Exosomes Released by Bone Marrow Mesenchymal Stem Cells Attenuate Lung Injury Induced by Intestinal Ischemia Reperfusion via the TLR4/NF kB Pathway
Purpose: Acute lung injury (ALI) is a primary component of multiple organ dysfunction syndromes triggered by intestinal ischemia reperfusion (IIR) which results in high mortality. Existing treatment options remain unsatisfactory. Mesenchymal stem cells (MSCs) have shown considerable promise as a biological therapy for ALI in preclinical studies. However, there are many limitations to stem cell treatment. This study aimed to investigate whether MSC derived exosomes, a non cellular alternative, are able to act in a protective capacity similar to that of MSCs for ALI triggered by IIR in a rat model and to explore the underlying mechanisms. Methods: The IIR model involved occlusion of the superior mesenteric artery of a rat for 75 min then reperfusion for 20 h. Rats then received an intravenous injection of either bone marrow derived MSCs or MSC derived exosomes. Pathologic alteration of lung tissue, levels of pro inflammatory cytokines, apoptotic proteins and TLR4/NF kB signaling were measured to evaluate the therapeutic effect of treatment with either MSCs or exosomes. Results: Manifestations of acute lung injury after IIR were observed as edema and hemorrhage of alveoli and mesenchyme, and inflammatory cell infiltration. MSCs and MSC derived exosomes both attenuated IIR induced lung damage by decreased apoptosis and inflammation accompanied by down regulation of TLR4 and NF kB expression. Conclusions: MSC derived exosomes provide protection similar to that of MSCs against IIR induced ALI via inhibition of TLR4/NF kB signaling, suggesting that a potential strategy against IIR mediated acute lung injury could be therapy with exosomes as a non cellular alternative to MSC transplantation.
International journal of medical sciences