imTo explore the relationship of asymmetric dimethylarginine （ADMA）and senescence of endothelial progenitor cells (EPC) in type 1 diabetic rats.MethodsThe rat model of type 1 diabetes mellitus was established by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg) for one time.The concentration of fasting blood glucose, the level of ADMA in plasma, the percentage of senescence of EPC from bone marrow and the mRNA expression of dimethylarginine dimethylaminohydrolase 2 (DDAH2) and SIRT1 were detected.ResultsThe senescence percentage of EPC（39 % ± 8 % vs 11 %±2%） and the level of ADMA （0.67± 0.06 μmol/L vs 0.55± 0.07 μmol/L ）in plasma were increased and the expression of DDAH2 and SIRT1 mRNA were down-regulated （0.56 ± 0.17 vs 1.00 ± 0.22，0.08 ± 0.17 vs 1.00 ± 0.39）.ConclusionThe senescence of EPC was related with the increased level of ADMA in plasma, which may involve the SIRT1/DDAH2 pathway.