Objective To investigate the effects of endothelial progenitor cells(EPC)-derived microp-articles(MPs)with different injury treatments on EPC.Methods EPC cells were cultured and EPCs were i-dentified by flow cytometry.EPCs were treated with high glucose(HG)and tumor necrosis factor(TNF)-a recombinant protein,and MPs were extracted.The structural changes of microtubules,Golgi bodies and other organelles in EPC were observed by transmission electron microscopy.MTT assay was used to detect cell pro-liferation.Cell scratch assay was used to evaluate cell migration ability.Cell lumen formation assay was used to detect lumen formation.The expression levels of endothelial nitric oxide synthase(eNOS),silent informa-tion regulator 1(SIRT1),rat sarcoma(RAS)and extracellular regulated protein kinase(ERK)in EPC after different treatments were detected by quantitative real-time fluorescence PCR(qPCR)and Western blot.Re-sults Compared with the control-EPC-MPs group,the microtubule structure of the HG-EPC-MPs group and the TNF-α-EPC-MPs group was complete,the length was shortened,and the Golgi structure was relatively complete.Compared with the control-EPC-MPs group,the proliferation rate of EPC in the HG-EPC-MPs group and the TNF-α-EPC-MPs group was down-regulated,the cell migration ability was decreased,and the tube formation was decreased(P＜0.05).Compared with the control-EPC-MPs group,the mRNA and protein expressions of eNOS,SIRT1,RAS and ERK in the HG-EPC-MPs group and the TNF-α-EPC-MPs group were down-regula-ted(P＜0.05).Conclusion HG and TNF-α mediated MPs derived from EPC injury may change the structure of organelles in EPC by regulating the expression of SIRT1/ERK1 pathway proteins,thus affecting the biolog-ical function of EPC.