电针干预慢性炎性痛及其焦虑情绪与海马不同区域GABA相关机制研究

Mechanism of Gamma-aminobutyric Acid in Different Hippocampal Regions and Chronic Inflammatory Pain and Relatedanxiety by Electroacupuncture Intervention

[目的]观察电针对完全弗氏佐剂(complete Freund’s adjuvant,CFA)诱导的慢性炎性痛模型大鼠机械痛阈(paw withdrawal threshold,PWTs)、焦虑行为,以及双侧海马角1(Cornu Ammonis 1,CA1)、海马角3(Cornu Ammonis 3,CA3)、齿状回(Dentate Gyrus,DG)中神经肽Y(neuropeptide Y,NPY)、小清蛋白(parvalbumin,PV)、生长抑制素(somatostatin,SOM)、谷氨酸脱羧酶65/67(glutamic acid decarboxylase 65/67,GAD65/67)及原癌基因蛋白(cellular protooncogene Fos,c-Fos)表达的影响,探讨其可能机制。[方法]将32只健康雄性SD大鼠随机分为空白对照组、模型对照组、电针治疗组和假电针治疗组,每组8只,并对空白对照组以外的其他3组足底注射CFA,建立大鼠慢性炎性痛模型。于造模后26 d分别对电针治疗组和假电针治疗组进行电针和假电针干预,并观察各组大鼠的PWTs及高架O迷宫(elevated zero maze,EZM)中的焦虑行为。用免疫荧光法检测CA1、CA3和DG区NPY、PV、SOM、GAD65/67及c-Fos的阳性细胞表达。[结果]造模后1 d,模型对照组、电针治疗组和假电针治疗组的PWTs显著降低,并在整个实验过程中显著低于空白对照组(P<0.01);在电针治疗第3天,电针治疗组大鼠的PWTs相较模型对照组和假电针治疗组显著升高(P<0.01)。在EZM中,与空白对照组比较,模型对照组大鼠的开放臂运动距离、开放臂停留时间和开放臂进入次数显著减低(P<0.01),电针干预后可改善上述指标,而假电针无作用(P>0.05)。与空白对照组比较,模型对照组双侧CA1、CA3、DG区NPY阳性细胞表达增多(P<0.01,P<0.01,P<0.05),c-Fos阳性细胞表达减少(P<0.01,P<0.05,P<0.01);电针干预后,电针治疗组大鼠双侧CA1、DG区、患侧CA3区NPY阳性细胞表达较模型对照组减少(P<0.01),假电针无此作用(P>0.05)。双侧CA1、CA3和DG区,四组大鼠PV、SOM以及双侧CA1、CA3区GAD65/67阳性细胞表达或阳性面积差异均无统计学意义(P>0.05)。[结论]电针干预能改善CFA大鼠的疼痛及其相关焦虑行为,该作用可能与增加大鼠海马CA1、CA3和DG区NPY的阳性细胞表达有关。

[Objective] To observe the effect of electroacupuncture(EA) on paw withdrawal thresholds(PWTs), anxiety behaviors, and neuropeptide Y(NPY), parvalbumin(PV), somatostatin(SOM), glutamic acid decarboxylase 65/67(GAD65/67) and cellular protooncogene Fos(c-Fos) expressions in bilateral Cornu Ammonis 1(CA1), Cornu Ammonis 3(CA3) and Dentate Gyrus(DG) in rats with chronic inflammatory pain induced by complete Freund’s adjuvant(CFA), and explore its possible mechanism. [Methods] Thirty-two healthy male SD rats were randomly divided into blank control group, model control group, EA group and sham EA group, with 8 rats in each group. The rats of the latter three groups were injected CFA to establish chronic inflammatory pain model. The rats of EA group received EA intervention and sham EA group received pseudo EA intervention after the 26th day of modeling, meanwhile, all groups’ PWTs and the anxiety behaviors in elevated zero maze(EZM) were observed. The positive expressions of NPY, PV, SOM, GAD65/67 and c-Fos in bilateral CA1, CA3 and DG were determined by immunofluorescence. [Results] One day after modeling, PWTs in model control group, EA group and sham EA group significantly declined, and were significantly lower than blank control group throughout the experiment(P <0.01). Compared with model control group and sham EA group, the PWTs of EA group was significantly increased after 3 days of EA intervention(P<0.01). Compared with blank control group, the distance in open arms, residence time in open arms and number of the open arm entries of model control group were significantly reduced in EZM(P<0.01), moreover, EA intervention could improve the above indicators and sham EA had no effect(P>0.05). Compared with blank control group, the NPY positive cells’ expression in bilateral CA1, CA3 and DG of model control group was significantly increased(P<0.01, P<0.01, P<0.05), while the c-Fos positive cells’ expression decreased(P<0.01, P<0.05, P<0.01).After EA intervention, compared with model control group, the NPY positive cells’ expression in bilateral CA1, CA3 and ipsilateral DG of EA group was significantly decreased(P<0.01), however sham EA had no effect(P>0.05). In the bilateral CA1, CA3, and DG, all groups of PV positive cells, SOM positive cells, and GAD65/67 positive area in the bilateral CA1 and CA3 expressions had no significant differences(P>0.05). [Conclusion] EA intervention could relieve the pain and its related anxiety behaviors in CFA rats, which may be relevant to the increase expression of NPY positive cells in rats’ CA1, CA3 and DG.