动脉内皮细胞黏附分子和核因子κB表达及银杏叶提取物的抑制作用

背景:以往的很多研究表明高同型半胱氨酸血症通过增强氧化应激诱导动脉粥样硬化,而银杏叶提取物可以清除氧自由基。目的:观察在同型半胱氨酸诱导细胞黏附分子表达中活性氧基团和核因子κB的作用及银杏叶提取物对这一过程的影响。设计:随机对照动物实验。单位:华中科技大学同济医学院附属协和医院神经内科。材料:选用健康雄性家兔24只,6月龄。蛋氨酸(Sigma公司);银杏叶提取物(贵州益佰制药股份有限公司提供,粉剂)。方法:实验于2003-02/2004-03在华中科技大学同济医学院附属协和医院神经内科实验室完成。①适应性喂养2周后,按随机摸球法分为3组:模型组(12只):按80mg/(kg·d)剂量皮下注射蛋氨酸;银杏叶提取物组(8只):皮下注射蛋氨酸前1h予喂饲(与食物混合)银杏叶提取物50mg/(kg·d);对照组(4只):注射与蛋白氨酸等剂量的生理盐水。连续用药7周。②光镜和透射电镜下观察动脉组织学变化;比色法(721型分光光度计)测定活性氧水平;免疫组织化学方法检测动脉内皮细胞黏附分子和核因子κB的表达。高效液相色谱法测定血浆同型半胱氨酸浓度。主要观察指标:各组动物动脉组织学变化、活性氧水平,以及动脉内皮细胞黏附分子和核因子κB的表达。结果:家兔24只均进入结果分析。①动脉内皮细胞活性氧水平:模型组给药结束时活性氧水平明显增高(2.92±0.20,2.48±0.26,P<0.05),银杏叶提取物组和对照组给药结束时分别为2.41±0.23和2.43±0.20,与给药前比较,差异不明显(2.31±0.27,2.47±0.32,P>0.05)。②动脉组织学变化:模型组颈总动脉动脉组织表现为早期动脉粥样硬化形态(内皮细胞脱落,平滑肌细胞排列紊乱);对照组和银杏叶提取物组动脉壁结构基本正常。③动脉内皮细胞细胞黏附分子和核因子κB表达:模型组细胞黏附分子和核因子κB表达明显高于对照组(P<0.05),银杏叶提取物组与对照组相近(P>0.05)。④血浆同型半胱氨酸浓度:给药7周后,模型组与银杏叶提取物组血浆同型半胱氨酸浓度分别为(25.01±6.80),(26.71±2.36)μmol/L,高于对照组(16.85±1.64)μmol/L,P<0.05]。结论:同型半胱氨酸可诱导家兔主动脉上皮细胞表达细胞黏附分子,主要由氧化应激作用激活核因子κB而介导。银杏叶提取物通过抑制活性氧水平和核因子κB活性而抑制细胞黏附分子的表达。

Ginkgo biloba extract inhibits the expressions of cell adhesion molecules and nuclear factor-kappa B in arterial endothelial cells

BACKGROUND: Previous studies have indicated that hyperhomocysteinemia can induce atherosclerosis by enhancing oxidative stress, whereas Ginkgo biloba extract (GbE) can scavenge oxygen-derived free radicals.OBJECTIVE: To observe the role of reactive oxygen species (ROS) and nuclear factor-kappa B (NF-κB) in the expression of cell adhesion molecules (CAMs) induced by homocysteine (Hcy), and investigate the effect of GbE.DESIGN: A randomized controlled animal trial.SETTING: Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.MATERrALS: Twenty-four healthy male rabbits of 6 months old. Dl-methionine (Sigma Chemical, Co.,Ltd.); GbE (Guizhou Yibai Pharmaceutical Company; powder).METHODS: The experiment was accomplished in the Laboratory of Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from March 2003 to April 2004. ① After adaptive feeding for 2 weeks, the rabbits were randomly divided into three groups: Model group (n =12): The rabbits were treated with subcutaneous injection of dl-methionine (80 mg/kg per day); GbE group (n =8): The rabbits were administrated with GbE (mixed with feed, 50 m/kg per day) at 1 hour before the subcutaneous injection of dl-methionine; Control group (n=4): The rabbits were injected with equivalent sodium chloride. They were administrated for 7 weeks continuously. ②Histological changes were observed under light and electron microscopes: ROS level was determined with colorimetries (721 visible spectrophotometer); The expressions of CAMs and NF-κB in endothelial cells were detected with immunohistochemical methods; The concentration of plasma Hcy was measured with high-performance liquid chromatography.MAIN OUTCOME MEASURES: Histological changes, ROS level and expressions of CAMs and NF-κB in endothelial cells.RESULTS: All the 24 rabbits were involved in the analysis of results. ① ROS level: After administration, the ROS level in the model group was obviously increased (2.92±0.20,2.48±0.26, P ＜ 0.05), whereas those in the GbE group and control group (2.41±0.23, 2.43±0.20) had no obvious differences as compared with those before administration (2.31±0.27,2.47±0.32, P ＞ 0.05). ② Histological changes: Aortas of rabbits in the model group presented initial changes of atherosclerosis, including shedding or necrosis of endothelial cells and nuclear pyknosis or standing in a clutter of smooth muscle cells. There were scarcely any changes in the GbE group and control group. ③ Expressions of CAMs and NF-κB in endothelial cells: After treatments, the expressions of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and NF-κB in the model group were obviously higher than those in the control group (P ＜0.05), and there were no significant differences between the GbE group and control group (P ＞ 0.05). ④ Concentration of plasma Hcy: After 7 weeks, the concentration of plasma Hcy was higher in the model group and GbE group than in the control group (25.01±6.80), (26.71±2.36), (16.85± 1.64) μmol/L, P ＜ 0.05].CONCLUSION: Hcy-induced oxidative stress plays an important role in NF-κB activation. GbE might suppress the activation of NF-κB and expression of CAMs by reducing ROS.