经颅多普勒联合颈动脉超声评估动脉粥样硬化兔的脑血管弹性储备

Assessment of cerebral vascular elasticity reserves in rabbits with atherosclerosis by transcranial Doppler ultrasonography and carotid artery ultrasonography

目的探讨经颅多普勒超声(TCD)联合颈动脉超声对动脉粥样硬化(AS)兔脑血管弹性储备评价的方法。方法将24只新西兰大白兔随机分为3组:正常对照组(A组)、AS组(B组)、阿托伐他汀治疗组(C组),每组8只。采用高脂饲料和免疫损伤制作AS模型;C组在B组喂食基础上,每天服用阿托伐他汀2.5mg/kg(饲料总量为100 g/d)。分别于高脂饲料饲喂前、饲喂后4、8、12周行颈动脉超声和TCD检测。拟定兔的颈动脉弹性传递指数(CETI):CETI1=颈内动脉血管弹性系数/颈总动脉血管弹性系数(EM_(ICA)/EM_(CCA)),CETI2=ICA搏动指数/CCA搏动指数(PI_(ICA)/PI_(CCA)),CETI3=基底动脉EM/EM_(CCA)CETI4=基底动脉PI/PI_(CCA)[血管弹性系数(EM)=Vm/PI]。12周取兔颈动脉行病理学检测。结果随着饲养时间的延长,①B组和C组颈总动脉内-中膜厚度逐渐增厚(与A组比,P<0.05);C组较B组增厚程度降低(P<0.05)。②B组CETI1、CETI4逐渐减小,与对照组比较,CETI1在第12周时、CETI4从第4周开始,差异有统计学意义(P<0.05);CETI2、CETI3有逐渐增大的趋势,与对照组比较,CETI2差异无统计学意义,而CETI3从第4周开始,各时间点差异有统计学意义(P<0.05)。C组的CETI1、CETI2各时间点变化不明显,CETI3、CETI4变化趋势与B组相同,但变化时间较B组滞后。③B组CETI1与PI_(ICA)呈负相关(r=-0.35,P<0.01);CETI2与PI_(ICA)呈正相关(r=0.6,P<0.01);颈动脉内-中膜厚度与PI_(ICA)呈正相关(r=0.69,P<0.01)。CETI4与PI_(BA)内-中膜厚度呈负相关(r=-0.46,P<0.01);CETI3与PI_(BA)无明显的相关性(r=0.28,P=0.08);IMT与PI_(BA)呈正相关(r=0.57,P<0.01)。结论 CETI可以作为评估颅内AS的指标,CETI升高,提示颅内血管的AS速度高于颈总动脉的速度;CETI下降,则提示颅内血管的AS速度低于颈总动脉的硬化速度。

Objective To investigate the assessing methods for cerebral vascular elasticity reserves in rabbits with atherosclerosis （AS） by using transcranial Doppler uhrasonography （TCD） and carotid artery ultra- sonography. Methods Twenty-four New Zealand white rabbits were randomly divided into 3 groups： the nor- real control group （group A）, The AS group（ group B）, and the atrovastatin group （group C） （n = 8 in each group）. An AS model was induced by higb-fat diet feeding and immune injury; group C took atorvastatin 2.5 mg· kg-1· d-1 （ a total of 100 g/d） on the basis of the feeding as the Group B. Carotid artery ultrasonogra- phy and TCD were performed at 4, 8, and 12 weeks before and after high fat;diet feeding. The Carotid Elasticity Transmission Index （CETI） of the rabbits was determined as： CETI1 -- EMICA/EMccA, CETI2 = PIicx/PICCA, CETI3 = EMBA/EMc（：A, and CETI4 = PIBJPICCA （elasticity modulus[ EM] = Vm/PI）. Carotid artery speci- mens were obtained for pathological examination at 12 weeks. Results （1）eommon carotid intima-media thick- ness （IMT） increased gradually in group B and group C （P 〈0.05）; The extent of IMT in group C was less than that in group B （at each time point, all P 〈0.05）. （1_CETI1 and CETI4 in group B reduced gradually. As compared to group A, there was significant difference for CETI1 at 12 weeks and for CETI4 from the 4th week （P 〈0.05） ; the changes of CETI1 and CETI2 were not obvious at each time point in group C, and the trend of CETL3 and CET4 was the same with group B, but the time of change was later than that in group B. （3）There was a negative correlation between CETIland PItcA in group B （r = -0.35, P 〈 0. 01 ） ; a positive correlation between CETI2 and PIica （r =0. 6, P 〈0. 01 ） ; and a positive correlation between IMT and PltcA （ r =0.69 ,P 〈 0. 01 ）. （4）ere was a negative correlation between CETI4 and Piss （r = -0. 46,P 〈0.01 ） ; there was no obvi- ous correlation between CETI3 and PIBA （r =0.28,P =0.08） ; and there was a positive correlation between IMT and PIsA （r = 0. 57,P 〈 0. 01 ）. Conclusion CETI can be used as an indicator for the assessment of intracrani- al AS. The increased CETI suggests that the AS progression of intracranial vessels was faster than that of CCA, and the decreased CETI may suggest that the AS progression is lower than that of CCA.