多普勒超声评价血流剪切力对血管内皮功能的影响

Effect of Shear Stress on Endothelial Function in the Model of Atherosclerotic Rabbits

目的 探讨血流剪切力对动脉粥样硬化血管内皮功能的影响。方法 大耳白兔 2 0只 ,体重 2 .0～ 2 .4kg ,兔龄5～ 6个月 ,以高脂饮食连续喂养 12周。生化测定Tch、LDL、NO和ET 1水平 ;采用多普勒超声测定髂外动脉血流剪切力、内皮依赖性舒张功能 (EDD)、内皮非依赖性舒张功能 (EID)。结果 与基态相比 ,动脉粥样硬化期NO水平明显下降 (P <0 .0 1) ,内皮素ET 1水平明显上升 (P <0 .0 1) ;EDD、EID明显受损 (P <0 .0 1,P <0 .0 1) ;下降的血流剪切力与EDD、EID明显相关 (r =0 .67,r =0 .78)。结论 本研究显示长期高脂饮食可导致动脉血流剪切力明显下降 ,低幅血流剪切力与EDD、EID呈正相关。多普勒超声在体测定血流剪切力有望为临床早期诊治动脉粥样硬化提供一项新的手段。

Objective To determine the effect of shear stress on endothelial function in rabbits fed with high cholesterol diet.Methods Twenty big ear white rabbits,weight 2.0-2.4 kg,age 5-6 months,were fed with high cholesterol diet for 12 weeks.Biochemical parameters such as Tch?LDL?NO?ET-1 were measured.Shear stress,endothelium-dependent dilation (EDD) and endothelium-independent dilation (EID) were measured with Doppler ultrasound in iliac arteries.Results In rabbits fed with high cholesterol diet for 12 weeks,the NO level decreased significantly (P<0.01),the ET-1 level increased significantly (P<0.01).EDD (%) and EID (%) of external iliac arteries were injured to a great degree.Compared with baseline group,shear stress decreased from (15.50±5.68) dynes/cm 2 to (9.76±2.81) dynes/cm 2 and there was a significant correlation between shear stress and EDD?EID (r=0.67,r=0.78).Conclusion Our study indicates that long-term high cholesterol diet would lead to a significant decrease of shear stress and that low shear stress was positively correlated to injured EDD and EID respectively.Quantitative analysis of shear stress with Doppler ultrasound has a great potential to evaluate atherosclerosis.