Electro-Acupuncture Ameliorated Cognitive Impairment Induced By Sleep Deprivation Through Inhibiting NLRP3 Inflammatory Signaling Pathway

ObjectiveIn this study,a rat model of cognitive impairment induced by sleep deprivation(SD)was established using modified multiple platform method(MMPM).The effects of electro-acupuncture(EA)at acupoints Baihui and Shenting on learning and memory ability of SD rats were observed.The therapeutic effect of EA on the improvement of cognitive impairment and the involved mechanisms were explored.We focused on whether EA exerted therapeutic effects on the improvement of mild cognitive impairment through inhibiting the activation of microglia and NLRP3 signaling pathway.This study presented the possible mechanism of EA,a therapy method in Traditional Chinese Medicine,involved in the improvement of the mild cognitive impairment,and provided some theoretical basis for clinical treatment of mild cognitive impairment.MethodSixty SPF Sprague-Dawley rats were randomly divided into three groups,control,SD,and SD group treated with electro-acupuncture(SD+EA).A rat SD model was established using MMPM,in which sleep of rapid eye movement(REM)was deprived for 5 days.Rats in SD+EA group received EA at acupoints Baihui and Shenting for 30 min every day during the modeling-establishing period.The changes of rat cognitive function were tested by behavioral experiments including Morris water maze(MWM)and novel object recognition(NOR).Immunofluorescence staining was used to observe the morphological changes of microglia in the hippocampus of rats from each group;the expression changes of and proteins related to NLRP3 signaling pathway,including NLR family protein containing a pyrin domain 3(NLRP3),cysteinyl aspartate specific proteinase 1(Caspase-1),and interleukin-1?(IL-1?)were determined by Western blot assay.Result1.Morris water maze behavioral results showed that,compared with the control group,SD rats spent more time to find the platform(escape latency),increased total swimming distance,decreased time in target quadrant and platform crossings in probe trials,suggesting that SD led to learning and memory impairment in rats,and SD model was established successfully.Compared with SD group,the escape latency in SD+EA rats was significantly decreased,and increased time in target quadrant and platform crossings in probe trials,indicating that EA treatment ameliorated the impaired learning induced by SD.Similarly,compared with the control rats,the exploration time of new objects in SD group was significantly reduced in NOR;compared with SD group,the exploration time of new objects in SD+EA group was increased.The results showed that EA treatment improved the mild cognitive impairment induced by SD.2.Immunofluorescence staining results showed that,compared with the control group,the number of microglia increased significantly in hippocampus of SD group;and the expression of IBA-1,a marker for microglia,increased significantly with expanded morphology,suggesting that microglia was activated after SD;compared with SD group,the expression of IBA-1 in hippocampus was decreased as well as the number of microglia,suggesting that EA treatment inhibited microglia activation in hippocampus of SD rats.3.Western blot results showed that the enhanced expression of NLRP3,Caspase-1 and IL-1? in the hippocampus of SD rats compared with the control;EA treatment led to the reduction of the expression of these proteins,suggesting that EA treatment exerted anti-inflammatory effects by inhibiting the inflammatory pathway.ConclusionIn this study,the rat SD model was successfully established by MMPM;and EA treatment improved rats mild cognitive impairment induced by SD;we further explored the mechanisms involved and found that EA treatment inhibited the activation of microglia in hippocampus of SD rats,inhibited the neuroinflammation associated with NLRP3 signal pathway,thus exerting anti-inflammatory effect to improve SD-induced cognitive impairment.