MRI评价兔动脉粥样硬化模型

目的 探讨1.5T MR仪检测兔颈动脉粥样硬化模型中粥样硬化斑块的形成。 方法 用动脉球囊扩张法损伤兔一侧颈总动脉血管内膜后高脂饲养15周,行MRI及损伤血管的病理学检查。 结果 15周后,MRI表现为损伤血管壁高信号区增厚并管腔狭窄,对应病理学检查显示:血管腔狭窄;损伤侧颈总动脉明显粥样斑块形成,符合动脉粥样硬化特点。MR成像与病理学所测血管壁厚度之间有相关关系(r＝0.953)。 结论 临床应用型1.5T MRI可成功检测兔颈动脉粥样硬化的形成。     

ApoE-/-小鼠颈动脉稳定性粥样硬化模型的建立及7.0TMR动态观察

目的 建立ApoE-/-小鼠颈动脉稳定性动脉粥样硬化(AS)模型,并探讨用高场强7.0T小动物MR检测AS的形成过程.方法 对10只ApoE-/-小鼠损伤并阻断一侧颈总动脉血流20 min,之后高脂饮食饲养7周,分别在术后4、7周进行7.0T MR检测与病理学检查.结果 4周后MRI显示患侧均出现不同程度的血管壁高信号,7周后MRI表现为损伤血管高壁信号区增厚并管腔狭窄、不规则,创伤后血管腔面积呈下降趋势.对应病理学检查显示,4周后颈总动脉腔内斑块形成,斑块内泡沫细胞及脂质坏死核心形成,其上覆盖厚纤维帽;7周后斑块内增生的内膜内见广泛钙质沉积.结论 用损伤及高脂饮食方法可成功建立ApoE-/-小鼠稳定期AS模型;高场强7.0T MR可成功检测小鼠颈动脉稳定期粥样硬化的形成过程,进一步研究ApoE-/-小鼠易损斑块提供研究基础.     

显微缝合联合高脂饮食建立兔颈动脉粥样硬化模型

目的建立一种兔颈动脉粥样硬化模型并对该模型进行评价。方法应用显微缝合法（microsurgical suture）造成兔颈动脉狭窄,在此基础上联合高胆固醇饮食建立兔颈动脉粥样硬化模型,采用HE、MASSON染色切片观察不同时间颈动脉壁的病理改变,以内膜/中膜厚度比值（I/M）及内膜/中膜面积比值（SI/SM）评价动脉粥样硬化程度。结果应用显微缝合联合高脂饮食法成功建立兔颈动脉粥样硬化模型,HE、MASSON染色切片显示模型动脉内膜增厚、动脉粥样硬化斑块形成。结论应用显微缝合联合高脂饮食制作兔颈动脉粥样硬化模型,方法简便,成模时间短,极大程度保留了动脉壁的弹性和血管内皮细胞的完整性,是一种较为理想的新型动脉粥样硬化动物模型。     

多沙唑嗪对兔血脂和血管内膜增生的影响

目的：探讨多沙唑嗪对兔动脉球囊损伤后血管狭窄的影响及与血脂的关系。方法：23只新西兰兔随机分为3组，正常对照组用普通饲料喂养并不予任何处理。另两组用高脂饲料喂养并行腹主动脉球囊损伤术，多沙唑嗪组术后应用多沙唑嗪控释片4mg／d灌胃，术后4周处死兔，观察各组血脂以及血管损伤处内膜、中膜厚度、新生内膜面积、管腔面积。结果：高脂喂养造成兔血脂明显增高。手术开始时多沙唑嗪组和球囊损伤组两组血脂水平无差异，手术4周后多沙唑嗪组总胆固醇较球囊损伤组降低，而高密度脂蛋白较球囊损伤组增高。术后多沙唑嗪组与球囊损伤组血管损伤处相比血管内膜增生减轻，新生内膜面积减少，管腔面积增加。结论：多沙唑嗪可以抑制高脂喂养加球囊损伤后兔腹主动脉血管的狭窄，可以降低血脂、抑制动脉粥样硬化进展。     

