NHS-MAG3为螯合剂的99mTc-寡核苷酸标记特性

目的 探讨以NHS-MAG，作为螯合剂的^99mTc-寡核苷酸(^99mTc-ON)的标记特性。方法将NHS-MAG，与长度为15个碱基的c-myc mRNA的反义(ASON)、正义(SON)和无义寡核苷酸(MON)偶联，进行^99mTc标记，Sephadex G25 柱层析分离纯化，评价^99mTc-ON的标记率、放化纯和稳定性；将ON-MAG，偶联物置-20℃贮存15 d、1月、2月后进行^99mTc标记，观察标记率的变化，评价ON-MAG3的稳定性；用三氯乙酸沉淀法测定^99mTc-ON的血浆蛋白结合率。结果 ^99mTc-ASON、^99mTc-SON和^99mTc-MON的标记率分别为68．41％、66．24％和69．38％，纯化后放化纯分别为96．98％、95．34％和94．62％。三者在室温和血清中均较稳定。ON-MAG3在-20℃保存2月后，标记率未见明显下降。三种^99mTc-ON的血浆蛋白结合率均小于13％。结论以NHS-MAG3作为螯合剂的^99mTc-ON具备优良的标记特性，标记率、放化纯较高，稳定性好，血浆蛋白结合率低，是一种有临床应用潜力的放射性标记药物。

The Radiolabeling Property of Oligonucleotide with 99mTc Using NHS-MAG3 as a Chelator

OBJECTIVE: To explore the radiolabeling property of oligonucleotide with 99mTc using NHS-MAG3 as a bifunctional chelator. METHODS: Three 15-base single-stranded amine-derivitized oligonucleotides, which were antisense(ASON), sense(SON) and mismatched oligonucleotides(MON) of c-myc oncogene mRNA, were coupled with NHS-MAG3 and labeled with 99mTc. The labeled oligonucleotide was purified by Sephadex G25 column chromatogram, then the stability was evaluated. The labeling efficiency of ON-MAG3 was assessed 15 days, 1 month and 2 months after storage at -20 degrees C. The binding rate of 99mTc-ON with plasma protein was measured by the trichloroacetic acid precipitation method. RESULTS: The average labeling efficiency of 99mTc-ASON, 99mTc-SON and 99mTc-ON was 68.41%, 66.24% and 69.38% respectively, and the radiochemical purity was 96.98%, 95.34% and 94.62%. 99mTc-ON was stable when placed at room temperature or incubated in human serum at 37 degrees C. The labeling efficiency of ON-MAG3 did not significantly change 2 months after storage at -20 degrees C. The plasma protein binding rate of 99mTc-ON was lower than 13%. CONCLUSION: 99mTc-ON labeled with NHS-MAG3 method showed superior radiochemical characteristics. The labeling efficiency and radiochemical purity were desirable. The label was stable in serum and the binding with plasma protein was low. 99mTc-ON could be a sort of potential radiopharmaceutical for in vivo applications.