Effects of rosiglitazone on the oxidative stress injury in endothelial outgrowth cells caused by asymmetric dimethylarginine

AIM: To observe the effects of rosiglitazone on the oxidative stress injury in endothelial outgrowth cells (EOCs), which caused by asymmetric dimethylarginine(ADMA). METHODS: The mononuclear cells were harvested from umbilical cord blood by density gradient centrifugation, and induced into EOCs and expanded in vitro. The endothelial characteristics of EOCs were identified by immunostaining and fluorescent staining. The second generation of EOCs was treated with 10 μmol/L ADMA and different concentrations of rosiglitazone (0, 1, 5, 10 μmol/L) for 72 h. Then the cells were harvested and the apoptosis rate, reproductive activity and vasculogenesis activity were measured by flow cytometry, MTT assay and Matrix gel vasculogenisis assay, respectively. The endothelial nitric oxide synthase gene expression was assayed by RT-PCR. RESULTS: EOCs possessed many endothelial characteristics. Immunostaining showed that the surface antigen factor VIII, CD34 and Flk-1 were positive. The fluorescent staining experiment revealed that EOCs both bound to FITC-UEA-1 and up-took DiI-ac-LDL. Incubation of EOCs with ADMA increased the apoptosis rate and inhibited the reproductive activity and vasculogenesis activity in the cells. Rosiglitazone at concentrations of 1 and 5 μmol/L counteracted such inhibition and stimulated reproductive activity in EOCs (P<0.01), while such protective effects were attenuated or abolished at concentration of 10 μmol/L. In addition, the vasculogenesis activity was inhibited by 10 μmol/L rosiglitazone cooperated with ADMA. RT-PCR assay revealed that eNOS gene expression in 5 μmol/L group was up-regulated and that in 10 μmol/L group was down-regulated. CONCLUSION: Rosiglitazone at lower concentration (<10 μmol/L) protects EOCs from the oxidative stress injury caused by ADMA, and stimulates reproductive activity of EOCs. Such protective effects are partially achieved through the up-regulation of eNOS gene expression.