[Alterations in reactive oxygen species and dimethylarginine dimethylaminohydrolase-asymmetric dimethyl-arginine system in the process of endothelial cell senescence induced by high glucose].

Objective To investigate the changes in reactive oxygen species (ROS) and dimethylarginine dimethylaminohydrolase-asymmetric dimethylarginine (DDAH-ADMA) system in the process of endothelial cell senescence after exposure to high glucose. Methods The human umbilical vein endothelial cells (HUVECs) were cultured with different concentrations of glucose, e.g. 5. 5 mmol/L (normal level),and high levels as 11. 0, 22. 0 and 33. 0 mmol/L. for 48 hours, respectively. Subsequently, SA-β-gal staining was used to evaluate senescence of cells. Telomerase activity was detected by polymerase chain reactionenzyme linked immunosorbent assay (PCR-ELISA). The intracellular ROS level was measured by flow cytometry. The ADMA concentration and DDAH activity were determined with high-performance liquid chromatography. Results Compared with normal glucose concentration group, after the endothelial cells were treated with high glucose concentration (11. 0 - 33. 0 mmol/L) for 48 hours, the number of SA-β-gal positive cells was increased significantly [(7.00±1. 73)%, (12. 67±2. 03)%, (16. 00±2. 26)% vs. (4. 00±1.33)%, P＞0.05, P＜0.05, P＜0.05] and the telomerase activity was inhibited dramatically [(91. 32±4.01)%, (78. 44±3. 78)%, (56. 04±3. 35)% vs. 100%, all P＜0. 05]. The ROS level (mfi) was increased in all high glucose groups (159. 84±27. 52, 188. 99±18. 77, 244. 56±20. 96 vs. 117.11±18. 76, P＜0. 05 or P＜0. 01). At the same time, the ADMA (μmol/L) production was increased (0. 78±0. 14, 0. 88±0.18,1. 08±0.15 vs. 0. 70±0. 12, P＞0. 05, P＜0. 05, P＜0. 05), and DDAH activity was decreased [(91. 32±4.01)%, (78.44±3.78)%, (56. 04± 3. 35)% vs. 100%, all P＜0.05]. Conclusion High glucose can accelerate endothelial cells senescence in dose-dependent manner and the underlying mechanism may be related to an increased oxidative stress and change in DDAH-ADMA system. Key words: High glucose;  Cell senescence;  Reactive oxygen species;  Dimethylarginine dimethylaminohydrolase;  Asymmetric dimethylarginine