Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2009, Vol. 20 ›› Issue (3): 170-176 doi: 10.13538/j.1001-8042/nst.20.170-176

• RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICIN • Previous Articles     Next Articles

SPECT imaging of cardiac reporter gene expression in living rabbits

LIU Ying1,2 LAN Xiaoli1,* ZHANG Liang1 WU Tao1 JIANG Rifeng1 ZHANG Yongxue1   

  1. 1Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology; Hubei Key Laboratory of Molecular Imaging of Hubei Province, Wuhan 430022 , China 2Department of Nuclear Medicine, the Second Affiliated Hospital of Guangzhou Medical College, Guangzhou 510260, China
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LIU Ying, LAN Xiaoli, ZHANG Liang, WU Tao. SPECT imaging of cardiac reporter gene expression in living rabbits.Nuclear Science and Techniques, 2009, 20(3): 170-176     doi: 10.13538/j.1001-8042/nst.20.170-176

Abstract:

This work is to demonstrate feasibility of imaging the expression of herpes simplex virus 1-thymidine kinase (HSV1-tk) reporter gene in rabbits myocardium by using the reporter probe 131I-2’-fluoro-2’-deoxy-1-β-D- arabinofuranosyl- 5-iodouracil (131I-FIAU) and SPECT. Rabbits of the study group received intramyocardial injection of Ad5-tk and control group received aseptic saline injection. Two sets of experiments were performed on the study group. Rabbits of the 1st set were injected with 131I-FIAU 600 μCi at Day 2 after intramyocardial transfection of Ad5-tk in 1×109, 5×108, 1×108, 5×107 and 1×107 pfu, and heart SPECT imaging was done at different hours. Rabbits of the 2nd were transferred various titers of Ad5-tk (1×109, 5×108, 1×108, 5×107, 1×107 pfu) to determine the threshold and optimal viral titer needed for detection of gene expression. Two days later, 131I-FIAU was injected and heart SPECT imaging was performed at 6, 24 and 48 h, before killing them for gamma counting of the hearts. Reverse transcription- polymerase chain reaction (RT-PCR) was used to verify the transferred HSV1-tk gene expression. Semi-quantitative analysis derived of region of interest (ROI) of SPECT images and RT-PCR images was performed and the relationship of SPECT images with ex vivo gamma counting and mRNA level were evaluated. SPECT images conformed 131I-FIAU accumulation in rabbits injected with Ad5-tk in the anterolateral wall. The optimal images quality was obtained at 24~48 h for different viral titers. The highest radioactivity in the focal myocardium was seen at 6 h, and then declined with time. The threshold was 5×107 pfu of virus titer. The result could be set better in 1~5×108 pfu by SPECT analysis and gamma counting. ROI-derived semi-quantitative study on SPECT images correlated well with ex vivo gamma counting and mRNA levels from RT-PCR analysis. The HSV1-tk/131I-FIAU reporter gene/reporter probe system is feasible for cardiac SPECT reporter gene imaging. The optimal Ad5-tk titer is 1~5×108 pfu and optimal imaging time is 24~48 h after transferred Ad5-tk in rabbit. The imaging of transgene expression in heart might be used for noninvasive imaging of gene therapy in cardiac diseases in human.

Key words: Reporter gene, Herpes simplex virus 1-thymidine kinase, 2’-fluoro-2’-deoxy-1-β-D-arabinofuranosyl-5- iodouracil, Single photon emission computed tomography, Cardiac