Objectives: To observe the effect of electroacupuncture (EA) on the proliferation of hippocampal neurons and Wnt/β-catenin and Notch signaling pathways in depression like behavior rats, so as to explore its mechanism underlying improvement of depression.
Methods: SD rats were randomly divided into blank, model, medication and EA groups, with 12 rats in each group. The depression model was established by chronic unpredictable mild stimulation combined with solitary raising for 35 consecutive days. After 14 days modeling, EA was applied to "Baihui"(GV20) and "Taichong"(LR3) for 15 min once daily for 3 weeks. For rats of the medication group, clomipramine (2.5 mg/kg) was given (i.p.) once a day for 3 weeks. The depression-like behavior was evaluated by open field test and forced swimming test. The ultrastructure of hippocampal neurons was observed by transmission electron microscope (TEM). The positive expression of 5-bromo-2'-deoxyuridine/neuron-specific nucleoprotein (BrdU/NeuN) in hippocampal dentate gyrus of rats was detected by immunofluorescence double labeling method. Western blot was used to detect the relative expression of Wnt/β-catenin and Notch pathway key proteins β-catenin, G1/S-specific cyclin-D1 (Cyclin D1), NICD and Hes1 in hippocampus of rats.
Results: Compared with the blank group, the total distance and average speed of open field movement were decreased (P<0.01), and the immobility time of forced swimming was increased (P<0.01). The positive expression of BrdU/NeuN in hippocampal dentate gyrus was decreased (P<0.01). The relative expression of β-catenin and Cyclin D1 protein in hippocampus were decreased (P<0.01), while the relative expression of NICD and Hes1 protein increased (P<0.01) in the model group. Following the treatment and compared with the model group, the total distance and average speed of movement in the open field were increased (P<0.05), and the immobility time of forced swimming was decreased (P<0.05) in both medication and EA groups. The positive expression of BrdU/NeuN in hippocampal dentate gyrus was increased (P<0.01). The relative expression of β-catenin and Cyclin D1 protein in hippocampus were increased (P<0.01), while the relative expression of NICD and Hes1 protein were decreased (P<0.01, P<0.05) in both medication and EA groups. TEM microscope observation showed irregularity of hippocampal neurons, rupture of nuclear membranes, disruption of mitochondrial structure, and dilation of endoplasmic reticulum in the model group, which was relatively milder in both medication and EA groups.
Conclusions: EA can improve the depressive state of depression model rats, which may be associated with its functions in regulating Wnt and Notch signaling pathways, thereby promoting the regeneration of hippocampal neurons.
目的: 观察电针对抑郁大鼠海马神经元增殖及Wnt/β-catenin与Notch信号通路的影响，探讨电针治疗抑郁症的作用机制。方法: SD大鼠随机分为空白组、模型组、西药组、电针组，每组12只。采用慢性不可预知温和刺激结合孤养复制抑郁大鼠模型。电针组取“百会”“太冲”进行电针干预，每次15 min，西药组予2.5 mg/kg氯丙咪嗪灌胃给药，两组均每日1次，治疗3周。旷场实验与强迫游泳实验观察抑郁大鼠行为学变化；透射电镜观察大鼠海马神经元超微结构；免疫荧光双标法检测大鼠海马齿状回5-溴脱氧尿嘧啶核苷/神经元特异性核蛋白（BrdU/NeuN）阳性表达；Western blot法检测大鼠海马组织Wnt/β-catenin与Notch通路关键蛋白β-catenin、G1/S-特异性周期蛋白-D1（Cyclin D1）、NICD、Hes1的相对表达量。结果: 与空白组相比，模型组大鼠旷场运动总距离、平均运动速度降低（P<0.01），强迫游泳漂浮不动时间增加（P<0.01）；海马神经元细胞核形态不规则，核膜破裂，线粒体结构破坏，内质网扩张；海马齿状回中BrdU/NeuN阳性表达细胞减少（P<0.01）；海马组织中β-catenin、Cyclin D1蛋白相对表达量降低（P<0.01），NICD、Hes1蛋白相对表达量升高（P<0.01）。与模型组相比，西药组与电针组大鼠旷场内运动总距离、平均运动速度增加（P<0.05），强迫游泳漂浮不动时间减少（P<0.05）；海马神经元细胞核核膜清晰完整，线粒体与内质网损伤程度减轻；海马齿状回BrdU/NeuN阳性表达细胞增加（P<0.01）；海马组织中β-catenin、Cyclin D1蛋白相对表达量升高（P<0.01），NICD、Hes1蛋白相对表达量降低（P<0.01，P<0.05）。结论: 电针可以改善抑郁模型大鼠抑郁状态，其机制可能与电针同步调控Wnt与Notch信号通路，实现Wnt激活/Notch抑制，从而促进抑郁大鼠海马神经元再生有关。.
Keywords: Depression; Electroacupuncture; Neuronal regeneration; Notch; Wnt.