Effects of valproic acid on endogenous neural stem/progenitor cells after spinal cord injury in rats

Objective:To investigate the effect of valproic acid (VPA) on neural stem cells/neural progenitor cells after spinal cord injury(SCI) in rats.Method:45 female Wister rats were randomly divided into three groups:the control group(group A,n=5);spinal cord injury at T10 level by Allen′s method(group B,n=20) and vipral acid treatment group after spinal cord injury(group C,n=20).The rats in goup C were injected with VPA 300mg/kg/d after SCI,while the animals in group B received equivalent amount of 0.9% normal saline likewise.The rats were killed at 1d,3d,1,4 and 8 weeks after injury,and two levels of the spinal cord with the length of 5mm harvested both rostral and caudal region to the injury center were the samples were analyzed by Nestin immunoreactivity.Result:There was little Nestin expression in ependymal cells and seldom observed in white matter in group A.In group B,Nestin expression was observed in ependymal cells and pia matter at 24h postinjury,which reached peak at 1 week after injury(P0.05).Moreover,Nestin expression was also observed in the white matter of ventral spinal cord,extending into arborizing processes centripetally from the pial surface toward the central canal.It decreased in ependyma at 4 weeks after injury.In group C,Nestin expression was no differrent at 24h with group B,but it was observed more than group B at 1w(P0.05),and it reached peak at 4 weeks.Until 8 weeks postinjury,Nestin expression was still observed.Conclusion:VPA can activate endogenous neural stem/progenitor cells after SCI in rat.