Acupuncture regulating microglial activation in Alzheimer's disease: Research progress in its neuroinflammation mechanism

Microglia (MG) activation and its mediated neuroinflammation are closely related to the occurrence and deterioration of Alzheimer's disease (AD). Acupuncture is one of the effective approach for AD, which can relieve the symptoms and slow the deterioration of AD. Based on the role of MG activation and its induced pro-inflammatory and anti-inflammatory phenotypes in neuroinflammation, this paper reviews the related literature on the mechanism of acupuncture in regulating MG activation and relieving neuroinflammation in AD. It is found that acupuncture can inhibit abnormal MG activation by regulating the release of MG surface immune receptors and pro-inflammatory/ anti-inflammatory cytokines. It can also modulate the activity of signaling pathways associated with MG polarization, downregulate the expression of M1, and promote MG polarization towards the M2 phenotype. Additionally, it adjusts the imbalance between M1 and M2 phenotypes of MG, thereby relieving the neuroinflammatory pathological procession of and repairing the neuronal damage so as to achieve its therapeutic effect.