骨髓间充质干细胞移植在哮喘小鼠肺组织中的作用

目的：探讨外源性骨髓间充质干细胞（MSCs）移植后在哮喘小鼠肺组织中的分布及对气道炎症的影响,为以MSCs为基础的哮喘疾病的防治提供实验依据.方法：取30只雌性BALB/c 小鼠随机分成空白对照组、哮喘组和MSCs处理组.在无菌条件下取绿色荧光蛋白（GFP）转基因小鼠骨髓MSCs,体外扩增并鉴定.哮喘组和MSCs处理组应用卵白蛋白（OVA）腹腔注射（第0、7、14天）和雾化吸入（第15~21天）制备慢性哮喘模型.第14天通过尾静脉注射将表达GFP的MSCs移植入MSCs处理组小鼠.于末次激发哮喘后24h,取3组动物支气管肺泡灌洗液（BALF）和外周血,计数细胞总数和嗜酸粒细胞数,取肺组织行病理切片,HE染色观察肺部气道炎症情况,并通过荧光显微镜观察MSCs在哮喘小鼠肺组织中的分布,Image-proplus图像分析软件测量支气管壁厚度和平滑肌厚度.结果：GFP转基因小鼠骨髓中分离的MSCs表达MSC特异性标志物并表达GFP.MSCs处理组和哮喘组小鼠BALF中细胞总数以及外周血和BALF嗜酸粒细胞百分比均高于空白对照组,但MSCs处理组上述指标明显低于哮喘组,差异有统计学意义（P〈0.05）.与哮喘组比较,MSCs处理组小鼠肺组织病理学变化改善,支气管壁厚度和平滑肌厚度均显著降低（P〈0.05）.结论：外源性MSCs体内移植能集中分布于哮喘小鼠肺组织并通过减少哮喘气道嗜酸粒细胞侵润等方式抑制哮喘小鼠的气道炎症.

Effects of exogenous mesenchymal stem cells on the lungs in mice with asthma

Objective：To investigate the distribution of exogenous mesenchymal stem ceils （MSCs） in lung of mice with asthma and to determine the effects of these transplanted cells on the injured lungs. Methods：Thirty female BALB/c mice were randomly divided into three groups： control group,asthma group and MSCs group. MSCs were obtained from green fluorescence protein （GFP） transgenic donor mouse under sterile condition. Ovalbumin was peritoneally injected at 0,7,14 days and inhaled from the 15th to the 21st day to reproduce asthmatic model in asthma group and MSCs group. Exogenous MSCs were transplanted via tail vein into the MSCs group at the 14th day. Twenty-four hours after the last administration of ovalbumin by inhalation, bronchoalveolar lavage fluid （BALF） and blood smear were examined to count the numbers of total cells and eosinophils. The status of inflammation of airway was determined by performing hematoxylin/eosin staining of lung biopsy tissue, and the distribution of exogenous GFP-expressing MSCs was also observed by fluorescence microscope. The thickness of total bronchial wall and the thickness of the smooth muscle were assayed by Image-pro plus image analysis system. Results：Cultured MSCs expressed MSC-speeifie markers as well as GFP. The total cell number and the percentage of eosinophils in BALF as well as the percentage of eosinophils in peripheral blood in MSC-treated group were significantly decreased compared with those of asthma model group （P〈0.05） ,but they were higher in both groups than those in control group. When compared with that of asthma group, both the thickness of bronchial wall and the thickness of smooth muscle were decreased in MSCs group （P〈0.05）. There were less inflammatory changes in the lungs of mice with asthma after the treatment of MSCs than in asthma group. Conclusions.. Exogenous MSCs can distribute in the lungs of asthmatic mice after transplantation via venous injection,and alleviate airway inflammation by decreasing the infiltration of eosinophils.