~(125)I-OxLDL-Ab在正常小鼠及动脉粥样硬化动物模型体内的生物分布

分别采用高效液相色谱法、紫外分光光度法对OxLDL-Ab进行定性、定量分析,评价~(125)I-OxLDL-Ab在正常动物和动脉粥样硬化模型动物的体内分布。正常动物采用昆明小鼠,模型采用载脂蛋白E基因敲除的小鼠(apolipoprotein E-deficient mice,ApoE~(-/-))。高效液相色谱条件为:磷酸缓冲液(PB,0.2 mol/L,pH=7.4)为流动相,流速1.0mL/min,检测波长220nm;紫外分光光度法测得蛋白浓度的标准曲线为:y=0.664 5x-0.008 3,r2=0.999 7。~(125)I-OxLDL-Ab在正常小鼠体内分布实验结果表明:除甲状腺外,各器官的放射性摄取随时间延长而减少,无明显浓集;在注射~(125)I-OxLDL-Ab后1d各器官代谢消除超过2/3,7d后血液中完全清除。~(125)I-OxLDL-Ab在ApoE~(-/-)鼠体内的分布实验中采用w=2%的KI溶液封闭了甲状腺,消除了甲状腺高摄取的影响;靶器官肺有较高放射性摄取,且在注射后4~8h显示出放射性浓集;除血外,其它各器官的靶器官/非靶器官的放射性摄取比值(T/NT)均大于1,其中T/Mu(肌肉)8,显示出~(125)I-OxLDL-Ab对靶器官有一定的选择性。标记抗体的体内靶向性是显像研究中至关重要的一环,要进一步用于动脉粥样硬化早期显像诊断,还需进一步提高靶器官/非靶器官的放射性摄取比值,提高其在体内与其抗原的亲和性。

Biodistribution of 125 I-OxLDL-Ab in Normal Mice and in Animal Models of Atherosclerosis in Vivo

Anti-oxidized low-density lipoprotein antibody(OxLDL-Ab)was analysized with high performance liquid chromatography(HPLC)and ultraviolet spectrophotometry(UV). The biodistribution of 125 I-OxLDL-Ab was evaluated in both normal animals and animal mod-els of atherosclerosis.Kunming mice were used as normal animals and ApoE knock-out mice (ApoE-/-mice)were used as animal models of atherosclerosis in the study of biodistribution. The optimum conditions of HPLC were as follows:phosphate buffer (0.2 mol/L,pH=7.4) was used as the mobile phase,the flow rate was 1 mL/min and the detection wavelength was 220 nm.The standard curve of concentration was obtained in the quantitative analysis of UV with y= 0.664 5x-0.008 3 (r2=0.999 7).Biodistribution in normal animal show that organ uptakes decrease with time and no obvious accumulation is observed in organs except hypothyroid;over 2/3 uptake clear away in 24 h after injection and couldn’t be detected 7 d later.The hypothyroids of ApoE-/-mice are blocked by 2% KI solution to avoid their high uptake in the biodistribution of 125 I-OxLDL-Ab.Uptake in lung (the target organ)is high in the early 4-8 h after inj ection of 125 I-OxLDL-Ab.The ratio of target/organs is more than 1 except blood,and the ratio of target/muscle is more than 8,which show the selectivity of 125 I-OxLDL-Ab to the targeted organ invivo.Futher studies need to be done to evaluate the possibility 125 I-OxLDL-Ab as a SPECT imaging agent in diagnose of early stage of atheroscle-rosis.