The Research Of Extracellular Vesicles In Alleviating Renal Ischemia-reperfusion Injury In Rats

OBJECTIVE:To investigate the effects of human umbilical cord mesenchymal stem cells(HUMSC)and rat renal progenitor-like tubular cells(RPTC)derived Extracellular Vesicles(EVs)in acute renal ischemia-reperfusion injury and further explore the proper mechanisms.METHODS:HUMSC and RPTC were acquired and cultured,and EVs were isolated and charaterized.Ischemic kidney injury animal was established by removing right kidney and clipping left renal pedicle for 45 minutes.Rats were separated randomly as HUMSC-EVs,RPTC-EVs,HUMSC-EVs treated with RNase,anti-NK cell or anti-Ig G antibody groups as required.24 hours and 2 weeks later,tissues were acquired for EVs tracking and the regulation of NK cells in the early stage.Further,renal capillary vessel density was assessed after two weeks.What is more,renal function and fibrosis was assessed 2 weeks after RPTC-EVs injection.In vitro,both HUMSC and RPTC derived EVs were co-cultured with injured tubular cells sepraterily to test the expression of vascular endothelial growth factor(VEGF)in HUMSC-EVs group and the protective effects of Antimycin A(AMA)treated tubular cells in RPTC-EVs group.RESULTS:1.HUMSC-EVs were retained in spleen,lung and kidney after induction,and decreased NK cell percent in spleen and injured kidney.EVs and NK cell antibody alleviated renal injury,EVs also modulated NK cell related chemokines in injured kidney.What is more,EVs decreased renal fibrosis and increased capillary vessel density 2 weeks after treatment.EVs up-regulated VEGF expression in injured kidney and these effects were abrotated by RNase treatment.In vitro,EVs fused and transfer RNAs to tubular cells,and up-regulated VEGF expression.2.RPTC-EVs engrafted in the injued kidney,reduced cell apoptosis,decreased renal fibrosis and improved its functions.A protective effect of RPTC derived EVs were observed in injured tubular cells in vitro.Furthermore,RPTC derived EVs transferred mitochondrial components to injured TEC,and partly restored the decline of cellular energy production.CONLUSION:HUMSC-EVs reduced the infiltration of NK cell and increased capillary vessel density in ischemic injured kidney to protect the injured kidney,which was regarded as an important mechanism of HUMSC-EVs in renal ischemic injury repaire.RPTC-EVs exert a protective effect in tubular cell injury both in vitro and alleviated ischemia-reperfusion induced kidney fibrosis,which established a theoretical basis for RPTC therapy in kidney repair through EVs.Overall,these studies build a theoretical basis for EVs therapy in kidney diseases.