title: A novel approach of proteomics to study the mechanism of action of grape seed proanthocyanidin extracts on diabetic retinopathy in rats.
abstract: BACKGROUND
  Diabetic retinopathy (DR) is a leading cause of visual impairment and blindness among the people of occupational age. To prevent the progress of retina injury, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating diabetic complications, while little is discussed about the functional protein changes.
  
  
  METHODS
  We used streptozotocin (STZ) to induce diabetes in rats. GSPE (250 mg/kg body weight per day) were administrated to diabetic rats for 24 weeks. Serum glucose, glycated hemoglobin and advanced glycation end products (AGEs) were determined. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate retina protein profiles among control, STZ-induced diabetic rats, and GSPE treated diabetic rats.
  
  
  RESULTS
  GSPE significantly reduced the AGEs of diabetic rats (P < 0.05). Moreover, GSPE significantly suppressed the vascular lesions of central regions, decreased capillary enlargements and neovascularization, similar to those of the control rats under light microscope. Eighteen proteins were found either up-regulated or down-regulated in the retina of STZ-induced diabetic rats. And seven proteins in the retina of diabetic rats were found to be back-regulated to normal levels after GSPE therapy. These back-regulated proteins are involved in many important biological processes such as heat shock, ubiquitin-proteasome system, cell proliferation, cell growth and glucose metabolism.
  
  
  CONCLUSIONS
  These findings might promote a better understanding for the mechanism of DR, and provide novel targets for evaluating the effects of GSPE therapy.
authors.affiliation: Department of Geriatrics, Qilu Hospital of Shandong University, Jinan, Shandong, China.
authors.forename: Man
authors.initials: M
authors.lastname: Li
authors.forename: Ya-bing
authors.initials: YB
authors.lastname: Ma
authors.forename: Hai-qing
authors.initials: HQ
authors.lastname: Gao
authors.forename: Bao-ying
authors.initials: BY
authors.lastname: Li
authors.forename: Mei
authors.initials: M
authors.lastname: Cheng
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Li
authors.forename: Xian-hua
authors.initials: XH
authors.lastname: Li
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000378:metabolism / Q000473:pathology; D003930:Diabetic Retinopathy / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D015180:Electrophoresis, Gel, Two-Dimensional; D006442:Glycated Hemoglobin / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000378:metabolism; D056604:Grape Seed Extract; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D044945:Proanthocyanidins / Q000494:pharmacology*; D040901:Proteomics / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D017127:Glycation End Products, Advanced; D056604:Grape Seed Extract; D010936:Plant Extracts; D044945:Proanthocyanidins; C511402:Grape Seed Proanthocyanidins