骨髓间充质干细胞移植对家兔急性肺损伤的保护作用

摘要

背景:急性呼吸窘迫综合征重要病理改变是肺泡一毛细血管膜屏障的损伤,以及所导致肺泡渗出液中富含蛋白质的肺水肿.骨髓间充质干细胞能够继续分化和不断自我更新,并最终分化为多种类型细胞,这有可能为治疗肺损伤提供一个新的途径.目的:探讨骨髓间充质干细胞移植对内毒素诱发急性肺损伤模型兔的保护作用.设计、时间及地点:随机对照动物实验,于2007-10/2008-01在唐都医院中心实验室完成.材料:家兔20只,2只用于制备骨髓间充质干细胞,剩余18只随机分为3组:盐水对照组、肺损伤模型组、细胞移植组,6只,组.内毒素为Sigma公司产品.方法:Ficoll法分离培养兔骨髓间充质干细胞,传至第3代备用.肺损伤模型组、细胞移植组兔通过向气管内滴注内毒素建立急性肺损伤,急性呼吸窘迫综合征模型,造模成功30 min后,细胞移植组经右侧颈静脉注入骨髓间充质干细胞悬浮液2 mL(细胞数1×105),盐水对照组、肺损伤模型组同法给予等量生理盐水.主要观察指标:支气管肺泡灌洗液中性粒细胞数日、肺组织湿干比及蛋白含量,肺组织病理变化.结果:湿十比值升高提示肺水肿的存在,中性粒细胞数量增加提示较重的炎性反应存在,蛋白含量升高提示肺泡一毛细血管内膜屏障受损.移植48 h后与盐水对照组比较,肺损伤模型组支气管肺泡灌洗液中性粒细胞数目、蛋白含量均明显降低(P<0.01),湿干比明显升高(P<0.01);与肺损伤模型组比较,细胞移植组支气管肺泡灌洗液中性粒细胞数目、蛋白含量均明显升高(P<0.01),湿干比明显降低(P<0.01).苏木精一伊红染色结果显示,盐水对照组肺泡组织结构正常,肺损伤模型组肺组织出现典型的急性肺损伤改变,细胞移植组肺组织病理变化较轻.结论:利用骨髓间充质干细胞移植可显著减轻内毒素诱导的急性肺损伤.%BACKGROUND: The important pathological changes of acute respiratory distress syndrome (ARDS) is disruption of the lung alveolar-capillary membrane barrier and resultant pulmonary edema associated with a proteinaceous alveolar exudate. Bone marrow mesenchymal stem cells (BMSCs) are able to carry on dividing and renewing themselves, and can eventually develop into many other types of cells. This provides a new treatment for treating injury of lungs.OBJECTIVE: To investigate the prevention of endotoxin-induced acute lung injury in rabbit by BMSCs.DESIGN, TIME AND SETTING: The randomized controlled animal study was performed at the Central Laboratory of Tangdu Hospital from October 2007 to January 2008.MATERIALS: A total of 20 rabbits were used in this study. Two rabbits were utilized to culture BMSCs. Eighteen rabbits were randomly assigned to three groups, saline control group, acute lung injury group and cell transplantation group (n = 6). Endotoxin was purchased from Sigma, USA.METHODS: Rabbit BMSCs were isolated and cultured by the Ficoll method. At the third passage, BMSCs were harvested for use.In the acute lung injury and call transplantation groups, endotoxin was infused into the trachea to establish models of acute lung injury/ARDS. Thirty minutes following model establishment, 2 mL BMSC suspension (1 x 105) was infused into the right jugular vein in the cell transplantation group. An equal volume of saline was injected into the saline control and acute lung injury groups.MAIN OUTCOME MEASURES: Number of neutrophilic granulocyte, wet to dry weight ratio of lung tissue, protein content and pathological changes in lung tissue in bronchoalveolar lavage fluid were measured.RESULTS: The increase in wet to dry weight ratio indicated the existence of pulmonary edema. The increase in neutrophilic granulocyte number suggested severe inflammatory reaction. The increased protein content showed the damage to lung alveolar-capillary membrane barrier. Following 48 hours of transplantation, neutrophilic granulocyte number and protein content in bronchoalveolar lavage fluid was significantly decreased (P < 0.01), and wet to dry weight ratio was significantly increased (P < 0.01) in the acute lung injury group compared with the saline control group. Compared with the acute lung injury group,neutrophilic granulocyte number and protein content was significantly increased (P < 0.01), and wet to dry weight ratio was significantly diminished (P < 0.01) in bronchoalveolar lavage fluid in the call transplantation group. Hematoxylin-eosin staining suggested that pulmonary alveoli was normal in the saline control group, presented typical acute lung injury in the acute lung injury group, and the pathological changes were mild in the cell transplantation group.CONCLUSION: BMSC transplantation can significantly reduce endotoxin-induced acute lung injury.