【作者】 蒋明东；

【导师】 白晋； 陈文直；

【作者基本信息】 重庆医科大学 ， 生物医学工程， 2004， 硕士

【摘要】 前期研究已证明高强度聚焦超声（high-intensity focused ultrasound，HIFU）辐照对1.1mm的动脉会产生损伤。由于临床诊断的肿瘤病人中老年人居多，根据临床资料提示：肝癌、胰腺癌等腹腔恶性肿瘤，中老年患者占68.97%，常常伴有高脂血症或动脉粥样硬化（atherosclerosis，AS）。HIFU是否对有AS血管产生严重损伤是HIFU治疗肿瘤的一个重要的安全性问题。本实验在前期研究基础上，结合临床腹腔恶性肿瘤病人的实际，在实验条件下，进一步研究HIFU辐照病理大血管（如AS腹主动脉）的安全性。兔是常用来建立AS模型的动物，模型的建立有多种方法，本实验选用高脂饲料喂养的方法来建立兔AS动物模型。一、兔粥样硬化腹主动脉模型的建立1．AS动物模型的建立1级新西兰大白兔68只，AS组n1=34，对照组（control，C）n2=34。AS组实验兔喂高脂饮食8周， C组实验兔喂普通兔饲料作为对照，每周定期称体重，以此调整进食量。于建立模型实验前、实验4周和实验8周测定血脂(TC、TG和HDL-c及LDL-c)水平；8周时随机取材（AS组：5只，C组：5只），进行大体观察和HE染色光镜下病理学<WP=8>观察，同时用生物医学病理图像分析系统分析处理AS斑块面积，计算面积百分比，了解AS病变严重程度。即鉴定AS动物模型成功建立。2．兔AS腹主动脉血管内径大小测量方法：AS组和C组兔随机各取5只（共10只），4%多聚甲醛连续灌注固定，保存兔腹主动脉在体形态。取材后用游标卡尺直接测量腹主动脉直径（d），或者测量周长后计算出d的大小（两种方法无显著性差异，p＞0.05）。结果：AS组与C组兔腹主动脉血管d均为2.2±0.2mm（两组无显著性差异，p＞0.05）。结论：病理组织学证实4%多聚甲醛连续灌注固定是一种良好保存动脉血管在体形态，进而测量血管直径大小可行可靠的方法。二、HIFU辐照兔粥样硬化腹主动脉后的病理学观察方法：采用HIFU参数：频率0.8MHz，声强10000w/cm2。48只新西兰兔随机分为AS组（n1=24）和C组（n2=24），实验兔HIFU辐照后即刻、五天和十天取材，分别进行大体肉眼观察，HE染色和弹力纤维维多利亚蓝和丽春红S双重组织化学特殊染色光镜观察兔腹主动脉病理组织学变化，透射电镜观察其超微结构变化。结果：HIFU辐照后，病理组织学可见兔AS腹主动脉血管内皮细胞凝固性坏死、部分消失，弹力纤维紊乱、断裂和局部溶解等损伤改变，C组血管亦见一定程度的损伤改变，无血管栓塞和破裂；五天、十天观察呈向正常恢复趋势，C组较AS组恢复更好。结论：频率0.8MHz，声强10000w/cm2 HIFU辐照，可造成直径2.2±0.2mm的AS组和C组兔腹主动脉一定程<WP=9>度损伤， AS组及C组兔腹主动脉的损伤性改变无明显差异。实验条件下，病理证实HIFU辐照兔AS腹主动脉是安全的。三、HIFU辐照兔粥样硬化腹主动脉后血流动力学的变化1．彩色多普勒超声血流显像（CDFI）检测方法：应用彩色多普勒超声血流显像（CDFI）测量HIFU辐照前、辐照后即刻、五天和十天AS及C组兔腹主动脉血流动力学变化。结果：HIFU辐照兔AS及C组腹主动脉后，即刻、五天和十天血管收缩期峰值血流速度（Vmax）及平均血流速度（Vmin）和对应血流量与HIFU辐照前比较均明显降低（p<0.01），各观察时间对应CDFI检测指标组间比较差异有显著性（p<0.05），随观察时间延长各检测值呈向正常恢复趋势。HIFU辐照前后不同观察时间AS及C组兔腹主动脉搏动指数（PI）和阻力指数（RI）亦降低，总体比较差异有显著性（p<0.05）。2．X线数字减影血管造影术（DSA）检测方法：AS及C组兔腹主动脉HIFU辐照前、辐照后即刻、五天和十天分别进行了DSA检测，观察血流动态变化。结果：HIFU辐照后不同观察时间，AS及C组兔腹主动脉DSA分别有明显血流充盈缺损、血流阻滞和血流充盈速度延迟等改变，无血管栓塞及破裂。DSA显示对应观察时间AS组血流改变较C组更明显；五天、十天观察呈向正常恢复趋势， C组较AS组恢复更好。结论：焦域声强10000w/cm2HIFU辐照直径2.2±0.2mm AS及C组兔腹主动脉后，CDFI检测指标较HIFU辐照前明显降低，表明AS及<WP=10>C组兔腹主动脉出现一定程度损伤；五天、十天观察CDFI检测指标呈向正常恢复趋势。DSA显示动脉血流充盈缺损、阻滞及充盈速度延迟，AS组较C组更明显，未发现血管栓塞和破裂；五天、十天观察呈向正常恢复趋势，C组较AS组恢复更好。因此实验条件下，HIFU辐照AS与C组兔腹主动脉具有安全性。更多还原

