FITC-NGR-Gd对HepG2细胞的体外靶向性研究

A study on the targeting efficiency of FITC-NGR-GD to HepG2 cells in vitro

目的构建异硫氰酸荧光素-NGR小肽-钆(FITC-NGR-Gd)靶向对比剂,观察其体外对Hep G2细胞靶向性能。方法利用酰胺键作用化学合成FITC-NGR-Gd稳定连接体。细胞荧光实验设立Hep G2实验组及HT-29对照组,观察该对比剂对Hep G2细胞的体外靶向性。细胞MRI体外实验设立Hep G2实验组及HT-29对照组,改变钆剂浓度,通过测量T1值变化,进一步观察本对比剂体外对Hep G2细胞的靶向能力。结果 FITC-NGR-Gd有较高的T1弛豫率;免疫荧光显示Hep G2实验组细胞膜表面有较多靶向红色荧光CY3(花青染料),HT-29对照组细胞膜未见明显红色荧光物质;FITC-NGR-Gd细胞荧光实验显示Hep G2实验组细胞膜表面有较多靶向绿色荧光FITC,HT-29对照组细胞膜未见明确绿色荧光物质存在。体外细胞MRI实验Hep G2实验组T1值较HT-29对照组明显升高,P<0.05,差异有统计学意义,且实验各梯度组随钆剂浓度升高,T1值递增,强化明显。结论 FITC-NGR-Gd体外可以以Hep G2细胞为靶点,靶向荧光及MR成像。

Objective To construct FITC-NGR-Gd targeting contrast agent and to study its targeting efficiency to HepG2 cells in vitro. Methods The stable connectors in the FITC-NGR-Gd molecules were chemically synthesized using amide linkage. HepG2 experimental group and HT-29 control group were established for cell fluorescence assay to study the targeting efficiency of contrast agent to HepG2 in vitro. For cell in vitro MRI test, HepG2 experimental group and HT-29 control group were also established with various gadolinium concentrations. The targeting efficiency was evaluated by measuring the changes in T1 values. Results FITC-NGR-Gd has a high T1 relaxivity. Immunofluorescence assay showed that, HepG2 experimental group has more CY3 targeted red fluorescence on the surface of cell membrane and the HT-29 control group has no marked red fluorescent substance on the cell membrane; FITC-NGR-Gd cell fluorescence assay shows that HepG2 experimental group has more green FITC targeted fluorescence on the surface of cell membrane and HT-29 control group has no marked green fluorescent substance on the cell membrane. In vitro cell MRI test shows T1 signal intensity of HepG2 experimental group are significantly higher than that of HT-29 control group, P 〈 0.05. There is statistically significant difference between two groups. With the increasing concentrations of gadolinium, T1 signal intensity of experimental groups increase progressively. Conclusion FITC-NGR-Gd can take HepG2 cells as target in vitro and realize targeted fluorescence imaging and MRI imaging.