补骨脂素和补骨脂酚舒张血管的作用机制研究

Study on the Vasodilatory Effect Mechanism of Psoralen and Bakuchiol

目的:探讨补骨脂素和补骨脂酚舒张血管的作用机制。方法:取大鼠胸主动脉制备离体血管环及去内皮血管环。采用血管收缩率为考察指标,分别以一氧化氮合酶抑制剂N-硝基-L-精氨酸甲酯(L-NAME,100μmol/L)预孵育内皮完整或去内皮血管环后,考察低、中、高剂量补骨脂素或补骨脂酚(0.1、1、10μmol/L)对去甲肾上腺素(NE,1μmol/L)或氯化钾(KCl,60 mmol/L)预收缩血管环的舒张作用;分别以钙依赖型钾离子通道抑制剂氯化四乙胺(TEA,0.1 mmol/L)、内向整流型钾离子通道抑制剂氯化钡(BaCl2,0.1 mmol/L)预孵育去内皮血管环后,考察低、中、高剂量补骨脂酚(0.1、1、10μmol/L)对NE(1μmol/L)预收缩去内皮血管环的舒张作用。采用胶原酶-中性蛋白酶混合消化法分离大鼠心脏微血管内皮细胞,采用酶联免疫吸附法考察低、中、高剂量补骨脂素或补骨脂酚(0.1、1、10μmol/L)对细胞中内皮型一氧化氮合酶(eNOS)蛋白表达的影响。结果:各剂量补骨脂素和补骨脂酚均能显著降低NE预收缩的内皮完整血管环收缩率(P<0.01),中、高剂量补骨脂素和补骨脂酚能显著降低KCl预收缩的内皮完整血管环收缩率(P<0.05或P<0.01),而去内皮和抑制一氧化氮合酶后血管环收缩率显著升高(P<0.05或P<0.01);中、高剂量补骨脂酚能显著降低NE预收缩去内皮血管环收缩率(P<0.05或P<0.01),而抑制血管平滑肌内向整流型钾离子通道后血管环收缩率显著升高(P<0.01)。各剂量补骨脂素和补骨脂酚均能显著提高大鼠心脏微血管内皮细胞中eNOS蛋白表达水平(P<0.01)。结论:补骨脂素和补骨脂酚可能通过内皮依赖性的NO途径以及促进内皮细胞中eNOS蛋白表达来发挥血管舒张作用;补骨脂酚还可能通过开放内向整流型钾离子通道这一非内皮依赖途径发挥血管舒张作用。

OBJECTIVE:To investigate the vasodilatory effect mechanism of psoralen and bakuchiol.METHODS:The rat thoracic aorta was isolated to prepare vascular rings and de-endothelium vascular rings.Using contraction rate as index,the intact endothelium or de-endothelium vascular rings were pre-incubated with N-nitro-L-arginine methyl ester(L-NAME,100μmol/L);vasodilatory effect of low-dose,medium-dose and high-dose of psoralen or bakuchiol(0.1,1,10μmol/L)on aortic vessels precontracted with norepinephrine(NE,1μmol/L)or potassium chloride(KCl,60 mmol/L)were investigated.The de-endothelium vascular rings were pre-incubated with calcium dependent potassium channel inhibitors tetraethylammonium chloride(TEA,0.1 mmol/L)and inward rectifying potassium channel inhibitor barium chloride(BaCl2,0.1 mmol/L);vasodilatory effect of low-dose,medium-dose and high-dose of bakuchiol(0.1,1,10μmol/L)on de-endothelium vascular vessels pre-contracted with NE(1μmol/L)were investigated.The microvascular endothelial cells were isolated by collagenase-neutral protease digestion;the effects of low-dose,medium-dose and high-dose of psoralen or bakuchiol(0.1,1,10μmol/L)on the expression of eNOS protein were studied by ELISA.RESULTS:Psoralen and bakuchiol could significantly reduce the contraction rate of endothelium-intact aortic rings pre-contracted with NE(P<0.01);medium-dose and high-dose of psoralen and bakuchiol could significantly reduce the contraction rate of endothelium-intact aortic rings pre-contracted with KCl(P<0.05 or P<0.01);while the contraction rate could be increased by de-endothelium and NOS inhibition significantly(P<0.05 or P<0.01).The medium-dose and high-dose of bakuchiol could significantly reduce the contraction rate of de-endothelium vascular vessels pre-contracted with NE(P<0.05 or P<0.01).The contraction rate could be increased by inhibiting inward rectifier potassium channels in vascular smooth muscle(P<0.01).Different dosages of psoralen and bakuchiol could significantly increase the expression levels of eNOS protein in rat cardiac microvascular endothelial cells(P<0.01).CONCLUSIONS:Psoralen and bakuchiol may play a role in vasodilation via endothelium-dependent NO pathway and by promoting eNOS protein expression in endothelial cells;bakuchiol may play a role in vasodilation via non-endothelium dependent pathway as opening inward rectifying potassium channel.