Ischemic preconditioning for 60 min can potentiates the protective effect of MSC on endotoxin-induced Acute Lung Injury through the secretion of Exosome.

Exosome was isolated from the culture supernatant of MSC. For ischemic preconditioning, MSCs were subjected to anoxia for 0 min (MSCs group), 30 min (MSCs(IPC-30) group), 60 min (MSCs(IPC-60) group) and 90 min (MSCs(IPC 90) group), and then used to treat endotoxin-injured mice. The exosome from the optimal group was used to treat endotoxin-injured mice. In addition, the exosome from the optimal group was also used to treat the endotoxin-stimulated RAW 264.7 cells for 6 h and 12 h.

To explore the effect of bone marrow mesenchymal stem cells (MSCs) on endotoxin-induced acute lung injury in mice and verify the role of exosome.

CD63 positive exosome were acquired through ExoQuick kits. Administration of MSCs, MSCs(IPC-30), MSCs(IPC-60) and MSCs(IPC-90) could reduce the level of white blood cells (WBC) and neutrophils into the bronchoalveolar lavage (BAL) fluid of endotoxin-injured mice, and the MSCIPC-60 group had the greatest reduction, which reduced WBC by 57% and neutrophils by 55%. Administration of MSCs(IPC-60) exosome could also reduce the level of WBC, neutrophils, MIP-2 and penetration protein into the BAL fluid of endotoxin-injured mice, which had the same effect as MSCs(IPC-60) and showed a dose dependent, compared to MSCs exosome. In addition, MSCs(IPC-60) exosome were used to treat endotoxin-stimulated RAW 264.7 cells, and the level of TNFα at 6 h and 12 h was significantly reduced, while the level of IL-10 at 12 h increased.