北五味子多糖对高脂血症大鼠血管内皮功能的影响

Effect of Schisandra polysaccharide on endothelial dysfunction in hyperlipidemic rats

目的:研究北五味子多糖对高脂血症大鼠血管内皮功能的影响,并探讨其机制。方法:采用高脂饲料喂养16周诱发高脂血症大鼠模型,将模型动物随机分为模型组及北五味子多糖治疗组,另设正常对照组以及正常北五味子多糖组。北五味子多糖处理组以50mg/kg灌胃给药12周,检测各组动物血脂、血清中一氧化氮和丙二醛含量;通过离体实验方法观察胸主动脉条的张力反应;免疫组织化学方法检测胸主动脉内皮一氧化氮合酶的表达。结果:北五味子多糖(50mg/kg)可显著降低高脂血症大鼠血清总胆固醇、低密度脂蛋白-胆固醇及甘油三酯水平;改善乙酰胆碱引起的内皮依赖性血管舒张反应,而硝普钠诱导的内皮非依赖性舒张反应各组间比较差异无显著性;北五味子多糖可增加血清中一氧化氮水平,提高胸主动脉内皮细胞一氧化氮表达,并可降低血中MDA含量。结论 :北五味子多糖具有降血脂和保护血管内皮功能作用,机制可能与其调节血脂、抑制脂质过氧化作用、保护一氧化氮功能有关。

Object：To investigate the effect of Schisandra polysaccharide on vascular endothelial function in hyperlipidemic rats and explore the pharmacological mechanism. Methods： Hyperlipidemic rats were induced by high-fat diet for 16 weeks. Rats were randomly divided into four groups： control group,control rats treated with Schisandra polysaccharide （50 mg/kg） group,hyperlipidemic group,and hyperlipidemic rats treated with Schisandra polysaccharide （50 mg/kg） group. After 12 weeks treatment,the serum lipid,nitric oxide （NO） and methane dicarboxylic aldehyde （MDA） levels were tested. For estimating vascular endothelial function,the thoracic strips experiment in vitro were performed. In addition,eNOS expression in thoracic tissue was measured by immunohistochemical method. Results： Compared to control rats, the serum total cholesterol,triglyceride,and low-density lipoprotein cholesterol levels were significantly decreased in hyperlipidemic rats treated with Schisandra polysaccharide （50 mg/kg） . Schisandra polysaccharide could improve acetylcholine-induced endothelium-dependent relaxation in the aorta from hyperlipidemic rats,while sodium nitroprusside （SNP） -induced endothelium-independent relaxation showed no difference among four groups. In addition,Schisandra polysaccharide increased the NO level in serum and eNOS expression of thoracic endothelial cells,reduced MDA content in hyperlipidemic rats. Conclusion： Schisandra polysaccharide has effects of regulating blood lipid and protecting vascular endothelial function on hyperlipidemic rats. The mechanism might be related to decreasing blood pipid,inhibiting lipid peroxidation,and enhancing NO bioavailability.