title: Green tea prevents hyperglycemia-induced retinal oxidative stress and inflammation in streptozotocin-induced diabetic rats.
abstract: OBJECTIVE
  Our objective was to investigate the effect of green tea (GT) on diabetes-induced retinal oxidative stress and proinflammatory parameters in rats.
  
  
  METHODS
  Treatment (200 mg/kg body weight) was carried out for a period of 16 weeks in streptozotocin-induced diabetic rats and was evaluated for hypoglycemic, antioxidant [reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT)] and anti-inflammatory [tumor necrosis factor (TNF) α, vascular endothelial growth factor (VEGF)] activity. Histological changes were evaluated by transmission electron microscopy.
  
  
  RESULTS
  Retinal GSH levels were 1.5-fold lower in diabetic rats as compared to normal rats (p < 0.05). However, in GT-treated rats, retinal GSH levels were restored close to those of the normal group. The antioxidant enzymes SOD and CAT showed a more than 2-fold decrease in activity in diabetic retinae as compared to normal retinae (p < 0.05). Both SOD and CAT enzymatic activities were restored close to normal in the GT-treated group. Expression of proinflammatory parameters (TNF-α and VEGF) was significantly inhibited in GT-treated retinae as compared to diabetic retinae (p < 0.05). Moreover, GT treatment prevented retinal capillary basement membrane thickness.
  
  
  CONCLUSIONS
  The beneficial effects of GT suggest its potential role in the prevention and treatment of diabetic retinopathy in human subjects.
authors: Department of Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, University of Delhi, New Delhi, India.
authors: Binit
authors: B
authors: Kumar
authors: Suresh Kumar
authors: SK
authors: Gupta
authors: Tapas Chandra
authors: TC
authors: Nag
authors: Sushma
authors: S
authors: Srivastava
authors: Rohit
authors: R
authors: Saxena
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D038321:Glycemic Index / Q000187:drug effects; D008297:Male; D046529:Microscopy, Electron, Transmission; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013662:Tea / Q000737:chemistry*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D013662:Tea; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione