靶向血栓纤维蛋白的氧化铁微粒MR探针制备及体外MR分子成像  

In vitro MRI of thrombosis using a fibrin-specific SPIO-based molecular MR probe

作　　者：赵艳娥[1] 滕兆刚[1] 孙晶[1] 田迎[1] 罗松[1] 张龙江[1] 卢光明[1] 

机构地区：[1]南方医科大学南京临床学院(南京军区南京总医院)医学影像科,南京医学博士研究生210002

出　　处：《医学研究生学报》2013年第10期1024-1027,共4页Journal of Medical Postgraduates

基　　金：江苏省自然科学基金(BK2009316)

摘　　要：目的血栓纤维蛋白是血栓分子成像的主要靶点之一。制备靶向血栓纤维蛋白的氧化铁微粒MR探针,研究其体外血栓分子成像的可行性。方法制备具有氨基的三明治结构的超顺磁性介孔氧化铁微粒(Fe3O4@SiO2@SiO2/NH2,简称氧化铁微粒),将多肽(促胸腺生成素32-36五肽Gly-Pro-Arg-Pro-Pro,GPRPP)连接到氧化铁微粒,制成靶向血栓纤维蛋白的MR探针。采用MRI测定不同浓度MR探针的T2弛豫时间。采集犬静脉血,体外自凝制备血栓。设立MR探针-血栓实验组和单纯血栓对照组,观察其体外MR成像效果,测定不同实验组T2*弛豫时间。统计学采用回归分析MR探针不同浓度与T2*弛豫时间的关系并计算弛豫率。独立样本t检验分析不同组间T2*弛豫时间差异。结果成功制备了靶向血栓纤维蛋白MR探针。MR探针T2*弛豫时间随其浓度增加而缩短,其弛豫率为0.007/(μg·ms)。血栓体外MR成像显示实验组T2*弛豫时间较对照组T2*弛豫时间明显缩短[(4.48±0.61)ms vs(8.78±2.19)ms,P=0.001]。结论靶向血栓纤维蛋白MR探针磁化特性符合顺磁性物质的特性,并在体外对血栓能显著增加阴性对比效果,为血栓体内分子成像研究打下基础。Objective The fibrin in the thrombus is one of the main targets of molecular imaging for thrombosis. This study was to prepare a fibrin-specific SPIO-based MR probe and investigate its application in the detection of thrombi in vitro. Methods Magnet- ic Fe3 04 @ SiO2 @ SiOJNH2 microspheres were synthesized using the two-step coating method, and a fibrin-specific SPIO-based MR probe was prepared by connecting the magnetic mierospheres with the pentapeptide Gly-Pro-Arg-Pro-Pro （ GPRPP）. The transverse relax- ation time （T2） of the MR probe was determined by MRI. Canine venous blood was phlebotomized and coagulated in vitro for thrombi. The MRI resuhs were observed and the transverse relaxation time determined in the experimental group （thrombus with the MR probe） and the control group （thrombus only）. The relationship between the concentration of the MR probe and T2 was determined, the relaxa tion rate of the MR probe calculated, and the difference in T2 between the two groups were analyzed by independent-sample t-test. Results A fibrin-specific SPIO-based MRI probe was prepared successfully. The transverse relaxation time of the MR probe was reduced with the increase of its concentration, with a relaxation rate of 0.007/（ μg . ms）. The transverse relaxation time was markedly shorter in the experimental than in the control group （ [ 4.48 ± 0.61 ] vs [ 8.78 ±2.19 ] ms, P = 0.001 ）. Conclusion The MR probe has the magnetic characteristics of paramagnetic materials and significantly increases the negative contrast of thrombi in vitro.

关 键 词：氧化铁微粒 多肽 MR探针 分子影像 磁共振成像 

分 类 号：R319[医药卫生—基础医学]