电针抗炎效应在SAMP8小鼠神经元损伤中的促保护作用

Electroacupuncture inhibits neuron injury of SAMP8 mice by reducing inflammatory response

目的:观察电针“百会”“肾俞”对SAMP8小鼠神经元病理损伤的影响及其抗炎效应对神经元修复的促进作用,为研究电针防治阿尔茨海默病提供新的实验依据。方法:将12只7月龄的SAMP8小鼠随机分为模型组和电针组,6只同龄且遗传背景相同的SAMR1小鼠作为正常组。电针组针刺“百会”和双侧“肾俞”,双侧“肾俞”连接韩氏电针仪,采用连续波,频率2 Hz,电流强度1 mA,15 min/d,10 d为1个疗程,共进行4个疗程,疗程间间隔1 d。疗程结束后,采用Morris水迷宫实验检测各组小鼠空间学习记忆能力;采用免疫荧光染色检测各组小鼠海马齿状回(DG)抗神经元特异性核蛋白(NeuN)阳性表达水平及阳性细胞数;Western blot检测各组小鼠海马区小胶质细胞特异性蛋白离子钙结合衔接分子-1(Iba-1)、肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-6、IL-1β蛋白表达水平;透射电镜观察海马DG区神经细胞超微结构。结果:与正常组相比,模型组平均逃避潜伏期明显延长、跨越原平台次数明显减少(P<0.01);海马DG区NeuN平均荧光强度和标记密度降低(P<0.05);海马Iba-1、TNF-α、IL-6、IL-1β蛋白表达水平升高(P<0.05)。与模型组相比,电针组平均逃避潜伏期明显缩短、跨越原平台次数明显增加(P<0.01);海马DG区NeuN的平均荧光强度和标记密度升高(P<0.05);海马Iba-1、TNF-α、IL-6、IL-1β蛋白表达水平降低(P<0.05)。正常组海马DG区神经细胞形态正常,胞质内细胞器结构清晰完整且规则分布;模型组海马DG区神经细胞形态严重不规则;电针组海马DG区神经细胞形态部分不规则,但较模型组有所缓解。结论:电针“百会”“肾俞”能够改善SAMP8小鼠的学习记忆能力,其机制可能与抑制神经炎性反应、增加海马DG区神经元数目、改善海马DG区超微结构以发挥神经元保护作用有关。

Objective To observe the effect of electroacupuncture(EA)at“Baihui”(GV20)and“Shenshu”(BL23)on the pathological injury of neurons in SAMP8 mice and the anti-inflammatory effect on neuron repair,providing a new experimental basis for EA prevention and treatment of Alzheimer’s disease.Methods Twelve 7-month-old SAMP8 mice were randomly divided into model and EA groups,and 6 SAMR1 mice of the same age and genetic background were used as normal group.Mice in the EA group were needled at GV20 and bilateral BL23,and EA(1 mA,2 Hz)was applied to bilateral BL23 for 15 min,once daily,10 d as a course for a total of 4 courses,with an interval of 1 d.Mice in the normal and model groups were captured and fixed in the same way as the EA group.The spatial learning and memory ability was detected by Morris water maze test.Neuronal nuclear antigen(NeuN)positive expression and the number of NeuN-positive cells in dentate gyrus(DG)were detected by immunofluorescence staining.The protein expression levels of ionized calcium binding adapter molecule 1(Iba-1),tumor necrosis factor-α(TNF-α),interleukin(IL)-6 and IL-1βin hippocampus were detected by Western blot.The ultrastructure of nerve cells in DG was observed by transmission electron microscopy.Results Compared with the normal group,the average escape latency was prolonged(P<0.01),the number of platform crossing was significantly reduced(P<0.01),the average fluorescence intensity of NeuN and the number of NeuN-positive cells in hippocampus DG region decreased(P<0.05),the expression levels of Iba-1,TNF-α,IL-6 and IL-1βin hippocampus were increased(P<0.05)in the model group.Compared with the model group,the ave-rage escape latency was shortened(P<0.01),the number of platform crossing times was significantly increased(P<0.01),the average fluorescence intensity of NeuN and the number of NeuN-positive cells in hippocampus DG region increased(P<0.05),the expression levels of Iba-1,TNF-α,IL-6 and IL-1βin hippocampus were decreased(P<0.05)in the EA group.The morphology of nerve cells in the hippocampus DG region was normal,and the organelles in the cytoplasm were clear,complete and regularly distributed in the normal group.However,the morphology of nerve cells in the model group was seriously irregular,which was also irregular in EA group but somewhat relieved compared with model group.Conclusion EA at GV20 and BL23 can improve the learning and memory ability of SAMP8 mice,which may be related to inhibiting the neuroinflammatory response,increasing the number of neurons and improving the ultrastructure of the DG region of the hippocampus to play the role of neuron protection.