MRI tracking of bone marrow mesenchymal stem cells labeled with ultra-small superparamagnetic iron oxide nanoparticles in a rat model of temporal lobe epilepsy

Transplantation of bone marrow mesenchymal stem cells (BMSCs) is a promising approach for treatment of epilepsy. To our knowledge, there is little research on magnetic resonance imaging (MRI) tracking of BMSCs labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles in a rat model of temporal lobe epilepsy (TLE). In this study, BMSCs were pre-labeled with USPIO nanoparticles, and then the cell apoptosis, proliferation, surface antigens, and multipotency were investigated. Lithium chloride-pilocarpine induced TLE models were administered by USPIO-labeled BMSCs (U-BMSCs), BMSCs, and saline through lateral ventricle injection as the experimental group, control I group and control II group, respectively, followed by MRI examination, electroencephalography (EEG) and Prussian blue staining. The cell experimental results showed that the labeled USPIO did not affect the biological characteristics and multiple potential of BMSCs. The U-BMSCs can be detected using MRI in vitro and in vivo, and observed in the hippocampus and adjacent parahippocampal cortical areas of the epileptic model. Moreover, electroencephalographic results showed that transplanted U-BMSCs, as well as BMSCs, were capable of reducing the number of epileptiform waves significantly (P< 0.01) compared with control II group. All of these findings suggest that it is feasible to track transplanted BMSCs using MRI in a rat model of TLE, and support that USPIO labeling is a valuable tool for cell tracking in the study of seizure disorders.