【作者】 赵洋；

【导师】 刘政；

【作者基本信息】 第三军医大学 ， 影像医学与核医学， 2010， 硕士

【摘要】 背景实体肿瘤的生长、转移依赖肿瘤新生血管生成,一旦新生血管长入肿瘤,有充分的血液供应,肿瘤组织将得到快速生长并难以控制。抗肿瘤血管生成治疗已成为继化疗和放疗之后的一种新型治疗模式。然而,目前已发现的抗肿瘤血管生成方法,几乎都是采用化学或者生物药物攻击肿瘤新生血管的特异性生物学靶点,有一定副作用,治疗效果并不理想。本实验前期研究发现,通过静脉注射脂质造影剂微泡联合脉冲式聚焦超声直接作用兔皮下VX2肿瘤区域,微泡增强的超声空化效应可以选择性阻断肿瘤微血管,而周边正常血管未见受到显著影响。目的本研究在前期微泡增强的超声空化损伤肿瘤微血管的基础上,采用兔VX2皮下移植性肿瘤作为研究对象,目的是探讨微泡增强的超声空化对肿瘤的生长抑制作用及对肿瘤转移的影响。材料和方法1.主要实验材料实验仪器:本实验室自行研制的小型脉冲式聚焦超声治疗仪,治疗头频率1.2 MHz,峰值声压4.6MPa,声强0.89 W/cm2。GE公司Logiq 9型彩色多普勒超声仪,9L高频探头,频率5～9 MHz,配有编码谐波超声造影模式。脂质微泡:本科实验室研制的“脂氟显”脂质微泡,核心气体为全氟丙烷,外观呈乳白色凝乳状,平均粒径2μm,其中98﹪<8μm,浓度约为4-9×109/ ml。速眠新Ⅱ注射液:为二甲苯胺噻唑、乙二胺四乙酸、盐酸二氢埃托啡和氟哌啶醇组成的复方制剂,军事医学科学院军事兽医研究所研制。实验动物:健康新西兰白兔30只,雌雄不限,体质量2.0～2.5 kg,由新桥医院动物实验中心提供。VX2肿瘤组织匀浆由重庆医科大学医学超声工程研究所提供。2.实验程序(1)30只移植有皮下VX2肿瘤的新西兰大白兔,随机分为超声微泡治疗组,单纯超声组和超声假照组进行实验研究。经静脉注射脂质微泡的同时,脉冲式聚焦超声直接辐照肿瘤区域。单纯超声组和假照组分别用5ml生理盐水和超声假照替代,每次10分钟,每隔72小时治疗一次,采集各时间点肿瘤二维超声图像和超声造影影像,测量肿瘤切面最大长径、短径。(2)第30天观察时间点,超声造影后即刻处死并解剖实验兔,观察肺、肝脏、肾脏、盆腔淋巴结有无转移灶。3.数据分析肿瘤生长抑制以肿瘤直径和体积为观察指标,采用SPSS 13.0统计学处理软件,肿瘤大小用x±s表示;治疗前各组肿瘤直径、体积及治疗后各组肿瘤直径大小比较采用单因素方差分析(Oneway ANOVA);治疗后各时间点肿瘤体积大小比较采用Kruskal-Wallis分析方法;肿瘤转移灶按转移个数分为0-3级,组间比较采用秩和检验做半定量分析。以P<0.05为差异有统计学意义。结果(1)兔VX2肿瘤生长抑制结果:兔VX2肿瘤在30天的实验周期内,微泡超声治疗组、单纯超声组和超声假照组的肿瘤平均直径,从1.1±0.1cm、1.2±0.2cm、1.2cm±0.1cm生长至1.7±0.3cm、3.4±0.7cm、3.6±0.8cm;三组的平均体积从0.4±0.2cm3、0.6±0.3cm3、0.5±0.2cm3生长至4.5±3.1cm3、35.1±46.7cm3、48.2±44.3cm3、微泡超声治疗组肿瘤直径、体积明显小于另两组(P﹤0.05)。单纯超声组和假照组,肿瘤直径和体积比较无显著差异(P﹥0.05)。(2)兔VX2肿瘤转移情况:微泡超声治疗组肿瘤转移情况评分多为0-1级;而单纯超声组和假照组评分多为2-3级,微泡超声治疗组与单纯超声组、假照组相比,在肺和肾脏的转移灶数量呈明显下降趋势(P﹤0.05),但在肝脏和盆腔淋巴结肿瘤转移方面无显著差异(P﹥0.05)。结论超声空化治疗在反复多次阻断肿瘤微循环的基础上,产生了一定程度的肿瘤生长抑制作用,并在一定程度上减少了肿瘤转移的发生。更多还原

【Abstract】 Background:Tumor angiogenesis is critical and essential in tumor growth and metastasis. Once the neovasculature is builded up to provide enough nutrition, tumor growth would become inevitable. Anti-angiogenesis therapy has been accepted as an new anti-tumor strategy. Nowadays, almost all of the anti-angiogenesis approaches take advantage of using chemical or biological drugs to attack specific receptor targets on angiogenesis. It is featured with insufficient therapeutic effect and some side-effects.This study is based on our previous findings that MBs enhanced ultrasound cavitation could selectively disrupt the microvasculature of rabbit VX2 tumor resulting in tumor circulation blockage.Objective:The purpose of this study is to investigate effects of MBs enhanced ultrasound cavitation on tumor growth and metastasis inhibition in a VX2 tumor model of rabbit.Materials and Methods:(1) Materials:Therapeutic ultrasound instrument: specific designed pulsed focused ultrasound (PFUS) devices, with the transducers frequency of 1.2 MHz, adjustable duty cycle and peak acoustic pressure.Diagnostic ultrasound imaging system: GE Logiq 9 ultrasound system, 9L probe, eligible to perform contrast enhanced ultrasonography (CEUS) with low MI. Microbubbles: Zhifuxian, a perfluoropropane filled lipid MB, with bubbles concentration of 4~9×109/ml, average 2μm in diameter, and 98% of the MBs less than 8μm in diameter.(2) Methods: Thirty New Zealand white rabbits bearing subcutaneous VX2 tumor were randomly divided into 3 groups for the impact factors including microbubbles (MB) and ultrasound (US). Pulsed focused ultrasound was delivered directly to the tumor surface for 10 minutes during intravenous infusion of microbubbles in the experimental (US+MB) group. The two control groups were applied with either ultrasound exposure (US) or saline injection (SHAM). The procedure was repeated every 72 hours until the 30th day. Contrast enhanced US and grey scale ultrasonography were acquired after every treatment to get the tumor perfusion images, size and volume measurements.At the end of the experiment, gross inspection and counting of tumor metastatic lesions at lung, liver, kidney and pelvic lymph nodes were performed following the animal sacrifice. The VX2 tumor metastasis was classified into 0-3 grade according to the counting number of meatastic lesions.Results:The average tumor volume of the US+MB, US, and the SHAM groups at the baseline were 0.4±0.2cm3,0.6±0.3cm3,0.5±0.2cm3 respectively. It grew to 4.5±3.1cm3,35.1±46.7cm3,48.2±44.3cm3 within a 30d experimental period, respectively. The average tumor volume of the US+MB group was significantly smaller than that of the two control groups at the end of experiment(P﹤0.05). The VX2 tumor metastatic counting also showed significant declines at lung and kidney in the experimental group(P﹤0.05). Conclusions:Multiple MBs enhanced ultrasound cavitation therapy can induce growth inhibition of VX2 tumor. It is also able to reduce VX2 tumor metastasis in lung and kidney.更多还原