科研之友
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摘要
Objective: To investigate the feasibility of superparamagnetic iron oxide (SPIO) nanoparticles ( SPIO) as a magnetic resonance (MR) contrast agent to enhance tumor imaging in vivo. @@@ Methods: Hydrophobic SPIO (oil-soluble SPIO; OSPIO) and hydrophilic SPIO (water-soluble SPIO; WSPIO) were loaded in methoxy-poly( ethylene glycol)-block-poly(D, L-lactic acid) (PEG-PDLLA) nanovesicles. Three groups of nude mice (n=12/group) xenografted with human colorectal carcinoma (LoVo) cells were injected into the caudal vein with WSPIO, OSPIO-loaded nanovesicles, or WSPIO-loaded nanovesicles. MRI scans were performed on all of the mice, and the relative T-2 values were measured in the tumor and the liver. The differences in these T-2 values between the three groups were compared. @@@ Results: The peak relative T-2 values in the tumors detected by the OSPIO- or WSPIO-loaded contrast agents were reduced by 10.12% and 11.40%, respectively. The relative T-2 values in the WSPIO- and OSPIO- loaded polymeric nanovesicle groups were more pronounced than the relative T-2 value in the WSPIO group (P<0.05), but there was no significant difference in the T-2 value between the OSPIO- and WSPIO- loaded vesicle groups (P > 0.05). The greatest T-2 value decreases in the liver in the WSPIO, OSPIO- loaded and WSPIO- loaded vesicle groups were 32.85%, 52.77% and 56.89%, respectively. The decrease in the T-2 values was more pronounced in the WSPIO- and OSPIO- loaded nanovesicle groups than in the WSPIO group (P<0.05) and was more apparent in the WSPIO- loaded nanovesicle group than in the OSPIO- loaded nanovesicle group ( P<0.05). @@@ Conclusion: SPIO-loaded polymeric nanovesicles generate significant T2WI signal intensity decreases in vivo and are anticipated to be used as novel and effective contrast agents for tumor imaging.
