Relaxing Effects of Phytoestrogen α-Zearalanol on Rat Thoracic Aorta Rings in Vitro

10.4077/CJP.2009.AMH006

Wen Wang；Dong-Qiao Jiang；Ying-Fen Zhu；Wei Liu；Jin-Hong Duan；Sun-Ling Dai

α-ZAL ； thoracic aortas ； vasorelaxation ； NO ； cGMP ； K(superscript +) channel ； Ca(superscript 2+) channel

The Chinese Journal of Physiology

52卷2期（2009 / 04 / 01）

41 - 47

英文

The aim of this research is to investigate the vasorelaxing effects and mechanisms involved in the phytoestrogen α-zearalanol (α-ZAL) in rat thoracic aortas rings. Intact or endothelium denuded rat thoracic aortas rings were put in individual organ chamber to observe the endothelium-dependent or independent vasorelaxing effects of α-ZAL (10^(-10)-10^(-5) M). The thoracic aortas rings were pre-contracted with phenylephrine. The relaxing effects of α-ZAL were observed and the influence of N(superscript ω)-nitro-Larginine methylester (L-NAME, NOS inhibitor), methylene blue (MB, guanylate cyclase inhibitor), charybdotoxin (ChTX, Ca(superscript 2+) -activated K(superscript +) channel blocker), glibenclamide (ATP-sensitive K(superscript +) channel blocker), (-) BayK8644 (L-type Ca(superscript 2+) channel agonist) and ICI182,780 (estrogen receptor antagonist) were pre-incubated with α-ZAL respectively to explore the possible mechanisms involved in this vasorelaxation. Furthermore, the Phospho-eNOS expression and cGMP level in the aortas tissue were detected by Western blot and radioimmunity respectively; the NO level in perfusate was assaied by chromatometry. Our result showed that α-ZAL (10^(-10)-10^(-5) M) induced both endothelium-dependent and -independent relaxation of rat thoracic aortas rings. The vasorelaxing effects of α-ZAL were dosedependent whether the endothelium intact or not. In endothelium-intact aortas rings, α-ZAL-induced vasorelaxation might be inhibited by L-NAME, MB, charybdotoxin, glibenclamide and (-) BayK8644, but not ICI182, 780. (-) BayK8644 can also inhibit α-ZAL-induced vasorelaxation in endotheliumdenuded aortas rings.10^(-7)-10^(-5) M α-ZAL might induce the Phospho-eNOS expression in thoracic aorta tissue, increase the NO level in perfusate and cGMP content in thoracic aorta tissue. Meanwhile, L-NAME might decrease both NO and its downstream cGMP level. Methylene blue might decrease the level of cGMP. These results suggest that α-ZAL induces a partly endothelium-dependent relaxation of rat thoracic aortas rings; the possible mechanisms involved in this rapid vasorelaxation include activation of eNOS/NO/cGMP pathway, opening of VSMCs ATP-sensitive and Ca(superscript 2+)-activated K(superscript +) channels through secretion of EDHF from endothelium. Furthermore, this relaxation also appears to be mediated by both direct and indirect inhibition of voltage-dependent Ca(superscript 2+) channel of VSMCs, while it is not concerned with activation of estrogen receptor.

