电针对抑郁症大鼠海马齿状回亚颗粒区小胶质细胞活化和学习记忆能力的影响

Effects of electroacupuncture of the subgranular area of the dentate gyrus on microglia activation,and learning and memory function,in depressed rats

目的探讨电针对抑郁症大鼠海马齿状回亚颗粒区(SGZ)小胶质细胞活化和学习记忆能力调控机制。方法SD大鼠随机分为对照组、模型组、NLRP3阻断剂组、电针组,采用孤养+慢性不可预知性温和刺激建立大鼠抑郁症模型。电针组给予电针刺激“百会”“印堂”穴位,持续20 min/d;NLRP3阻断剂组尾静脉注射MCC950溶液(3 mg/kg),连续21 d。采用旷场实验记录动物造模前后自主活动能力,Morris水迷宫实验检测学习记忆功能,免疫荧光双标法定量和定位SGZ中小胶质细胞标志物离子钙结合衔接分子(Iba-1)和炎性小体NOD样受体3(NLRP3)蛋白表达,实时荧光定量PCR法检测SGZ中半胱天冬酶-1(Caspase-1)和白细胞介素-1β(IL-1β)基因相对表达量。结果与对照组比较,模型组大鼠自主活动和学习记忆功能明显减弱,SGZ中小胶质细胞出现明显的活化状态,NLRP3蛋白阳性率明显增加,Caspase-1和IL-1β蛋白相对表达量也相应升高(P<0.01);与模型组比较,电针组和NLRP3阻断剂组可明显改善大鼠的自主活动和学习记忆能力,NLRP3+Iba-1蛋白表达阳性率和Caspase-1 mRNA减少(P<0.05,P<0.01)、IL-1βmRNA相对表达量趋势性降低。结论电针可改善抑郁症模型大鼠学习记忆能力,这可能与调控海马亚颗粒区小胶质细胞活化状态和NLRP3/Caspase-1信号通路有关。

Objective To investigate the regulation mechanism of microglia activation,and learning and memory function,by electroacupuncture of the subgranular area of the dentate gyrus(SGZ)of depressed rats.Methods SD rats were randomly divided into four groups:the control group,model group,NLRP3 blocker group,and electroacupuncture group.The rat depression model was established by orphan rearing and chronic unpredictable gentle stimulation.The electroacupuncture group was administered electroacupuncture stimulation at the“Baihui”and“Yintang”acupoints for 20 min/d.The NLRP3 blocker group was injected with MCC950 solution(3 mg/kg)through the tail vein for 21 days.An open field experiment was used to record the autonomous activity of animals before and after modeling.The Morris water maze test was used to detect learning and memory function,and the immunofluorescence double-staining method was used to quantify and locate the protein expression of SGZ microglia marker Iba-1 and inflammasome Nod-like receptor 3.The relative expression levels of Caspase-1 and interleukin-1βin the SGZ were detected by real-time quantitative PCR.Results Compared with the control group,autonomous activity and learning and memory function were significantly reduced,the activation of SGZ microglia was obvious,the positive detection of NLRP3 protein was significantly increased,and the relative expression levels of Caspase-1 and IL-1βprotein were also increased in the model group(P<0.01).Compared with the model group,the electroacupuncture group and the NLRP3 blocker group showed significantly improved autonomous activity and learning and memory function,and decreased positive detection rates of NLRP3+IBA-1 protein expression and relative expression of Caspase-1 mRNA(P<0.05,P<0.01)and IL-1βmRNA.Conclusions Electroacupuncture improved the learning and memory ability of depressed rats,which may be related to the regulation of the activation state of microglia and the NLRP3/caspase-1 signaling pathway in the subgranular area of the hippocampus.