预针刺对阿尔茨海默病样大鼠学习记忆能力及海马区NLRP3炎性小体相关蛋白的影响

Effect of pretreatment of acupuncture on learning-memory ability and related protein of NLRP3 inflammasome in hippocampus in Alzheimer’s disease like rats

目的:观察预针刺对阿尔茨海默病(AD)样大鼠海马区核苷酸结合寡聚化结构域样受体3(NLRP3)、胱天蛋白酶-1(Caspase-1)、白介素1β(IL-1β)以及活化的小胶质细胞(MG)数量的影响,探讨预针刺防治AD的作用机制。方法:将36只SD大鼠随机分为空白组、模型组、电针组,每组12只。模型组、电针组采用连续8周腹腔注射D-半乳糖溶液(120 mg·kg-1·d-1)的方法制备AD样大鼠模型。电针组同时予"百会""足三里"穴电针刺激,连续波,频率50 Hz,电流1 mA,每次20 min,每日1次,连续干预8周。干预结束后采用Morris水迷宫实验评估各组大鼠空间学习记忆能力,Western blot法检测各组大鼠海马组织NLRP3、Caspase-1、IL-1β蛋白表达水平,免疫荧光标记法检测海马组织活化的MG数量。结果:与空白组比较,模型组大鼠平均逃避潜伏期延长(P<0.01),平台穿越次数减少(P<0.01),目标象限探索时间缩短(P<0.01);与模型组比较,电针组大鼠平均逃避潜伏期缩短(P<0.01),平台穿越次数增多(P<0.01),目标象限探索时间延长(P<0.01)。与空白组比较,模型组大鼠海马组织NLRP3、Caspase-1、IL-1β蛋白表达增多(P<0.01),活化的MG数量增多(P<0.01);与模型组比较,电针组大鼠海马组织NLRP3、Caspase-1、IL-1β蛋白表达减少(P<0.01),活化的MG数量减少(P<0.05)。结论:预针刺可防治AD样大鼠模型学习记忆功能障碍,其机制可能与抑制NLRP3炎性小体相关蛋白表达及小胶质细胞活化有关。

Objective To observe the effect of pretreatment of acupuncture on the expression of nucleotide-binding oligomerization domain-like receptor 3(NLRP3), Caspase-1, interleukin1β(IL-1β) and the number of activated microglia(MG) in the hippocampus in Alzheimer’s disease(AD) like rats, so as to explore the mechanism of pretreatment of acupuncture in preventing and treating AD. Methods A total of 36 SD rats were randomly divided into a blank group, a model group and an electroacupuncture(EA) group, 12 rats in each group. The AD like rat model was established by 8-week continuous intraperitoneal injection of D-galactose(120 mg·kg-1·d-1) in the model group and the EA group. The rats in the EA group were intervened with EA at "Baihui"(GV 20) and "Zusanli"(ST 36), continuous wave, 5 Hz in frequency, 1 mA in intensity, 20 min each intervention, once a day, for 8 weeks. After the intervention, the spatial learning-memory ability was evaluated by the Morris water maze test. The expression levels of NLRP3, Caspase-1 and IL-1β protein in hippocampus were detected by Western blot method. The number of activated MG in hippocampus was detected by immunofluorescence labeling method. Results Compared with the blank group, the average escape latency was prolonged(P<0.01), the number of platform crossing was reduced(P<0.01), and the exploration time of target quadrant was shortened(P<0.01) in the model group. Compared with the model group, the average escape latency was shortened(P<0.01), the number of platform crossing was increased(P<0.01), and the exploration time of target quadrant was prolonged(P<0.01) in the EA group. Compared with the blank group, the expression levels of NLRP3, Caspase-1, IL-1β protein in hippocampus were increased(P<0.01), and the number of activated MG was increased(P<0.01) in the model group.Compared with the model group, the expression levels of NLRP3, Caspase-1, IL-1β protein in hippocampus were decreased(P<0.01), and the number of activated MG was decreased(P<0.05) in the EA group. Conclusion Pretreatment of acupuncture could prevent and treat the learning-memory dysfunction in AD like rats, and its mechanism may be related to the inhibition of NLRP3 inflammatsome related protein and MG activation.