Biodistribution of ¹²⁵I-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 ¹²⁵I-OxLDL-Ab was evaluated in both normal animals and animal models 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 ¹²⁵I-OxLDL-Ab. Uptake in lung (the target organ) is high in the early 4.8 h after injection of ¹²⁵I-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 ¹²⁵I-OxLDL-Ab to the targeted organ in vivo. Futher studies need to be done to evaluate the possibility ¹²⁵I-OxLDL-Ab as a SPECT imaging agent in diagnose of early stage of atherosclerosis.