苗药杆努尽烟对慢性阻塞性肺疾病大鼠糖皮质激素耐药作用的分子机制

Effect of Lysionotus pauciflorus Maxim.on glucocorticoid resistance in rats with chronic obstructive pulmonary disease and its molecular mechanism

目的探讨苗药杆努尽烟对慢性阻塞性肺疾病(COPD)大鼠糖皮质激素耐药作用的分子机制。方法称取杆努尽烟全草制取水提物,选取10只Sprague-dawley(SD)大鼠作为对照组(正常饲养),40只大鼠采用烟熏结合脂多糖(LPS)气管注射法,制作COPD大鼠模型并随机均分为模型组(生理盐水灌胃)、杆努尽烟组(杆努尽烟水提液灌胃)、地塞米松组(雾化吸入地塞米松)及联合用药组(杆努尽烟灌胃联合地塞米松雾化吸入),造模同时给予相应药物干预28 d麻醉取心脏血,采用酶联免疫吸附试验(ELISA)检测各组大鼠血清白细胞介素-2(IL-2)的水平;处死大鼠,取肺组织采用苏木精-伊红染色(HE)法观察各组大鼠肺组织的组织学特征,并采用实时荧光定量聚合酶链反应(RT-qPCR)和免疫印迹法(Western blot)测定各组大鼠肺组织中P38促分裂素原活化蛋白激酶(P38MAPK)、GC受体-α(GR-α)及热休克蛋白90(HSP90)mRNA和蛋白的表达。结果与对照组相比,杆努尽烟组、地塞米松组、模型组及联合用药组COPD大鼠均有不同程度的喘息、咳嗽、精神状态不佳,其中联合用药组呼吸系统症状最轻;杆努尽烟组、地塞米松组血清IL-2含量较模型组降低(P<0.05),杆努尽烟组、地塞米松组及联合用药组COPD大鼠肺组织P38MAPK、GR-α及HSP90 mRNA和蛋白表达较模型组降低(P<0.05)。结论苗药杆努尽烟可改善COPD大鼠GC耐药作用,减轻肺组织炎症细胞浸润、降低血清IL-2水平,其机制可能与下调P38MAPK含量提高GR-α、HSP90表达有关。

Objective To explore the effect of Lysionotus pauciflorus Maxim.on glucocorticoid(GC)resistance in rats with chronic obstructive pulmonary disease(COPD)and its molecular mechanism.Methods Water extract from whole grass Lysionotus Pauciflorus Maxim.was weighed.Ten Sprague Dawley(SD)rats were selected as control group(normal feeding),and 40 SD rats were smoked and intratracheally injected with lipopolysaccharide(LPS)to establish COPD model.Rats with COPD were randomly divided into model group(physiological saline by gavage),Lysionotus pauciflorus Maxim.group(water extract by gavage),dexamethasone group(nebulized inhalation of dexamethasone),and combined medication group(water extract by gavage+nebulized inhalation of dexamethasone).Rats were simultaneously administered with corresponding medication intervention for 28 days during modeling.Enzyme linked immunosorbent assay(ELISA)was used to detect the level of inflammatory factor interleukin-2(IL-2)in cardiac serum.Hematoxylin eosin(HE)staining was applied observe the histological characteristics of rat lung tissues in each group.Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)and Western blot were used to determine the expression levels of heat shock protein 90(HSP90)mRNA,P38 mitogen activated protein kinase(P38 MAPK)and glucocorticoid receptor-α(GR-α)in rat lung tissues,respectively.Results When compared with control group,rats with COPD exhibited different degrees of wheezing,coughing and poor mental state in model,Lysionotus pauciflorus Maxim.,dexamethasone and combined medication groups.Among rats with COPD,combined medication group had the mildest respiratory symptoms.Serum IL-2 level in Lysionotus pauciflorus Maxim.and dexamethasone groups were lower than that in model group(P<0.05).P38 MAPK,GR-αproteins and HSP90 mRNA in rat lung tissues were also lower in Lysionotus pauciflorus Maxim.,dexamethasone and combined medication groups than those in model group(P<0.05).Conclusion Lysionotuspauciflorus Maxim.can improve GC resistance in rats with COPD,reduce inflammatory cell infiltration in lung tissues and decrease serum IL-2 level.Its mechanism may be related to downregulating P38 MAPK expression and upregulating the expression of GR-αand HSP90.