基于BDNF/TrkB/AMPK/SIRT1信号通路探讨耳电针刺激对癫痫大鼠记忆力和癫痫发作的影响

Effects of auricular electroacupuncture stimulation on memory and seizures in epileptic rats via BDNF/TrkB/AMPK/SIRT1 signaling pathway

目的基于脑源性神经营养因子(BDNF)/原肌球蛋白相关激酶B(TrkB)/腺苷酸活化蛋白激酶(AMPK)/沉默信息调节因子1(SIRT1)信号通路,探讨耳电针刺激对癫痫大鼠记忆力、癫痫发作的影响及其分子机制。方法将36只雄性SD大鼠随机分为正常4周组、模型4周组、耳电针4周组、正常8周组、模型8周组、耳电针8周组,每组6只。2个模型组和2个耳电针组大鼠均建立锂-匹鲁卡品癫痫模型。癫痫模型建立24 h后,耳电针4周组和耳电针8周组大鼠分别给予耳电针刺激4周和8周,每周连续刺激3 d。每组干预结束后,采用抑制性回避试验测定大鼠空间记忆力,脑电图测定48 h内癫痫大鼠自发癫痫次数,ELISA测定大鼠海马组织中BDNF含量,Western blot法测定大鼠海马组织中TrkB、AMPK、SIRT1蛋白表达情况。结果模型4周组、模型8周组大鼠的黑盒滞留时间均明显长于对应时间的正常组(P均<0.05),48 h内出现多次自发癫痫,海马组织中BDNF含量和p-TrkB、p-AMPK、SIRT1蛋白相对表达量均明显低于对应时间的正常组(P均<0.05);耳电针4周组和耳电针8周组大鼠的黑盒滞留时间均明显短于对应时间的模型组(P均<0.05),48 h内自发癫痫次数均明显少于对应时间的模型组(P均<0.05),海马组织中BDNF含量和p-TrkB、p-AMPK、SIRT1蛋白相对表达量均明显高于对应时间的模型组(P均<0.05),且耳电针8周组上述指标改善情况均明显优于耳电针4周组(P均<0.05)。结论耳电针刺激可呈时间依赖性改善癫痫大鼠的记忆能力,减少癫痫发作,机制可能与调控海马组织中BDNF/TrkB/AMPK/SIRT1信号通路有关。

Objective It is to investigate the effects of auricular electroacupuncture stimulation on memory,seizures of epileptic rats and their molecular mechanisms based on brain-derived neurotrophic factor(BDNF)/proto-myosin-related kinase B(TrkB)/AMP-activated protein kinase(AMPK)/silent information regulator 1(SIRT1)signaling pathway.Methods Thirty-six male SD rats were randomly divided into normal 4-week group,model 4-week group,auricular acupuncture 4-week group,normal 8-week group,model 8-week group,and auricular acupuncture 8-week group,with 6 rats in each group.Lithium-pilocarpine epilepsy models were established in the two model groups and two auricular acupuncture groups.24 hours after the the epilepsy models were established,the rats in the auricular acupuncture 4-week and auricular acupuncture 8-week group were stimulated with electroacupuncture for 4 weeks and 8 weeks,respectively,and stimulated continuously for 3 days per week.At the end of the intervention in each group,the spatial memory of the rats was measured by inhibitory avoidance test,the time of spontaneous seizures with 48 h of the epileptic rats was detected by electroencephalogram(EEG),the content of BDNF in hippocampus was detected by ELISA,and the protein expressions of TrkB,AMPK and SIRT1 in rat hippocampal tissue were detected by Western blot.Results The black box retention times of rats in the 4-week and 8-week model groups were significantly longer than those of the normal group of the corresponding time(all P<0.05),spontaneous seizures attacked several times within 48 h,the contents of BDNF and the relative protein expressions of p-TrkB,p-AMPK,and SIRT1 in hippocampal tissues were all significantly lower than those of the normal group of the corresponding time(all P<0.05);the black box retention times of rats in the 4-week and 8-week auricular acupuncture groups were significantly shorter than those of the model groups of the corresponding time(all P<0.05),the times of spontaneous seizures within 48 h were significantly lower than those of the model group of the corresponding time(all P<0.05),the contents of BDNF and the relative protein expressions of p-TrkB,p-AMPK,and SIRT1 in hippocampal tissues were significantly higher than those of the model group of the corresponding time(all P<0.05)and the improvements of the above indexes in the auricular acupuncture 8-week group were all significantly better than those in the auricular acupuncture 4-week group(all P<0.05).Conclusion Auricular acupuncture stimulation can improve memory ability and reduces seizures in epileptic rats in a time-dependent manner,and the mechanism may be related to regulating the BDNF/TrkB/AMPK/SIRT1 signaling pathway in hippocampal tissues.