【Abstract】 Background and Objective: The application of the technique of high-intensity focused ultrasound (HIFU) to treat the malignant tumor (especially deep malignant tumor) has gained notable clinical effects. To study the vascular safety during the treatment, we constructed a rabbit model of atheromatous abdominal aorta to investigate the effect of HIFU on vascular pathology and hemodynamics.1、Model construction and measurement of vascula boreModel constructionOne grade big New Zealand rabbits had been feed for 8 weeks with high fat food, and the food quantity was adjusted according to individual weight increase. Blood lipid, such as TC，TG，HDL-c were assessed before experiment and at the 4th, the 8th week after experiment respectively. At the same time, samples were randomly collected to observe the pathological changes by naked eyes and microscope, and the area of Atherosclerotic fibrous plaque was also disposed, which all together to <WP=12>judge the degree of the disease and to evaluate the construction of model.Measurement of the vascula bore of rabbit’s abdominal aortaMethods: Randomly select ten rabbits from the research group（n=34）and the control group(n=34), The sample rabbits were continually perfused with 4% formaldehydum polymerisatum in vivo. After that, the vascula bore were measured by mean of slide gaud or were calculated from the perimeter, and the mean was calculated. Results: the vascula bore of rabbit’s abdominal aorta was 2.1mm (No statistics difference was found between research group and control group). Conclusions: continued perfusion with 4% formaldehydum polymerisatum in vivo was a good method to preserve the vascula form to measure the bore.2、Pathological observation of the atheromatous abdominal aorta of rabbits treated by HIFUMethods: After subdivided into two groups, the research group and the control group were exposured in HIFU with different degree of 0.8MHz/10000w/cm2. Later, by means of HE staining and special elastic fibers staining, the change of morphology and Ultrastructure of vascula endothelial cells and smooth muscle cells were studied at the very day, the fifth day and the tenth day after exposured in HIFU respectively. Results: After exposured in HIFU, the vascula endothelial cells of abdominal aorta were damaged, or even disappeared. And derangement, breakage and <WP=13>solution had taken place to elastic fibers. Conclusions: Both the two different HIFU would result in coagulation necrosis to rabbit abdominal aorta to some degree. No statistics difference was found between the research group and the control group, so did that between the individual subgroups.3、Hemodynamics observation of the atheromatous abdomial aorta of rabbits treated by HIFUBlood stream Detect by color Doppler ultrasoundMethod: The technique of color Doppler ultrasound blood stream Detect was used to study the Hemodynamics change of the atheromatous abdominal aorta of rabbits at the day before exposure in HIFU, the very day, the fifth day and the tenth day after exposured in HIFU respectively. Results: Vmax and Vmin of the atheromatous abdominal aorta were significantly slow after exposured in either of the two sorts of different HIFU, and there were significant difference among every time groups. PI and RI of the atheromatous abdominal aorta were also significantly changed among all the time groups before and after treatment by HIFU.X-ray DSA detectMethod: By means of X-ray DSA, the atheromatous abdominal aorta of rabbits were detected at the day before exposure in HIFU, the very day, the fifth day and the tenth day after exposured in HIFU respectively. <WP=14>Results: After exposured in HIFU, the blood stream block, the blood filling delay as well as the Vascular wall defect were found in atheromatous abdominal aorta, but those Pathological changes would remised as the time passed. No Vascular embolism and Vascular rupture were found. Conclusion: Although HIFU would damaged 2.1mm atheromatous abdominal aorta of rabbits to some deg更多还原