家兔脑动脉粥样硬化性狭窄模型的建立

目的:探索建立稳定的家兔脑动脉粥样硬化性狭窄模型的方法。方法:将25只新西兰大白兔随机分成3组:对照组5只,普通饲料喂养,行股动脉切开手术;单纯高脂饲料喂养组10只,高脂饲料喂养并行股动脉切开手术;高脂喂养联合球囊损伤组10只,高脂饲料喂养并行经股动脉血管内椎动脉颅内段球囊损伤术。各组手术均在适应性喂养2周后实施,术后继续以原饲料喂养。分别在术后2周和4周行目标椎动脉数字减影血管造影术(digital subtraction angiography,DSA),并进行血脂水平检测及病理组织学检查。结果:对照组与单纯高脂饲料喂养组的目标椎动脉DSA及血管病理切片均未发现明显差异。高脂喂养联合球囊损伤组术后2周DSA提示,3例有目标段椎动脉轻度管腔狭窄,6例仅见管壁毛糙;术后4周DSA提示,5例可见目标段椎动脉管腔轻度狭窄,2例管腔中度狭窄,2例仅管壁毛糙。血脂水平检测显示,高脂喂养的两个实验组动物血脂水平高于对照组(均P0.05),单纯高脂喂养组与高脂喂养联合球囊损伤组的血脂水平差异无统计学意义。病理检查提示,高脂喂养联合球囊损伤组可见目标段椎动脉内皮结构紊乱,连续性中断,内膜下见泡沫细胞沉积。结论:通过高脂喂养联合血管内球囊损伤,可成功建立较为稳定的家兔脑血管粥样硬化性狭窄模型,为后续研究奠定了基础。     

高同型半胱氨酸血症及其所致动脉粥样硬化动物模型的复制

背景：高同型半胱氨酸是动脉粥样硬化的危险因素之一,而血管拉伤后的新生内膜增生可能有助于动脉粥样硬化的形成。目的：研究采用高蛋氨酸饲料喂养结合球囊损伤腹主动脉的方法复制兔高同型半胱氨酸血症及其所致动脉粥样硬化模型的可行性。方法：将32只白兔随机分成4组：分别给予腹主动脉内膜球囊损伤和（或）2%L-蛋氨酸颗粒饲料,以正常饲养的兔作为对照。分别于实验的第0,2,12周采血化验,并于实验的第12周处死白兔取腹主动脉标本观察。结果与结论：给予2%L-蛋氨酸颗粒饲养2周后,兔血清高同型半胱氨酸水平明显增高（P〈0.05）,此时予腹主动脉内膜球囊损伤,12周后在兔损伤血管段形成了特有的动脉粥样硬化病变,并且同时给予腹主动脉内膜球囊损伤和2%L-蛋氨酸颗粒饲料的兔粥样斑块面积更大、内膜损伤更严重。说明采用蛋氨酸饲料喂养结合球囊损伤兔腹主动脉内膜的方法可在短时间内建立高同型半胱氨酸血症及动脉粥样硬化模型。     

颈动脉超声检查对缺血性脑血管疾病的预防意义

目的探讨缺血性脑血管疾病与颈动脉粥样硬化之间的关系。方法缺血组为2001-10/2003-12期间平顶山煤业集团总医院神经内科的住院及门诊脑血管病患者201例,入院后立即行颈动脉超声检查。对照组为同期在门诊进行体检的单位职工,同样进行颈动脉超声检查,将两组的结果进行比较。结果缺血组粥样硬化的检出率缺血组为94.0%,对照组为7.5%,血管内膜增厚检出率缺血组为60.2%,对照组5.0%;血管狭窄检出率缺血组为16.4%,对照组为1.9%,动脉粥样硬化斑检出率缺血组为40.3%,对照组为0.6%。结论颈动脉超声检查能确定颈动脉粥样硬化的性质、稳定性、动脉狭窄的程度,为预防缺血性脑血管疾病提供客观依据。     

小型猪颈动脉支架和球囊扩张的血管内超声研究

目的 应用血管内超声(IVUS)探讨小型猪颈动脉支架和球囊扩张后冉狭窄机制.方法 12只中国广西巴马小型猪高脂饲养后随机分两组,每组6只.一组于左侧颈动脉置入7枚支架,另一组于左侧颈动脉行球囊扩张,并于术前、术后即刻、术后13周进行一系列IVUS和DSA检查.结果 13周后IVUS显示支架组和球囊组血管面积分别狭窄(18.31±7.79)%和(37.28±7.89)%.支架内再狭窄与支架内膜增生明显相关(r=0.897,P<0.05);球囊扩张后再狭窄与外弹力膜面积减少显著相关(r=0.856,P <0.05).结论 支架再狭窄与血管内膜过度增生有关,球囊扩张再狭窄与外弹力膜减少有关.     

