减毒活菌卡介苗不同时间和剂量干预对哮喘小鼠气道炎症的影响

Effects of bacillus calmette-guerin by different dosages at different times on airway inflammation in mouse models of asthma

目的 探讨以不同时间和不同剂量给予减毒活菌卡介苗 (BCG)对哮喘小鼠气道炎症和气道粘液分泌的影响。方法 选择C5 7BL/6小鼠 ,以卵白蛋白 (OVA)致敏激发建立小鼠哮喘模型 ,阴性对照组以生理盐水致敏激发。BCG干预组分 6组 ,其中 4组分别选择第一次抗原致敏前 4d(组 1)、后 10d(组 2 ) ,最后一次抗原激发后 1h(组 3) ,以及第一次抗原致敏前 4d与后 10d两次 (组4 ) ,以BCG 10 5CFUs皮内注射干预 ;另二组在第一次抗原致敏后 10d分别以BCG 10 6(组 5 )、10 4CFUs(组 6 )皮内注射干预 ,在最后一次抗原激发后 4 8h收集支气管肺泡灌洗液 (BALF) ,计数其中嗜酸性粒细胞 (EOS) ,肺组织PAS染色鉴定粘液分泌。结果 OVA致敏激发组BALF中EOS为 (41 16±6 4 2 )× 10 4,阴性对照组BALF中几乎见不到EOS。组 1、组 2和组 3BALF中EOS分别为 (10 6 9±4 35 )× 10 4、(7 92± 2 30 )× 10 4及 (17 4 6± 8 0 0 )× 10 4,组 5和组 6BALF中EOS分别为 (8 71± 3 83)×10 4及 (17 19± 4 4 9)× 10 4,均较OVA致敏激发组明显降低 (P <0 0 5 ) ;致敏前、后BCG两次干预 (组4 )对BALF中EOS[(0 79± 0 36 )× 10 4]的抑制更为明显 ,达 98%以上。肺组织见OVA致敏激发组气道上皮杯状细胞增生肥大 ,有大量粘液分泌 ;阴性对?

Objective To investigate the effects of subcutaneous injection of bacillus calmette-guerin (BCG) by different dosages at different times on the airway inflammation and airway mucus secretion in a mouse model of asthma.Methods A group of C57BL/6 mice were sensitized and challenged by ovabumin (OVA) as positive group and other mice were treated by saline as negative group.Six groups of mice were infected with BCG at different times with different dosages as follows:subcutaneous BCG 10 5 CFUs (1)4 days before (group 1),(2) 10 days after the first OVA sensitization (group 2),(3)1 hr after the last OVA challenge (group 3),(4)both 4 days before and 10 days after the first OVA sensitization (group 4).Mice in the other two groups were injected subcutaneously with BCG10 6 (group 5) or 10 4 CFUs (group 6)10 days after the first OVA sensitization.Then the bronchoalveolar lavage(BALF)eosinophil numbers and airway mucus secretion 48 hours after the last OVA challenge were analysed.Results In asthma group ,the EOS numbers in BALF were (41.16±6.42)×10 4 but these cells were scarcely seen in negative group.EOS in BALF of each BCG infected group decreased compared with the asthma group( P <0.05) as follows:(10.69±4.35)×10 4 in group 1,(7.92±2.30)×10 4 in group 2,(17.46±8.00)×10 4 in group 3,(8.71±3.83)×10 4 in group 5,and(17.19±4.49)×10 4 in group 6.When BCG 10 5 CFUs were infected twice (group 4),the decrement of EOS in BALF was more obviously( P <0.01) with inhibition ratio more than 98%.There were mucus hypersecretion in the epithelial cells in the asthma group but no mucus secretion in negative group.In BCG-infected mice mucus secretion was suppressed significantly.Conclusions Subcutaneous injection of BCG 10 5 CFUs inhibited the accumulation of EOS in BALF by twice more significantly than BCG 10 6 CFUs by single time.Either before or after OVA sensitization or after OVA challenge BCG infection can inhibit EOS accumulation in BALF and decrease mucus hypersecretion in the airway epithelial cells,suggesting that BCG could not only prevent but also treat the the airway inflammation in a mouse model of asthma.