Adipose Mesenchymal Stem Cell-Derived Exosomes Relieve Postoperative Abdominal Adhesion By Activating the MAPK-ERK 1/2 and PI3K-Akt Pathways

Abstract Background: Mesenchymal stem cells (MSCs) have shown potential for peritoneal repair and regeneration. However, the roles of exosomes (Exos) derived from MSCs are not well understood. Therefore, our aim was to elucidate the therapeutic effect of MSC-derived Exos on peritoneal injury. Methods: Adipose-derived mesenchymal stem cells-derived Exos (ADSC-Exos) were isolated using ultracentrifugation and then injected through the tail vein. Rat peritoneal mesothelial cells (RPMCs) were extracted using enzymatic digestion of the peritoneal cavity. Postsurgical adhesions were brought on by scratching rat cecums. The anti-adhesion effects of ADSC-Exos in rats were evaluated using the Nair’s scoring system at 8 and 15 days after abdominal surgery. In addition, the levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) in rat peritoneal fluid were determined via enzyme-linked immunosorbent (ELISA) assays at 8 days after operation. Expression differences in inflammatory and apoptotic markers were detected using immunofluorescence at 4 days after surgery. H&E staining and immunohistochemistry were employed to observe histological changes and expression changes of extracellular matrix (ECM)-related indices after 15 days. In vitro, ADSC-Exo-driven RPMC proliferation was assessed via 5-ethynyl-2-deoxyuridine assay. Cell migration was determined using scratch-wound and transwell assays. Related signaling networks were estimated based on sequencing and bioinformatics analyses. The roles of the MAPK-ERK1/2 and PI3K-Akt signaling networks were analyzed using immunoblotting.Results: ADSC-Exos were incorporated into RPMCs, where they induced cell proliferation and migration in proportion to dosage. This was likely mediated via stimulation of the MAPK-ERK 1/2 and PI3K-Akt axes. In vivo, the ADSC-Exos group had a lower adhesion score than the control group at 15 days. At postoperative day 4, inflammation and apoptosis were markedly inhibited by ADSC-Exos. At 8 days, ADSC-Exos treatment decreased PAI-1 expression and increased tPA expression in peritoneal fluid. At 15 days, ADSC-Exos potentially helped regulate the ECM balance.Conclusions: ADSC-Exos may promote the healing of injured peritoneal tissue, suggesting a promising therapeutic approach for peritoneal adhesions.