rTMS调节AD认知功能的突触可塑性机制研究

As the population worldwide continues to age, the number of individuals at risk will also increase, particularly among the very old. Alzheimer’s disease (AD) is the leading cause of dementia beginning with impaired memory. Application of the non-invasive and non drug therapeutic way for treating AD has been under concern. Repetitive transcranial magnetic stimulation (rTMS) is safe and reliable. In this study, APP23/PS45 double mutant transgenic mice (served as an AD model) will be used. Low-frequency (1 Hz) and high-frequency (20 Hz) rTMS will be applied by using a special stimulating coil which is suitable for small animals. To explore the effects of different frequency rTMS on learning and memory function of AD transgenic mice, pathological and behavioral experiments (including object recognition, passive avoidance and Morris water maze) will be carried out. . We will further explore the possible mechanism of rTMS on regulating cognitive function of AD transgenic mice in aspect of synaptic plasticity. Synaptic plasticity of hippocampal Scharffer-CA1 pathway will be detected electrophysiologically in vivo. spontaneous inhibitory\excitatory postsynaptic currents, neuronal excitability and characteristics of L-type calcium channel will also be recorded by using patch clamp technology on adult mouse hippocampal slices in vitro. Through western blot and immunofluorescence, we will detect the expression of relevant synaptic receptors and L-type calcium channels.. The aim of this study is to provide new ideas, theoretical basis and experimental support for clinical application of rTMS on treating AD patients.

随着人口老龄化，痴呆患病风险增加。AD是导致痴呆的主要原因。非药物无创治疗AD备受关注。rTMS是常用的非药物干预技术，研究提示rTMS有助于缓解认知功能障碍。现有研究多集中于高频rTMS，我们最新的研究发现更具安全性的低频rTMS能改善Aβ模型大鼠认知功能。本研究以APP23/PS45 AD小鼠为研究对象，应用低频（1 Hz）和高频（20 Hz）rTMS干预。通过病理和行为学实验（物体识别、被动逃避和Morris水迷宫）探究不同频率rTMS对AD小鼠认知功能的修复作用。并从突触可塑性的角度，应用在体电生理实验检测突触可塑性，离体成年小鼠海马脑片膜片钳实验检测突触受体电流、神经元兴奋性和L-型钙通道特性，同时通过Western blot和免疫荧光检测突触相关受体和L-型钙通道表达，以期探索rTMS调节AD小鼠认知功能的分子机制。从而为rTMS辅助治疗AD的临床应用提供新的思路和理论依据。

本课题围绕AD认知功能障碍这个科学问题，选用AD模型鼠为研究对象，应用rTMS进行干预，采用行为学、电生理和分子生物学等技术从整体动物、离体脑片、细胞和分子水平来探究rTMS对AD小鼠认知功能的调节作用及相关分子机制。我们证实APP23 / PS45双转基因小鼠（一种常用的AD小鼠模型）空间学习、记忆严重缺陷，并伴随着海马CA1区域的长时程增强抑制。连续2周低频rTMS（1Hz）治疗增强了该AD小鼠的空间学习记忆能力，并增强海马CA1区突触可塑性。 与此同时，低频rTMS显着降低海马中beta淀粉样蛋白前体蛋白（APP）及其C末端片段（包括C99和C89）以及b位点APP切割酶1（BACE1）含量。 这些结果表明，作为一种非侵入性神经刺激，低频率rTMS能有效改善AD小鼠的认知和突触功能，其潜在的机制可能是rTMS诱导了Ab的减少。这为临床上应用rTMS治疗AD提供了新的实验证据。