SPIO-labeled Rat Bone Marrow Mesenchymal Stem Cells:Alterations Of Biological Activity And Labeling Efficiency Assay In Vitro

Objective:to study the different concentrations of SPIO labeled rat bone marrow mesenchymal stem cells on the effect of biological activity and MRI imaging in vitro, provide the experimental foundation for clinical application of SPIO.Methods:by whole bone marrow adherent method, cultured rMSCs. Next packaged SPIO(25μg/ml,50μg/ml,100μg/ml) with poly lysine (0.75μg/ml), and used it incubated with cells for24h,48h,72h. After incubation, by Prussian staining, determination of iron content, TEM, detected the labeling rate of SPIO; Used3.0T MRI (T1WI, T2WI, T2*WI) to scan cells of SPIO(25μg/ml,50μg/ml,100μg/ml) labeled, and by MRI automatic measurement system, measured signal strength for each image, by CCK-8, cell cycle, apoptosis and other experiments, detected cell viability; by cell differentiation experimental (adipogenic, osteogenic, chondrogenic, endothelial), detected the different concentrations of SPIO labeled rMSCs on the effect of differentiation activity.Results:Prussian blue staining positive rate (%)of25μg/ml group were70.1±9.4,75.5±8.6,76.3±7.9, and compared with50μg/ml group,100μg/ml group having no significant difference (p>0.05); cell iron content (pg/cell) of25μg/ml group were14.4±1.05,14.9±0.7,16.9±0.08, and compared with50μg/ml group,100μg/ml group having no significant difference (p>0.05); MRI signal strength of25μg/ml group,50μ g/ml group,100μg/ml group cell was reduced by an average of (65.6±7.9)%,(70.2±0.8)%,(72.7±10.3)%.Among them,25μg/ml,50μg/ml and100μg/ml group had no significant difference (P>0.05). Cell proliferation index of100μg/ml group were (%) were19.9±1.4,10.1±0.3,9.5±0.2, and compared with the control group, having statistical difference (p<0.05); the vWF immunohistochemical positive image gray value (Image Pro Plus America) of control group,25μg/ml group,50μg/ml group,100μg/ml group cells were54.7±5.5,53.9±7.9,51.1±3.4,35.6±8.7. Among them, only100μ g/ml group and the control group had significant difference (p<0.05).Conclusion:Use PLL-SPIO (0.75μg/ml;25μg/ml) to incubate with cells for24h can effectively label rat bone marrow mesenchymal stem cells. Clinical MRI (T1WI, T2WI, T2*WI) signal change obviously. Among them, the group of25μg/ml can obviously cause signal change,and the most sensitive sequence is T2*WI. But use100μg/ml SPIO to incubate cells for24h can affect biological activity and multiple differentiation capacity of cells.