哮喘大鼠HIF-1α、转化生长因子-β的表达及调控

Expression of HIF-1α and TGF- β 1 mRNA in asthmatic rats

目的 探讨HIF-1α、TGF-β1在哮喘急性发作期中的作用及两者间的相关性.方法 选取健康清洁级雄性SD大鼠48只,随机均分为4组：正常对照组、哮喘组、地塞米松治疗组（地塞米松组）、布地奈德治疗组（布地奈德组）.制备大鼠哮喘模型,观察各组大鼠肺组织病理变化、分析支气管肺泡灌洗液（BALF）中的细胞总数和分类计数,并采用免疫组织化学法和原位杂交法测定各组大鼠肺组织中HIF-1α、TGF-β1的表达情况,并作相关性分析.结果 正常对照组大鼠气道及肺实质无异常改变,细胞结构完整;哮喘组大鼠气道腔内有大量炎症细胞及分泌物充塞,形成黏液栓,气道上皮细胞损伤、脱落、基底膜增厚且形态不规则、平滑肌肥大增生;布地奈德组和地塞米松组大鼠气道腔内无明显分泌物,其它症状亦较哮喘组明显减轻.哮喘组细胞总数及EOS、PMN、Lym计数比例均显著高于正常对照组（P〈0.01）,Mφ计数比例显著低于正常对照组（P〈0.01）;布地奈德组和地塞米松组细胞总数及EOS、Lym计数比例均显著低于哮喘组（P〈0.01）,Mφ计数比例显著高于哮喘组（P〈0.01）.哮喘组大鼠肺组织HIF-1α及TGF-β1的表达均显著高于正常对照组（P〈0.01）,地塞米松组和布地奈德组HIF-1α的表达均明显高于正常对照组（P〈0.05）,布地奈德组和地塞米松组大鼠肺组织HIF-1α及TGF-β1的表达均显著低于哮喘组（P〈0.01）.哮喘大鼠肺组织中HIF-1α与TGF-β1的表达呈显著正相关（P〈0.01）.结论 哮喘急性发作期HIF-1α及TGF-β1的表达显著增加,两者间呈现显著正相关;糖皮质激素干预可以降低HIF-1α及TGF-β1的表达,减轻哮喘气道炎症.

Objective To investigate the expression of hypoxia-inducible factor-1 alpha （HIF-1α） and transforming growth factor- β1 （TGF- β1） in asthmatic rats. Methods Forty eight male rats were randomly divided into 4 groups： the asthma group （group A）, control group （group C）, dexamethasone-treated group （group D） and budesonide-treated group （group B）. The Asthma of rats was induced by the ovalbumin （OVA） challenge methods; 24h after the last challenge the animals were sacrificed and blood, lung tissue and bronchoalveolar lavage fluid （BALF） samples were collected. The total cell numbers and differentiation cell numbers were counted in BALF, the expressions of HIF-1α protein and TGF- β1 mRNA were detected by immunohistochemistry and hybridioation in situ respectively.Results In asthmatic rats （group A） histopathology showed that there were irregular bronchial wall and proliferation of smooth muscle, infiltration of inflammation cells around the bronchi and the vessels; the arrangement of airway epithelial cells were damaged and replaced by lymphocytes and macrophages; also showed bronchial mucus plugs and goblet cells proliferation. In budesonide and dexamethasone groups （group B and D） the above pathological changes were milder. The total cell numbers, the ratios of eosinophil （EOS）, polymorphonuclear leukocyte （PMN） and lymphocyte （Lym） to the total cell numbers of BALF in group A were significantly higher than those in group C （P〈0.01）; while the ratios of macrophage （MФ） in group A were significantly lower than those in group C （P〈0.01）.The total cell numbers, the ratios of EC）S and Lym in group D and group B were decreased and the ratios of MФ were increased compared to those in group A （both P〈0.01）, and there were no differences in the ratios of PMN in group D and group B compared to those in group A （P〉0.05）. Immunohistochemistry showed that HIF-1α expressions in lung tissue of group A were significantly increased than those in groups C, D and B （P〈0.01）; and HIF-1α expressions in group D and group B were significantly increased than those in group C （P〈0.05）. Hybridization in situ showed that TGF- β1 mRNA expressions in tung tissue of group A were significantly increased than those in group C, D and B （P〈0.01）. There was a significant positive correlation between the expression of HIF-1α and TGF- β1 in lung tissue （r=0.770, P〈0.01）. Conclusion Glucocorticoids （dexamethasone and budesonide） can down-regulate the expression of HIF-1α and TGF- β1 in lung tissue, which might be associated with inhibition of inflammation in bronchial wall.