title: Silymarin improves vascular function of aged ovariectomized rats.
abstract: Both aging and estrogen depletion lead to endothelial dysfunction, which is the main reason of many cardiovascular diseases. Previous reports have shown that cell protective effect of silymarin (SM) depends on its antioxidant and phytoestrogenic properties. We investigated the effect of SM on vascular stiffness of aged menopausal rats and the involvement of estrogenic activity in this effect. Isolated rat aortas were obtained from 22-month-old rats, after 18 months of ovariectomy (OVX) follow-up. Each ring was incubated in tissue bath either with SM (50 mg/L) and 17β-estradiol (10 μM, E2) or in the presence of SM/fulvestrant (50 mg/L, 10 μM). Endothelium-intact rings were precontracted with phenylephrine (0.001-30 μM) or high potassium (40 mM); endothelium-dependent/independent relaxant responses were obtained using acetylcholine (0.001-30 μM) and sodium nitroprusside (0.0001-3 μM), respectively. While phenylephrine sensitivity was significantly increased in OVX rats, relaxations were significantly less in aged OVX rats compared with young rats. In spite of the presence of estrogen antagonist, immediate SM treatment restored the endothelial function and vascular tone better than estrogen replacement. Additionally, as a complementary and alternative medicine, it does not cause estrogenic side effects when taken acutely.
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Adnan Menderes University, Aydin, 09100, Turkey.
authors.forename: Buket
authors.initials: B
authors.lastname: Demirci
authors.forename: Turhan
authors.initials: T
authors.lastname: Dost
authors.forename: Filiz
authors.initials: F
authors.lastname: Gokalp
authors.forename: Mustafa
authors.initials: M
authors.lastname: Birincioglu
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004548:Elasticity; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D000077267:Fulvestrant; D066298:In Vitro Techniques; D009599:Nitroprusside / Q000494:pharmacology; D010052:Ovariectomy; D010656:Phenylephrine / Q000494:pharmacology; D048789:Phytoestrogens / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012838:Silymarin / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
chemical_list: D004967:Estrogens; D048789:Phytoestrogens; D012838:Silymarin; D009599:Nitroprusside; D010656:Phenylephrine; D000077267:Fulvestrant; D004958:Estradiol; D000109:Acetylcholine
keywords: endothelium; menopause; oophorectomy; silymarin; vascular reactivity