In vivo MR imaging of nanometer magnetically labeled bone marrow stromal cells transplanted via portal vein in rat liver

Objective To evaluate in vivo magnetic resonance imaging with a conventional 1.5-T system for tracking og intra-portal vein transplantation nanometer magnetically labeled BMSCs in rat liver. Methods BMSCs were isolated from 5 SD rats bone marrow with the density gradient centrifugation method. Then BMSCs were labeled with nanometer superpara-magnetic iron oxide and transfection agent. Cell labeling efficiency was assessed with determination of the percentage of Perls Prussian blue stain. Then BMSCs transplanted into normal rats′ livers via portal vein. The receipts were divided into 5 groups ,including sham control、2 h 、3 d、7 d and 2 w after transplantation. Follow-up serial T_1WI、T_2WI and T_2*-weighted gradient-echo MR imaging were performed at 1.5 T MRI system. MR imaging findings were compared with histology. Results Cell labeling efficiency was more than 95% by Perls Prussian blue stain. After transplantation of labeled BMSCs via portal vein, livers had diffuse granular signal intensity appearance in T_2*WI MRI. Cells were detected for up to 2 w in receipts′ livers. At histologic analysis, signal intensity loss correlated with iron-loaded cells. Conclusion MR imaging could aid in monitoring of magnetically labeled BMSCs administered via portal vein in vivo.