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目的作为配体,肽对于多种受体显示出良好的靶向性,例如在肿瘤表面过度表达的整合素家族受体。本文主要研究和表征分别用精氨酸-甘氨酸-天冬氨酸(RGD)三肽和甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(GRGDS)五肽修饰的载药脂质体。方法分别采用RGD和GRGDS对包载阿霉素的立体稳定脂质体(SSL-doxorubicin)进行修饰,以制备RGD-SSL-doxorubicin和GRGDS-SSL-doxorubicin。在体外表征试验中,测定了各种脂质体的包封率、粒径、Zeta电位和释放率,采用SRB试验研究了各脂质体对卵巢癌细胞的细胞毒作用,并应用流式细胞仪和共聚焦显微镜考察了肿瘤细胞对各脂质体包封的阿霉素的摄取情况。结果所有脂质体的包封率均在95%以上,采用RGD或GRGDS进行的修饰并未影响长循环脂质体的包封率。各种脂质体的平均粒径在105.7±3.5nm和130.5±3.0nm之间,Zeta电位在–3.3±0.3和–6.1±0.3mV之间,在模仿体内环境的释放介质(含胎牛血清)中,12小时内约有2/5的阿霉素从脂质体中释放。与游离阿霉素相比,修饰后的脂质体对肿瘤细胞的抑制率略有下降;在研究对阿霉素摄取的流式细胞试验和共聚焦试验中,也有类似现象出现。将各种脂质体分别加入肿瘤细胞后,阿霉素主要分布于SKOV-3的细胞核。结论本研究成功制备了两种分别用精氨酸-甘氨酸-天冬氨酸(RGD)三肽和甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(GRGDS)五肽修饰的阿霉素脂质体。体外表征结果显示,该修饰不会显著改变立体稳定脂质体的性质。
Objective As a ligand, peptides show good targeting to a wide range of receptors, such as integrin family receptors that are overexpressed on the tumor surface. In this paper, the drug-loaded liposomes modified with arginine-glycine-aspartic acid (RGD) tripeptide and glycine-arginine-glycine-aspartic acid-serine (GRGDS) pentapeptide were mainly studied and characterized. Methods RGD and GRGDS were used to modify doxorubicin-loaded liposomal SSL-doxorubicin to prepare RGD-SSL-doxorubicin and GRGDS-SSL-doxorubicin. In vitro characterization test, the encapsulation efficiency, particle size, Zeta potential and release rate of various liposomes were determined. The cytotoxic effect of each liposome on ovarian cancer cells was studied by SRB assay. Flow cytometry Tissue and confocal microscopy examined tumor cell uptake of each liposome-encapsulated doxorubicin. Results The encapsulation efficiency of all liposomes was above 95%. The modification with RGD or GRGDS did not affect the entrapment efficiency of long-circulating liposomes. The average size of the various liposomes was between 105.7 ± 3.5 nm and 130.5 ± 3.0 nm and the zeta potential was between -3.3 ± 0.3 and -6.1 ± 0.3 mV in the release medium that mimicked the in vivo environment (fetal bovine serum ), About two-fifths of doxorubicin was released from the liposomes within 12 hours. Compared with the free doxorubicin, the modified liposomes showed a slight decrease in the inhibitory rate of the tumor cells. A similar phenomenon was observed in the flow cytometry and confocal test for the uptake of doxorubicin. Adiponectin was mainly distributed in the nuclei of SKOV-3 after various liposomes were added to tumor cells respectively. Conclusions In this study, two doxorubicin modified with arginine-glycine-aspartic acid (RGD) tripeptide and glycine-arginine-glycine-aspartic acid-serine (GRGDS) Liposomes. In vitro characterization results show that this modification does not significantly alter the properties of sterically stabilized liposomes.