NHS-MAG_3为螯合剂的^(99m)Tc-寡核苷酸标记特性

The Radiolabeling Property of Oligonucleotide with ^(99m)Tc Using NHS-MAG_3 as a Chelator

目的 探讨以 NHS- MAG3作为螯合剂的 99m Tc-寡核苷酸 (99m Tc- ON)的标记特性。方法 将 NHS-MAG3与长度为 15个碱基的 c- m yc m RNA的反义 (ASON)、正义 (SON)和无义寡核苷酸 (MON)偶联 ,进行 99m Tc标记 ,Sephadex G2 5柱层析分离纯化 ,评价 99m Tc- ON的标记率、放化纯和稳定性 ;将 ON- MAG3偶联物置 - 2 0℃贮存 15 d、1月、2月后进行 99m Tc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 99m Tc-ON的血浆蛋白结合率。结果 99m Tc- ASON、99m Tc- SON和 99m Tc- MON的标记率分别为 6 8.4 1%、6 6 .2 4 %和6 9.38% ,纯化后放化纯分别为 96 .98%、95 .34%和 94 .6 2 %。三者在室温和血清中均较稳定。 ON- MAG3在 - 2 0℃保存 2月后 ,标记率未见明显下降。三种 99m Tc- ON的血浆蛋白结合率均小于 13%。结论 以 NHS- MAG3作为螯合剂的 99m Tc- 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 。

Objective To explore the radiolabeling property of oligonucleotide with 99mTc using NHS-MAG 3 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-MAG 3 and labeled with 99mTc. The labeled oligonucleotide was purified by Sephadex G25 column chromatogram, then the stability was evaluated. The labeling efficiency of ON- MAG 3 was assessed 15 days,1 month and 2 months after storage at -20℃. 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 ℃. The labeling efficiency of ON- MAG 3 did not significantly change 2 months after storage at -20 ℃. The plasma protein binding rate of 99mTc-ON was lower than 13%. Conclusion 99mTc-ON labeled with NHS-MAG 3 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.