Tumor angiogenesis targeting nano-probe differentiate inflammation and malignant on an animal model by Magnetic Resonance dynamic Imaging

1217 Objectives The purpose of this study is to distinguish inflammation and malignant by dynamic MRI imaging of c(RGDfK) peptide conjuncted BaGdF5 core nanoparticles. Methods Acute inflammation animal models(n=4) were established by 0.2 ml of turpentine oil injection in the muscle of left limbs, 24 hours before imaging studies. VX2 tumors bearing rabbits(n=4) were established by VX2 tumor fragments transplantation in the muscle of right limbs of the same rabbits, 2 weeks before imaging studies. Two kinds of nanoparticles, BaGdF5-PEG core and BaGdF5-PEG-c(RGDfK) prober were synthesized for imaging experiments. The longitudinal relaxation time T1 and T1 color mapping were performed by a 3.0 T MRI instrument. The relaxivity r1 of the gadopentetate dimeglumine(control group) and BaGdF5-PEG and BaGdF5-PEG-c(RGDfK) (the experimental group) were calculated. Dynamic enhancement MR imaging scan just after nanoparticles injection. The T1 value of VX2 tumors and inflammation lesions were measured ,The MR dynamic curves was drew according to the T1 value in LAVA protocol. The rabbit were sacrificed for histology observation in 1 day and 1 week after the injection. Results The diameter of the particles are 10-20nanometer. In vivo imaging visualized the longitudinal relaxivity (r1) was determined to be 3.27 s_1 (mM). BaGdF5-PEG has longer half life in blood. Both inflammatory and tumor showed increased T1 value . The effects of contrast in tumor were significantly higher than it in inflammation. The T1 value change over the time. The peak time of T1 value of the c(RGDfK) peptide modified nanoprobe in tumor was 1.2 h and that of BaGdF5 core nanoparticels was 1.5h. Conclusions BaGdF5-PEG-c(RGDfK) nanoprobe is expected to be a promising tumor angiogenesis targeting MRI enhancement agent. The dynamic MR imaging of tumor angiogenesis targeting nano-probe might be differentiate inflammation and malignant.