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目的探讨香烟烟雾对哮喘大鼠肺组织内皮素2(ET-2)表达的影响。方法大鼠腹腔注射鸡卵清蛋白/Al(OH)3混合液1 m L致敏建立哮喘模型(哮喘模型组,n=6),在哮喘模型组基础上烟熏(10支/d)连续4周为香烟烟雾哮喘组(烟雾哮喘组,n=6),分别以地塞米松2 mg/(kg·d)腹腔注射1周、ET受体抑制剂波生坦100 mg/(kg·d)灌胃及联合处理分为地塞米松处理组、波生坦处理组、地塞米松及波生坦处理组,每组6只,设正常对照(正常对照组,腹腔注射生理盐水1 m L,n=6)及香烟烟雾对照[在正常对照组基础上,连续烟熏(10支/d)4周,n=6]。收集左肺上叶支气管肺泡灌洗液(BALF)检测细胞计数及分类,右肺上叶HE染色观察肺组织病理学改变;其余肺组织行Western blot法及免疫组织化学染色法分别检测肺组织c-Jun氨基末端激酶1/2(JNK1/2)、ET-2蛋白水平,硫代巴比妥酸法测丙二醛(MDA)水平,微量酶标法测谷胱甘肽(GSH)水平。结果与对照组比较,香烟烟雾对照组、哮喘模型组、香烟烟雾哮喘组BALF中白细胞数、中性粒细胞数及嗜酸性粒细胞数升高,肺组织中ET-2蛋白、JNK1/2蛋白、MDA及GSH水平升高;而与香烟烟雾哮喘组比较,地塞米松处理组、波生坦处理组、地塞米松及波生坦处理组BALF中白细胞数、中性粒细胞数及嗜酸性粒细胞数均降低。肺组织中ET-2蛋白、JNK1/2蛋白、MDA及GSH表达降低。地塞米松处理组、波生坦处理组、地塞米松及波生坦处理组气道炎症均有改善,地塞米松及波生坦处理组改善最明显。ET-2在地塞米松处理组、波生坦处理组、地塞米松及波生坦处理组肺组织染色强度减少,地塞米松及波生坦处理组染色强度减少更明显。结论香烟烟雾暴露可加重哮喘大鼠气道炎症,ET受体抑制剂波生坦可改善气道炎症,香烟烟雾暴露哮喘发生的炎症机制可能与ET-2及JNK1/2通路有关。
Objective To investigate the effects of cigarette smoke on the expression of endothelin 2 (ET-2) in lung tissue of asthmatic rats. Methods The asthma model was established by intraperitoneal injection of chicken ovalbumin / Al (OH) 3 mixture at a concentration of 1 mL (asthma model group, n = 6). On the basis of asthma model group, The rats in the cigarette smoke asthma group (n = 6) were treated with 2 mg / (kg · d) of dexamethasone for 1 week, and the ET receptor inhibitor bosentan 100 mg / (kg · d ), Gavage and combination therapy were divided into dexamethasone treatment group, bosentan treatment group, dexamethasone and bosentan treatment group, 6 rats in each group. The normal control group (normal control group, intraperitoneal injection of normal saline 1 m L , n = 6), and cigarette smoke control [four weeks after continuous smoking (n = 6) on the basis of the normal control group, n = 6]. The bronchoalveolar lavage fluid (BALF) in the left upper lung was collected to detect the cell count and classification. The lung tissues of the right upper lobe were stained with HE for histopathological changes. The remaining lung tissues were examined by Western blot and immunohistochemical staining The levels of JNK1 / 2, ET-2, and MDA were measured by thiobarbituric acid method and glutathione (GSH) by micro-enzyme-labeled method. Results Compared with the control group, the number of leucocytes, neutrophils and eosinophils in BALF of cigarette smoke control group, asthma model group and cigarette smoke asthma group were significantly higher than those in control group. The levels of ET-2 protein, JNK1 / 2 protein , MDA and GSH levels increased; while compared with the cigarette smoke asthma group, the number of white blood cells, neutrophils and eosinophils in the BALF of dexamethasone treated group, bosentan treated group, dexamethasone and bosentan treatment group The number of granulocytes decreased. The expression of ET-2 protein, JNK1 / 2 protein, MDA and GSH in lung tissue decreased. Dexamethasone treatment group, bosentan treatment group, dexamethasone and bosentan treatment group, airway inflammation were improved, dexamethasone and bosentan treatment group to improve the most obvious. The staining intensity of ET-2 in dexamethasone treated group, bosentan treated group, dexamethasone and bosentan treatment group decreased and the staining intensity of dexamethasone and bosentan treated group decreased more obviously. Conclusions Cigarette smoke exposure may aggravate airway inflammation in asthmatic rats. Bosentan, an ET receptor inhibitor, may improve airway inflammation. The possible mechanism of inflammation may be related to ET-2 and JNK1 / 2 pathways.