在胃肿瘤治疗中5-氟尿嘧啶聚乳酸纳米颗粒和微囊体的靶向性和控释性的研究

摘要

The aim of this paper was to evaluate controlled release behavior and the therapeutic efficacy of 5-FU-loaded Poly(lactic acid) (PLA)microspheres to human gastric cancer xenograft, and the targeting effect of VEGF/5-FU loaded PLA nanoparticles. 5-FU-loaded PLA microspheres were prepared by an emulsion evaporation method, and were characterized by scanning electron microscopy (SEM). 5-FU loaded PLA nanoparticles were characterized by (TEM), and particle size analyzer determined the distribution of nanoparticles size. The release performances of 5-FU microspheres in vitro were studied in PH 7.4 phosphate buffered saline. The therapeutic efficacy of 5-FU-loaded PLA microspheres in vivo were studied using MGC-803 (human stomach cancer) xenograft. 32 nude mice were divided into four groups (n =8), 5-FU loaded PLA microspheres were injected at tumor site. VEGF121monoclonal antibody was connected with 5-FU loaded PLA nanoparticles through carbodimide. The targeted effect of VEGF 5-FU loaded nanoparticles in vivo were observed by single photon emission computed tomography (SPECT)after tail vein injection at 1 h and 2 h. SEM observation showed that microspheres were spherical, and the diameters of two kinds of microspheres were 1 μm and 5 μm respectively. The mcan diameter of nanoparticles was 191.0 nm,and the index of polydispersity was 0.202. The drug was released following biphasic kinetics, initial burst and the following steady phase. 1 μm and 5 μm 5-FU-loaded microspheres both resulted in increased life span (1 μm microspheres median survival time=40.63 days, 5 μm microspheres median survival time=62.25 days), against 5-FU pure drug (median survival time=14.5 days). These results strongly suggest that 5-FU-loaded PLA microspheres increase life span of nude mice bearing MGC-803 tumors. After injection for 2 h, almost all the VEGF/5-FU loaded PLA nanoparticles could centralize at the human gastric cancer xenograft sites. That demonstrated VEGF monoclonal antibody remain its bioactivity after connection with nanoparticles, VEGF/5-FU loaded PLA nanoparticles had very exact targeting function for gastric tumor xenograft.