电针刺激改善焦虑大鼠行为学及对脑源性神经营养因子表达、下丘脑-垂体-肾上腺轴的影响

The effect of electroacupuncture stimulation on behavior and expression of Brain-de⁃rived Neurotrophic Factor and Hypothalamic-pituitary-adrenal axis in anxious rats

目的观察电针百会、风府穴对焦虑模型大鼠行为学及脑源性神经营养因子(Brain-derived neuro⁃trophic factor,BDNF)、促肾上腺皮质释放激素(Corticotropin releasing hormone,CRH)、皮质醇(Cortisol,CORT)表达的影响,探讨针刺治疗焦虑障碍效应及作用机制。方法将30只SPF级SD雄性大鼠按随机数字表法分为正常组、模型组、电针组,每组各10只。采用慢性不可预见性应激刺激法制备焦虑大鼠模型。电针组取“百会”“风府”穴进行电针操作,隔日1次,20 min/次,造模与干预共计15 d。15 d后,采用高架十字迷宫实验(Elevated plus maze,EPM)和自发活动旷场实验(Open field test,OFT)测试大鼠行为学变化,HE染色法观察大鼠海马形态,免疫组化法观察海马组织内BDNF蛋白表达,酶联免疫吸附法检测血清BDNF、CRH与CORT的含量。结果与正常组比较,模型组大鼠进入开臂次数百分比(The percentage of open arm entry,OE%)、开臂停留时间百分比(The per⁃centage of open arm time,OT%)明显降低,差异有统计学意义(P<0.05),水平得分、垂直得分明显下降,差异有统计学意义(P<0.01),血清BDNF、CRH、CORT含量明显升高,差异有统计学意义(P<0.01),海马神经元数量和BDNF蛋白阳性明显减少,差异有统计学意义(P<0.05);与模型组比较,电针组OE%、OT%值明显升高,差异有统计学意义(P<0.01),水平得分、垂直得分明显升高,差异有统计学意义(P<0.01),海马神经元数量和BDNF蛋白阳性含量明显增加,差异有统计学意义(P<0.05),血清BDNF、CRH、CORT含量明显降低,差异有统计学意义(P<0.01)。结论电针可改善焦虑大鼠的焦虑样行为症状,其抗焦虑的机制可能与上调海马BDNF水平,抑制血清中BDNF、CORT、CRH的表达,使下丘脑-垂体-肾上腺(Hypothalamic–pituitary–adrenal,HPA)轴亢进受抑有关。

Objective To observe the effects of electroacupuncture at Baihui and Fengfu points on the behavior and expression of brain-derived neurotrophic factor(BDNF),corticotropin releasing hormone(CRH)and cortisol(CORT)in anxiety model rats,and to explore the effect and mechanism of acupuncture on anxiety disorder.Methods Thirty male SD rats in SPF grade were divided into a normal group,a model group and an electroacupuncture group according to the random number table,10 rats in each group.The anxiety rat model was prepared by chronic unpredictability stress stimula⁃tion.In the electroacupuncture group,“Baihui”and“Fengfu”points were selected for electroacupuncture operation,once every other day,20 min each time,and the modeling and intervention lasted for a total of 15 days.After 15 days,the behav⁃ioral changes of the rats were measured by the elevated plus maze(EPM)experiment and spontaneous activity opening field test(OFT).The morphology of hippocampus was observed by HE staining.The expression of BDNF protein in hippocampus tissues was observed by immunohistochemistry.The contents of serum BDNF,CRH and CORT were detected by enzyme-linked immunosorbent assay.Result Compared with the normal group,the percentage of open arm entry(OE%)and the percentage of open arm time(OT%)in the model group significantly decreased(P<0.05);the horizontal scores and verti⁃cal scores significantly decreased(P<0.01);the serum contents of BDNF,CRH and CORT significantly increased(P<0.01);the number of hippocampus neurons and positive BDNF proteinsignificantly decreased(P<0.05).Compared with the model group,the values of OE%and OT%in the electroacupuncture group significantly increased(P<0.01);the hor⁃izontal scores and vertical scores significantly increased(P<0.01);the number of hippocampal neurons and the positive BDNF protein significantly increased(P<0.05);the contents of BDNF,CRH and CORT in serum significantly decreased P<0.01).Conclusion Electroacupuncture can improve the anxiety-like behavior symptoms of anxious rats,and its anti-anxiety mechanism may be related to up-regulating the level of BDNF in hippocampus,inhibiting the expression of BD⁃NF,CORT and CRH in serum,and suppressing the hyperactivity of hypothalamic-pituitary-adrenal(HPA)axis.