经皮电刺激对脊髓损伤后GFAP和NT-3表达的影响

The impact of percutaneous electrical stimulation on the expressions of GFAP and NT-3 after spinal cord injury in rats

目的研究经皮电刺激对脊髓损伤后胶质纤维酸性蛋白(GFAP)和神经营养因子-3(NT-3)表达的影响,探讨经皮电刺激对治疗脊髓损伤的意义。方法 60只SD大鼠随机分为3组(每组20只):电刺激组、损伤对照组及正常对照组。电刺激组及损伤对照组采用Allen's打击致伤方法建立大鼠脊髓损伤模型,建模后损伤对照组只予常规护理,电刺激组给予电刺激治疗:取夹脊穴和足三里穴进行经皮电刺激,每次30min,每天1次。正常对照组不予任何处理。电刺激组及损伤对照组按时间段(第1、3、5、7天)进行灌注取材。标本脱水石蜡包埋,制作石蜡切片,进行免疫组化染色,然后采用Olympus数码照像机采集图像进行图像分析,观察与分析GFAP与NT-3的表达。运动功能评分采用BBB评分法。结果从脊髓损伤后3d开始大鼠后肢功能的恢复电刺激组明显优于损伤对照组(P<0.05)。电刺激组与损伤对照组脊髓组织内GFAP的表达与正常对照组相比前3d无明显变化(P>0.05),此后逐渐增加,脊髓损伤后5d达到高峰,7d已低于5d(P<0.05)。5d和7dGFAP的表达电刺激组明显低于损伤对照组(P均<0.05)。大鼠NT-3免疫阳性细胞数在电刺激组和损伤对照组均随着时间的延长持续增加,分别于7d和5d时达到峰值,但电刺激组大鼠NT-3阳性细胞数在5d和7d均比损伤对照组增加显著(P均<0.05)。结论经皮电刺激可以抑制脊髓损伤后大鼠GFAP的表达,促进NT-3的表达,抑制星形胶质细胞的增殖,可能对大鼠脊髓损伤后神经元的修复、重建及相关功能的恢复有促进作用。

Objective To observe the influence of percutaneous electrical stimulation on the expressions of glial fibrillary acidic protein （GFAP） and neurotrophic factor-3 （NT-3） after spinal cord injury and explore the value of percutaneous electrical stimulation for treating spinal cord injury.Method Sixty SD rats were randomly divided into three groups （n=20, each）： injury control group （group A）, electrical stimulation therapy group （group B） and normal control group （group C）. The model of spinal cord injury was established by Allen＇s pounding traumatogenic method in groups A and B; after establishing model, routine nursing was given alone in group A , and percutaneous electrical stimulation was added in group B. No special treatment was given in group C. In group B, percutaneous electrical stimulation on jiaji acupoint and zusanli acupoint was given for 30 minutes every day after establishing model. Perfusion sampling in different time points （1-,3-,5-,7-day） was made in A and B groups, and then dehydration and paraffin embedding were conducted to make paraffin sections. The immunohistochemistry assay and Olympus digital camera images were used to observe and analyze the expressions of GFAP and NT-3. Motor function score was used by BBB （Basso, Beattie Bresnahan locomotorrating scale） method.Result The functional recovery of rats, hind limb from the 5th day in group B was better than that in group A （all P0.05）. The GFAP expression levels in the first three days remained unchanged in group A and B compared with group C （all P0.05）, then gradually increased and peaked at 5th day which were significantly higher than that in 7th day （P0.05）. The GFAP expression levels at 5-and 7-day in groups A were all higher than those in group B （all P0.05）. Along with the prolongation of time, NT-3 immunoreactive cells in group A and B constantly increased and peaked on 5th day, and then declined. Compared with group A, NT-3 positive cell numbers on the 5-and 7-day in group B significantly increased （all P0.05）. Conclution Percutaneous electrical stimulation therapy can inhibit the expression of GFAP and promote the expression of NT-3, therefore, inhibit the astrocytosis and promote renovation and reconstruction of neurons and recovery of relative functions after spinal cord injury in rats.