Selective drug delivery system to bone:: Small peptide (Asp)6 conjugation
Selective drug delivery system to bone:: Small peptide (Asp)6 conjugation
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DOI：
10.1359/jbmr.2000.15.5.936
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发表时间：
2000-05-01
影响因子：
6.2
通讯作者：
Ohya, K
中科院分区：
文献类型：
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作者：
Kasugai, S;Fujisawa, R;Ohya, K
将药物靶向羟基磷灰石 (HA) 可能是一种有前途的选择性药物递送至骨骼的方法，因为 HA 是硬组织（骨骼和牙齿）中的无机成分，但软组织中不存在。几种与 HA 结合的骨非胶原蛋白在其结构中具有酸性氨基酸的重复序列作为可能的 HA 结合位点。因此，我们认为重复酸性氨基酸的小肽可以作为选择性药物递送至骨骼的载体。为了检验这一假设，我们将 (Asp) 与异硫氰酸荧光素 (FITC) 结合，在体外评估其与 HA 的亲和力，并检查其注射到大鼠后的组织分布。虽然荧光素本身不与HA结合，但(Asp)(6)-FITC与WA以及钙黄绿素和四环素结合，给大鼠静脉注射(Asp)(6)-FITC后24小时，处死动物，制作硬组织磨碎切片和软组织冷冻切片。在共焦激光扫描显微镜下，在骨骼和牙齿中观察到清晰的标记线，而在软组织中没有检测到标记。在单独施用荧光素的大鼠中，在硬组织和软组织中均未检测到荧光标记。 (Asp)(6)-FITC给药后对血液、尿液和骨骼的荧光分析显示，血液中FITC的生物半衰期很短（60分钟），24小时内，95%的给药FITC以尿液形式排出，而2%的FITC在骨骼中积累。给小鼠皮下注射(Asp)(6)-FITC后，定期测量残留在股骨中的荧光强度，在这些小鼠中，生物半衰期FITC 在股骨中的停留时间为 14 天。目前的结果表明，(Asp) 作为选择性药物递送至骨的载体是有效的。
Targeting a drug on hydroxyapatite (HA) could be a promising way for selective drug delivery to bone, because HA, an inorganic component in hard tissues (bone and teeth), does not exist in soft tissues. Several bone noncollagenous proteins, which bind to HA, have repeating sequences of acidic amino acids in their structures as possible HA-binding sites. Thus, we think that a small peptide of repetitive acidic amino acid could work as a carrier for selective drug delivery to the bone. To test this hypothesis, we conjugated (Asp), to fluorescein isothiocyanate (FITC), evaluated its affinity to HA in vitro, and examined its tissue distribution after injection into rats. Although fluorescein itself did not bind to HA, (Asp)(6)-FITC bound to WA as well as calceine and tetracycline, Twenty-four hours after intravenous injection of (Asp)(6)-FITC to rats, animals were killed, and ground sections of hard tissues and cryosections of soft tissues were made. Under a confocal laser scanning microscope, clear labeling lines were observed in bones and teeth, whereas no labeling was detected in soft tissues. In the rats administered with fluorescein alone, the fluorescent labeling was detected in neither hard nor soft tissues. Fluorescent analysis of blood, urine, and bones after (Asp)(6)-FITC administration revealed that biological half-life of FITC in blood was short (60 minutes) and that within 24 h, 95% of the administered FITC was excreted as urine whereas 2% of the FITC accumulated in bones, After subcutaneous administration of (Asp)(6)-FITC to mice, fluorescent intensity remaining in the femurs was measured periodically, In these mice the biological half-life of FITC in the femur was 14 days. Present results indicate that (Asp), is effective as a carrier for selective drug delivery to bone.