Protective effects of bone marrow mesenchymal stem cell-derived exosomes on smoke inhalation injury in rats / 医学研究生学报

ABSTRACT

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 groupsnormal 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.