肺表面活性物质对哮喘小鼠模型树突细胞功能的调节机制

Role of pulmonary surfactant in regulating dendritic cell function of murine asthma models

目的:研究外源性肺表面活性物质对小鼠哮喘模型的免疫调节作用及其对树突细胞(DC)功能的影响.方法:BALB/c小鼠50只,分为3组:哮喘组15只[采用卵蛋白(OVA)致敏和激发]、对照组15只(以生理盐水代替OVA致敏和激发)、治疗组20只[每次OVA激发后10min以肺表面活性物质(PS)20g/L雾化吸入,时间为2,5,10,15和20min].用HE染色方法评定哮喘模型.分离培养脾脏DC,用流式细胞仪(FACS)检测DC表面共刺激分子CD80的表达变化.取DC培养液3mL,加入OVA,调整OVA浓度至10mg/L.分别在2,4,6,12,24h取DC培养液,1300r/min离心5min,取上清液,ELISA法检测IL-12P70.结果:哮喘组小鼠的肺组织表现为嗜酸细胞及淋巴细胞浸润为主的炎症变化,治疗组和对照组无此变化.哮喘组DC阳性表达率明显高于治疗组(P<0.01);吸入PS对DC表面共刺激分子的抑制作用在2min时最强.哮喘组DC上清液IL-12低于治疗组(P<0.01);治疗组DC上清液IL-12可以在高水平维持较长时间,而哮喘组的DC上清液IL-12含量降低,且维持时间较短.结论:小鼠哮喘模型中存在明显的DC功能缺陷;外源性吸入PS,能明显改善DC功能,从而保护哮喘发作时小鼠的肺功能.

AIM： To explore the mechanisms of exogenous pulmonary surfactant （PS） in regulating the immunity of murine asthma models and its effect on dendritic cell （DC） function of the spleen of the asthma models. METHODS： Murine asthma models were established with ovalbumin （OVA） sensitization and challenge and the models were confirmed by histological analysis of lung tissues. FACS was used to measure the expression of CD80 on DC derived from the spleen of OVA-sensitized and challenged mice. PS was inhaled after OVA challenge by 20 g/L for 2, 5, 10, 15 and 20 min. IL-12 in DC culture medium was tested at 2, 4, 6, 12 and 24 h and data were analyzed with SPSS 10.0 software. REUILTS： Histological analysis results of lung tissues were consistent with the characteristics of murine asthma model. The expression rate of CD80 on spleen-derived DC in asthma group significantly increased compared with that in PS group （ P 〈 0.01 ） and CD80 expression rate was the lowest when PS was in haled for 2 min. IL-12 in asthma group decreased compared with that in PS group （P 〈0.01）.PS group kept IL-12 at a high level for a long time while IL-12 expression level was low and lasted for a short time in asthma group. CONCLUSION： Abnormal DC function is existent in murine asthma models and exogenous surfactant can regulate the DC function by suppressing the expression of CD80 on DC and increasing the level of IL-12 secreted by DC, which can improve the respiratory function when the asthma is challenged.