Neurogenesis Of Transplanted Neural Stem Cells Induced By Oscillating Electric Field Promotes Nerve Repair After Spinal Cord Injury

Object: Spinal cord injury(SCI)refers to the temporary or permanent loss of spinal cord function caused by nerve injury.The primary trauma of the spinal cord will drive serious and lasting inflammatory reaction in the tissue.The degree of necrosis and apoptosis of neurons and glial cells far exceeds the impact of the initial impact.Microglia and astrocytes are the key regulators of inflammatory reaction in the central nervous system and play an important role in the prognosis of SCI.The purpose of this study was to investigate the regulatory effect of oscillating field stimulation(OFS)on local reactive astrocytes and microglia of injured spinal cord and its effect on the recovery of neural function in rats with SCI.Methods: The oscillating electric field device was implanted into the back(T9-T10)of SCI rats,and the injured tissue was treated with OFS continuously.After surgery,anesthetized rats were perfused and collected spinal cord tissue centered on the injured site,and then dehydrated,and sectioning after paraffin embedding.Immunofluorescence method was used to detect the effect of OFS on the proliferation of reactive astrocytes and microglia in the injured area.Nissl staining was used to observe the survival of local neurons.HE staining was used to detect the cavity formation after SCI and the recruitment of inflammatory cells to the lesion site.In addition,BBB scores was used to evaluate the lower limb motor function of rats after SCI.Results: In the local area of SCI,OFS treatment can obviously inhibit the proliferation of reactive astrocytes and microglia.The number of fluorescent positive cells at the injury site decreased significantly after the action of OFS.At the same time,the number of Nissl bodies of neurons at the lesion site increased significantly,indicating that OFS can alleviate the injury of neurons.HE staining showed that OFS can reduce the formation of cavities,improve the integrity of injured local tissues,and reduce the number of inflammatory cells at the lesion site to a certain extent.In addition,OFS can significantly improve the BBB motor function score after SCI in rats.Conclusion: OFS can effectively reduce the inflammatory reaction in the lesion site and promote the recovery of neural function after SCI in rats.Object: Transplantation of neural stem cells(NSCs)has been widely used to study the treatment of central nervous system diseases and is considered as a potential treatment for spinal cord injury,which can play a beneficial role through mechanisms such as neurogenesis and replacement of lost neurons.In order to improve the therapeutic potential of NSCs,it is important to induce their neurogenesis in the process of repair.The purpose of this study was to investigate the regulatory effect of oscillating field stimulation(OFS)on the mi R-124/Tal1 axis signal pathway in NSCs and its effect on the neurogenesis of NSCs.Methods: Fetal rat brain-derived NSCs were extracted,purified and cultured.Take NSCs with good growth status cultured to the third generation,add differentiation promoting medium and transfer them into sterile stainless steel culture dish,apply oscillating electric field device to NSCs,and take samples after continuous stimulation for one week.Quantitative Real-time PCR(RT-q PCR)was used to detect the effect of OFS on mi R-124/Tal1 axis signal expression.Western Blot(WB),RT-q PCR and immunofluorescence were used to detect the effect of OFS on neurogenesis of NSCs.In addition,through lentivirus transfection to knock down the expression of Tal1 in NSCs,we explored the role of mi R-124/Tal1 axis in the process of NSCs neurogenesis promoted by OFS.Results: After the action of OFS,immunofluorescence staining showed that the number of neurons differentiated by NSCs was significantly increased,and the number of cell body branches of neurons was more.The results of WB and RT-q PCR also showed that the expression of neuron specific marker β-Tubulin III increased significantly under the action of OFS,indicating that OFS can effectively promote the neurogenesis of NSCs cultured in vitro.RT-q PCR showed that OFS could significantly down-regulate the expression of mi R-124 in NSCs,while the expression of Tal1 increased significantly.After the lentivirus knocks down Tal1,WB and RT-q PCR results showed that the expression of neuron specific marker β-Tubulin III was significantly reduced,and the effect of OFS on the neurogenesis of NSCs was significantly weakened,indicating that mi R-124/Tal1 axis plays a key role in the process of OFS promoting the neurogenesis of NSCs.Conclusion: OFS can effectively promote the neurogenesis of NSCs in vitro by regulating the mi R-124/Tal1 axis.Object: The injury and loss of neurons is the main cause of disability and death in patients with spinal cord injury(SCI).Up to now,there is no exact and effective clinical method to enhance nerve regeneration and functional recovery after injury.Neural stem cells(NSCs)are potential therapeutic cells for SCI.Transplantation of NSCs is an ideal therapeutic strategy.However,due to the complexity of the local microenvironment of the injury,its fate at the injury site after transplantation is still unpredictable.The purpose of this study was to explore whether oscillating field stimulation(OFS)could induce the neurogenesis of transplanted NSCs at the injured site,thus promoting the nerve repair after SCI.Methods: The rat model of T9-T10 segment SCI was constructed.NSCs were transplanted at the injury site immediately after surgery,and the OFS device was implanted.The OFS was continuously applied to treat the injured tissue.After surgery,anesthetized rats were perfused and collected spinal cord tissue centered on the injured site,and paraffin embedded and sectioned after dehydration.The survival of NSCs after transplantation and the effect of OFS on their neurogenesis were detected by immunofluorescence method,and the axon regeneration at the injured site was also observed.Hematoxylin eosin(HE)staining was used to detect the cavity formation after SCI.In addition,BBB score was used to evaluate the recovery of motor function of both lower limbs of rats.Results: Immunofluorescence staining showed that under the action of OFS,the number of transplanted NSCs derived neurons at the injured site increased significantly,and the overall number of neurons also increased significantly,indicating that OFS can effectively promote the neurogenesis of transplanted NSCs and promote nerve regeneration.At the same time,mature axons can be observed at the tissue injury site after combined treatment,indicating that OFS and NSCs transplantation can effectively promote axon regeneration at the injury site.HE staining showed that the area of cavity formation at the site of SCI was significantly reduced after the combination of OFS and NSCs transplantation,indicating that the combination of OFS and NSCs transplantation can effectively promote the repair of injured spinal cord tissue.In addition,this combined treatment can significantly improve the BBB motor function score after SCI in rats.Conclusion: OFS can promote the neurogenesis of transplanted NSCs and improve the neural repair after SCI.