半乳糖化脂质体-聚阳离子-DNA复合物的肝靶向性研究

目的 研究半乳糖苷修饰的脂质体-聚阳离子-DNA复合物(Gal-LPD)在体外的肝细胞靶向性.方法 合成胆甾五半乳糖苷(Gal-chol),并用薄膜-超声分散法制备空白阳离子脂质体,再与鱼精蛋白-DNA复合物形成Gal-LPD;用激光粒度仪及电位分析仪测定其粒径和电位;以lacZ质粒DNA作为报告基因,用HepG2肝癌细胞和A549肺癌细胞考察LPD的转染效率;用MTT法测定其细胞的毒性.结果 Gal-LPD的粒径为200 nm;Zeta电位随阳离子成分DDAB-DNA比例的不同而在20～55 mV间变化;与未用半乳糖修饰的LPD.相比,Gal-LPD在HepG2细胞中的转染率提高了2.4倍,但在A549细胞中的转染率却有所下降,而且半乳糖能竞争抑制Gal-LPD在HepG2细胞中的转基因效率;Gal-LPD无明显的细胞毒性.结论 Gal-LPD在HepG2细胞中有较高的转基因效率,具有体外的肝细胞靶向性.

Liver targeting of galactosylated liposome-polycation-DNA complexes

OBJECTIVE To investigate the hepatocyte targeted properties of galactosylated liposome-polycation-DNA complexes(LPD).METHODS Cholesterylated thiogalactoside with five galactose residues was synthesized to prepare Gal-LPD,which was composed of galactosylated cationic liposomes,protamine sulfate and plasmid DNA.The particle size and surface charge of LPD were measured by photon correlation spectroscopy.Evaluation of transfection efficiency was performed on hepatoma cells HepG2 and lung cancer cells A549,taking lacZ plasmid DNA as the reporter gene.Cytotoxicity of LPD was studied using MTT assay.RESULTS The particle size of Gal-LPD was 200 nm;and the Zeta potential changed with the ratio of DDAB/DNA.Transfection efficiency of Gal-LPD was 2.4 fold higher than that of non-galactosed control LPD0 on HepG2 cells,but lower on A549 cells.The results of MTT assay showed that LPD had no obvious cytotoxicities.CONCLUSION Galactosylated liposome-polycation-DNA complexes show higher gene transfection activity in HepG2 cells,so it may be a good non-viral vector for hepatocyte-specific gene delivery in vivo.