title: [The role of DNA double strains damage repairing mechanisms in high glucose-induced endothelial senescence].
abstract: OBJECTIVE
  To investigate the roles of DNA double stains damage repairing mechanisms in high glucose-induced cellular senescence.
  
  
  METHODS
  Human umbilical vein endothelial cells (HUVECs) were incubated with different concentrations of glucose (5.5 mmol/L, 11 mmol/L, 22 mmol/L and 33 mmol/L) for 72 hrs before the assay of senescence-associated beta-galactosidase staining. The superoxides were detected by flow cytometry. The levels of NO were detected by enzyme assay. Gamma-H2AX and phosphorylated P53 protein were measured by Western blot. Changes after co-incubation with KU55993 (an inhibitor of ATM) were examined with methods mentioned above.
  
  
  RESULTS
  Compared with control group, percentage of positive cells of senescence-associated beta-galactosidase staining increased significantly in high glucose groups. The corresponding levels of reactive oxygen increased and NO decreased in a concentration-dependent manner. Intra-cellular levels of gamma-H2AX and phosphorylated P53 protein were significantly increased in high glucose groups. Statistical significances were revealed between high-glucose group and control group, as well as among different high-glucose groups, but no significant difference was observed between mannitol and control group. KU55993, an inhibitor of ATM, significantly reduced the levels of gamma-H2AX, phosphorylated P53 protein, and positive rate of senescence-associated beta-galactosidase staining.
  
  
  CONCLUSIONS
  High glucose may promote DNA double strains damage by enhancing oxidative stress and decreasing NO, and thus accelerate cellular senescence. ATM-P53 pathway, the key proteins related to DNA double strain damage repairing mechanisms, may play an important role in high glucose induced cellular senescence and atherosclerosis.
authors.affiliation: Department of Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Ting-yuan
authors.initials: TY
authors.lastname: Xu
authors.forename: Qun-fang
authors.initials: QF
authors.lastname: Ding
authors.forename: Zhao-hui
authors.initials: ZH
authors.lastname: Wan
authors.forename: Li
authors.initials: L
authors.lastname: Zeng
authors.forename: Bin-bin
authors.initials: BB
authors.lastname: Chang
authors.forename: Xin-jun
authors.initials: XJ
authors.lastname: Zhang
mesh_terms: D002478:Cells, Cultured; D016922:Cellular Senescence / Q000187:drug effects*; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D005947:Glucose / Q000494:pharmacology*; D006657:Histones / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D009025:Morpholines; D009569:Nitric Oxide / Q000032:analysis; D011753:Pyrones; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: C495818:2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one; C468783:H2AX protein, human; D006657:Histones; D009025:Morpholines; D011753:Pyrones; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D009569:Nitric Oxide; D001616:beta-Galactosidase; D005947:Glucose