1. Belcher, S.M.,Zsarnovszky, A.(2001).Estrogenic actions in the brain: estrogen, phytoestrogens, and rapid intracellular signaling mechanisms.J. Pharmacol. Exp. Ther.,299,408-414.
2. Bhathena, S.J.,Velasquez, M.T.(2002).Beneficial role of dietary phytoestrogens in obesity and diabetes.Am. J. Clin. Nutr.,76,1191-1201.
3. Binko, J.,Murphy, T.V.,Majewski, H.(1998).17Beta-oestradiol enhances nitric oxide synthase activity in endothelium-denuded rat aorta.Clin. Exp. Pharmacol. Physiol.,25,120-127.
4. Cassidy, A.,Hooper, L.(2006).Phytoestrogens and cardiovascular disease.J. Br. Menopaus.e Soc.,12,49-56.
5. Cohen, R.A.,Vanhoutte, P.M.(1995).Endothelium-dependent hyperpolarization. Beyond nitric oxide and cyclic GMP.Circulation,92,3337-3349.
6. Dai, S.,Duan, J.,Lu, Y.,Cheng, J.,Ren, J.,Deng, W.,Wu, Y.(2004).Alpha-Zearalanol, a phytoestrogen for cardiovascular therapy.Endocrine,25,117-119.
7. Dai, S.,Duan, J.,Lu, Y.,Zhang, Y.,Cheng, J.,Ren, J.,Zhao, X.,Wu, Y.,Yu, Y.,Zuo, P.,Wu, Y.,Ge, Q.(2004).Phytoestrogen alphazearalanol inhibits atherogenesis and improves lipid profile in ovariectomized cholesterol-fed rabbits.Endocrine,25,121-129.
8. Deng, W.H.,Wu, Y.Y.,Duan, J.H.,Yang, L.,Wang, S.,Dai, S.L.(2004).Effects of phytoestrogen alpha-zearalanol on normal human breast.Zhongguo Yi Xue Ke Xue Yuan Xue Bao,26,566-570.
9. Duan, J.,Dai, S.,Fang, C.X.,Sun, R.,Shavali, S.,Sharma, S.K.,Ebadi, M.,Ren, J.(2006).Phytoestrogen alpha-zearalanol antagonizes homocysteine-induced imbalance of nitric oxide/endothelin-1 and apoptosis in human umbilical vein endothelial cells.Cell Biochem. Biophys.,45,137-145.
10. Duan, J.,Xu, H.,Dai, S.,Wang, X.,Wu, Y.,Zhang, Y.,Sun, R.,Ren, J.(2008).Phytoestrogen alpha-zearalanol inhibits homocysteineinduced endothelin-1 expression and oxidative stress in human umbilical vein endothelial cells.Atherosclerosis,197,549-555.
11. Farhat, M.Y.,Abi-Younes, S.,Dingaan, B.,Vargas, R.,Ramwell, P.W.(1996).Estradiol increases cyclic adenosine monophosphate in rat pulmonary vascular smooth muscle cells by a nongenomic mechanism.J. Pharmacol. Exp. Ther.,276,652-657.
12. Furchgott, R.F.(1999).Endothelium-derived relaxing factor: discovery, early studies, and identification as nitric oxide.Biosci. Rep.,19,235-251.
13. Furchgott, R.F.,Zawadzki, J.V.(1980).The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine.Nature,288,373-376.
14. Glazier, M.G.,Bowman, M.A.(2001).A review of the evidence for the use of phytoestrogens as a replacement for traditional estrogen replacement therapy.Arch. Intern. Med.,161,1161-1172.
15. Han, S.Z.,Karaki, H.,Ouchi, Y.,Akishita, M.,Orimo, H.(1995).17beta-Estradiol inhibits Ca2+ influx and Ca2+ release induced by thromboxane A2 in porcine coronary artery.Circulation,91,619-2626.
16. Huang, Z.,Wu, H.(2001).Effect of Yiqitongyanghuatan recipe on experimental atheroslerosis in rabbits.J. Tongji Med.,21,326-327.
17. Leuranguer, V.,Gluais, P.,Vanhoutte, P.M.,Verbeuren, T.J.,Félétou, M.(2008).Openers of calcium-activated potassium channels and endothelium-dependent hyperpolarizations in the guinea pig carotid artery.Naunyn. Schmiedebergs. Arch. Pharmacol.,377,101-109.
18. Li, H.F.,Tian, Z.F.,Qiu, X.Q.,Wu, J.X.,Zhang, P.,Jia, Z.J.(2006).A study of mechanisms involved in vasodilatation induced by resveratrol in isolated porcine coronary artery.Physiol. Res.,55,365-372.
19. Li, X.M.,Li, J.(2003).Environmental hormones and their effects on human health.Zhonghua Yu Fang Yi Xue Za Zhi,37,209-211.
20. Ogata, R.,Inoue, Y.,Nakano, H.,Ito, Y.,Kitamura, K.(1996).Oestradiol-induced relaxation of rabbit basilar artery by inhibition of voltage-dependent Ca channels through GTP-binding protein.Br. J. Pharmacol.,117,351-359.
21. Standen, N.B.,Quayle, J.M.,Davies, N.W.,Brayden, J.E.,Huang, Y.,Nelson, M.T.(1989).Hyperpolarizing vasodilators activate ATP-sensitive K+ channels in arterial smooth muscle.Science,245,177-180.
22. Stark, A.,Madar, Z.(2002).Phytoestrogens: a review of recent findings.J. Pediatr. Endocrinol. Metab.,15,561-572.
23. Torregrosa, G.,Burguete, M.C.,Pérez-Asensio, F.J.,Salom, J.B.,Gil, J.V.,Alborch, E.(2003).Pharmacological profile of phytoestrogens in cerebral vessels: in vitro study with rabbit basilar artery.Eur. J. Pharmacol.,482,227-234.
24. Usui T.(2006).Pharmaceutical prospects of phytoestrogens.Endocr. J.,53,7-20.
25. Wang, H.P.,Gao, Q.,Mei, R.H.,Zhao, M.H.,Lu, Y.,Li, X.Y.,Bruce, I.C.,Xia, Q.(2006).Mechanisms underlying biochanin A-induced relaxation of the aorta differ between normotensive and hypertensive rats.Clin. Exp. Pharmacol. Physiol.,33,802-807.
26. Wang, W.,Zhu, G.J.,Zu, S.Y.(2004).Effects of 17β-estradiol and phytoestrogen α-zearalanol on tissue factor in ovariectomized rats and endothelial cells.Chinese J. Physiol.,47,62-72.
27. Xu, H.S.,Duan, J.,Dai, S.,Wu, Y.,Sun, R.,Ren, J.(2004).Phytoestrogen alpha-zearalanol antagonizes oxidized LDL-induced inhibition of nitric oxide production and stimulation of endothelin-1 release in human umbilical vein endothelial cells.Endocrine,25,235-245.

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