Comparative study on imaging of 99 Tcm-survivin mRNA antisense peptide nucleic acid in tumor and inflammation animal models

Objective To investigate the value of 99Tcm labeled survivin mRNA antisense peptide nucleic acid (PNA) as an imaging agent in the specific diagnosis for carcinoma.Methods Survivin mRNA antisense PNA was labeled directly with 99Tcm by the ligand-exchange method.Twenty nude mice with lung carcinoma A549 xenografts were randomly divided into 4 groups.Three groups were used for biodistribution study and one group was used for imaging study.Other twenty mice infected by staphylococcus aureus underwent the same procedure.The biodistribution and imaging of 99Tcm-survivin mRNA antisense PNA was studied at 1,2 and 4 h respectively after the intravenous injection in nude mice bearing lung carcinoma A549 xenografts or inflammation models.SPSS 13.0 was used in the study and all data were analyzed by t test.Results Biodistribution results showed that the highest radioactivity was found in the liver,and then in the kidney.Four hours after the administration of the imaging agent,the radioactivity ratios of target-tonon target (T/NT,tumor or inflamumatory lesions to the contralateral regions) in tumor model group were significantly higher than those in inflammation model group ( 3.69 ± 1.13 vs 2.03 ± 0.47,t =3.01,P =0.02 ).Tumors were clearly visible in the tumor model groups at 0.5 h and still clearly seen at 4 h after the injection of antisense PNA.On the contrary,inflammatory lesions could not be seen clearly.Conclusion 99Tcm labeled survivin mRNA antisense PNA can be used to distinguish tumor from inflammation and it may provide a new feasible method for specific tumor diagnosis. Key words: Peptide nucleic acids;  Technetium;  Tumor cells, cultured;  Inflammation; Radionuclide imaging;  Mice, nude