BMSCs通过调控TLR4/MyD88/NF-κB信号通路抑制LPS诱导急性肺损伤小鼠炎症反应

BMSCs inhibit inflammation in mice with LPS-induced acute lung injury by regulating TLR4/MyD88/NF-κB signaling pathway

目的探讨骨髓间充质干细胞(BMSCs)对脂多糖(LPS)诱导急性肺损伤(ALI)小鼠炎症反应的影响。方法32只SPF级KM小鼠,4周龄,随机分为4组:对照组,LPS组,地塞米松(DEX)治疗组(LPS+DEX),BMSCs移植组(LPS+BMSCs);后3组经气管穿刺法注入LPS建立小鼠ALI模型,建模24 h后经尾静脉一次性注射移植同源BMSCs,同时,LPS+DEX组经尾静脉注射DEX,连续3 d;细胞移植后第4天或DEX注射完毕后24 h,记录小鼠存活数量,检测小鼠肺功能,测肺W/D重量比;收集小鼠支气管肺泡灌洗液(BALF)中的炎症细胞,检测血清炎性细胞因子,观察肺组织病理学变化;经绿色荧光蛋白标记染色观察BMSCs在肺组织中的归巢;用RT-PCR及Western blot分别检测肺组织TLR4-MyD88-NF-κB信号通路相关基因和蛋白质表达(TLR4、MyD88和NF-κB)。结果与对照组相比,LPS组小鼠肺功能降低,肺W/D重量比、血清中炎症因子、BALF中炎性细胞数量明显增加,肺组织损伤严重;与LPS组比较,LPS+DEX组、LPS+BMSCs组小鼠存活数量增高,肺功能改善,肺组织损伤减轻,肺W/D重量比、血清炎性细胞因子、BALF中炎性细胞数量明显下降,TLR4-MyD88-NF-κB信号通路相关基因和蛋白表达降低。结论同源BMSCs移植可以有效缓解LPS诱导的急性肺损伤,其机制可能与调控TLR4-MyD88-NF-κB信号通路,减轻炎症反应有关,该研究为BMSCs同源移植治疗ALI提供了实验依据。

Objective To investigate the effect of bone marrow mesenchymal stem cells(BMSCs)on the inflammatory response of lipopolysaccharide(LPS)induced acute lung injury(ALI)in mice.Methods 32 SPF KM mice,aged 4 weeks were randomly divided into four groups,control group,LPS group,dexamethasone treatment group(LPS+DEX)and BMSCs treatment group(LPS+BMSCs).The latter three groups were injected with LPS by tracheal puncture to establish mouse ALI model 24 h after modeling,BMSCs isolated from the femur of mice were injected into the caudal vein,and DEX were injected into caudal vein at the same time in LPS+DEX group for 3 consecutive days.On the 4th day after cell transplantation or 24 h after DEX injection,the survival quantity of mice was recorded,lung function was detected,and the wet/dry weight ratio(W/D)of lung was measured.Then inflammatory cells in bronchoalveolar lavage fluid(BALF),lung pathological changes and serum inflammatory cytokines were collected.Green fluorescent protein(GFP)staining was used to observe the homing of BMSCs in lung tissues.The mRNA and protein expression of TLR4,MyD88 and NF-κB in lung tissues were detected by RT-PCR and Western blot assay respectively.Results Compared with the control group,LPS model group showed decreased lung function,significantly increase in the W/D weight ratio of lung,inflammatory cytokines in serum and inflammatory cells in BALF,and severe damage in lung tissue.Compared with LPS group,LPS+DEX group and LPS+BMSCs group showed improved lung function,reduced lung tissue damage,significantly decrease in the W/D weight ratio of lung,inflammatory cytokines in serum and inflammatory cells in BALF.And the expression of TLR4-MyD88-NF-κB signaling pathway-related genes and proteins decreased,the survival quantity increased.Conclusion Homologous BMSCs transplantation can effectively treat LPS-induced acute lung injury,and the mechanism may be related to the regulation of TLR4-MyD88-NF-κB signaling pathway and the reduction of inflammatory response.These findings provide the experimental basis for BMSCs homologous transplantation for ALI.