| Objective: Glial scar formed at the injured site after spinal cord injury(SCI)is an important physical and biochemical barrier to hinder axon regeneration and delay functional recovery.Ski is a multifunctional transcriptional co-regulatory factor,which is widely involved in a variety of physiological and pathological processes.Previous studies of our group found that Ski was significantly up-regulated in spinal cord injury in vivo and astrocytes activated in vitro,indicating that Ski may be a new molecule regulating astrocyte activation after spinal cord injury.Further studies found that intervention of Ski expression through knockdown and overexpression can significantly affect the proliferation and migration of activated astrocytes.The purpose of this study was to investigate the effects of knockdown of Ski expression on glial scar formation,axonal regeneration and motor function recovery after spinal cord injury in rats.Methods: Normal adult female Sprague Dawley(SD)rats,SPF grade,weighed200 ±20g.The rat model of thoracic 10 spinal cord injury was established by Allen’s hitting method.The sham operation group(Sham group)only bit open the lamina without hitting.During the operation,lentivirus LV-Ski and LV-e GFP solution were injected into the head and caudal side of the injured spinal cord by microsyringe in the Knockdown group(KD group)and the blank control group(NC group).The control group(C group)and sham operation group(group Sham)were injected with the same volume of normal saline.The motor function was evaluated by BBB score and inclined plate test at 1 day before spinal cord injury and 1d,3d,5d,1w,2w,3w,4w,5w,6w,7w and 8w after spinal cord injury.After 1w,2w,3w,4w,5w,6w,7w and 8w,the samples of each group were taken,and the expression of Ski,the marker molecule of glial scar glial fibrillary acidic protein(Gfap)and Vimentin,the key molecule of axonal regeneration neurofilament-200(Nf-200)and synaptic formation molecule Synaptophysin were detected by Western Bolt and q RT-PCR.At the same time,immunofluorescence technique was used to observe the axonal regeneration and synaptic formation in each group 8 weeks after spinal cord injury.Results: Compared with the sham operation group,the expression of Ski in the spinal cord injury group increased significantly.Knockdown of Ski expression after spinal cord injury can significantly inhibit the expression of glial scar marker molecules Gfap and Vimentin,and increase the expression of Nf-200 and Synaptophysin,the key molecules of axonal regeneration and synapse formation.In addition,knockdown Ski also promoted the recovery of motor function after spinal cord injury.Conclusion: To sum up,these results demonstrate that Ski is an important regulatory factor in regulating glial scar formation at the injury site and promoting axon regeneration and synaptic formation after spinal cord injury,and it is also a potential target for targeted therapy after spinal cord injury. |
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