急性期和慢性期哮喘小鼠模型在哮喘致病过程中的对比研究

Comparative study of acute and chronic murine asthma model in the pathogenesis of asthma

【摘要】目的比较卵清蛋白（ovalbumin，OVA）诱导的急性期和慢性期哮喘小鼠模型在气道炎症、气道重塑和气道高反应方面的差异，明确在哮喘致病过程中肺组织的病理变化。方法48只BALB／c小鼠随机分为急性组和慢性组，其中急性组包括正常对照组（A1组）和急性哮喘组（A2组），慢性组包括正常对照组（B1组）和慢性哮喘组（B2组）。OVA致敏和激发方法分别构建急性早期哮喘模型和慢性期哮喘模型后，测定气道阻力，BALF细胞计数和分类计数，酶联免疫吸附测定（enzyme-linked immunosorbent assay，ELISA）检测IL-4、IL-5、转化生长因子-β1（transforminggrowthfactor-β1，TGF-β1）、血管内皮生长因子（vascularendothelialgrowthfactor，VEGF）和r干扰素（interferon-γ，IFN-γ）。HE染色观察气道炎症，A昏PAs和Masson染色测定气道重塑。结果与正常小鼠相比，A2组和B2组小鼠气道阻力均明显升高，但B2组小鼠气道阻力在基础值即发生明显改变。相比于慢性组哮喘小鼠，急性组哮喘小鼠BALF中细胞总数和嗜酸粒细胞数，IL-4、IL-5和IFN-γ水平，肺组织气道血管周围炎症细胞聚集，以及气道黏液分泌水平等炎症性改变更为明显。相比于A2组，B2组哮喘小鼠BALF中TGF-α，和VEGF水平，气道平滑肌增厚，上皮下胶原沉积，上皮下纤维化等改变更为显著。结论在急性早期哮喘中主要是以炎症性改变为主，但在哮喘早期即开始出现轻度的重塑性改变；而在慢性期哮喘中虽然存在炎症性改变，但影响哮喘症状的因素却主要以器质性改变为主。

Objective To explore the differences in airway inflammation, airway remodeling and airway hyperresponsiveness of ovalbumin （OVA） induced murine asthma model during acute and chronic terms, and clear the pathological changes in the pathogenesis of asthma. Methods 48 BALB/c mice were randomly divided into acute and chronic groups, in which acute groups including normal control group （A1 group） and acute asthma group （A2 group）, chronic group including normal control group （β1 group） and chronic asthma group （B2 group）. Using OVA sensitized and challenged methods induced acute and chronic asthma model, then assessed the airway resistance, total cell numbers and different cell numbers in the BALF, and detected the levels of IL-4, IL-5, transforming growth factor-β1 （TGF-β1）, vascular endothelial growth factor （VEGF） and IFN-γ by enzyme-linked immunosorbent assay （ELISA）. Then HE staining was used to observe airway inflammation. AB-PAS and Masson staining were used to measure airway remodeling. Results Compared with normal mice, the airway resistance of the acute asthma group and the chronic asthma group were significantly increased, there was no diference between the twogroups, but the basic airway resistance in the chronic phase was significantly changed. Compared to the chronic asthmatic mice, the inflammatory changes, such as numbers of total cells and EOS cells, levels of IL-4, IL-5 and IFN-γ, aggregation of inflammatory ceils around the airway and vascular and secretion of airway mucus were more obvious during acute phase. However, changes such as the levels of TGF-β1 and VEGF in the BALF, the thickening of airway smooth muscle, the subepithelial collagen deposition and subepithelial fibrosis were more significant in the chronic phase when compared with the acute asthma group. Conclusions In the early stage of asthma is mainly inflammatory changes, but the mild remodeling changes have been presented during this stage. And in the chronic stage of asthma although the inflammatory changes are continued, but the mainly factors that impact asthma symptoms are the organic changes.