Abstract:Objective To observe the effect ferritin reporter gene Fth1 labeling on biological characteristics and magnetic resonance imaging (MRI) findings of bone marrow mesenchymal stem cells (MSCs) in vitro. Methods Rat MSCs were isolated and cultured by plastic adherence method, and the lentiviral vectors carrying the ferritin heavy chain gene Fth1 were constructed to transfect the 4th passage MSCs transfected with Fth1, and the MSCs were cultured in the medium added with 1 mol/L ferric citrate. Prussian blue staining was used to evaluate the iron uptake ability of the transfected MSCs, trypan blue staining was used to evaluate cell viability, and CCK-8 assay was used to evaluate the proliferation activity of transfected MSCs. The MRI signal differences between transfected MSCs and normal MSCs were observed by MRI FSE T2WI and SWAN sequence. Results MSCs were successfully transfected with Fth1 gene, with the Prussian blue staining efficiency being 87%. For transfected MSCs without ferric citrate medium, the cell survival rate was (92.17±1.91)% and absorbance (D) value was 1.094±0.068, which were not significantly different from those of the normal MSCs ([94.23±2.42]% and 1.027±0.122, P>0.05). For transfected MSCs treated with ferric citrate medium for 3 days, the cell survival rate was (77.47±4.10)% and D value was 0.493±0.024, which were significantly different from those without ferric citrate treatment (P<0.05). The signal strength of MRI FSE T2WI and SWAN sequence for transfected MSCs treated with ferric citrate medium was 656.6±18.2, which was significantly different from without ferric citrate treatment and the normal MSCs (807.3±17.1 and 847.1±10.5, P<0.05); and difference between without ferric citrate treatment and the normal MSCs was not statistically significant (P>0.05). Conclusion MSCs can be successfully transfected with Fth1 reporter gene, and the transfected MSCs can efficiently overexpress and uptake iron. The cell viability and proliferation is not affected in ferric citrate free medium, but is affected when iron concentration is 1 mol/L. MRI can detect in vitro labeled MSCs after incubated in ferric citrate medium for 5 days, with FSE T2WI and SWAN sequences showing low signal intensity.
