超声辐照促纳米多聚体释放DNA的体内研究

Ultrasound enhances PLGA nanoparticle-mediated gene delivery in vivo

目的通过研究不同超声参数与绿色荧光蛋白表达之间的关系，探讨超声辐照促进绿色荧光蛋白基因（GFP）与雄激素受体抗体标记的PLGA纳米颗粒（NP—PLGA—GFP—AR）的体内降解与释放的作用。方法建立人前列腺癌PC-3细胞裸鼠动物模型，将NP—PLGA—GFP—AR纳米粒注射于瘤内2h后，对癌瘤使用不同强度和类型的超声进行局部辐照，通过激光共聚焦荧光显微镜观察GFP表达，从而评价转染效果。结果粒径优选后的纳米粒能稳定转染GFP与雄激素受体抗体标记的DNA质粒，超声辐照组较非辐照组的GFP表达提前，占空比为50％的连续波超声较脉冲波超声对前列腺癌的转染效果好。结论优化后的超声辐照可有效靶向增强体内DNA转染，局部超声辐照结合特异PLGA纳米粒能有效用于DNA靶向递送。

Objective To investigate the feasibility and the efficacy of ultrasound in promoting PLGA nanoparticle-mediated gene transfection in vivo. Methods Prostate cancer cell line _Pt2-3 was used to generate xenografts in nude mice for gene transfection experiment in vivo. GFP plasmid was encapsulated in PLGA-based nanoparticles. Nanoparticles were injected into tumors locally. Two hours later, xenografts were exposed to ultrasound. Xenograft tissues were harvested in different time points to assess the efficiency of gene expression with regard to different parameters of ultrasound. Results PLGA nanoparticle- encapsulated GFP plasmids were readily transfected to PC-3 cells in vivo. A large number of GFP expressing cells were observed after exposed to ultrasound with 1.0 MHz 50% duty factor continuous wave. In comparison,ultrasound exposure with 400% duty factor pulse wave in vivo had low efficacy in terms of GFP expression. No animal death was noticed due to ultrasound exposure. Conclusions Ultrasound exposure can enhance the release of plasmid DNA content delivered by PLGA nanoparticles in vivo, local exposure to ultrasound wave would be used in conjunction with PLGA nanoparticle-mediated targeted delivery to the tissue or organ of interest.