LyP-1肽的131碘标记及其生物分布研究

目的：探讨Na131 I标记LyP-1肽的可能性以及Na131 I标记的LyP-1肽在乳腺癌裸鼠体内的生物分布。方法：包含LyP-1序列的十环肽（YCGNKRTRGC）通过固相合成法合成。在两个半胱氨酸之间形成二硫键以维持肽的环形结构。LyP-1肽通过氯胺-T 法进行Na131 I标记。通过尾静脉途径将Na131 I标记LyP-1肽以及对照肽注射于荷MDA-MB-435乳腺癌裸鼠体内并测量其生物分布情况。结果：LyP-1肽的Na131 I标记率可达80％±5％（n＝5），放射化学纯度约96％。在37℃新鲜人血清中Na131 I标记 LyP-1肽24h其放射化学纯度仍然达92％。在生物分布研究中，Na131 I标记 LyP-1肽在肿瘤中的聚集水平明显高于其他组织。结论：通过氯胺-T 法可以成功的将131 I标记于LyP-1肽。131 I标记的LyP-1肽在37℃新鲜人血清中24h仍然保持稳定，并可被肿瘤组织高度摄取。

The Study of 131I Labeling and Biodistribution of LyP-I Peptide

Objective ：To observe the possibility of 131 I labeled LyP-1 peptide and its metastasis .Methods ：The 10-mer cyclic peptide contained the LyP-1 sequence （YCGNKRTRGC） was synthesized through the solid phase method .Disul-fide bonds between the cysteines maintain the cyclic structure .The LyP-1 peptide was labeled by 131 I using the chlora-mine-T measure .Control peptide and 131 I labeled LyP-1 peptide were injected into the nude mice bearing MDA-MB-435 xenografts via tail vein .Biodistribution in vivo was obtained .Results：The labeling efficiencies of LyP-1 peptide could reach 80% ± 5% （n= 5） .The radiochemical purity reached 96% .The radiochemical purity of the labeled compound maintained 92% in human blood serum at 37℃ at 24h .In the biodistribution studies ,the 131 I labeled LyP-1 peptide ac-cumulated in the tumor to a higher level than in the other organs .Conclusion：The LyP-1 peptide could be labeled with 131 I effectively and the labeled compound was stable at 24h in human blood serum at 37℃ and was evidently absorbed by tumor tissue .