具有线粒体靶向性的雷公藤甲素TPP-PEG-PCL脂质体的制备及其促肝肿瘤细胞凋亡研究

目的 成功制备雷公藤甲素（3-丙羧基）三苯基溴化膦（TPP）-聚乙二醇-b-聚己内脂（PEG-PCL）脂质体（Tr@TPP/Lip），评价其靶向性及促肝肿瘤细胞凋亡效果。方法 采用正交试验优选Tr@TPP/Lip的制备工艺，再研究该载药系统的粒径、Zeta电位、载药量、包封率和多分散系数及透射电镜微观形态，评价Tr@TPP/Lip的稳定性、溶血性、释放情况；采用荧光试验，研究脂质体与肝肿瘤细胞的融合情况、线粒体靶向性和肝脏靶向性；在等剂量给药条件下，评价Tr@TPP/Lip促肝癌细胞凋亡效果。结果 正交试验优选的Tr@TPP/Lip粒径为（113.5±17.6）nm，Zeta电位（12.6±0.7）mV，包封率为（71.3±3.2）%，载药量为（3.9±1.1）%，多分散系数为0.12±0.04；透射电子显微镜图片显示Tr@TPP/Lip呈规则圆球形，该脂质体稳定性良好，具有较小的溶血率和良好的缓释药物性能；荧光试验结果显示，TPP阳离子能促进脂质体与肿瘤细胞的融合，并靶向线粒体，还能提高药物在肝肿瘤部位的靶向和滞留效果；细胞药效结果显示，Tr@TPP/Lip具有良好的促肝肿瘤细胞凋亡效果，能明显降低线粒体膜Zeta电位、增加细胞内活性氧水平和Caspase-3的释放，显著增加促凋亡蛋白Bcl-2、减少抗凋亡Bax蛋白的表达，这些细胞凋亡试验结果均明显优于雷公藤甲素普通脂质体和雷公藤甲素。结论 Tr@TPP/Lip具有较好的线粒体靶向功能，能增强药物促肝肿瘤细胞凋亡效果。

Preparation of triptolide TPP-PEG-PCL liposomes with mitochondrial targeting and its promotion apoptosis of hepatic tumor cells

Objective To prepare triptolide TPP-PEG-PCL liposomes and evaluate its mitochondrial targeting and hepatic tumor cell apoptosis promoting effect. Methods Orthogonal test was used to optimize the preparation process of triptolide TPP-PEG-PCL liposomes, and the particle size, Zeta potential, drug loading capacity, encapsulation rate, polydispersion coefficient and transmission electron microscope morphology of the drug delivery system were studied. The stability, hemolysis and release of triptolide TPP-PEG-PCL liposomes were evaluated. Fluorescence test was used to study the fusion of liver tumor cells and liposomes, mitochondrial targeting and in vivo liver targeting. Under the conditions of equal dose administration, the effect of triptolide TPP-PEG-PCL liposomes on promoting apoptosis of liver cancer cells was evaluated. Results The particle size of triptolide TPP-PEG-PCL liposomes was (113.5 ±17.6) nm, Zeta potential was (12.6 ±0.7) mV, encapsulation rate was (71.3 ±3.2)%, drug loading was (3.9 ±1.1)% and polydispersity index was 0.12 ±0.04. Transmission electron microscopy pictures showed that triptolide TPP-PEG-PCL liposomes were in regular round spheres. The liposomes had good stability, low hemolysis rate and good sustained-release drug properties; Fluorescence test results showed that TPP cations could promote the fusion of liposomes and tumor cells, and target mitochondria, and could also improve the targeting and retention of drugs in liver tumors. The cell efficacy results showed that triptolide TPP-PEG-PCL liposomes had a good effect on promoting liver tumor cell apoptosis, and significantly reduced the mitochondrial membrane potential, increased the level of intracellular ROS and the release of Caspase-3 significantly, increased the expression of pro-apoptotic protein Bcl-2 and decreased the expression of anti-apoptotic Bax protein. The results of these apoptosis tests were significantly better than that of triptolide liposomes and triptolide. Conclusion Triptolide TPP-PEG-PCL liposomes had a good mitochondrial targeting function and can enhance the effect of drugs on promoting liver tumor cell apoptosis.