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目的:研究木兰脂素(magnolin,Mag)的舒张血管作用、作用机制和细胞毒性。方法:应用离体血管环技术观察Mag对大鼠胸主动脉环张力的作用,记录去氧肾上腺素(phenylephrine,PE,1μmol·L-1)预收缩的离体大鼠胸主动脉环张力变化。采用一氧化氮合酶(eNOS)抑制剂L-硝基精氨酸甲酯(L-NAME,100μmol·L-1)预处理后观察Mag对血管环张力改变的影响,并用MTT方法观察对大鼠肾细胞(NRK)增殖的影响。结果:木兰脂素(0.1~1 000μmol·L-1)对PE预收缩的血管环具有浓度依赖的舒张作用,该舒张作用为内皮依赖性。50%最大效应浓度(Half maximal effective concentration,EC50)为24.43μmol·L-1。内皮型一氧化氮合酶(endothelial nitric oxide synthesis,eNOS)抑制剂-NG-硝基-L-精氨酸甲酯(NG-Nitro-L-arginine methyl ester hydrochloride,L-NAME,100μmol·L-1)预处理可以抑制Mag对具内皮血管的舒张效应。木兰脂素(0.1~1 000μmol·L-1)处理NRK的相对增殖率在84.17%和134.60%。结论:木兰脂素具有内皮依赖性舒张血管作用,其机制可能与内皮型一氧化氮合成酶激活有关,且没有肾细胞毒性。
Objective: To study the vasodilatation, mechanism of action and cytotoxicity of magnolin (Mag). Methods: The effect of Mag on the tension of the thoracic aorta in rats was observed by using the ex vivo vascular ring technique. The changes of the tension of the thoracic aorta of precontracted isolated rat were recorded by phenylephrine (PE, 1 μmol·L-1) . The effect of Mag on the tension of vascular rings was observed by pretreatment with L-NAME (100μmol·L-1), an inhibitor of nitric oxide synthase (eNOS) Effect of rat kidney cell (NRK) proliferation. Results: Magnolin (0.1-1000 μmol·L -1) had a concentration-dependent relaxation effect on PE precontracted vascular rings, which was endothelium-dependent. The half maximal effective concentration (EC50) was 24.43μmol·L-1. N-Nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of endothelial nitric oxide synthase (eNOS) 1) Pretreatment can inhibit the relaxation of endothelium with Mag. The relative proliferation rates of Magnoliacetin (0.1-1000 μmol·L-1) treated NRK were 84.17% and 134.60%. Conclusions: Magnolina has an endothelium-dependent vasodilatation effect, and its mechanism may be related to the activation of endothelial nitric oxide synthase without renal cytotoxicity.