【作者】 舒洪灶；

【导师】 许玉杰；

【作者基本信息】 苏州大学 ， 放射医学， 2010， 硕士

【摘要】 目的:研制壳聚糖-乙二胺四乙酸(CTS-EDTA)纳米粒(以下简称CEC-Nano),观察其对小鼠体内放射性锶核素的促排作用,为研制新型、高效、广谱的体内污染放射性核素促排药物提供实验依据。方法:选择以螯合能力强、生物相容性好的低分子量壳聚糖CTS,通过酰化反应将EDTA与CTS连接,合成CTS-EDTA复合物(以下简称CEC),并采用离子凝胶法将其制备成纳米制剂,使产物形成两性离子型螯合物具备强大的螯合能力,同时该产物又有纳米材料的一些优良生物学特性,可加速体内放射性污染核素的排出,通过动物实验研究其药效作用。通过单次给药方式观察CEC-Nano、CEC、EDTA-Na2对小鼠体内放射性核素89Sr的促排效果;采用多次给药形式,通过测量收集的尿粪和动物尸体焚化残灰中的放射性、小动物整体成像等方法观察并比较CEC-Nano、CEC、EDTA-Na2对体内污染的放射性核素89Sr的促排效果。结果:本实验利用高脱乙酰度低分子量的壳聚糖(CTS)通过N-酰化反应与乙二胺四乙酸(EDTA)合成水溶性的CEC,并采用离子凝胶法将CEC氨基基团与TPP聚阴离子通过静电作用制备了粒度均一的CEC-Nano,平均纳米粒径为10.18nm(PDI=0.573),同时又有纳米材料的一些优良生物学特性。通过单次给药实验明确体内放射性锶蓄积的主要器官是骨骼,单次给药后30min、2h时相点CEC-Nano和CEC对骨骼中的放射性锶核素的促排作用较EDTA-Na2明显(p<0.05),且CEC-Nano的促排效果更好(p<0.05)。用药48h后,虽然CEC-Nano和CEC对沉积在股骨中的放射性锶核素的促排效果差异无统计学上的意义,但从整体上观察CEC-Nano和CEC的促排效果,发现两者的促排效果要明显优于传统药物EDTA-Na2,且CEC-Nano的促排效果更好。通过多次给药实验,收集小鼠尿粪并进行放射性核素测定,明确体内污染的放射性锶的排出途径是消化道和泌尿系统。放射性核素污染后48h内,CEC-Nano、CEC通过消化、泌尿系统的促排作用都明显强于传统的促排药物EDTA-Na2(p<0.05);CEC-Nano的促排作用更优于CEC(p<0.05)。但到48h后至72h,CEC-Nano与CEC相比则没有统计学上的差异(p>0.05)。通过收集小鼠体内残灰并进行总放射性的测定,多次给药后24h和48h内CEC-Nano对放射性锶的促排作用要强于传统药物EDTA-Na2(p<0.05),也高于CEC;但72h后CEC-Nano、CEC与EDTA-Na2相比效果相近。通过小动物成像系统ROI勾画技术,计算静态图像内代表放射性核素滞留区域的平均强度,其结果证实了前述结论,并且显示CEC-Nano、CEC对体内放射性锶核素的促排效果要优于传统的促排药物EDTA-Na2(p<0.05),且CEC-Nano即使到72h后,仍通过发挥纳米剂型促排剂的作用特点,其促排效果要优于非纳米型药物CEC和传统的促排药物EDTA-Na2 (p<0.05),而此时CEC与EDTA-Na2相比无统计学上的差异,此结果更进一步证实了纳米剂型促排剂的优势。结论:通过本实验室建立的方法,制备得到的新型纳米型放射性核素促排剂CEC-Nano,是一种比传统促排药物EDTA-Na2有更高促排效率的新型放射性核素促排剂,其不仅可以作为放射性锶89Sr2+的促排剂,也为进一步研制广谱放射性核素内污染促排剂提供了一定的实验依据。更多还原

【Abstract】 Objective:To research and develop a new radionuclide chelating agent Chitosan-EDTA (CTS-EDTA) nanoparticles (CEC-Nano), investigate its promote exclusive effect on the polluted radioactive strontium radionuclide in mice, and provide experimental data for the development of a novel, highly efficient, broad-spectrum contaminative radionuclide chelating pharmaceutical.Method:The low molecular weight chitosan(CTS) with chelating ability and fine biocompatibility was connected with EDTA by N-acylation reaction. The CEC-Nano, which may be powerful chelating ability and special biological characteristics of nano-materials, was prepared by cross-linking CTS-EDTA with sodium tripolyphosphate(TPP).The radionuclide chelating effect of CEC-Nano in mice was investigated by survey and evaluating the radioactivity of radioactive strontium 89 in thighbone, collected urine and feces, collected residual ash of whole body, which was compared with non–nanomaterial CEC and EDTA-Na2. In addition, the residual strontium 89 in the mice was evaluated by small animal whole imaging.Results: The prepared CTS-EDTA-Nano nanoparticle (CEC-Nano) was a uniform spherical nanoparticle (PDI = 0.573), and the average particle diameter was 10.18 nm, determined by laser particle size analyzer and transmission electron microscopy.The einmal dose experiment had been carried out, and the chelating agents were injected one time by mouse caudal vein respectively. The radioactivity of strontium 89 accumulated in mouse thighbone was decreased significantly (p<0.05) after injection. Especially at the 30min and 2h after drug administration, the chelating effect of CEC-Nano and CEC was more effective than that of EDTA-Na2 significantly (p<0.05), and the CEC-Nano showed higher efficiency than non-nanomaterial CEC (p<0.05). However, at the 48h after administration, the chelating effect between CEC-Nano and CEC was no statistical difference (p>0.05). The repeated dose experiments had been carried out and the chelate agents were injected three times per day by mouse caudal vein respectively. The main excretion way of polluted radioactive strontium was the digestive and urinary systems. Within 48 hours, the chelating effect of CEC-Nano and CEC was stronger than that of the conventional chelator EDTA-Na2 by compared the radioactivity of strontium 89 in collected excrete urine and feces (p<0.05), and the CEC-Nano was better than the CEC (p<0.05). However, after 72 hours, there was no difference between CEC-Nano and CEC (p>0.05). The similar result had been confirmed by measuring the radioactivity of the collected residual ash of whole body. Within 48 hours, the chelating effect of CEC-Nano was better than that of CEC and EDTA-Na2 (p<0.05). After 72 hours, there was no difference between CEC-Nano and CEC (p>0.05). The residual strontium 89 in the mice was also calculated by drawn ROI on the whole mouse radioactive image. It was confirmed that the CEC-Nano had stronger chelating effect than the CEC and traditional chelating drugs EDTA-Na2 during 48 hours after injection (p<0.05). Even after 72 hours, the chelating effect of CEC-Nano was still better than that of CEC and EDTA-Na2 (p<0.05).Conclusion: A novel nanoparticle agent CEC-Nano for polluted radionuclide chelating had been developed. These results above mentioned had confirmed the advantages of the nano-formulation chelating agent. Not only may it be a powerful chelating agent of polluted radioactive strontium 89, but also a broad-spectrum radionuclide chelating agent potentially.更多还原