丙戊酸对大鼠脊髓损伤后内源性神经干细胞的影响

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

目的:探讨丙戊酸(valproicacid,VPA)对大鼠脊髓损伤后内源性神经干细胞的影响。方法:45只Wister成年大鼠,随机分为正常对照组(A组,n=5)、单纯损伤组(B组,n=20)、损伤后VPA治疗组(C组,n=20)。B组和C组采用Allen′s打击模型(25gcm),在T10段造成急性脊髓损伤,C组损伤后半小时给予VPA治疗,每日300mg/kg,经腹腔分两次注射,直至取材;B组以相同方法给予等量生理盐水。于损伤后1d、3d、1周、4周、8周进行取材,对距离损伤中心5mm处脊髓进行巢蛋白Nestin免疫组化检测,应用图像分析软件进行Nestin阳性区域面积测算。结果:A组脊髓室管膜细胞中极少数细胞胞浆内有Nestin表达,白质中几乎无表达。B组损伤后24hNestin表达于室管膜以及软膜,1周达到高峰(P<0.05),并相向延伸至脊髓白质和灰质;损伤后4周Nestin表达明显下降,8周时很少或几乎无表达。C组Nestin表达在伤后24h与B组无显著性差异,1周时在中央管周围Nestin阳性细胞明显较B组多(P<0.05),持续至4周时仍高表达,8周时仍有表达。结论:VPA在大鼠脊髓损伤后能够激活内源性神经干细胞。

Objective：To investigate the effect of valproic acid （VPA） on neural stem cells/neural progenitor cells after spinal cord injury （SC1） 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 SCl,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 5ram 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.ln group B,Nestin expression was observed in ependymal cells and pia matter at 24h postinjury,which reached peak at I week after injury （P〈0.05）.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（P〈0.05）,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.