SOX2 Transfection Of Astrocytes Promotes The Recovery Of Nerve Function After Spinal Cord Injury In Rats

ObjectiveHow to promote the recovery of nerve function after spinal cord injury(SCI)is a difficult point in research.Nerve regeneration is an ideal way to replenish lost cells and repair damage,but the adult spinal cord has a limited ability to produce new neurons.Cell reprogramming can solve the problem of replenishing neurons.Relevant literature found that transfection of neurogenic transcription factors in vivo and in vitro can promote the transformation of astrocytes into neural stem cells or neurons.In this experiment,with the help of a clamp-on rat SCI model,SOX2 was used to transfect astrocytes in rat spinal cord injury with lentivirus,and the transformation into neural stem cells and neurons was investigated.The use of valproic acid(Valproic acid,VPA)promotes its maturation into functional neurons and improves the movement of rat hind limbs.Methods1.60 clean male SD rats,weighing about 240g,were divided into sham operation group(Sham group,n=12),spinal cord injury group(SCI group,n=12),spinal cord injury+lentivirus group(S OX2-NC)Group,n=12),spinal cord injury+overexpression SOX2 lentivirus group(SOX2-OE group,n=12),spinal cord injury+overexpression SOX2 lentivirus+valproic acid group(SOX2-OE+VPA group,n=12).Construct a rat clamp-type SCI model.In the sham operation group,only the spinal canal was opened,and the T10 segment of the rat was clamped for 1 min with 70g aneurysm clamps in the other groups.Sham and SCI groups(inject 0.9%sodium chloride at the upper and lower ends of the injury),SOX2-NC group(inject lentivirus at the upper and lower ends of the injury),SOX2-OE and SOX2-OE+VPA groups(inject overexpressing SOX2 lentivirus at the upper and lower ends of the injury).The SOX2-OE+VPA group was given valproic acid intraperitoneally for 4 weeks,and the other groups were given the same amount of 0.9%sodium chloride.After Id,3d,7d,14d,21d,28d,BBB motor score and Rivlin test were used to evaluate the recovery of spinal cord movement.BrdU was injected into the abdominal cavity 1 week before sampling.2.4 weeks after injection of lentivirus,perfuse and collect materials,observe the shape of the injured segment spinal cord,liquefaction,adhesion to surrounding tissues,routine dehydration,embedding,HE staining to detect spinal cord shape,syringomyelia and demyelination;toluidine Observe the number and shape of Nissl bodies by blue staining.3.The expression of SOX2 and BrdU were detected by immunohistochemistry,and the number of proliferation of transfected astrocytes and neurons were observed respectively.4.WB detects the expression of SOX2 and DCX protein,and observes the transfection of astrocytes and neural stem cells.Results1.After modeling,the BBB score and Rivlin experiment of each group decreased,and the number of each component gradually increased with the development of time.The scores of the Sham group at each observation time point were higher than those of the other groups(P<0.05).The scores of the SOX2-OE and SOX2-OE+VPA groups were higher than those of the SCI group at 7 days and subsequent observation time points after modeling(P<0.05).2.The results of HE staining showed that the spinal cord structure in the Sham group was clear,the number of white matter nerve fibers was abundant,and there was no obvious demyelination;the number of gray matter neurons was abundant;the gray matter in the SCI group was unclear,demyelinated,and syringomyelia was obvious.Severe reduction of cells;SOX2-OE and SOX2-OE+VPA group gray matter scores are still clear,a small amount of demyelination,syringomyelia area is small,and neurons are moderately reduced.3.The results of toluidine blue showed that the positive areas of Nissl bodies in SOX2-OE and SOX2-OE+VPA groups were higher than those in SCI group(P<0.05).4.The results of immunohistochemistry and Western Blot blotting showed that the SOX2-OE and SOX2-OE+VPA groups were significantly more transfected with astrocytes,proliferating neurons,and DCX-positive neural stem cells than the SCI group.Conclusions1.SOX2 transcription factor can improve the behavioral scores of rats after SCI and improve the recovery of neuromotor.2.SOX2 transcription factor can reduce the formation of syringomyelia and the degree of demyelination,promote axon regeneration,and promote the repair of spinal nerve conduction pathways.3.The transfection of SOX2 transcription factor into astrocytes can promote the increase of neural stem cells and neurons,thereby promoting the recovery of rats’exercise.