高脂饲料喂养与动脉内膜球囊损伤结合建立兔腹主动脉粥样硬化模型

背景:以往研究多采用单纯饲喂高脂饲料、正常或高脂血症动物动脉内膜损伤致动脉粥样硬化狭窄模型.目的:拟采用喂养高脂饲料与动脉内膜球囊损伤相结合的方法建立腹主动脉粥样硬化的模型.设计、时间及地点:对比观察实验,于2007-01/03在解放军总医院动物实验中心完成.材料:新西兰白兔20只,随机分为单纯饲喂高脂饲料组、高脂饲料与动脉内膜损伤结合组,每组10只.高脂饲料由普通颗粒饲料+4%胆固醇+10%猪油组成+10%蛋黄粉组成.方法:单纯饲喂高脂饲料组单纯喂养高脂饲料,高脂饲料与动脉内膜损伤结合组喂养高脂饲料4周后,行腹丰动脉内膜球囊损伤术.主要观察指标:12周后取主动脉行病理检查,计算机计算脂纹脂斑厚度,内、中膜厚度,内膜厚度比值,并进行血清总胆固醇、三酰甘油和高密度脂蛋白胆固醇、低密度脂蛋白胆固醇的测定.结果:12周后,两组兔血脂血清总胆固醇、三酰甘油、高密度脂蚩白胆固醇、低密度脂蛋白胆固醇均升高,高脂饲料与动脉内膜损伤结合组升高更明显(P<0 05).喂养高脂饲料的两组动物均出现动脉粥样硬化斑块,横段而纤维斑块切片出现钙化.与单纯饲喂高脂饲料组比较,高脂饲料与动脉内膜损伤术结合组内膜明显增厚,形成了明显的斑块及纤维帽结构,斑块厚度与内中膜厚度比值增加明显(P<0.01).结论:所诱导产生的斑块与人类斑块成分具有一定相似性,包括斑块的纤维帽、钙化、脂核等,提示采用动脉内膜损伤与高脂饮食结合方式来制作动脉粥样硬化斑块的模型是可行的、实用的.     

加味补阳还五汤对兔髂动脉球囊损伤血管狭窄和氧化应激的影响

背景:近年研究证明,补阳还五汤具有扩张血管、改善微循环、抗炎、抗氧化应激和保护血管内皮细胞的功能,但其具体机制尚不清楚,尤其是对经皮腔内冠状动脉成形后再狭窄形成过程有何影响,目前很少见报道.目的:观察加味补阳还五汤对兔髂动脉球囊损伤后血管狭窄及氧化应激的影响.方法:将新西兰兔以随机抽签法分为对照组、模型组和药物组.对照组给予普通饲料,模型组、药物组给予高脂饮食.饲养2周后,模型组、药物组行髂动脉内膜剥脱术,对照组兔行假手术对照,药物组术后饲料中添加加味补阳还五汤药颗粒2 mL/(kg·d),对照组及模型组喂食同前.4周后光镜观察兔髂动脉内膜的损伤情况,并检测血脂水平、血清超氧化物歧化酶活性和丙二醛水平的变化.结果与结论:对照组髂动脉内膜薄且结构完整,无动脉硬化斑块;模型组内膜增厚,管腔明显狭窄,可见明显动脉粥样硬化斑块;药物组动脉粥样硬化斑块厚度减小,管腔狭窄程度较轻.药物组兔血清总胆固醇、三酰甘油和低密度脂蛋白胆固醇、丙二醛水平明显低于模型组,而高密度脂蛋白胆固醇、血清超氧化物歧化酶水平明显高于模型组(P<0.05).结果说明加味补阳还五汤具有较好的防止家兔球囊扩张损伤髂动脉所致的管腔狭窄及抗实验性动脉粥样硬化作用,其机制可能与其清除氧自由基抗氧化应激、调节脂质代谢等作用有关.     

大鼠颈动脉血管成形术模型的实验研究

目的通过建立大鼠颈动脉血管成形术模型,观察大鼠损伤血管的增生及再狭窄变化。方法用2F Fogarty球囊导管损伤大鼠左颈总动脉,分别在不同时间点取材,观察术后不同时间点血管壁的变化。结果大鼠颈总动脉损伤后引起血管内皮细胞剥脱,新生内膜形成并增生,导致管腔狭窄。结论大鼠颈动脉血管成形术造成血管再狭窄,其造模成功率高,操作简便,疾病模型接近人类,能够为进一步研究提供理想的动物模型。     

颅颈动脉三维磁共振管壁成像技术及其应用进展

颅颈动脉粥样硬化是引起缺血性脑卒中的主要原因。MR管壁成像技术可直接显示动脉管壁的形态学特征,是目前评价颈动脉斑块的最佳无创性影像学手段之一。近年来,随着三维MR管壁成像技术的发展,其在颅内和颅外颈动脉粥样硬化病变的临床诊断中发挥着越来越重要的作用。本文主要对颅颈动脉三维磁共振管壁成像技术及其应用进展做一综述。     

Serum cholesterols have a more important role than triglycerides in determining intima-media thickness of the common carotid artery in subjects younger than 55 years of age.

