血管内皮生长因子在支气管哮喘小鼠气道中表达变化及其对气道重构的影响

Correlation of airway remodeling with expression of vascular endothelial growth factor in lung tissues of bronchial asthma mice

目的研究血管内皮生长因子（VEGF）在支气管哮喘（哮喘）小鼠气道中表达变化及其对气道重构的影响。方法将40只雌性BALB/c小鼠随机分为4组（每组10只）：生理盐水对照组（A组）;哮喘组（B组）;VEGF受体抑制剂干预组（C组）;地塞米松干预组（D组）。用鸡卵白蛋白致敏和雾化激发建立慢性哮喘小鼠模型。收集小鼠的支气管肺泡灌洗液（BALF）,行白细胞和嗜酸粒细胞（EOS）计数;ELISA法检测BALF和血清中VEGF的水平;用SABC免疫组化法检测VEGF在肺组织的表达水平并行抗Ⅷ因子免疫组化染色在显微镜下计数气管黏膜固有层、黏膜下层血管密度;用逆转录-聚合酶链反应（RT-PCR）方法检测VEGF mRNA的表达变化;采用医学图像分析软件测定支气管管壁厚度（WAt/Pbm）及肺组织切片中的血管数。结果B组BALF中白细胞总数、EOS百分比、VEGF浓度及血清中VEGF浓度明显高于A组,差异有统计学意义（P〈0.01）;C、D两组与B组比较差异均有统计学意义（P〈0.01）,C组与D组比较差异无统计学意义（P〉0.05）。抗Ⅷ因子免疫组化染色及图像分析结果显示：B组气管血管密度、WAt/Pbm及肺组织切片中的血管数明显高于A组（P〈0.01）,C、D两组与B组比较均显著减少（P〈0.01）,C组与D组比较差异无统计学意义（P〉0.05）。免疫组化及RT-PCR检测结果显示：B组小鼠肺组织中的VEGF表达较A组显著增加（P〈0.01）,C、D两组小鼠肺组织中VEGF的表达与B组比较均显著减少（P〈0.01）,C组与D组比较差异无统计学意义（P〉0.05）。结论VEGF在小鼠哮喘模型气道及肺组织内过度表达,参与了哮喘的发病和气道重构的过程,VEGF受体抑制剂可以降低哮喘模型的气道炎症,减轻气道重构的程度。

Objective To investigate the correlation of airway remodeling with the expression of vascular endothelial growth factor（VEGF） in lung tissues of bronchial asthma（asthma） mice.Methods Forty female BALB/c mice were randomly divided into four groups（10 mice a group）：saline control group（group A）;asthma group（group B）;VEGF receptor inhibitor group（group C）;dexamethasone group（group D）.The asthma model was established by sensitizing and challenging with ovalbumin.Bronchoalveolar lavage fluid（BALF） was collected for counting WBC and the percentage of esosinophils（EOS）;VEGF concentration was measured by ELISA.The pathologic changes of bronchial and lung tissue were evaluated.Anti-factor ⅧAg antibody was used to detect vessels,the number of vessels in proper lamina and submucosa of tracheae were counted microscopically.Immunohistochemistry and RT-PCR were used to measure the level of VEGF in the lung tissues of asthma mice,the airway wall thickness（WAt/Pbm） and vascular counts were measured by using image analysis system.Results The total WBC,percentage of EOS,concentrations of VEGF in group B were significantly higher than those of group A（P〈0.01）,both group C and group D were significantly different from group B（P〈0.01）,group D was not significantly different from group C（P〉0.05）.The density of vessels in group B increased significantly compared with that of group A（P〈0.01）,both group C and D were decreased compared with that of group B（P〈0.01）,there was no difference between group C and D（P〉0.05）.Immunohistochemistry and RT-PCR showed that the expression of VEGF protein and mRNA in lung tissue in group B were increased compared with that of group A（P〈0.01）,both group C and D were reduced compared with group B（P〈0.01）,but there were no difference between group C and D（P〉0.05）.Image analysis system showed that the airway wall thickness（WAt/Pbm） and vascular counts in group B were higher than those in group A.Conclusions VEGF was over-expressed in the asthma mice and involved in airway remodeling,VEGF receptor inhibitor can relieve the allergic inflammation of airway and airway remodeling in asthma mice.