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| Application of 99Tcm-Syt I-C2A in apoptosis imaging of cardiocytes based on myocardial ischemia-reperfusion |
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Abstract Objective To investigate application of mutation protein of C2A domain of synaptotagmin I（Syt I-C2A-G4C） labeled with technetium in myocardial apoptosis imaging. Methods （1） The C2A domain of Syt I was labeled with 99Tcm using reduction photoetry of Tin chloride. Radiochemical purity was determined with thin layer chromatography. The binding activity with phosphatidylserine of radiolabeled protein was assessed using cell binding experiment.（2） Myocardial ischemia-reperfusion models were produced in 5 pigs. SPECT images were acquired at 2h after post injection of 99mTc-Cyt-C2A-G4C via the tail， and the ratio of target/background was also cal- culated using region of interest（ROI） method. Apoptosis in the ischemic myocardium was assessed using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Results （1） The radiochemical purity of 99Tcm-Syt I-C2A-G4C was（96.42±0.76）%.（2） The radioactivity in the camptothecin-treated group was （5.23±0.38） folds higher than that of non-treated viable control group.（3）At 2 h post-injection of the radiotracer， the focal uptake of radioactivity was observed at the ischemic myocardium areas， and T/B ratio was 3.40± 0.43 . Myocardial apoptosis was confirmed by TUNEL assay in the ischemic myocardium with high radioactivity. Conclusion 99Tcm-Syt I-C2A-G4C should be a potential radiotracer for imaging of myocardial apoptosis.
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2012, Vol. 21 
