CD8+调节性T细胞来源小细胞外囊泡对输血相关急性肺损伤小鼠的保护作用及机制研究OA

Objective To isolate small extracellular vesicles(sEVs)derived from the supernatant of CD8+regulatory T cells induced from human peripheral blood mononuclear cells(TR-sEVs),and explore their intervention effect and preliminary mechanism against transfusion-related acute lung injury(TRALI)in mouse model.Methods TR-sEVs were extracted by differential centrifugation combined with ultracentrifugation,and identified via nanoparticle tracking analysis(NTA),transmission electron microscopy(TEM),and Western blotting(WB).A mouse model was established and grouped according to the two-hit hypothesis of TRALI.Mice received an intraperitoneal injection of lipopolysaccharide(LPS)as the first insult at 0 h.After 2 h,gradient doses of TR-sEVs were administered via tail vein,and anti-mouse H-2Kd antibody was injected via the tail vein at 24 h to establish the second insult.Mouse survival time and lung wet-dry weight ratio were recorded.Hematoxylin-eosin(HE)staining and immunohistochemical staining were performed to evaluate pulmonary pathological damage and inflammatory infiltration.The level of interleukin-6(IL-6)in bronchoalveolar lavage fluid was detected by enzyme-linked immunosorbent assay(ELISA).An LPS-induced inflammatory injury model of EA.hy926 endothelial cells was established in vitro.Quantitative real-time polymerase chain reaction(qRT-PCR)and flow cytometry were used to detect the expression of intercellular adhesion molecule-1(ICAM-1)in endothelial cells,and the adhesion effect of Tohoku Hospital Pediatrics-1(THP-1)monocytes to endothelial cells was further evaluated.Results TR-sEVs increased the survival rate of TRALI mice,decreased lung wet-dry weight ratio(6.21±0.15 in control group vs 4.45±0.12 in intervention group),alleviated pulmonary inflammation and reduced IL-6 level.In vitro,TR-sEVs inhibited endothelial ICAM-1 expression and weakened monocyte-endothelial adhesion.Conclusion Infusion of TR-sEVs alleviates pulmonary lesions,inflammatory cell infiltration and the release of inflammatory cytokines in mice with transfusion-related acute lung injury.Its mechanism may exert effects via downregulating ICAM-1 expression in endothelial cells and suppressing monocyte-endothelial cell adhesion.