Han Fangfang, Zhu Shuyang, Chen Bi, Li Jingjing
Department of Respiratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221000, China.
Department of Respiratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221000, China. *Corresponding author, E-mail:
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi. 2017 Aug;33(8):1030-1034.
Objective To study the effect of cigarette smoke exposure on the expression of endothelin 2 (ET-2) in bronchial epithelium of asthmatic rats. Methods Asthma models were established through intraperitoneal injection of 1 mL chicken ovalbumin (OVA)/Al(OH) mixture (asthma model group, n=6); based on the asthma models, exposure to smoking gas lasted four weeks with 10 cigarettes per day (smoke-exposed asthma group, n=6); based on the smoke-exposed asthma models, the rats were treated with intraperitoneal injection of dexamethasone 2 mg/(kg.d), intragastric administration of ET receptor inhibitor bosentan 100 mg/(kg.d) and combined use, respectively named dexamethasone treated group, bosentan treated group, and dexamethasone-bosentan treated group, 6 rats in every group. What's more, other 6 rats were only subjected to intraperitoneal injection of 1 mL normal saline as normal controls; in addition to the injection of saline, cigarette smoke control group (n=6) was set up by the exposure to smoking gas for four weeks with 10 cigarettes per day. Bronchoalveolar lavage fluid (BALF) was collected from the upper lobe of the left lung for cell counting and classification. Pathological changes of the right upper lung lobe tissues were observed by HE staining. In other lung tissues, the expression of JNK1/2 was detected by Western blotting; ET-2 was tested by Western blotting and immunohistochemistry; thiobarbituric acid reactive substances (TBARS) assay and trace enzyme standard method were used to measure malondialdehyde (MDA) and glutathione (GSH), respectively. Results Compared with normal control group, the number of airway inflammation cells increased in the BALF, and the expressions of ET-2, JNK1/2, MDA and GSH increased in the lung tissues of cigarette smoke control group, asthma model group and cigarette smoke-exposed asthma group. Compared with cigarette smoke-exposed asthma group, the number of airway inflammation cells decreased in the BALF, and the expressions of ET-2, JNK1/2, MDA and GSH decreased in the lung tissues of the dexamethasone treated group, bosentan treated group, and dexamethasone-bosentan treated group. Airway inflammation was attenuated and the staining intensity of ET-2 in the lung tissue was reduced in the dexamethasone treated group, bosentan treated group, and dexamethasone-bosentan treated group, which were more obvious in the dexamethasone-bosentan treated group. Conclusion Cigarette smoke exposure obviously aggravates airway inflammation in asthmatic rats, and bosentan can effectively alleviate the airway inflammation. The mechanism of the inflammation may be related to ET-2 and JNK1/2 signaling pathway.
目的 研究香烟烟雾暴露对哮喘大鼠支气管上皮中内皮素2（ET-2）表达的影响。方法 通过腹腔注射1 mL鸡卵清蛋白（OVA）/Al(OH)混合物建立哮喘模型（哮喘模型组，n = 6）；在此哮喘模型基础上，每天暴露于香烟烟雾10支，持续4周（烟雾暴露哮喘组，n = 6）；在烟雾暴露哮喘模型基础上，分别腹腔注射地塞米松2 mg/(kg·d)、灌胃给予ET受体拮抗剂波生坦100 mg/(kg·d)及联合使用，分别命名为地塞米松治疗组、波生坦治疗组和地塞米松-波生坦治疗组，每组6只大鼠。另外，6只大鼠仅腹腔注射1 mL生理盐水作为正常对照组；除注射生理盐水外，设置香烟烟雾对照组（n = 6），每天暴露于香烟烟雾10支，持续4周。收集左肺上叶支气管肺泡灌洗液（BALF）进行细胞计数和分类。采用HE染色观察右上肺叶组织的病理变化。采用蛋白质免疫印迹法检测其他肺组织中JNK1/2的表达；采用蛋白质免疫印迹法和免疫组织化学法检测ET-2；分别采用硫代巴比妥酸反应物质（TBARS）法和微量酶标法测定丙二醛（MDA）和谷胱甘肽（GSH）。结果 与正常对照组相比，香烟烟雾对照组、哮喘模型组和烟雾暴露哮喘组BALF中气道炎症细胞数量增加，肺组织中ET-2、JNK1/2、MDA和GSH的表达增加。与烟雾暴露哮喘组相比，地塞米松治疗组、波生坦治疗组和地塞米松-波生坦治疗组BALF中气道炎症细胞数量减少，肺组织中ET-2、JNK1/2、MDA和GSH的表达降低。地塞米松治疗组、波生坦治疗组和地塞米松-波生坦治疗组气道炎症减轻，肺组织中ET-2染色强度降低，其中地塞米松-波生坦治疗组更明显。结论 香烟烟雾暴露明显加重哮喘大鼠气道炎症，波生坦可有效减轻气道炎症。炎症机制可能与ET-2和JNK1/2信号通路有关。
