[en] Objective: To explore the feasibility and efficiency of transfecting human thrombomodulin (hTM) gene into rabbit's endothelial progenitor cells (EPCs) in order to provide experimental evidence for further animal experiments. Methods: The eukaryotic expression plasmid of hTM gene was constructed. Rabbit's peripheral blood mononuclear cells (MNCs) were isolated. EPCs were isolated from the MNCs by adherence method, which were expanded and characterized by CD34, KDR, vWF, Dil-ac-LDL, FITC-UEA-1, and then modified with hTM by using X-tremeGENE HP DNA Transfection Reagent. Direct immunofluorescence was performed to observe hTM expression after 48 hours, and the expression of hTM was detected by Western blot after 72 hours. MTT assay was used to evaluate cell survival and proliferation. Results: The recombinant hTM with recombinant plasmid was confirmed by double endonuclease digesting and sequencing. EPCs were characterized by being positive for the endothelial cellmarks of CD34, KDR, vWF and internalization of Dil-Ac-LDL and binding to FITC-UEA-1. The gene expression was significantly improved in the pcDNA3.1-hTM group compared to control group as demonstrated by direct immunofluorescence and Western Blot analysis. The difference of survival rate was not significant among pcDNA3.1-hTM group, pcDNA3.1 (+)-neo group and untransfected group through MTT analysis. Conclusion: The recombinant plasmid of pcDNA3.1-hTM can be successfully and effectively transfected into rabbit's peripheral blood EPCs by using X-tremeGENE HP DNA Transfection Reagent, and the transfection causes no significant changes in viability and proliferation capacity of EPCs. (authors)