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 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.
ABSTRACT
Objective To cultivate,identify and sort bronchoalveolar stem cells(BASC)derived from normal adult mouse lung.Methods After enzymatic digestion of lung tissue with dispase and collagenase in combination,the Sca-1+ cells were isolated from the obtained pulmonary cells by magnetic cell sorting.These Sca-1+ cells were cultured in dishes coated with collagen and mouse fibroblast cell line Swiss-3T3 under a serum-free culture system for BASC,which were identified by the dual-color immunofluorescent staining clara cell specific antigen(CCA)and surfactant protein C(SP-C).Finally,these pure BASC were isolated by the flow cytometry.Results One lung of normal adult mouse could yield(1.6-1.8)?107 nucleated cells in this enzyme digestion procedure.The percentage of Sca-1+ cells we sorted from lung tissue was much higher than the unsorted [(87.3?5.9)% and(9.6?1.8)%,P