Progress of researches on the mechanism of acupuncture treatment for Alzheimer's disease by modulating synaptic plasticity.

Alzheimer's disease (AD) is a neurodegenerative disease with high incidence in the elderly population, and the synaptic changes in central neurons are the key pathological feature. The clinical effect of acupuncture and moxibustion in the treatment of AD is positive, and the research on the mechanism of acupuncture intervention of AD from the perspective of central synaptic plasticity regulation has been conducted uninterruptedly. In the present paper, we made a summation about the relevant experimental studies in recent years, and analyzed its mechanisms underlying improvement of AD by regulating synaptic plasticity from 1) repairing synaptic structure (synaptic contact area ［total number of synapses, synaptic surface density, synaptic number density］, postsynaptic dense zone thickness, synaptic gap width, and interface curvature), 2) improving synaptic transmission efficiency (regulating long-term potentiation and long-term depression), 3) promoting the expression of synapse related proteins (synaptophysin, postsynaptic density protein 95, growth associated protein 43), 4) regulating the expression of neurotransmitters (acetylcholine, monoamines, amino acids, etc.) and receptors (α7 nicotinic acetylcholine receptor, glutaminergic receptor, etc.), and 5) improving the level of neurotrophic factors (brain derived neurotrophic factor, BDNF) and BDNF/SYN/microtubule-associated protein 2 signaling, etc., hoping to provide a reference for future studies.