电针对脑缺血再灌注大鼠脑缺血耐受和炎性痛大鼠镇痛效应的穴位特异性研究

Study on efficacy specificity of electroacupuncture at“Zusanli”(ST36)and“Baihui”(GV20)in cerebral ischemia and inflammatory pain rats

目的:观察电针“足三里”“百会”对脑缺血再灌注大鼠脑缺血耐受以及炎性痛大鼠的镇痛作用,探讨不同穴位抗脑缺血及炎性痛的特异性。方法:(1)在脑缺血再灌注实验中,将大鼠分为假手术组、模型组、百会组、足三里组、假电针组,每组16只。采用线栓法复制大脑中动脉栓塞模型。各电针组在造模前120 min电针1次。利用Longa评分观察大鼠行为学改变,利用TTC染色观察脑梗死体积。(2)在炎性痛实验中,将大鼠分为对照组、模型组、足三里组、百会组、假电针组,每组8只。右后足注射完全弗氏佐剂(CFA)复制炎性痛模型。造模后电针1次,90min再电针1次。用机械痛阈值和热痛阈值检测大鼠行为学改变,用免疫荧光技术观察脊髓背角c-fos蛋白表达。结果:(1)在脑缺血再灌注实验中,模型组大鼠表现出明显的行为学缺损和严重的脑梗死(P<0.01)。与模型组比较,各电针组行为学评分和脑梗死体积明显降低(P<0.05,P<0.01),假电针组无明显变化(P>0.05)。百会组与足三里组比较差异无统计学意义(P>0.05)。(2)在炎性痛模型实验中,注射CFA后150min,与对照组比较,模型组机械痛阈值和热痛阈值明显降低(P<0.01),c-fos表达明显增多(P<0.01)。与模型组比较,百会组和足三里组机械痛阈值和热痛阈值升高(P<0.01,P<0.05),同时脊髓背角浅层c-fos表达明显减少(P<0.01),假电针组变化差异无统计学意义(P>0.05)。结论:电针“百会”与“足三里”在抗脑缺血再灌注损伤和镇痛效应方面不存在穴位特异性,电针“百会”对CFA诱发的炎性痛具有抑制作用。

Objective To explore the efficacy difference between electroacupuncture(EA)at“Zusanli”(ST36)and“Baihui”(GV20)for inflammatory pain and cerebral ischemia-reperfusion injury(CIRI)in rats.Methods In 1st part of this study,90male SD rats were randomly divided into sham-operation,model(induced by occlusion of the middle cerebral artery and reperfusion),GV20EA,ST36EA,and sham EA groups(n=16in each group).In the 2nd part of the study,40male SD rats were randomized into saline injection(control),inflammatory pain model(subcutaneous injection of complete Freund’s adjuvant[CFA]into the right paw),ST36EA,GV20EA,and sham EA groups(n=8in each group).In these two parts,EA(2Hz/15Hz,1mA)was applied to ST36or GV20.The mechanical withdrawal threshold(MWT)and thermal withdrawal latency(TWL)were detected 2.5hafter administration of CFA by using Von Frey and plantar tester,respectively.The neurological deficit scores(NDS)were assessed by using Longa’s method and the infarct size of the brain assessed after staining with 2%triphenyltetrazolium chloride(TTC).The expression of c-fos protein in the dorsal horns(DHs)of the spinal cord was detected by immunohistochemistry.Results(1)Twenty-four hours following CIRI,the NDS and infarct volume were significantly increased in the model group compared with the sham-operation group(P<0.01),and obviously decreased in the GV20EA and ST36EA groups relevant to the CIRI model group(P<0.05,P<0.01).There were no significant differences between the two EA groups in the NDS and infarct volume levels(P>0.05).(2)After administration of CFA,both the MPT and TPT were notably decreased in the inflammatory pain model group in contrast to the saline-injection group(P<0.01),but were considerably increased in both ST36EA and GV20 EA groups(P<0.05),rather than in the sham EA group(P>0.05).The number of c-fos positive cells was significantly increased in the medial half of Ⅰ—Ⅱ and Ⅲ—Ⅳ lamina of DHs in the L4—L6segments of spinal cord in the inflammatory pain model group relevant to the saline-injection group(P<0.01,P<0.05),and was remarkably decreased in the lamina Ⅰ-Ⅱ(not in the deeper lamina)in both ST36EA and GV20EA groups(P<0.01),rather than in the sham EA group(P>0.05).No significant differences were found in the number of c-fos positive cells between the ST36EA and GV20EA groups(P>0.05).Conclusion Our data do not support the specificity of functions at least between GV20EA and ST36EA in both CIRI and inflammatory pain model rats.This is the first study reporting the effect of EA at GV20for relieving CFA-induced inflammatory pain.