities of superoxide dismutase(SOD),methane dicarboxylic aldehyde(MDA)in serum were detected by colorimetric method,The contents of TGF-β1,Smad3,Smad2 and Smad7 in lung tissue were detected by ELISA.The pathology of lung tissues were measured by HE staining.Results Compared with the control group,the level of MDA in serum increased and SOD activity in serum decreased in the asthma model group(P<0.05);Compared with the asthma model group,the level of MDA in serum increased and SOD activity in serum decreased in the PM2.5 group(P<0.05);Compared with PM2.5 group,the level of MDA in serum,and SOD activity in serum increased in the positive control group,PM2.5+FA low(19.4 mg/kg)and moderate(38.8 mg/kg)dose groups(P<0.05);The level of MDA in serum increased and SOD activity in serum decreased in PM2.5+FA high(77.6 mg/kg)dose group compared with PM2.5+FA low(19.4 mg/kg)and moderate(38.8 mg/kg)dose groups(P<0.05).Compared with the control group,the contents of TGF-β1,Smad2 and Smad3 in lung tissue increased(P<0.05),Smad7 content in lung tissue decreased in asthma model grouop(P<0.05);Compared with the asthma model group,the contents of TGF-β1 and Smad3 in lung tissue were increased in PM2.5 group(P<0.05);Compared with PM2.5 group,the contents of TGF-β1,Smad2 and Smad3 in lung tissue decreased,Smad7 content in lung tissue increased in the positive control group,PM2.5+FA low(19.4 mg/kg)and moderate(38.8 mg/kg)dose groups(P<0.05);The content of Smad7 in lung tissue increased in PM2.5+FA low(19.4 mg/kg)and moderate(38.8 mg/kg)dose groups compared with PM2.5+FA high(77.6 mg/kg)dose group(P<0.05).Conclusion A certain concentration of FA can effectively inhibit PM2.5-induced respiratory tract injuries in asthmatic rats.These protective effects may be achieved by inhibiting oxidative injuries and regulating TGF-β1/smads signaling pathway.