The Research Of Mesenchymal Stem Cells Derived Extracellular Vesicles In Ameliorating Renal Ischemia/Reperfusion Injury

BACKGROUND: Renal ischemia-reperfusion injury is one of the main causes of acute renal injury.Extracellular vesicles of mesenchymal stem cells(MSCs)have been used in the interventional treatment of various disease models.Its main effects include reducing oxidative stress and restoring mitochondrial function,but the key active components are not clear.We tried to verify the application of extracellular vesicles of human umbilical cord mesenchymal stem cells in the treatment of renal ischemia reperfusion injury in mice.At the same time,proteomics and bioinformatics analysis on extracellular vesicles were applied to screen out the key components that may play therapeutic roles,and the results were expected to lay a foundation for further research in the future.METHODS:The primary cultured mesenchymal stem cells(MSCs)were separated from the human umbilical cord.The serum-free medium was replaced until the cell growth was 80%-90%.After 24 hours,the conditioned medium was used to extract extracellular vesicles by ultracentrifugation.The extracellular vesicles were identified by Transmission Electron Microscope(TEM)and Nano Flow Detector(NanoFCM).The mouse model of left kidney ischemia for 25 min and right kidney resection was established.Randomly divided into Sham group,IRI + PBS control group,IRI + EVs treatment group.Reperfusion was performed simultaneously with PBS or MSC-EVs in the vein.In the acute phase(24h after surgery),serum and tissue samples were collected for detection of renal function,renal morphology assessment and renal tissue apoptosis.Relative quantitative protein profiling was performed on the extracellular vesicles of mesenchymal stem cells and control fibroblasts,and the results were analyzed by bioinformatics.RESULTS: In the renal IRI mice experiment,compared with PBS control group,mice in the MSC-EVs tratment group had significantly lower serum creatinine levels,lower renal morphological Jablonski scores,and less renal tissue apoptotic cells at 24 h after surgery.Bioinformatics analysis indicated that the proteins of MSC-EVs in differential proteins were significantly enriched in the molecular function of mitochondrial components,Comparing with the EVs of homologous fibroblasts,we screened the top five mitochondrial proteins with the most differential expression,the first one was superoxide dismutase 2(SOD2),followed by ALDH18A1,GOT2,ETFA.And OGDH.CONCLUSION: The extracellular vesicles of human umbilical cord MSCs can alleviate acute kidney injury in mice with renal ischemia-reperfusion.According to proteomics and bioinformatics analysis,five mitochondrial proteins were screened from the MSC-EVs.that may be related to the therapeutic effects.