title: The role of oxidative stress in diabetic retinopathy.
abstract: OBJECTIVE
  To investigate the role of oxidative stress in the development of diabetic retinopathy.
  
  
  METHODS
  This study included 25 patients with diabetic retinopathy (group I), 34 patients with non-insulin-dependent diabetes mellitus without any angiopathy complications (group II) and 26 healthy subjects (group III). The serum malondialdehyde (MDA)-like metabolite levels as an index of lipid peroxidation, the erythrocyte glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and serum vitamin C levels of the patients and healthy subjects were measured.
  
  
  RESULTS
  The mean serum concentration of MDA-like metabolites of patients in group I was 4.38 +/- 1.31 nmol/ml, in group II was 3.38 +/- 0.95 nmol/ml and in group III was 2.61 +/- 0.85 nmol/ml. There were significant differences between the groups (p = 0.001 for group I compared with group II, p = 0.0001 for group I compared with group III and p = 0.002 for group II compared with group III). There was a significant correlation between the serum lipid peroxidation concentrations and duration of the disease (r = 0.36, p = 0.047). The mean erythrocyte GSH-Px and SOD levels of group I were respectively 68.97 +/- 18.04 and 1597.78 +/- 296.46 U/g Hb, of group II were 64.30 +/- 19.26 and 1581.33 +/- 278.08 U/g Hb, and of group III were 65.52 +/- 17.58 and 1587.44 +/- 281.17 U/g Hb. There were no significant differences among the antioxidant enzyme levels in the three groups (p > 0.05). The mean serum vitamin C level in group I was 42.72 +/- 8.90 mumol/l, in group II was 49.26 +/- 11.52 mumol/l and in group III was 58.57 +/- 9.75 mumol/l. There were significant differences among the mean serum vitamin C levels of the three groups (p = 0.02 for group I versus group II p = 0.001 for group I versus group III and p = 0.002 for group II versus group III).
  
  
  CONCLUSIONS
  Free radicals forming in diabetes mellitus and increasing over time may play a role in the development of diabetic retinopathy, which is an important complication of the disease.
authors: Department of Ophthalmology, Harran University, Faculty of Medicine, Sanliurfa, Turkey. gurlerb@doruk.net.tr
authors: B
authors: B
authors: Gürler
authors: H
authors: H
authors: Vural
authors: N
authors: N
authors: Yilmaz
authors: H
authors: H
authors: Oguz
authors: A
authors: A
authors: Satici
authors: N
authors: N
authors: Aksoy
mesh_terms: D000328:Adult; D000368:Aged; D001205:Ascorbic Acid / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000097:blood / Q000503:physiopathology*; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood; D006801:Humans; D015227:Lipid Peroxidation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D013482:Superoxide Dismutase / Q000097:blood
chemical_list: D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D001205:Ascorbic Acid