电针对焦虑大鼠室旁核促肾上腺皮质素释放激素及其Ⅰ型受体mRNA表达的影响

Effect of Electroacupuncture on the Expression of Corticotropin Releasing Hormone (CRH) and CRHR1mRNA in Paraventricular Nucleus of Hypothalamus in Stress-induced Anxiety Rats

目的:通过观察电针对下丘脑-垂体-肾上腺皮质(HPA)轴应激系统的关键结构之一下丘脑室旁核(PVN)、促肾上腺皮质素释放激素(CRH)及其Ⅰ型受体mRNA(CRHR1mRNA)表达的影响,探讨电针抗焦虑效应的部分神经内分泌作用机制。方法:SD雄性大鼠33只,随机分为空白组、模型组、电针组,采用不可预知的情绪应激刺激方法,建立慢性情绪应激焦虑模型。电针"百会""三阴交"穴,每日1次,每次15min,治疗21d。运用高架十字迷宫测试大鼠焦虑行为,免疫组化法检测下丘脑室旁核CRH的表达,原位杂交法观察下丘脑室旁核CRHR1mRNA的表达。结果:模型组大鼠在开臂停留时间(OT)和进入开臂的次数(OE)分别占进入两臂区停留总时间和总次数的百分比(OT%和OE%)与空白组比较明显下降(P<0.01);电针能显著提高模型动物的OE%和OT%值(P<0.05,P<0.01),并接近正常水平。模型组大鼠下丘脑室旁核CRH和CRHR1mRNA表达明显高于空白组(P<0.05,P<0.01);电针可显著降低模型大鼠CRH和CRHR1mRNA表达(P<0.05,P<0.01)。结论:抑制HPA轴的关键激活环节——下丘脑室旁核CRH及其受体表达,可能为电针抗焦虑效应的重要途径之一。

Objective To investigate the effects of electroacupuncture （EA） on the expression of corticotropin releasing hormone （ORH） and CRHR 1 mRNA in paraventricular nucleus （PVN） of hypothalamus, to explore its mechanism in anti-anxiety. Methods Thirty-three male SD rats were randomly divided into control, model and EA groups. Chronic emotional stress anxiety model was established by using chronic unpredictable emotional stress stimulation for 21 days. EA （15/25 Hz, 1 -2 mA）was ap- plied to ＂Baihui＂ （GV 20） and ＂Sanyinjiao＂ （SP 6） for 15 min/d and 21 days. The expression of ORH and ORHR 1 mRNA in hypothalamic PVN was measured by immunohistochemistry and in situ hybridization techniques separately. Results Compared with control group, the values of open-arms entries （OE%） and open-arms time （OT%） in model group were decreased significantly （P〈0.01）. In comparison with model group, OE% and OT% in EA group were increased obviously （P〈0.05, P〈0.01）. Compared with control group, the optical density values of CRH immuno-reaction positive products and ORHR 1 mRNA expressed neurons of hypothalamic PVN in model group were increased obviously （P〈0.05, P〈 0.01） ; while in comparison with model group, those of ORH and ORHR 1 mRNA in EA group were significantly decreased （P〈0.05, P〈0.01）. Conclusion EA can effectively relieve chronic stress stimulation induced anxiety in the rat, which is closely related to its effect in down regulating both CRH and CRHR 1 mRNA expression in PVN of hypothalamus.