摘要
目的观察局灶性脑梗死大鼠皮质轴突生长导向因子-1(netrin-1,Ntn1)和臂板蛋白3a(semaphorin-3a,sema3a)的表达及电针干预对其表达的影响。探索Ntn1与sema3a在电针对脑梗后神经可塑性影响中的作用。方法将130只雄性SD大鼠分为正常组(n=10)、模型组(n=60)及电针组(n=60)。利用线栓法制作大脑中动脉闭塞模型。分别在术后1、3、7、14 d时,对术后大鼠进行神经功能评分(modified neurologic severity scores,mNSS),利用免疫组化检测缺血侧大脑脑皮质中Ntn1、sema3a、神经丝蛋白200(NF200)分布和表达,免疫印迹法检测缺血侧大脑皮质Ntn1和sema3a的蛋白表达。结果免疫组化结果显示在各个时相点大鼠脑皮质均表达Ntn1和sema3a,主要集中在细胞质阳性表达。Western blot检测结果显示,与正常组相比,模型组Ntn1蛋白的表达水平在脑梗死后1 d即开始明显上升(P<0.01),3 d时呈上升趋势(P<0.01),7 d时达峰值(P<0.01),14 d时仍显著高于基础水平(P<0.01),电针组与模型组相比,Ntn1蛋白表达趋势相同,但表达量明显高于模型组,术后1、3、7、14 d时有统计学差异(P<0.05,P<0.01)。与正常组相比,模型组sema3a蛋白的表达水平在术后1 d即开始上升(P<0.01),7 d时达高峰(P<0.01),14 d时仍高于基础水平(P<0.01)。同时相点电针组与模型组相比sema3a均呈现低表达,1、3 d和7、14 d时有统计学差异(P<0.05,P<0.01),峰值同样在7 d时出现。Western blot检测结果与免疫组化分析结果基本相符。7、14 d时电针组与模型组相比mNSS评分存在统计学差异(P<0.05),14 d时电针组与模型组相比NF200的表达量存在统计学差异(P<0.05)。结论局灶性脑梗死后大鼠皮质Ntn1与sema3a表达明显上调,给予电针干预后可提高Ntn1的表达并抑制sema3a的表达,促进轴突的再生与修复,这可能是电针促进脑梗死后神经功能恢复的机制之一。
Objective To observe the expression of netrin-1（Ntn1） and semaphorin-3a（sema3a） in the cortex of rats after middle cerebral occlusion（MCAO）,and determine the effect of electro-acupuncture（EA） intervention on their expression,so as to explore the roles of Ntn1 and sema3a in neural plasticity after cerebral infarction.Methods A total of 130 male Sprague Dawley（SD） rats were randomly divided into control group（n = 10）,model group（n = 60） and EA group（n = 60,in the acupuncture points PC6 and ST36,80 to 100 Hz,1 to 3 mA,1 to 3 V,for 30 min,performed in 90 min after anesthesia recovery）,and further assigned into 4 time point,that is,in 1,3,7 and 14 d after model establishment.Modified neurologic severity scores（mNSS） were carried out to evaluate neurologic injury at every time point.Immunohistochemical assay was used to detect the expression and distribution of Ntn1,sema3a and NF200 in the cortical ischemic region.Western blotting was employed to detect the expression of Ntn1 and sema3a in the affected cortex.Results Immunohistochemical results showed that the rat brain cortex expressed Ntn1 and sema3a at every time point,and they mainly located in the cytoplasm.Western blotting indicated that the model group had higher expression of Ntn1 at 1 d（P 0.01）,kept in elevation at 3 d（P 0.01）,reached peak at 7 d（P 0.01）,and maintained still higherat at 14 d than normal levels（P 0.01）.Compared with the control group,the expression of Ntn1 in EA group had the same trend,but the expression level was significantly higher than the model group,with significant differences in 1,3,7 and 14 d（P 0.05,P 0.01）.Compared with the control group,sema3a protein level in the model group began to rise in 1 d after model surgery（P 0.01）,increased and reached the peak in 7 d（P 0.01）,and was still higher than the normal level in 14 d（P 0.01）.Compared to the model group,EA group presented low expression of sema3a at the same time point,with significant differences in 1,3,7 and 14 d（P 0.05,P 0.01）,and reached peak in 7 d.The results of Western blotting and immunohistochemical assays were basically consistent.Compared with model group,the mNSS of EA group had significant differences in 7 and 14 d（P 0.05）.Significant difference was seen in the expression of NF200 between model group and EA group in 14 d（P 0.05）.Conclusion Cerebral infarction significantly up-regulates the expression of Ntn1 and sema3a.EA intervention improves Ntn1 expression but suppresses sema3a,and promotes axon regeneration and repair,which may be one of the mechanisms that EA promotes the recovery of neurological function after cerebral infarction.
出处
《第三军医大学学报》
CAS
CSCD
北大核心
2013年第18期1941-1946,共6页
Journal of Third Military Medical University
基金
重庆市自然科学基金(CSTC2010BB5380)~~
