131I标记多肽K237的最佳条件及标记肽的体外生物活性

摘要

目的 探索131I标记多肽K237,获得放射化学纯度高于95%的131I-K237的最佳条件,研究标记产物的体外稳定性及生物学活性.方法 应用Iodogen法对K237进行131I标记,采用正交实验筛选最佳标记条件.用高效液相色谱仪(HPLC)联合薄层层析法(TLC)测定标记率及放射化学纯度,SephadexG25层析柱分离纯化131I-K237.将分离纯化的131I-K237(放射化学纯度大于95%)分别放置于室温及37℃水浴箱,于不同时间测定其放射化学纯度以观察其稳定性.应用cck-8法进行人脐静脉内皮细胞(HUVEC)增殖抑制实验,分别计算K237及131I-K237对HUVEC的抑制率,判定131I-K237的生物活性.结果 最佳标记条件中,K237 100 μg与Iodogen 50 μg,在37℃条件下反应时间40 min,标记率可达70%以上.稳定性实验结果表明,131I-K237在体外放置24 h后,其放射化学纯度＞90%.131I-K237和K237对HUVEC细胞增殖的抑制率差异无统计学意义(P＞0.05),说明K237被131I标记后,其生物学活性未改变.结论 Iodogen法131I标记多肽K237简单高效,标记产物的生物活性得到保留,未受明显破坏.%Objective To explor the optimum conditions of the radiolabeling of the peptide K237 with the ra-dionuclide 131I and to investigate the stability and bioactivity of 131I - K237 in vitro. Methods Iodogen method was used to label the peptide K237 and the orthogonal experiment was used to screen the optimum conditions. The labeling rate and radiochemical purity of the 131I - K237 was measured by the HPLC and TLC. 131I - K237 was isolated and purified by the SephadexG25. Its stability was studied by determining the radio-chemical of the 131I - K237 at special time. The cell proliferation assays and cell affinity assays of the HUVEC were studied by the cck - 8 method. The inhibition of the HUVEC by the K237 and the 131I - K237 were measured to investigate the biological activity of 131I - K237. Results The optimum conditions of the radiolabeling of the peptide K237 with 131I were K237 100μg, iodogen 50μg, reaction temperature 37℃ and reaction time 40min. The labeling rate was higher than 70% . The radiochemical purity of 131I - K237 was still higher than 90% when stayed in vitro 24 hours. There were no significant differences between the inhibition of the HUVEC treated with K237 and the 131I - K237. The biological activity of K237 was not changed by labeling. Conclusion K237 can be labeled readily with 131I by the Iodogen method and its biological activity is not changed.