| Purpose To develop a new nanobiosystem based on folate functionalized silica-coated gold nanorods and to investigate its cellular uptake and intra-organ biodistribution in vivo. In addition to investigate the therapeutic effect of the combination use of GNRs@Si O2-FA and 125 Iseeds on the apoptosis and the expression of associated protein bax、caspase-3 and Bcl-2 of rabbit VX2 hepatocarcinomaProcedures Ellipsoidal silica-coated gold nanorods(GNRs@SIO2) were prepared by seeded growth method using silicon dioxide(SIO2) as the shell material.Rhodamine-labeled GNRs@Si O2-FA were obtained by reacting the amino group located on GNRs@Si O2-FA with rhodamine isothiocyanate. The characteristics of the prepared GNRs@Si O2-FA were studied using transmission electron microscopy(TEM) and UV spectra. The 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyltetrazolium bromide(MTT)colorimetric method was used to assess the biocompatibility of GNRs@Si O2-FA. Rabbit liver VX-2 tumor model was established with CT guided puncture tumor tissue method,CT and ultrasound were performed to distinguish the hypovascular liver tumor.Two weeks later, twenty seven white rabbits were randomly divided into three groups,injecting saline, GNRs@Si O2-FA by portal vein and GNRs@Si O2-FA intratumoral respectively. After 24 h, 48 h, 72 h,three rabbits were sacrificed respectively. In vivo experiments of cellular uptake and study of the intra-organ biodistribution of GNRs@Si O2-FA were detected using intrinsic two-photon luminescence. As the same operation method, 24 Rabbit liver VX-2 tumor model was established. After two weeks,the rabbits were randomly and equally divided into 4 groups: blank control group(empty 125 I seeds),simple GNRs@Si O2-FA group, simple 125 I seeds group and combination group(GNRs@Si O2-FA plus 125 I seeds), The apoptosis of tumor cells was determinedby flow cytometry. The expression of bcl-2、bax、caspase-3 of tumor cells were tested by Western Blot.Results Analysis of UV spectra confirmed the successfu1 preparation of GNRs@Si O2-FA. Results of the MTT assay demonstrated that surface modification of GNRs@Si O2-FA resulted in excellent biocompatibility. We found that GNRs exhibit bright luminescence and could be visualized in vivo by direct imaging of these particles within the tissue. Additionally, GNRs@Si O2-FA could specifically bind to tumor cells and enter the cells via endocytosis, which could connect to cancer cells with high folic acid expression.GNRs@Si O2-FA entered tumor cells within 24 h and had a heterogeneous distribution with higher accumulation at the tumor cytoplasm. The flow cytometry examination showed that the apoptosis rate of tumor cells in the simple GNRs@Si O2-FA group and simple 125 I seeds group was higher than that in blank control group(P < 0.05), and the apoptosis rate of the combination group was significantly higher than that of the simple GNRs@Si O2-FA group and the simple 125 I seeds group(P < 0.05). Western blotting analysis showed the apoptosis-related protein of Bax and caspase-3 were significantly up-regulated, the expression of Bcl-2 was down-regulated(P < 0.05).Conclusion GNRs@Si O2-FA can bind to cells and were found to be internalized by targeted folate receptor-expressing cells via a ligand-receptor-mediated endocytosis pathway. The the combination use of GNRs@Si O2-FA and 125 I seeds may increase the expression of Bax, caspase-3 proteins and decrease the expression of Bcl-2 proteins;... |
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