BCG干预对哮喘小鼠气道炎症及调节性T细胞生成的影响

Effect of BCG Treatment on Airway Inflammation and T Regulatory Cell of Asthma Mouse

目的观察减毒卡介活菌疫苗(BCG)干预后哮喘小鼠气道炎症及调节性T细胞生成的变化,以探讨其可能的作用机制。方法24只昆明小鼠随机分为哮喘组、BCG干预组、正常对照组。昆明小鼠以卵白蛋白(OVA)致敏激发建立哮喘模型,于OVA致敏前及后5d分别以BCG皮内注射干预;正常对照组小鼠以生理盐水代替OVA致敏激发。所有小鼠在最后一次激发后24h收集支气管肺泡灌洗液(BALF)和外周血。计数BALF中的细胞总数及嗜酸性粒细胞(EOS)数。并用流式细胞仪分析外周血CD4+CD25+调节性T细胞(Treg)的百分比。开腹取脾,制备脾单细胞悬液并培养48h,收集上清液。Elisa法测定上清液中的IL-10含量。结果哮喘组小鼠BALF中的细胞总数及EOS计数较正常对照组显著增高(P<0.01),而BCG干预组其BALF中的细胞总数及EOS的计数较OVA致敏激发组降低(P<0.01);哮喘组外周血CD4+CD25+Treg百分比为(11.59±1.33)%,较正常对照组的(13.66±1.68)%显著下降(P<0.01);而BCG干预组CD4+CD25+Treg百分比为(14.4±2.75)%,较哮喘组明显上升(P<0.05)。BCG干预组脾细胞培养上清液中IL-10的水平(7.79±1.34pg/ml)较哮喘组(5.54±0.66pg/ml)显著升高(P<0.01)。结论BCG能明显抑制哮喘小鼠气道的炎症反应,其干预机制可能与促进Treg生成有关。

Objective To explore the effect of BCG treatment on T regulatory cell of asthma mouse. Methods Twenty four Kunming mouse were randomly divided into asthma group, BCG treatment group and control group. Kunming mouse were sensitized and challenged with OVA to establish asthma model. Asthma mouse in BCG treatment group were injected intradermally with BCG 5 days before and after sensitization. The mice in control group were challenged with saline. After 24 hours of last challenge , bronchoaveolar lavage fluid （BALF） and peripheral blood were collected . The total ceils and eosinophils were counted in BALF. The percentage of CD4^＋ CD25^＋ in peripheral blood was analyzed with flow cytometry. Single spleen cell suspension was prepared and cultured in 1640 medium , after 48 hours, supernatant was harvested and the level of cytokine IL-10 was determined by Elisa. Results Compared with the normal control group, the total cells and eosinophils in BALF were more in asthma mouse （ P 〈 0.01） . The number of total ceils and eosinophils in BALF were reduced in asthma mouse treated with BCG compared with asthma mouse （ P 〈 0.01 ）. The percentage of CD4^＋ CD25^＋ in peripheral blood of asthma mouse（11.59 ± 1.33） % was lower than that in the control group（ 13.66 ± 1.68）% （ P 〈 0. 01 ）. The percentage of CD4^＋CD25^＋ in asthma mouse treated with BCG（14.4 ± 2.75）% was higher than asthma mouse （ P 〈 0.05）. The level of IL-10 in spleen cell supernatant within BCG group（7.79 ± 1.34 pg/ml） was also elevated contrasted with asthma mouse（5.54 ± 0.66 pg/ml） （ P 〈 0.01）. Conclusion BCG can markly inhabit airway inflammation of asthma mouse by mechanism that promote the production of regulatory T cell.