CpG ODN对哮喘小鼠肺组织共刺激分子B7和CD40表达的影响

Effects of CpG ODN on B7 and CD40 Costimulatory Molecule Expression in Asthma Model of Mice

目的观察CpG ODN对哮喘小鼠肺组织共刺激分子B7和CD40表达的影响,探讨其诱导免疫耐受的可能机制。方法清洁级雄性Balb/c小鼠48只,随机分为对照组(A组)、哮喘组(B组)、地塞米松(DXM)组(C组)、CpG ODN组(D组),每组12只。用卵白蛋白(OVA)致敏和激发建立小鼠哮喘模型。观察肺组织病理变化,支气管肺泡灌洗液(BALF)中白细胞总数及分类计数,反转录-聚合酶链反应(RT-PCR)法及免疫组织化学法分别测定肺组织中B7、CD40 mRNA及蛋白表达。结果①肺组织病理变化:B组支气管、血管周围及间质和肺泡腔内有较多炎性细胞浸润,支气管上皮多处断裂,细小支气管内可见黏液栓和炎性渗出物,C组、D组与B组相比明显减轻;②BALF中D组嗜酸性粒细胞平均计数为(2.76±0.25)×107/L,C组为(1.05±1.72)×107/L,均低于B组的(12.09±2.62)×107/L,差异有统计学意义(P<0.01),D组与C组比较差异无统计学意义(P>0.05);③RT-PCR、免疫组化结果:C、D组显著低于B组(P<0.05),C组与D组比较无统计学差异(P>0.05);④相关分析:肺组织共刺激分子B7和CD40表达呈正相关(P<0.05,n=40)。结论 CpG ODN能降低共刺激分子B7、CD40在肺组织的表达,具有改善气道炎症和诱导免疫耐受的作用。

Objective To investigate the possible mechanisms induced by CpG ODN on the expression of costimulatory molecule B7, CD40 of lung tissue in acute asthma model of mice. Methods Forty - eight male Balb/c mice were randomly divided into the control group （group A）, asthma model group（ group B）, dexamethasone control group （group C）, CpG ODN treatment group （group D） with 12 in each. Group B were sensitized by OVA to establish the acute mice asthma model. Lung were fixed and sections were used for his- topathological examination by opticsmicroscope to observe condition of lung inflammation; Bronchoalveolar lavage fluid （BALF） were col- lected and the total cell numbers were counted. The expression of B7, CD40 in the lung were measured by reverse transcriptase polymer- ase chain reaction （ RT - PCR） and Immunohistochemistry. Results @There were infiltration of inflammatory cells in bronchial contrac- tion, narrow lumen and perivascular surrounding. Mucus secretion increased significantly, epithelium exfoliated, basement membrane was exposed, and bronchial secretions were storage, following the basement membrane and the smooth muscle were hypertrophy in Group B, whereas group D and group C showed significantly milder changes. （~）In the BALF, the mean numbers of EOS were （2.76± 0.25 ）× 107/ L in group D and （ 1.05 ＋ 1.72） ~ 107/L in group C, respectively, and were both significantly lower than group B, which was （ 12.09 ~ 2.62 ） x 107/L （ P 〈 0.01 ）. （~）The expression of B7 and CD40 in group D and group C was significantly higher than group B （ P 〈 0.05 ） , and there was rio difference between group C and group D（P 〉 0.05）. @The expression of B7 was positively correlated with CD40（P 〈 0.01 ,n = 40）. Conclusion CpG ODN lower costimulatory molecules B7, CDg0 expression in the lung tissue and improve airway inflam- mation, induce immune tolerance.