OBJECTIVE: The role of serum cholesterol and triglycerides in carotid artery atherosclerosis is controversial. We measured carotid artery intima-media thickness (IMT), a marker of atherosclerosis in subjects younger than 55 years of age with a 6-fold range of serum cholesterol levels (3.93-25.03 mmol/L) and a 200-fold range of triglyceride levels (0.36-75.97 mmol/L). METHODS: Eighty-six patients with increased serum lipid values and 30 subjects with normal lipid values were included. Serum lipids were measured after an overnight fast. High-resolution sonographic investigations of the carotid arteries of all patients were videotaped. Intima-media thickness was measured offline at 1-mm increments in the distal 10-mm segments of both common carotid arteries by a reader blinded to patient characteristics. First, IMT was compared among groups defined by their cholesterol and triglyceride levels with the use of traditional cutoff values. Next, all subjects were pooled, and general regression analysis was performed to identify significant predictors of IMT with age, body mass index, lipid values, sex, diabetes, hypertension, and smoking status as independent variables. RESULTS: Intima-media thickness was larger in patient groups with high cholesterol levels (ie, the hypercholesterolemic and combined hyperlipidemic groups) than in the control, borderline, and isolated hypertriglyceridemic groups (P < .01). In the general multiple regression model, IMT correlated positively with total cholesterol level (beta = 0.343; P = .002) and age (beta = 0.3; P = .006) but not with triglyceride level. CONCLUSIONS: Both the group comparisons and the general regression analysis of the pooled data suggest that hypercholesterolemia has an important role in early onset IMT changes in the common carotid artery, whereas hypertriglyceridemia does not have an appreciable role.     

What have we learned about coronary artery disease from high-frequency epicardial echocardiography?

We have used a high frequency epicardial echocardiographic technique to visualize and measure coronary artery lumens and walls in patients undergoing cardiac surgery. A 12 MHz probe (Surgiscan, Biosound Corp.) is sterilized and placed on the exposed epicardial coronary arteries. Transverse cross-sectional views are obtained from the arteries on the anterior surface of the heart: the right coronary artery to the cardiac margin and the left anterior descending coronary artery to the cardiac apex. Numerous echocardiographic-angiographic-pathological correlations have been obtained from this work. We have validated the echocardiographic lumen and wall measurements by comparing the echo measurements to histological material from pressure-distended coronary arterial segments (from animals and fresh human autopsy specimens). We have shown by comparison with angiography that coronary arteries which appear normal or only minimally diseased by angiograms are often diffusely and severely atherosclerotic. We have also evaluated the shape of atherosclerotic lesions and demonstrated a wide range of lumen shapes (oval, circular, complex) and location within the residual coronary lumen (eccentric vs. concentric). Highly eccentric lesions are characterized by relative preservation of portions of the arterial wall, and this may preserve vasoreactivity of the atherosclerotic vessel. We have also demonstrated remodeling of atherosclerotic lesions: enlargement of the total arterial area (wall plus lumen) as a compensatory mechanism to preserve the arterial lumen in the face of encroaching atherosclerosis. High frequency epicardial echocardiography offers an accurate, real-time, in-vivo method for the anatomic and functional evaluation of coronary atherosclerosis. This dynamic, in-vivo technique supports and extends information previously obtainable only from pathologic studies. It contributes to our understanding of the pathologic anatomy of coronary artery disease.     

Ultrasonographic analysis versus histopathologic evaluation of carotid advanced atherosclerotic stenosis in an experimental rabbit model

