探讨过敏性哮喘中Eotaxin致气道炎症的机制

Role of eotaxin in airway inflammation of allergic asthma

目的 探讨过敏性哮喘中嗜酸粒细胞趋化因子Eotaxin致气道炎症的机制 .方法 将豚鼠 4 0只随机分为哮喘组和对照组 ,卵蛋白致敏及诱发过敏性哮喘 . 1收集支气管肺泡灌洗液 (BAL F) ,观察细胞总数 (TC)及嗜酸粒细胞(Eos)、巨噬细胞 (AM)、淋巴细胞 (L)、中性粒细胞 (N)比例变化 ;2豚鼠肺组织病理标本经 HE染色 ,观察病理学改变 ;3采用原位分子杂交技术观察肺组织中 Eotaxin m RNA的表达 ;4采用 Northern blot方法观察肺组织中 Eotaxin m RNA表达情况 .结果 过敏性哮喘豚鼠 BAL F中 TC,Eos比例较对照组明显升高 (P<0 .0 1) ,AM比例显著下降 (P<0 .0 1) ,L和 N比例与对照组相差不明显 (P>0 .0 5 ) .哮喘豚鼠肺组织中可见气道炎症反应及 Eos和 L粘膜下浸润 .支气管粘膜、粘膜下层及周围肺组织中 Eotaxin m RNA阳性细胞表达率(198± 4 6 ) mm- 2较对照组 (16± 8) mm- 2明显增加 (P<0 .0 1) .Nortthern blot杂交可见哮喘组表达 Eotaxin m RNA较对照组明显升高 .结论 过敏性哮喘中 Eotaxin基因表达明显增强 ,同时伴有 Eos肺内募集及激活 。

AIM To study the role of eotaxin in the airway inflammation of asthma. METHODS ① Ovalbumin (Ova) sensitized and challenged guinea pigs; ② Bronchial alveolar lavage fluid (BALF) of guinea pigs were collected, and the cells were classified and counted; ③ The pathologic samples of lung tissue were stained with HE; ④ The expression of eotaxin mRNA in lung tissue of guinea pigs was examined by in situ hybridization (ISH) and Northern blot. RESULTS In airway allergic inflammation, the infiltration of eosinophils was the predominant pathologic change of asthma; The counts of eosinophils enhanced more prominently in BALF of asthmatic guinea pigs than in that of the normal control group ( P <0.01). Compared with the normal subjects, the epithelium of bronchial mucosa and alveolus were severely injured; Eotaxin mRNA was expressed at higher levels in lung tissues of asthmatic guinea pigs (198±46) cells·mm -2 than in those of the normal guinea pigs (16±8) cells·mm -2 ( P <0.01) by ISH and the same result also can be found by Northern blot. CONCLUSION Bronchial asthma is a disease which is characterised by airway allergic inflammation and infiltratration of eosinophils. Eotaxin gene is expressed at high levels in asthmatic lung tissues, which can selectively accumulate and activate eosinophils. We believe that eotaxin and eosinophils can play a key role in allergic asthma.