耳甲电针对抑郁模型大鼠海马Raf/ERK/RSK/CREB信号通路的影响

Auricular electroacupuncture improves depression possibly by promoting hippocampal Raf/ERK/RSK/CREB signaling in chronic unpredictable mild stress induced depression rats

目的:观察耳甲电针对慢性不可预知性温和刺激(CUMS)诱导的抑郁大鼠海马细胞外信号调节激酶(ERK)信号转导通路的影响,探讨耳甲电针抗抑郁效应的机制。方法:SD大鼠随机分为空白组、模型组、耳甲电针组、PD98059抑制剂(PD)组、二甲基亚砜(DMSO)组、PD+耳甲电针组,每组10只。采用孤养结合连续21 d CUMS方法制备抑郁大鼠模型。耳甲电针组、PD+耳甲电针组于耳甲区的"心"和"神门"耳穴给予连续28 d电针刺激,每天30 min;PD组、DMSO组、PD+耳甲电针组分别给予连续28 d侧脑室注射PD98059、DMSO、PD98059,每只5μL/d。记录造模前后、干预后各组大鼠糖水消耗量。采用Western blot法检测干预后各组大鼠海马Raf、p-Raf、ERK、p-ERK、RSK、CREB、p-CREB蛋白的相对表达量。结果:与空白组比较,模型组大鼠糖水消耗量及海马Raf、p-Raf、ERK、p-ERK、RSK、CREB、p-CREB均显著降低(P<0.01)。与模型组比较,耳甲电针组大鼠糖水消耗量及海马Raf、p-Raf、ERK、p-ERK、RSK、CREB、pCREB均显著升高(P<0.05,P<0.01),PD+耳甲电针组p-Raf、ERK、CREB明显升高(P<0.01,P<0.05),PD组p-ERK明显下降(P<0.05)。与耳甲电针组比较,PD+耳甲电针组p-ERK、RSK和pCREB明显下降(P<0.05,P<0.01)。结论:海马内Raf/ERK/RSK/CREB信号通路可能参与了耳甲电针的抗抑郁效应,且该效应在一定程度上可被ERK阻断剂所抑制。

Objective To observe the effect of auricular electroacupuncture(EA)on intracellular Raf/extracellular signal-regulated kinase(ERK)/ribosomal S6 kinase(RSK)/cAMP response element-binding protein(CREB)signal pathway in the hippocampus of depression model rats,so as to explore its anti-depressive mechanism.Methods A total of 60 male SD rats were randomly divided into control,model,auricular EA,PD98059(ERK inhibitor),DMSO(Dimethylsulfoxide),PD98059+EA groups(n=10 in each group).The rats in the control group were fed with normal diet without any treatment.The depression model was induced by chronic unpredictable mild stress(CUMS)for consecutive21 days.EA(20 Hz,2 mA)was applied to bilateral auricular"Xin"(Heart)and"Shenmen"for 30 min,once daily for28 days.Rats of the PD98059,DMSO and PD98059+EA groups received intracerebroventricular injection of PD98059(100 μmol/L),DMSO and PD98059(dissolved by DMSO)solutions(5 μL/d),respectively,once daily for 28 days.Sucrose preference test(sucrose consumption)was conducted at the baseline,before and after the intervention.The expression of hippocampal Raf,phosphorylated(p)-Raf,ERK,p-ERK,RSK,CREB and p-CREB proteins were detected by Western blot after EA intervention.Results Following modeling,the sucrose consumption volume,and the expression levels of hippocampal Raf,p-Raf,ERK,p-ERK,RSK,CREB,p-CREB proteins were significantly lower in the model group than those in the control group(P<0.01).Following the treatment,the sucrose consumption and the expression levels of Raf,p-Raf,ERK,p-ERK,RSK,CREB,p-CREB in the auricular EA group and those of p-Raf,ERK and CREB in the PD98059+EA group were obviously increased in comparison with the model group(P<0.05,P<0.01),the expression level of p-ERK in the PD98059 group was obviously decreased in comparison with the model group(P<0.05),suggesting an improvement of depression after auricular EA.Compared with auricular EA group,the expression level of p-ERK,p-CREB and RSK in the PD98059+EA group were significantly decreased(P<0.05).Conclusion EA of auricular"Xin"and"Shenmen"is able to improve depression in depression rats,which is probably related to its effect in promoting activities of hippocampal Raf/ERK/RSK/CREB signaling.