The Study Of SPIONs-(miR-26a)-OECs Promoting The Repair Of Spinal Cord Injury Via The Effect Of Magnetic Mechanical Force

Spinal cord injury(SCI)is a difficult problem in clinical practice,which often leads to lifelong disability of patients and imposes a heavy burden on individuals,families and society.Therefore,the research on spinal cord injury repair is urgent.Previous studies have found that cell transplantation is a promising method to treat spinal cord injury.Olfactory ensheathing cells(OECs)are glial cells that exist widely in olfactory nervous system.However,OECs were transplanted into spinal cord injury,which resulted in decreased migration ability and decreased activity of promoting nerve repair.The formation of local scar further limits the application of OECs in central nerve injury.Nevertheless,OECs are still one of the most attractive seed cells for repairing central nerve injury due to their excellent properties of promoting nerve repair and non-tumorigenicity.In this study,superparamagnetic nanoparticles(SPIONs)loaded with mi R-26 a were used to transfect OECs to improve the intrinsic ability of promoting nerve repair.At the same time,relying on the excellent magnetization characteristics of SPIONs,the magnetic mechanical force is generated to guide the directional migration of transplanted OECs with the assistance of external magnetic field,so as to improve their migration ability,break through the physical barrier formed by local glial scar of spinal cord injury,and construct a favorable neural regeneration microenvironment.We found that high expression of mi R-26 a in OECs after transfection could inhibit the expression of PTEN in neurons,further inhibit GSK3-β,and increase the expression of Smad1,then promote the growth of axons.In addition,we also found that SPIONs-mi R-26a-OECs can inhibit the activation of astrocytes,reduce the expression of GFAP in host astrocytes,and enhance their directional migration ability along magnetic mechanical force under the action of external magnetic field,which can break through the glial scar formed by astrocytes.It further significantly improved the nerve repair efficiency of OECs transplantation after spinal cord injury.In this study,both in vivo and in vitro conditions were studied,and experimental results were obtained,which explored a new approach to improve the efficiency of cell transplantation to promote nerve repair after spinal cord injury.