Abstract: Objective To test the efficiency of transfecting 99Tcm-labeled anti-miR208b oligonucleotide into early hypertrophic
cardiac myocytes in vitro. Methods The anti-oligonucleotide targeting miR208b (AMO) was synthesized and modified with
LNA followed by conjugation with N-hydroxysuccinimidyl S-acetyl-meraptoacetyl triglycine (NHS-MAG3) and radiolabeling
with 99Tcm. NHS-MAG3-LNA-AMO and labeled AMO were purified with Sep-Pak C18 column chromatography, and the
former was examined for UV absorption at the 260 nm using Gene Quant DNA/RNA calculator. The labeling efficiency,
radiochemical purity, stability and molecular hybridization activity were analyzed. An angiotensin II-induced cell model of
hypertrophic cardiac myocytes was transfected with 99Tcm-NHS-MAG3-LNA-AMO via liposome, and the relative expression of
miRNA208b and retention ratio of the labeled AMO in early hypertrophic cells were determined. Results The labeling
efficiency and radiochemical purity of the labeled AMO after purification exceeded 84% and 86%, respectively. The radiochemical
purities of the labeled AMO incubated in serum and normal saline for 12 h were both higher than 80%, and the
labeled AMO showed a capacity to hybridize with the target gene. In the hypertrophic model of cardiac myocytes, the
retention ratio of labeled AMO at 6 h was higher than 20%. Conclusion The 99Tcm-labeled antisense probe can be efficiently
transfected into hypertrophic cardiac myocytes in vitro, which provides an experimental basis for subsequent radionuclide
imaging studies.