title: [Effects of advanced glycation end products and its receptor on oxidative stress in diabetic wounds].
abstract: OBJECTIVE
  To investigate the accumulation of advanced glycation end products (AGE) and the inflammatory response of skin and wound in diabetic patients, and to analyze their relationship in vitro.
  
  
  METHODS
  Histological staining and immunohistochemical staining was respectively performed on skin and wound tissue specimens collected from 10 patients with Type II diabetes mellitus (diabetes group) and 12 non-diabetic patients with skin injury (control group) to observe the arrangement of collagen and the distribution of inflammatory cells, and to determine the expression levels of AGE and its receptor (RAGE). Malondialdehyde (MDA) levels in skin and wound tissue homogenates were assayed by enzyme-linked immunosorbent assay. In vitro, human neutrophils were isolated and treated with RPMI-1640 culture medium or that containing AGE-human serum albumin in the concentration of 0.315, 0.625, 1.250 mg/mL, and they were identified as normal control (NC) group, low concentration (L) group, moderate concentration (M) group, and high concentration (H) group. Cell viability in each group was determined by MTT colorimetric assay, and the reactive oxygen species (ROS) in cell was measured with 2', 7'-dichlorofluorescein-diacetate. Data were processed with t test.
  
  
  RESULTS
  Compared with those of skin in control group, collagens of skin tissues in diabetes group atrophied and disorderly arranged. Inflammatory cells in wounds in diabetes group were dispersed, in which collagens arranged loosely and irregularly, as compared with those of wounds in control group. Expression levels of AGE and RAGE of skin in diabetes group were higher than those in control group. In diabetes and control groups, especially in diabetes group, the numbers of RAGE-positive cells in wound tissue were more than those in skin tissue. Large amount of inflammatory cells with positive expression of RAGE were observed in diabetes group. MDA level of skin and wound tissue in diabetes group was respectively (6.3 ± 1.0), (7.1 ± 2.4) nmol per milligram protein, which were obviously higher than those in control group [(2.9 ± 1.0), (3.6 ± 1.4) nmol per milligram protein, with t value respectively 8.017, 4.349, P < 0.05 or P < 0.01]. Cell viability and ROS levels in neutrophils were increased in L, M, and H groups [(59 ± 8)%, (77 ± 5)%, (67 ± 6)% and 1.67 ± 0.14, 2.13 ± 0.17, 3.48 ± 0.48] as compared with those in NC group [(34 ± 5)% and 0.58 ± 0.06, with t value respectively 7.195, 14.890, 11.130 and 20.195, 24.905, 16.864, P < 0.05 or P < 0.01].
  
  
  CONCLUSIONS
  Abnormal oxidative stress in diabetic skin leads to an atypical origin of wound repair. AGE-RAGE effect is a critical mediator for oxidative stress in diabetic wound tissue during wound healing.
authors.affiliation: Shanghai Institute of Burns, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Yi-wen
authors.initials: YW
authors.lastname: Niu
authors.forename: Ming-yuan
authors.initials: MY
authors.lastname: Miao
authors.forename: Wei
authors.initials: W
authors.lastname: Dong
authors.forename: Jiao-yun
authors.initials: JY
authors.lastname: Dong
authors.forename: Xiao-zan
authors.initials: XZ
authors.lastname: Cao
authors.forename: Shu-liang
authors.initials: SL
authors.lastname: Lu
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000473:pathology; D005260:Female; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000378:metabolism*; D012709:Serum Albumin / Q000378:metabolism; D000075462:Serum Albumin, Human; D012867:Skin / Q000378:metabolism / Q000473:pathology; D014945:Wound Healing
chemical_list: D017127:Glycation End Products, Advanced; D017382:Reactive Oxygen Species; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D012709:Serum Albumin; C109748:advanced glycation end products-human serum albumin; D000075462:Serum Albumin, Human