Advanced carotid atherosclerosis with severe stenosis (>70%) is a major clinical risk factor for ischemic stroke. Our ability to test new protocols for the treatment of atherosclerotic stenosis in humans is limited for obvious ethical reasons; therefore, a suitable animal model is required. The aim of this study was to generate an easily reproducible and inexpensive experimental rabbit carotid model of advanced atherosclerosis with morphological similarities to the human disease and the subsequent assessment of the reliability of B-mode ultrasound technology in the study of lumen area stenosis in this model. Briefly, New Zealand white rabbits underwent primary perivascular cold injury at the right common carotid artery followed by a 1.5% cholesterol-rich diet injury for eight weeks. All of the rabbits' arteries were imaged by B-mode ultrasound weekly, after which the rabbits were sacrificed, and their vessels were processed for histopathology. Ultrasound longitudinal view images from three cardiac cycles were processed by a new computerized analyzing method based on dynamic programming and maximum gradient algorithm for measurement of instantaneous changes in arterial wall thickness and lumen diameter in sequential ultrasound images. Histopathology results showed progressive changes, from the lipid-laden cells and fibrous connective tissue proliferation in neointimal layer, up to the fibro-lipid plaque formation, resulting in vessel wall thickening, remodeling and lumen stenosis. The B-mode ultrasound images and the histologic measurements showed an increase in the mean wall thickness and the lumen area stenosis within eight weeks. Quantitative and morphometric analysis of the mean wall thickness and the lumen area stenosis percentage showed a significant correlation between the B-mode ultrasound and the histological measurements at each time point (R = 0.989 and R = 0.995, p < 0.05, respectively). In conclusion, we successfully produced advanced atherosclerosis in the rabbit carotid artery that is similar to the condition seen in patients. This condition in rabbits can be properly assessed by B-mode ultrasound image processing.     

血管紧张素Ⅱ快速诱导ApoE-/-小鼠腹主动脉夹层动脉瘤模型的建立及其MR成像

目的 建立ApoE-/-小鼠腹主动脉夹层动脉瘤模型,探讨超高场强7.0T MR检测ApoE-/-小鼠腹主动脉瘤的价值. 方法 10月龄ApoE-/-小鼠饲以高脂饮食10周后,背部埋置血管紧张素Ⅱ缓释泵,Ang Ⅱ分为1000 ng/(kg·min)和500 ng/(kg·min)组,对照组埋置生理盐水,装泵前及装泵后14天内行MR活体扫描,扫描后取腹主动脉行病理学检查. 结果 Ang Ⅱ灌注高剂量组第6或第7天即形成夹层动脉瘤,T2WI示一侧管壁周可见新月形超高信号,病理证实为中膜与外膜间出血;低剂量组第13、14天后也见腹主动脉夹层动脉瘤形成,MR示管壁信号于T2WI及PDWI均明显增加,并可见斑点状高信号向腔外突出,与病理内膜断裂血流冲击中膜形成主动脉夹层一致. 结论用2种剂量的血管紧张素Ⅱ灌注2周内均可成功建立ApoE-/-小鼠腹主动脉夹层动脉瘤模型,前组可在更短时间内建模成功.超高场强MR可成功用于活体检测腹主动脉夹层动脉瘤形成.     

3.0T MRI观察兔腹主动脉粥样硬化斑块演变过程

目的 探讨MRI在识别兔动脉粥样硬化斑块中的诊断价值.方法 20只新西兰白兔,随机设置实验组16只,对照组4只,结合球囊拉伤腹主动脉和间断高脂饲料喂养,建立动脉粥样硬化模型;在建模后2、3、4个月分别行高分辨MR成像.通过测量腹主动脉管壁厚度和面积、管腔面积、管壁信号增强程度等指标,观察腹主动脉壁的重构过程,并对模型最终的斑块成分进行MRI和组织病理结果对照研究.结果 对17只兔(实验组14只,对照组3只)完成3次MR检查,并获得组织病理学结果.MRI显示,实验组腹主动脉管壁厚度和面积逐渐增厚,且与同期对照组相比差异均有统计学意义(P＜0.01);实验组腹主动脉管腔进行性扩张,管壁强化程度较对照组增加明显,但演变过程不明显.另外,MRI对兔腹主动脉硬化斑块的成分判别限制在纤维、脂质和钙化斑块,对纤维斑块、脂质斑块识别率较高.结论 高分辨MRI可以无创性地观察动脉粥样硬化动物模型腹主动脉管壁重构的演变过程,有助于对动脉硬化斑块的预后和药物干预进行探索.     

颈动脉与冠状动脉粥样硬化的病理对比分析

目的探讨颈动脉粥样硬化与冠状动脉粥样硬化病变之间的关系。方法应用图象分析对17例尸检患者的272段颈动脉和冠状动脉血管进行测量,比较内容包括动脉壁厚比值腔面积/截面积比值和狭窄血管支数比值。结果颈动脉和冠状动脉粥样硬化病变血管支数的比值呈正相关(r=0.79,P<0.01),其余比值无相关性。结论颈动脉粥样硬化病变的存在可以预示冠状动脉有病变,但二者病变的严重程度无明确的相关性。