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目的探讨植物雌激素白藜芦醇和根皮素对离体主动脉血管收缩的舒张作用特点是否同雌激素以及有关的作用机制。方法将家兔离体主动脉平滑肌条置于灌流肌槽中,记录其等长张力变化。结果白藜芦醇和根皮素可明显抑制离体血管对去甲肾上腺素(NE)、KCl和CaCl2的浓度依赖性收缩反应,使其量效曲线明显右移, pD2′值分别为2.89,3.34, 3.37和3.23, 3.52, 3.77;对KCl预收缩血管条具有浓度依赖性的舒张效应。去除血管内皮、Nω-L-硝基精氨酸(L-NNA)或亚甲蓝对白藜芦醇舒张血管作用具有明显的抑制作用,但对根皮素诱发的血管舒张无明显影响。吲哚美辛和普萘洛尔温育后,对二者的舒血管作用均无明显影响。在无钙Krebs液(含0.01 mmol·L-1EGTA)中,白藜芦醇和根皮素可抑制NE诱发的由肌细胞内钙释放引起的Ⅰ相收缩,但不影响CaCl2诱发的由肌细胞外钙内流引起的Ⅱ相收缩。结论白藜芦醇和根皮素对离体主动脉血管的舒张作用可能与其抑制钙离子内流及细胞内钙释放有关;另外白藜芦醇的舒张作用部分与内皮细胞有关,但根皮素的舒血管作用与内皮细胞无关。
Objective To investigate whether the vasodilator effect of phytoestrogen resveratrol and phloretin on isolated aortic vasoconstrictors is the same as that of estrogen and its related mechanism of action. Methods Rabbit aorta smooth muscle strips were placed in the perfusion muscles and their isometric tension was recorded. RESULTS: Resveratrol and phloretin significantly inhibited the concentration-dependent contraction of norepinephrine (NE), KCl and CaCl2 in vitro, resulting in a significant shift in the dose-response curve. The pD2’ values were 2.89 and 3.34, respectively. , 3.37 and 3.23, 3.52, 3.77; concentration dependent diastolic effects on KCl precontracted vascular strips. Removal of vascular endothelium, Nω-L-nitroarginine (L-NNA) or methylene blue had a significant inhibitory effect on the vasodilation of resveratrol, but had no significant effect on vasodilation induced by phloretin. Incubation with indomethacin and propranolol had no significant effect on the vasodilatory effects of both. In the calcium-free Krebs solution (containing 0.01 mmol·L-1 EGTA), resveratrol and phloretin inhibited NE-induced I-phase contraction induced by intracellular calcium release in muscle cells, but did not affect CaCl2-induced extracellular myocytes. Influx of calcium caused by phase II contraction. Conclusion The effect of resveratrol and phloretin on the relaxation of isolated aortic blood vessels may be related to its inhibition of calcium influx and intracellular calcium release. In addition, the relaxation effect of resveratrol is related to endothelial cells, but phloretin Vascular function has nothing to do with endothelial cells.