热物理在肿瘤治疗及纳米药物靶向输送方面的应用研究

Applied Research of Thermal Physics in Tumor Therapy and Nano Particles for Targeted Drug Delivery

目的 从在体动物模型和细胞水平上研究局部温热促进微纳米颗粒靶向输送并初探其机理。方法 利用无菌外科手术将鼠源乳腺癌 4T1组织块接种到裸鼠皮脊翼视窗 ,接种后第 4d ,7d ,8d ,10d分别观察肿瘤新生血管的生长情况。利用激光共聚焦荧光显微镜三维实时定性和定量研究微纳米脂质体在正常组织和肿瘤组织间质的渗透和扩散。将脐静脉内皮细胞 (HUVEC)接种至模拟肿瘤环境的ECM6 2 5胶上 ,形成类似血管的管状结构 ,研究温热作用对生长在肿瘤环境下的血管内皮细胞的影响。结果 肿瘤新生血管随着时间的变化生长逐渐加快 ,组织学研究表明肿瘤新生血管在肿瘤内生长受到抑制 ,在肿瘤边缘的肿瘤新生血管生长非常活跃。微纳米脂质体在正常组织中 ,在常温和 4 2℃ ,作用 1h基本不渗漏 ;在肿瘤组织中 ,4 2℃ ,加热 1h ,微纳米脂质体渗漏显著增加 ,与常温相比 ,相对荧光强度提高了 4倍左右。 4 2℃ ,加热 1h可促使生长在ECM6 2 5胶上的血管内皮细胞变圆 ,细胞之间连接松散 ,甚至断裂。结论 肿瘤新生血管内皮细胞对热敏感 ,局部温热作用促使了肿瘤环境下内皮细胞之间连接的破坏 ,进而促进了微纳米脂质体在肿瘤组织中的渗透。

Purpose: Study of hyperthermia in tumor therapy and nano particles for targeted drug delivery on animal model and cellular level, respectively. Method: Murine mammary carcinoma 4T1 was implanted in the nude mice dorsal skinfold window chamber. Rhodamine labeled liposome nanoparticles were injected into the mouse tail vein. The hyperthermic condition was imposed on the tumor through a thermal chamber. Tumor angiogenesis was observed through the window chamber on the 4,7,8,10th day after the tumor was implanted in the chamber. Laser confocal microscopy was used to study the real time 3D transport of nanoparticles in tumor and normal tissues under normal and hyperthermic conditions. Transport of the nanoparticles from the vasculature to the inters!tial space was quantified by measuring both spatial and temporal fluorescence intensity variations. HUVEC were cultured on ECM625 that was a solid gel of basement proteins prepared from mouse tumor, aligned and formed tube-like structures. The effect of hyperthermia on endothelial cells on ECM625 was studied. Results: Tumor vasculature grew rapidly with time. Histological examinations showed that the angiogenesis inside tumor were somewhat restrained, but very active in the tumor periphery. The liposome nanoparticles hardly extravasate into the interstitial of normal tissues under both normal and hyperthermic conditions. The extravasation of the nanoparticles in tumor tissues was greatly enhanced by increasing the local temperature to 42 °C. After heated, the cells became round, and cell junctions were damaged. Conclusions: Local hyperthermia significantly increased nanoparticles extravasation in tumor tissue. This could be partly attributed to the morphological change of endothelium which is more sensitive to heat in tumor angiogenesis.