虎杖苷扩血管作用及机制初探

Effect of polydatin on vasodilation of rat isolated thoracic aortas

目的观察虎杖苷(Polydatin,PD)对血管的舒张作用,初步探讨其机制。方法以累计浓度法观察PD对苯肾上腺素预收缩血管的舒张效应,并观察不同信号通路阻断剂对PD效应的影响。结果 PD呈浓度依赖地舒张内皮完整的血管,去除内皮后该效应几乎被取消;PPARβ阻断剂GSK0660、NF-κB阻断剂PDTC及NOS抑制剂L-NAME均明显抑制PD舒张血管效应(P<0.05);但COX-2抑制剂美洛昔康对PD的作用无明显影响(P>0.05)。结论 PD具有直接舒张血管作用,该作用依赖于内皮功能的完整性,其机制可能与PPARβ、NF-κB信号通路及NO释放有关,而与前列环素的作用无关。

Objective To investigate the effect of polydatin（ PD） on isolated vascular smooth muscle tension and to explore the mechanisms of PD. Methods The isolated thoracic aortic rings of Sprague Dawley rats were mounted in the organ bath and tension was recorded by BL-420 S biological signal assay system. The rings with endothelium-intact or endothelium-denuded were pre-contracted by phenylephrine（ PE,10-6mol /L）,and the effect of PD on the vessel reaction induced by various drugs were recorded. Results PD（ 1 × 10-9-- 3 × 10-4mol /L） relaxed the contractions induced by PE in a concentration-dependent manner in endothelium-intact aortic rings,the maximum relaxation effect and-log IC50 are 79. 75% ± 8. 34% and 6. 13 ± 1. 55,respectively. However,PD could not inhibit the contraction in endothelium-denuded aortic rings,the maximum relaxation effect and-log IC50 lowed to 11. 15% ± 2. 89% and 0. 47 ± 2. 96,respectively（P〈0. 05）. The vasodilative effect of PD was significantly reduced by GSK0660（ PPARβ blocker,10-6mol /L）,PDTC（ NF-κB blocker,10-6mol /L） or L-NAME（ NOS inhibitor,10-5mol / L） in endothelium-intact aortic rings（P〈0. 05）,but was not inhibited by meloxicam（ COX-2 inhibitor,10-6mol /L）（P〈0. 05）. Conclusion These results indicate that PD possesses the endothelium-dependent relaxation which is probably,at least partly,related to PPARβ and /or NF-κB signal transduction pathways,promoting the release of nitric oxide,but prostacyclin is not involved in PD-induced vasodilatation.