title: The effect of supplementation of grape seed proanthocyanidin extract on vascular dysfunction in experimental diabetes.
abstract: Increased oxidative stress and impaired endothelium-dependent relaxation could underlie many of the vascular complications associated with diabetes. We aimed to investigate the effect of supplementation with grape seed proanthocyanidin extract (GSPE), a natural antioxidant, on vascular responses and oxidative stress in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into three groups: control rats, untreated diabetic rats, and GSPE (100 mg/kg, for 6 weeks)-supplemented diabetic rats. Thoracic aorta rings of the rats were mounted in organ baths, and relaxant responses to acetylcholine (ACh), A23187, and sodium nitroprusside (SNP) were assayed in tissues precontracted with 60 mM KCl. Plasma samples used for the measurement of malondialdehyde (MDA) level and superoxide dismutase (SOD) activity. The endothelium-dependent relaxations in response to ACh and A23187 were impaired, but endothelium-independent relaxation in response to SNP did not change in diabetic rats. Supplementation with GSPE significantly improved the relaxant responses to ACh and A23187. The MDA level was significantly elevated and the plasma SOD activity was decreased in diabetic rats, but supplementation with GSPE attenuated the elevated MDA levels and increased plasma SOD activity. Thus supplementation of GSPE may attenuate oxidative stress through the inhibition of lipid peroxidation and may restore endothelial function and reduce the risk of vascular disease in diabetes.
authors.affiliation: Department of Physiology, Selçuk University, Konya, Turkey.
authors.forename: Nilsel
authors.initials: N
authors.lastname: Okudan
authors.forename: Hülagu
authors.initials: H
authors.lastname: Barışkaner
authors.forename: Hakkı
authors.initials: H
authors.lastname: Gökbel
authors.forename: Ayşe Saide
authors.initials: AS
authors.lastname: Sahin
authors.forename: Muaz
authors.initials: M
authors.lastname: Belviranlı
authors.forename: Hatice
authors.initials: H
authors.lastname: Baysal
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000473:pathology; D019587:Dietary Supplements; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology*; D056604:Grape Seed Extract / Q000494:pharmacology*; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D009599:Nitroprusside / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D044945:Proanthocyanidins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000097:blood / Q000378:metabolism
chemical_list: D000975:Antioxidants; D056604:Grape Seed Extract; C511402:Grape Seed Proanthocyanidins; D044945:Proanthocyanidins; D009599:Nitroprusside; D008315:Malondialdehyde; D013482:Superoxide Dismutase; D000109:Acetylcholine