荷瘤小鼠髓系来源抑制性细胞对哮喘小鼠气道炎症的影响

Effects of Myeloid Derived Suppressor Cells Derived from 4T1 Tumor-Bearing Mice on Airway Inflammation of Asthmatic Mice

目的初步探讨髓系来源抑制性细胞(MDSC)对哮喘小鼠气道炎症的影响。方法将6周龄SPF级BALB/c雄鼠5只制成4T1乳腺癌细胞成瘤小鼠,用于制备MDSC。6周龄SPF级BALB/c雌鼠30只随机分为正常对照组、哮喘模型组和细胞移植组。采用免疫磁珠技术分选肿瘤小鼠骨髓中的MDSC,在粒细胞巨噬细胞集落刺激因子(GM-CSF)的诱导下外扩增培养,光学显微镜观察其体外培养过程中的形态特征,流式细胞仪(FACS)分析其表型特征。哮喘模型组和细胞移植组予卵白蛋白(OVA)腹腔注射致敏,OVA雾化诱发哮喘。细胞移植组在诱导哮喘的第10 d经尾静脉注入MDSC。HE染色观察小鼠肺部病理改变,检测支气管肺泡灌洗液(BALF)中细胞总数及分类。结果肺组织病理观察显示正常对照组支气管周围基本无炎症细胞浸润;哮喘模型组支气管周围大量炎症细胞浸润,杯状细胞增生;细胞移植组支气管、血管黏膜下和周围肺组织炎症较哮喘模型组减轻。哮喘模型组和细胞移植组BALF细胞总数、嗜酸粒细胞和中性粒细胞计数均显著高于正常对照组(P<0.05),而细胞移植组嗜酸性粒细胞计数则明显低于哮喘模型组(P<0.05)。结论静脉输注荷瘤小鼠MDSC可一定程度上抑制哮喘小鼠气道炎症。

Objective To investigate the effect of myeloid derived suppressor cells（MDSCs） on airway inflammation of asthmatic mice.Methods Five male BALB/c mice aged 6 weeks were used for preparing 4T1 tumor bearing mice.Thirty female BALB/c mice aged six weeks were randomly divided into a normal control group,an athmatic model group,and a cell transplantation group.The MDSCs were separated from myeloid tissue of tumor-bearing mice using a magnetic cell sorting system and cultured in RPMI medium 1640 containing GM-CSF.The morphologic characteristics of these cells were observed under light microscope and the phenotypic figures were analyzed with flow cytometry.The mice in the model group and the cell transplantation group were sensitized by ovalbumin and then stimulated with nebulized ovalbumin.The mice in the cell transplantation group were intravenously administered MDSCs which purified by magnetic cell sorting system at 10 days after sensitization.The airway inflammation was evaluated by HE staining.The total and differential cell counts in bronchoalveolar lavage fluid（BALF） were measured.Results The neutrophil and eosinophil infiltration in pulmonary tissue was dramatically increased in the model group,but not observed in the normal control group and was much milder in the cell transplantation group.The total cell count,the eosinophil and lymphocyte counts in BALF of the model group and the cell transplantation group were significantly higher than those of the normal control group（P0.05）,and the number of eosinophils in BALF of the cell transplantation group was decreased when compared with that of the model group（P0.05）.Conclusion MDSCs via intravenous infusion can effectively suppress airway inflammation in a mouse asthma model.