Therapy Of Focal Cerebral Ischemia By SPIO-labeled Adipose-derived Stem Cells Via Intravenous Transplantation Under Magnet Field

Objective To label adipose-derived stem cells (ADSCs) withsuperparamagnetic iron oxide (SPIO) and to observe whether the magneticfield could improve the efficacy of ADSCs intravenous transplantation in thetre atment of acute cerebral ischemia in SD rats．Methods ADSCs of SD rats were isolated and cultured. CD29,CD45, CD54of ADSCs were detected by flow cytometric. ADSCs werelabeled with SPIO and labeling efficiency evaluated by Prussian bluestaining. The proliferation and viability of SPIO-labeled cells wereevaluated with CCK-8assay and trypan blue staining,respectively．SPIO-labeled cells were seeded into a culture dish that had aneodymium magnet below its center to assess their migration in vitro.Transwell culture system were used to test the migration effect of externalmagnetic field on SPIO-labeled cells. A SD rat model of middle cerebralartery occlusion (MCAO) was established. Rats were divided into threegroups: ischemia with injection of cells (IC).ischemia with injection of SPIO-labeled cells (ICS), and ischemia with injection of labeled cells and magnetexposure(ICSM). One and seven days after the transplantation the neurological severityscore (NSS) was used to evaluate neurological function recovery of rats. Thetransplanted ADSCs were analyzed by Prussian blue staining. The infarct volumes ofrats’ brain were analyzed by TTC staining. The iron contents of rats’ brain weredetermined by atomic absorption furnace spectrophotometry.Results CD45was not expressed and CD29and CD54wereexpressed in ADSCs. SPIO labeled ADSCs were close to100％．Theproliferation and viability of SPIO-labeled cells had no significantdifferences with or without magnet （P＞0.05).24hr after cells seeding, theSPIO-ADSCs migrated to the magnet area. The closer the distance betweencells and the magnet, the more cells are（P<0.01）.External magnetic fieldcan increase the numbers of cells crossing the membrane in the transwellculture system （P＜0.01），while without the magnetic field labeledcells and unlabeled cells had no significant difference in migration rate（P＞0.05）．Significant improvement in NSS was observed in ICSMgroup compared with other two groups seven days after the transplantation(P<0.05). Compared with ICS and IC group, ICSM group had more prussianblue-positive cells, smaller infarct volume and higher ironconcentration(P<0.01).Conclusions External magnetic field can induce SPIO-labeledADSCs to migrate to specific direction in vitro and in vivo and improve theefficacy of therapy in ischemic brain injury.