血管回声跟踪技术评价动脉血管弹性变化的动物实验

目的 应用血管回声跟踪(ET)技术评价兔腹主动脉粥样硬化动脉弹性变化,探讨其评价动脉硬化弹性变化的病理基础及应用价值.方法 雄性新西兰兔30只,随机分为三组,A组为对照组;B、C组为实验组,分别高脂喂养8周、12周.A、B两组于喂养8周,A、C两组于喂养12周时应用ET技术检测兔腹主动脉弹性参数(Ep)、僵硬化系数(β)、脉搏波传导速度(PwVp)、增大指数(AI)、顺应性(AC)等参数,同时对比观察腹主动脉二维超声及病理变化.结果 各组二维超声均未见明显腹主动脉管壁增厚及斑块形成.ET检测指标显示:C组Ep、β、PWVβ较A、B组高,AC低于A、B两组,差异有统计学意义(均P<0.05);AI各组间差异无统计学意义(P>0.05).病理检查B组腹主动脉内膜泡沫细胞形成,动脉弹力层及平滑肌层未见明显破坏.C组腹主动脉内膜大量胆固醇结晶形成,动脉弹力层及平滑肌层破坏断裂.结论 ET技术可早于二维超声发现腹主动脉粥样硬化时动脉弹性改变.当动脉粥样硬化引起其管壁弹力层、平滑肌层破坏时,ET即能检测到相关参数变化,因此弹力层、平滑肌层损伤可能是动脉弹性改变的病理基础.

Animal experiment of the echo tracking technique in evaluating artery elasticity

Objective To assess the value of echo tracking(ET) technique on atherosclerosis in the rabbit models, and to probe the pathological foundation of its indexes changes and the usefulness in evaluating arterial elasticity. Methods Thirty New Zealand rabbits were divided into 3 groups randomly: group A was the control group;group B,C were fed with high lipid feedstuffs for 8 weeks and 12 weeks, respectively. The ET examination of abdominal aorta was performed in group A and group B at the end of 8 weeks,it was performed in group A and group C at the end of 12 weeks. The parameters of elasticity were measured including pressure-strain elastic modulus (Ep), stiffness parameters(β), pulse wave velocity (PWVβ), augmentation index (AI), arterial compliance (AC), etc. Two dimensional ultrasound and pathological examination of abdominal aorta were performed at the same time. Results No obvious plaque and arterial wall thickness were seen in the abdominal aorta. Ep,β,PWVβ of group C were higher than that of group A and B, while AC of group C was lower than that of group A and B, and the difference had statistical significance (P<0.05). AI had no significant difference in all groups (P>0.05). Pathological examinations indicated that foam cell formation was seen in the abdominal aorta intima, the elastic fiber layer and smooth muscle layer were kept well in B group. Lots of cholesterol crystal formation was seen in the abdominal aorta intima and the two layer were obvious destroyed in group C. Conclusions ET can detect the atherosclerosis earlier than two-dimensional ultrasound. ET can detect the elasticity changes only when the elastic fiber layer and smooth muscle layer were destroyed . So it can be concluded that the destroy of elastic fiber layer and smooth muscle layer may be the pathological foundation of ET elasticity parameters changes.