骨髓间充质干细胞来源外泌体对烟雾吸入伤大鼠的保护作用

摘要

Objective Acute lung injury induced by variety causes can be reduced by mesenchymal stem cells.Some studies have shown that mesenchymal stem cell-derived exosomes have similar features with mesenchymal stem cell,but its role in acute lung injury is less studied.The study was to investigate the protective role and underlying mechanisms of bone marrow mesenchymal stem cell-derived exosomes (BMSC-DEs) on smoke inhalation injury (SⅡ) in rats.Methods Thirty Wistar rats were randomly divided into 3 equal groups:normal control group,smoke inhalation injury (SⅡ) model group and bone marrow mesenchymal stem cell-derived exosomes (BMSC-DEs) treated group.12 h after establishing the SⅡ model,BMSC-DEs treated group was injected with 0.5 mL BMSC-DEs (derived from 4× 106 BMSCs),and normal control group and SⅡ model group were injected with equivalent volume of normal saline.7 days later,samples were collected.The histopathologic changes of lung were observed after HE staining;BCA was used to test the amounts of total protein in bronchoalveolar lavage fluid (BALF);Enzyme linked immunosorbent assay was used to test the levels of tumor necrosis factor-α (TNF-α) and keratinocyte growth factor (KGF) in the lung tissue;Immunohistochemical was used to test the levels of pulmonary surfactant protein C(SP-C).Results The BALF levels of total protein of SⅡ group was significantly higher than those of normal control group (P＜0.01) and BMSC-DEs groups(P＜0.05);Compared with normal group [(0.164±0.021) ng/L],the levels of tumor necrosis factor-α of SII and BMSC-DEs groups [(0.355±0.106)、(0.234±0.024) ng/L] (P＜ 0.05) were significantly higher,and SⅡ group was higher than that of BMSC-DEs group(P＜0.01);Compared with normal group,the KGF protein expression level in lung tissue of SⅡ group was significantly lower (P＜0.05),but BMSC-DEs group was higher (P＜0.05).BMSC-DEs group was higher than SⅡ group (P＜0.01);Immunohistochemistry showed that the SP-C expression level in lung tissue of SⅡ group was significantly lower than those of other groups (P＜0.05).There was no statistically difference between BMSC-DEs group and control group (P＞0.05).Conclusion BMSC-DEs has a protective effect of smoke inhalation injury rats,the underlying mechanism may be related to BMSC-DEs to reduce inflammation and promote restoration of the alveolar epithelial type Ⅱ.%目的 间充质干细胞可以减轻多种原因诱导的急性肺损伤,一些研究表明间充质干细胞来源外泌体具有与母细胞相似的功能,但其对急性肺损伤的作用研究较少.文中旨在探讨骨髓间充质干细胞来源外泌体(BMSC-DEs)对烟雾吸入伤(SⅡ)大鼠的保护作用及其可能机制. 方法 30只wistar大鼠随机均分为对照组,烟雾吸入伤模型组(SⅡ组),骨髓间充质干细胞来源外泌体治疗组(BMSC-DEs组).建立大鼠SⅡ模型,12h后BMSC-DEs组经尾静脉注射0.5 mL大鼠BMSC-DEs(来源于4× 106BMSCs),对照组和SⅡ组注射等量等渗盐水,7d后收集实验标本.HE染色观察肺组织病理变化,BCA法测定肺泡灌洗液中总蛋白含量,ELISA法检测肺组织匀浆中炎性因子TNF-α及角质细胞生长因子KGF的水平,免疫组化检测肺表面活性物质相关蛋白C的表达. 结果 与对照组BALF中总蛋白[(0.164±0.021) ng/L]相比,SⅡ组[(0.355±0.106) ng/L]较高(P＜0.01);BMSC-DEs组BALF中总蛋白含量[(0.234±0.024) ng/L]低于SII组(P＜0.05).与对照组肺组织匀浆炎性因子TNF-α水平相比,SⅡ组和BMSC-DEs组明显升高(P＜0.05),且SⅡ组高于BMSC-DEs组(P＜0.01).SⅡ组肺组织匀浆KGF表达低于对照组(P＜0.05),而BMSC-DEs组KGF表达高于对照组和SII组(P＜0.05).免疫组化染色示:BMSC-DEs组和对照组SP-C表达均高于SⅡ组(P＜0.05),BMSC-DEs组和对照组间差异无统计学意义(P＞0.05). 结论 骨髓间充质干细胞来源外泌体对烟雾吸入伤大鼠具有保护作用,其机制可能与外泌体减轻炎症反应和促进Ⅱ型肺泡上皮修复有关.