枸杞多糖对肾性高血压大鼠离体血管反应性的影响及其机制

THE EFFECT OF LYCIUM BARBARUM POLYSACCHARIDE ON VASCULAR TENSION IN TWO-KIDNEY, ONE CLIP MODEL OF HYPERTENSION

本工作利用两肾—夹（2KlC）肾性高血压（RH）大鼠模型，观察枸杞多糖（LBP）对高血压大鼠血压的影响以及离体主动脉环内皮细胞在调节血管张力中的功能改变，探讨LBP对高血压发生发展的影响及其机制。结果表明，LBP可防止2KlC大鼠高血压的形成。离体主动脉环灌流表明RH组对苯肾上腺素（PE）的收缩反应明显高于对照组，去除内皮后组间差异消失；而LBP组由—氧化氮（NO）合成酶抑制剂卜硝基-L-精氨酸甲基酯（LNAME）及鸟苷酸环化酶抑制剂美蓝（MB）引起的收缩反应较RH组明显增加；LBP组对乙酸胆碱（ACh）的内皮依赖性舒张反应较RH对照组明显增加，而对非内皮依赖舒张剂硝普钠（SNP）的舒张反应无组间差异；NO合成底物L-精氨酸（L-Arg）能显著提高RH大鼠对ACh的内皮依赖性舒张，而对LBP组无明显作用。上述结果表明，LBP降低2lIC大鼠增强的血管收缩反应，增加内皮依赖性的舒张。此作用与LBP对内皮的保护、内皮源性舒张因子（EDRF）生成增多以及促进LArg的代谢有关。

In the present study, the effects of lycium harbarum polysaccharide (LBP) on endothelial function in the twO-kidney, one clip model of hypertension were abserved.The results shawed that the increase of blood pressure in hypertension rats (HR) could be prevented significantly by treatment with 10% LBP. In isolated aortic rings of LBPtreated rats, the contraction of phenylepdrine (PE) was reduced as compared with HRrats. Removal of the endothelium abolished the difference of PE-induced vasoconstriction among groups. In vitro incubation of aortic rings from LBP-treated rats with methyl blue (MB) or N-nitro-harginine methyl ester (hNAME) increased the magnitude of PEinduced contraction. Meanwhile the response to acetylcholine (ACh) was significantly increased in LBP-treated rats, but the response to nitroprusside had no significant difference among groups. Pretreatment with Larginine paltially restored ACh-induced relaxation in RH rats, hut no effect in lsp-treated rats. These results suggest6d that the role of LBP in decreasing vasoconstriction to PE may be mediated by increase of the effects or/and production of endothelium-derived relaxation factor (EDRF). LBP increased formation of EDRF may he related to increase the substrate of EDRF.