靶向ELAM-1的磁共振分子探针USPIO-PEG-sLe~x的制备及体内外MR成像研究

发布时间：2018-03-18 09:34

本文选题：磁共振成像　切入点：超小顺磁性氧化铁颗粒　出处：《广西医科大学》2017年硕士论文　论文类型：学位论文

【摘要】：目的1、探讨利用超小顺磁性氧化铁(USPIO)偶联唾液酸化酶x(s Lex)构建靶向内皮细胞粘附分子-1(ELAM-1)的特异性磁共振成像的分子探针的制备方式,并研究其物理化学特征。2、采取裸鼠构建鼻咽癌移植瘤模型,探究超小顺磁性氧化铁(USPIO)偶联唾液酸化酶x(sLex)构成靶向血管内皮细胞粘附分子-1(ELAM-1)的特异性磁共振成像的分子探针(USPIO-PEG-sLex)在鼻咽癌移植瘤的运用价值。方法利用物理沉积方法合成USPIO纳米颗粒,通过疏水作用,合成较好水溶性的USPIO-PEG,其表面-COOH充分活化,常温下与sLex充分孵育,超滤离心和去离子水洗涤,形成磁共振分子探针USPIO-PEG-sLex。采用透射电子显微镜(TEM)分析USPIO-PEG-sLex的形态和粒径,动态光散射(DLS)分析偶联前与偶联后USPIO-PEG-sLex的平均水动力尺寸,粒径分析仪检测偶联前后USPIO-PEG-s Lex的Zeta电位。将10只鼻咽癌裸鼠移植瘤模型随机分为实验组和对照组,分别于尾静脉注入USPIO-PEG-sLex和USPIO-PEG前后行磁共振T2 mapping成像,比较分析注射造影剂前后移植瘤的T2值变化。MRI扫描完后取移植瘤组织,应用免疫组织化学染色技术分析肿瘤组织新生血管内皮细胞上ELAM-1的表达。结果透射电镜测定USPIO-PEG平均粒径为10±2.6nm,分散性较好,大小适宜;动态光散射测定偶联前后其平均水动力尺寸分别为(34.06±9.95)nm,(53.35±16.99)nm;偶联前的PEG化磁性纳米颗粒的Zeta电位为(11.6±3.96)mV,偶联后为(-12.6±5.33)mV。USPIO-PEG-s Lex具有良好表征。对照组和实验组的鼻咽癌移植瘤的平扫T2值差异没有统计学意义(PO.05),增强扫描后两组的T2值下降,两组的T2值差异有统计学意义(PO.05);实验组的强化率更低,两组的强化率差异有统计学意义(P0.05)。实验组中瘤体与肌肉的强化率差异有统计学意义(PO.05)。免疫组化结果显示E-选择素蛋白在血管内皮细胞胞浆或胞膜呈棕黄色表达。HE染色结果显示胞核为深蓝色且具有显著异型性,胞浆及纤维组织为深浅不一的红色。结论化学交联法可成功制备磁共振分子探针USPIO-PEG-sLex,该分子探针的表征良好,有望用于体内、外实验特异性地结合ELAM-1。USPIO-PEG-s Lex纳米磁性颗粒有望作为鼻咽癌ELAM-1表达的靶向造影剂,在非创伤动态监测ELAM-1的表达方面具有良好的潜在应用前景。
[Abstract]:Objective 1 to investigate the preparation of a molecular probe for specific magnetic resonance imaging targeting endothelial cell adhesion molecule-1 (ELAM-1) using ultra-small paramagnetic ferric oxide USPIO-coupled salivary acidifier xs Lexus. The physicochemical characteristics of nasopharyngeal carcinoma (NPC) were studied in nude mice, and the model of transplanted nasopharyngeal carcinoma (NPC) was established in nude mice. To explore the application value of USPIO-PEG-sLexus, a molecular probe for magnetic resonance imaging targeting vascular endothelial cell adhesion molecule-1 (ELAM-1), coupled with the salivary acidifier xansLexus, in the treatment of nasopharyngeal carcinoma (NPC) transplanted tumors. Methods physical deposition was used to investigate the application of USPIO-PEG-sLexs in nasopharyngeal carcinoma (NPC) xenografts. Methods USPIO nanoparticles were synthesized. A better water-soluble USPIO-PEG was synthesized by hydrophobic interaction. The surface of USPIO-PEG was fully activated, fully incubated with sLex at room temperature, ultrafiltration centrifugation and deionized water washing to form magnetic resonance molecular probe USPIO-PEG-sLex.Tem was used to analyze the morphology and particle size of USPIO-PEG-sLex. Dynamic light scattering (DLS) was used to analyze the mean hydrodynamic size of USPIO-PEG-sLex before and after coupling. The Zeta potential of USPIO-PEG-sLex before and after coupling was measured by particle size analyzer. Ten nude mice with nasopharyngeal carcinoma were randomly divided into experimental group and control group. The T 2 mapping imaging was performed before and after the injection of USPIO-PEG-sLex and USPIO-PEG into the caudal vein. The T 2 value of the transplanted tumor before and after the injection of contrast media was compared and analyzed. The expression of ELAM-1 on tumor neovascularization endothelial cells was analyzed by immunohistochemical staining. Results the average diameter of USPIO-PEG was 10 卤2.6 nm by transmission electron microscopy. The mean hydrodynamic size before and after coupling was 34.06 卤9.95 nmnmand the Zeta potential of the PEG magnetic nanoparticles before coupling was 11.6 卤3.96mV, and that after coupling was -12.6 卤5.33mV.USPIO-PEG-s Lex. The Zeta potential of the nasopharyngeal carcinoma transplanted tumor in the control group and the experimental group was better than that in the control group and the experimental group. There was no significant difference in T _ 2 value between the two groups, but the T _ 2 value of the two groups decreased after enhanced scan. The T2 value of the two groups was significantly different from that of the control group, and the enhancement rate of the experimental group was lower than that of the control group. There was significant difference in enhancement rate between the two groups (P 0.05). There was a significant difference between the enhancement rate of tumor and muscle in the experimental group (P < 0.05). The immunohistochemical results showed that the expression of Eselectin protein in the cytoplasm or membrane of vascular endothelial cells was brownish yellow. The staining results showed that the nucleus was dark blue and had significant heterogeneity. Conclusion the magnetic resonance molecular probe USPIO-PEG-sLexus can be successfully prepared by chemical crosslinking. ELAM-1.USPIO-PEG-s Lex nanoparticles can be used as a target contrast agent for ELAM-1 expression in nasopharyngeal carcinoma and have a good potential application in non-invasive dynamic monitoring of ELAM-1 expression.
【学位授予单位】：广西医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R445.2;R739.63

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