Phytoestrogen α-zearalanol improves vascular function in ovariectomized hyperhomocysteinemic rats

• Published in: Atherosclerosis 2011-04, Vol.215 (2), p.309-315
• Main Authors: Zhen, Pan-pan, Duan, Jin-hong, Zhao, Qian, Hou, Dan-dan, Wang, Hong-xia, Hong, Ni, Zhen, Hui-xian, Wang, Wen
• Format: Article
• Language: English
• Subjects: 17β-Estradiol; acetylcholine; Acetylcholine - pharmacology; adults; animal models; Animals; Aorta, Thoracic - drug effects; Aorta, Thoracic - pathology; Aorta, Thoracic - physiology; apoptosis; atherosclerosis; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; blood; Blood and lymphatic vessels; Cardiology. Vascular system; Cardiovascular; diet; Endocrinopathies; endothelial nitric oxide synthase; Endothelin-1 - metabolism; endothelium; estradiol; Estradiol - pharmacology; Female; homocysteine; Homocysteine - blood; human umbilical vein endothelial cells; Hyperhomocysteinemia; Hyperhomocysteinemia - chemically induced; Hyperhomocysteinemia - physiopathology; Medical sciences; Methionine; Nitric Oxide Synthase Type III - metabolism; nitroprusside; Nitroprusside - pharmacology; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Ovariectomy; oxidative stress; phenylephrine; Phenylephrine - pharmacology; Phytoestrogen; Phytoestrogens - pharmacology; protective effect; Rats; Rats, Wistar; scanning electron microscopes; scanning electron microscopy; single nucleotide polymorphism; Thyroid. Thyroid axis (diseases); Vascular function; Western blotting; Zeranol - pharmacology; α-Zearalanol
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2010.12.029

Abstract Previous studies have showed that phytoestrogen α-zearalanol (α-ZAL) could antagonize homocysteine (Hcy) induced endothelin-1 (ET-1) expression, oxidative stress and apoptosis in human umbilical vein endothelial cells in vitro , however, its effect on vascular function in vivo remains to be determined. This study was designed to investigate the effects of α-ZAL on vascular function in ovariectomized (OVX) hyperhomocysteinemia (HHcy) rats and explore the mechanisms involved primarily. HHcy rat model was induced by diets containing 2.5% methionine (Met) for 12 weeks. Forty adult female Wistar rats were assigned randomly into five groups: (1) Con ; (2) Met ; (3) OVX + Met ; (4) OVX + Met + α-ZAL ; (5) OVX + Met + 17β-E 2 (17β-estradiol). Blood was collected to analyze plasma estradiol, Hcy and ET-1. Thoracic aortas were isolated to detect its response to phenylephrine (PE) and acetylcholine (ACh) or sodium nitroprusside (SNP). Aortas eNOS expression was determined by Western blot. Thoracic aortas histological characterization was analyzed by optical microscope and scanning electron microscope (SEM). Rat plasma Hcy was significantly elevated after fed with 2.5% methionine diets, and ovariectomy aggravated this elevation. Phytoestrogen α-ZAL or 17β-E2 could attenuate this elevation. Plasma ET-1 levels increased significantly in ovariectomized HHcy rats, and supplement with α-ZAL or 17β-E2 could reverse these changes. In rats of OVX + Met group, PE elicited significantly greater contraction in a dose-dependent manner in endothelium-intact thoracic aortas rings; ACh elicited significantly less percentage relaxation. These effects were significantly attenuated by supplement with α-ZAL or 17β-E2 . There was no significant difference between groups in relaxation induced by SNP whether endothelium intact or not. Thoracic aortas morphology study also showed severe endothelium injury in ovariectomized HHcy rats, both α-ZAL and 17β-E2 could attenuate this change. Aortas eNOS expression was decreased in ovariectomized HHcy rats, and supplement with α-ZAL or 17β-E2 could reverse these changes. These findings demonstrated that α-ZAL could effectively alleviate the impairment of endothelial cells and improve vascular function in ovariectomized HHcy rats by decreasing plasma Hcy and antagonizing decreasing of aortas eNOS expression. This protective effect is somewhat similar with 17β-E2.