电针对抑郁模型大鼠海马一氧化氮-环磷酸鸟苷信号转导通路的影响

目的:观察电针对抑郁模型大鼠海马一氧化氮-环磷酸鸟苷(NO-cGMP)信号转导通路的影响,探讨电针治疗抑郁症的部分作用机制。方法:SD大鼠随机分为正常组、模型组和电针组,每组10只。用慢性不可预见性轻度刺激结合孤养的方法制造抑郁模型。造模同时针刺治疗电针组动物,选取"百会"印堂"穴,电针20min,每日1次,连续针刺21d。治疗结束后取大鼠海马组织,用免疫组化法检测神经细胞性一氧化氮合酶(nNOS)表达量,用放射免疫法测定cGMP含量。结果:模型组大鼠海马区的nNOS免疫反应阳性颗粒数目减少,电针组nNOS免疫反应阳性颗粒数目较模型组增多。各组测得的nNOS灰度值,模型组明显高于正常组(P<0.01),电针组明显低于模型组(P<0.01)。模型组大鼠海马中cGMP含量与正常组比较有降低的趋势,但差异无统计学意义(P>0.05);电针组大鼠海马中cGMP含量与模型组比较显著升高(P<0.01)。结论:电针"百会"印堂"穴能够提高抑郁模型大鼠海马区nNOS的表达水平,同时提高海马中cGMP的含量,维持NO-cGMP信号转导通路的信息传递功能,从而起到抗抑郁作用。

Effect of Electroacupuncture on Hippocampal NO-cGMP Signaling Pathway in Depression Rats

Objective To observe the effect of electroacupuncture(EA) on hippocampal nitric oxide (NO)-cyclic guanosine 3,5-monophosphate (cGMP) signaling pathway in depression rats in order to explore the underlying mechanism of EA in improving depression. Methods Thirty male SD rats were equally randomized into control, model and EA groups. Depression model was established by using chronic unpredictable mild stress stimulation (forced ice-water swimming, electric shock, tail-clamping, etc.) combined with lonely raising for 21 days. EA (2 Hz, 0. 6 mA, 20 min) was applied to "Baihui" (GV 20) and "Yintang" (EX-HN 3), once daily for 21 days. The expression of neuronal nitric oxide synthase (nNOS) and the content of cGMP in the hippocampus were determined by immuno-histochemistry and radioimmunoassay separately. Results Many nNOS immu-no-reaction (IR)-positive granular cells were observed in the hippocampus in control group, fewer found in EA group and fewest in model group. Image analysis showed that the grey value of model group was significantly higher than that of control group (P<0. 01), and that of EA group was obviously lower than that of model group (P<0. 01), suggesting upregulation of nNOS ex-pression after EA. Compared with control group the content of cGMP in hippocampus in model group showed a decreasing trend, but without significant difference between two groups (P>0. 05). In comparison with model group, hippocampal cGMP content of EA group increased considerably (P<0. 01), being comparable to that of control group (P>0. 05). Conclusion Electroacu-puncture of "Baihui"(GV 20) and "Yintang"(EX-HN 3) can upregulate the expression of nNOS and the content of cGMP in the hip pocampus in depression rats, maintaining a normal activity of the NO/cGMP signaling pathway, which may contribute to its effect in relieving depression.