SD Rat Adipose Derived Stem Cells Labeled with Ultrasmall Superparamagnetic Iron Oxide

  Objective  To investigate the efficacy and safety of ultrasmall superparamagnetic iron oxide (USPIO) labeling adipose derived stem cells (ADSCs) of SD rats and explore the feasibility of tracing labeled cells with magnetic resonance imaging (MRI).

  Methods  ADSCs were incubated with culture medium containing USPIO and poly-L-lysine (PLL) for 24h. The efficacy and safety of labling with USPIO was assessed, and the labeled cells were imaged with MRI in vitro.

  Results  Prussian blue staining showed the percentage of labeled ADSCs reached 99% after coincubating for 24 h. Transmission electron microscopy showed iron particles inside the cells were mainly in lysosomes. Trypan-Blue stain showed the proportion of living cells was greater than 95%. MTS3-(4, 5-dimethylthiazol-2-yl)-5 (3-carboxymethoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium experiments suggested that USPIO at different concentrations (10, 20, 40, 80, 160μg/ml) exerted no significant influence on the proliferation of ADSCs. Enzyme-linked immunosorbent assay (ELISA) revealed VEGF level was not significantly different between labeled cells and unlabeled cells. The signal intensity of MRI was positively correlated with the amount of labeled cells in vitro.

  Conclusion  USPIO is safe and efficient in labeling ADSCs and the signal intensity of MRI is associated with the amount of labeled cells, indicating that USPIO can be used for tracing the labled cells under MRI in vitro.