咪喹莫特对哮喘小鼠气道反应性及气道重塑的影响

Effects of imiquimod on airway hyperresponsiveness and airway remodeling in an asthmatic mouse model

目的:观察咪喹莫特对哮喘小鼠气道反应性,气道重塑和肺组织血管内皮生长因子(VEGF)表达的影响。方法:30只小鼠按随机数字表法分成3组,每组10只。正常对照组、哮喘组、咪喹莫特组。小鼠于第0、14天以鸡卵白蛋白(OVA)致敏,第24天开始雾化吸入1%OVA激发并持续28天,建立哮喘气道重塑模型,咪喹莫特组在吸入OVA前2h雾化吸入咪喹莫特30min。于最后一次雾化结束后24h,利用肺功能仪测小鼠气道阻力;收集支气管肺泡灌洗液(BALF)进行细胞计数及分类;对肺组织切片行HE染色观察病理学改变;运用医学图像分析软件测定肺组织切片中的血管计数、血管壁平滑肌厚度、血管壁平滑肌细胞计数;用免疫组化方法检测肺组织VEGF的蛋白表达水平;用RT-PCR检测肺组织VEGF mRNA表达水平。结果:哮喘组小鼠呼气阻力(Re)高于对照组(P<0.05),咪喹莫特组Re低于哮喘组(P<0.05);哮喘组BALF中细胞总数及各种炎症细胞数均较对照组升高(P<0.05),咪喹莫特组较哮喘组降低(P<0.05);哮喘组血管计数、血管壁平滑肌细胞计数较对照组增高,差异均有统计学意义(P<0.05),咪喹莫特组血管计数较哮喘组下降,差异有统计学意义(P<0.05);对照组VEGF蛋白和mRNA在气道不表达或轻度表达,哮喘组VEGF蛋白和mRNA表达较对照组增加,差异有统计学意义(P<0.05),咪喹莫特组能减少VEGF蛋白和mRNA的表达,与哮喘组比较差异有统计学意义(P<0.05),但较对照组仍增加,差异无统计学意义(P>0.05)。结论:早期预防性雾化吸入咪喹莫特通过部分抑制哮喘肺组织VEGF蛋白和mRNA的过度表达,阻止慢性哮喘小鼠的血管生成,可在一定程度上减轻哮喘小鼠的气道重塑和气道高反应性。

Objective：To observe the effects of imiquimod on airway hyperresponsiveness, airway remodeling and the expression of vascular endothelial growth factor （VEGF） in an asthmatic mouse model. Methods：Mice were randomly divided into a control group （A group）, an asthmatic group（B group） and an imiquimod group（C group）, each in ten. Mice were sensitized on days 0 and 14 by OVA and challenged from days 24 to 51 by OVA repeatedly to establish a chronic asthmatic model. C group were interfered with aerosol Imiquimod 30 rain before challenge. A group was treated with saline instead of OVA. The airway resistance （Re） was measured with pulmonary function meter. Bronchial alveolar lavage fluid was performed and cell differential was examined by Wright-Giemsa staining; the vascular counts were measured by image analysis system. The protein expression of VEGF was determined by immuno-histochemistry. The mRNA expression of VEGF was detected by RT-PCR. Results：Re of B group was higher than A group （P 〈 0.05）, Re of C group was reduced compared with B group （P 〈 0.05）. Total cell counts, EOS and lymphocyte in B group were higher than those in A group（P 〈 0.05）,while decreased in C group（P 〈 0.05）. in B group, the expressions of VEGF and mRNA increased when compared with A group（P 〈 0.05）,and decreased in C group（P 〈 0.05）. Conclusion：The experimental data suggest that imiquimod aerosol inhalation may inhibit airway hyperresponsiveness and airway remodeling, decrease the protein and mRNA expressions of VEGF in a mouse model of chronic asthma.