Effect of External Magnetic Field on the Efficacy of ADSC Transplantation in Rats with Spinal Cord Injury

To assess the effect of intravenously injected superparamagnetic iron oxide nanoparticle (SPION)-labeled adipose-derived stem cells (ADSCs) under an external magnetic field on the efficacy of ADSC transplantation in rats with spinal cord injury (SCI).

ADSCs were isolated from rats, labeled with SPIONs, and divided into magnetic and non-magnetic groups. A rat model of SCI was established, and SCI rats were randomly divided into magnetic, non-magnetic, and control groups, with ten rats in each group. Rats in the magnetic and non-magnetic groups were injected with SPION-labeled ADSCs via the tail vein. A 300-mT neodymium iron boron magnet was placed externally at the SCI site of the rats in the magnetic group. One and two weeks after successful modeling, SCI rats were scored for the degree of SCI followed by histopathology of the spinal cord, number of ADSCs at the SCI site, and growth-associated protein-43 (GAP-43) expression were determined in the spinal cord tissues.

One and two weeks after modeling, the Basso-beattie bresnahan (BBB) scores were the highest in the magnetic group, followed by the non-magnetic group, and the lowest in the control group. HE staining showed that the histopathological manifestations of the spinal cord in the magnetic group were somewhat improved compared to those in the non-magnetic and control groups. Two weeks after modeling, Prussian blue staining revealed that the number of ADSCs was significantly higher in the spinal cord tissue of the magnetic group than in that of the non-magnetic group. One and two weeks after modeling, western blotting revealed that the magnetic group exhibited the highest GAP-43 expression.

An external magnetic field applied at the SCI site in rats exerted a directional effect on SPION-labeled ADSCs, directing their migration and improving the efficacy of stem cell-targeted therapies for SCI.