中文摘要：

目的研究小于扰RNA（siRNA）的新型阳离子脂质体的制备，考察此脂质体-小干扰RNA复合物对LNCap细胞中靶mRNA的沉默效应。方法采用逆向蒸发法制备新型阳离子脂质体，并加入鱼精蛋白和小牛胸腺DNA以增加其对小干扰RNA的压缩，评价其理化性质；以LNCap细胞为模型，以lipofectamine2000作为阳性对照，用RT—PCR方法研究脂质体-小干扰RNA复合物对前列腺癌细胞中靶基因Plk-1的沉默效应。结果制备的脂质体（2，3-二油氧基丙基）三甲基氯化铵胆固醇的最佳比例为3：1，粒径为（117±4．3）nm，Zeta电位为（47±3．6）mV；新型阳离子脂质体小干扰RNA复合物的入胞效率显著提高，荧光显微镜显示LNCap细胞内小干扰RNA含量明显升高。结论本实验所制备的阳离子脂质体具有较高转染效率，脂质体-小干扰RNA复合物的沉默效果显著。此新型阳离子脂质体有望成为小干扰RNA等基因治疗药物的高效传递系统。

英文摘要：

OBJECTIVE To investigate the preparation of novel cationic liposomes encapsulating siRNA, and evaluate their si-lence efficiency on target mRNA in LNCap cells. METHODS Reverse evaporation technique was used to prepare the cationic lipo-somes. Protamine and calf thymus DNA were added to increase the encapsulation efficiency. The physicochemical property of the lipo-somes was evaluated. Human prostate cancer cells, LNCap, were used as the cell model. The silence efficiency on target gene in LN-Cap cells was evaluated with lipofectamine 2000 as the positive control. RESULTS The optimum liposomes were obtained when the ratio of DOTAP and cholesterol was 3：1 and the ratio of liposomes and siRNA was 300： 1. The size distribution and Zeta potential of the liposomes were （ 117 ± 4. 3 ） nm and （43 ± 3.6） mV, respectively. The liposomes significantly improved siRNA accumulation in cells. CONCLUSION The novel cationic liposome showed high transfection efficiency and distinct silence efficiency for target gene, which are expected to become a highly effective drug delivery system for anti-cancer drugs.