介入途径下中药白芨提取物作为基因递送载体的可行性

Feasibility of a polysaccharide isolated from Bletilla striata used as a gene vector administered through an interventional pathway

目的:探讨经介入途径中药白芨提取物作为基因递送载体的可行性.方法:从中药白芨中提取其有效成分-白芨多糖,采用胺化还原法制备阳离子型白芨多糖,体外实验检测该阳离子型多糖对质粒DNA的结合与保护作用,以及阳离子白芨多糖载基因复合物对肝癌细胞系HepG2的转染,进一步通过介入途径经肝动脉给予该复合物,以GFP作为报告基因检测复合物在体内对活体兔肝细胞的转染.结果:所制备的阳离子型白芨多糖载基因复合物可以结合并保护质粒DNA免受DNA酶的降解;体外实验证实该复合物可以转染入体外培养肝癌细胞,以阳离子白芨多糖作为转染载体时转染效率要低于脂质体组,差异具有统计学意义(28.87%±3.27% vs 36.64%±6.87%,P<0.05).采用介入方法经肝动脉给药时复合物能靶向转染入活体兔肝细胞内并实现表达.结论:采用介入途径经肝动脉给药时阳离子白芨多糖载基因复合物可以实现活体肝细胞靶向转染,有望作为一种新型的多聚阳离子型的基因载体在基因治疗中发挥作用.

AIM： To research into the feasibility of a polysaccharide isolated from Bletilla striata as a gene vector administered through an interventional pathway. METHODS： Bletilla striata polysaccharide （BSP） was isolated from a Chinese medicinal herb Bletilla striata, from which we prepared the cationic BSP （BSP＋） by reductive amination. We further tested the ability of the BSP＋ to incorporate and protect plasmid DNA, and the ability of the BSP＋/pDNA complex to transfect into HepG2 cells. Then, we investigated the transfected effect of the BSP＋/pDNA complex in vivo using green fluorescence protein （GFP） gene as a reporter gene administered through the hepatic artery. RESULTS： The synthesized cationic Bletilla striata polysaccharide （BSP＋） incorporated and protected plasmid DNA to avoid enzymolysis by DNase. The transfection ratio was lower in the liposome group than in BSP＋ group （28.87% ± 3.27% vs 36.64% ± 6.87%, P 〈 0.05）. The BSP＋/pDNA complex was transfected into HepG2 cells in vitro and host cell in vivo. CONCLUSION： The BSP＋/pDNA complex could target transfect into liver cell in vivo when administered through the hepatic artery using the interventional method, which could produce a marked effect as a new-type polycation gene vector in gene therapy.