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 nitric oxide 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.%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 nicotinam-ide adenine dinucleotide phosphate( NADPH ) oxidase subunit P47phox in aortas were deteced by Western blotting. In addition, vasorelaxation response to acetylcho-line( 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.
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