芝麻素对2型糖尿病大鼠主动脉内皮功能的保护作用

目的探讨芝麻素改善2型糖尿病大鼠主动脉内皮功能损伤的作用及可能机制。方法采用长期高脂饮食加小剂量链脲佐菌素(streptozotocin,STZ)建立2型糖尿病大鼠模型。灌服不同剂量芝麻素(120、60 mg.kg-1.d-1)8周后处死动物。离体血管灌流法测大鼠主动脉内皮依赖性舒张反应及NO生物活性,测血清丙二醛(malondialdehyde,MDA)含量和总抗氧化能力(total antioxidative capacity,T-AOC),Western blot测主动脉内皮型一氧化氮合酶(endothelial nitricoxide synthase,eNOS)、硝基酪氨酸(nitrotyrosine,NT)和还原型辅酶Ⅱ(NADPH)氧化酶亚基P47phox蛋白表达。结果与模型组相比,芝麻素(120 mg.kg-1.d-1)组内皮依赖性血管舒张功能增强,NO活性升高;血清MDA含量降低,T-AOC水平升高;主动脉eNOS蛋白表达增高,NT和P47phox蛋白表达降低。结论芝麻素可改善糖尿病大鼠血管内皮功能,其机制与上调血管eNOS表达和减轻NO氧化失活有关。

Protective effect of Sesamin on endothelial function of type-2 diabetic rats

Aim To study the ameliorative effect of sesamin(Ses) on endothelial dysfunction in diabetic rats and related mechanism.Methods Diabetic rats were induced by low dose streptozotocin(STZ) and fed with high-fat diet.Then,rats were randomly divided into model group and Ses(120,60 mg·kg-1·d-1,respectively ig,for 8 weeks.) groups.In addition,control group was set up.Eight weeks later,rats were sacrificed,the malondialdehyde(MDA) content,total antioxidative capacity(T-AOC) in serum were tested,and the protein expression of endothelial nitric oxide synthase(eNOS),nitrotyrosine(NT) and nicotinamide adenine dinucleotide phosphate(NADPH) oxidase subunit P47phox in aortas were deteced by Western blotting.In addition,vasorelaxation response to acetylcholine(ACh),and functional assessment of nitric oxide(NO) bioactivity were also determined in aortic rings.Results Compared with model group,vasodilation response of Ses(120 mg·kg-1) group was significantly improved.The MDA content was markedly decreased,T-AOC and NO level were increased.The protein expression of eNOS was significantly increased,while NT and P47phox were significantly decreased.Conclusion Ses can improve endothelial dysfunction through alleviated oxidative stress,enhance NO bioavailability by up-regulating eNOS expression and down-regulating NT and P47phox expression.