Preparation and imaging of arthritis of 99Tcm-DTPA-CB86 for TSPO targeted imaging
Objective To develope a novel radiolabeled translocator protein(TSPO) ligand CB86 targeting agent 99TTcm-diethylene-triaminepentaacetic acid (DTPA)-CB86 and evaluate its biological properties.Methods DPTA-CB86 was prepared by coupling with a bifunctional chelating agent,and then labeled with 99Tcm to obtain 99Tcm-DTPA-CB86.The labeling efficiency,radiochemical purity,and stability were determined in vitro.In vitro cellular uptake and efflux were performed using RAW264.7 macrophage cells.Biodistribution and micro-SPECT/CT images were investigated on Freund's adjuvant-induced left arthritis in mice.SPSS 18.0 analysis software(t-test)was used to fit the normal distribution and homogeneity of variance.Results The labeling yields and radiochemical purity of 99Tcm-DTPA-CB86 were (95.86±2.4.5)％ and (97.45±0.69)％,respectively.99Tcm-DTPA-CB86 displayed good stability,with a radiochemical purity of more than 90％,in phosphate-buffered solution(PBS) at 4 h.It also exhibited high specific TSPO binging in RAW264.7 macrophage cells in vitro.The highest uptake ratio was (36.45±2.18)％ at 3 h after incubation,which then decreased significantly [(10.43 ± 2.01)％;t =6.217,P＜ 0.05)] after adding excessive unlabeled DTPA-CB86.The difference was significant.Cell efflux analysis showed that 99Tcm-DTPA-CB86 had good cell retention by RAW264.7cells,with only about 13.99％ [decreased from (33.31 ±2.34)％ to (19.32±2.01)％ of total input radioactivity] of 99Tcm-DTPA-CB86 efflux observed during 4.5 h to 8 h of incubation.Biodistribution and SPECT/CT imaging demonstrated that the uptake of 99Tcm-DTPA-CB86 in the left arthritic ankles was significantly increased compared with that in contralateral normal ankles.Uptake in the arthritic ankles could be largely blocked by an excess of DTPA-CB86.Conclusion 99Tcm-DTPA-CB86 can be readily synthesized and clearly visualize arthritis with low background,thus demonstrating its potential as a promising molecular probe targeting TSPO for arthritic SPECT imaging.
NETL
NSTL
万方数据
维普
