Electroacupuncture Attenuates Colitis in Mice Through Activation of Vagus Cholinergic Antiinflammatory Pathways.

BACKGROUND: Colitis impairs life quality, and treatments are limited. Acupuncture may engage vagal anti-inflammatory pathways, but the precise circuits are unclear. OBJECTIVE: This study aimed to examine the effects of electroacupuncture (EA) at "Shangjuxu" (ST37) on murine colitis and the involvement of the cholinergic vagus system. METHODS: Mice were divided into control, model, EA (electro-acupuncture), and MLA (EA with α7nAChR antagonist) groups. A colitis model was induced in mice by freely drinking a 2.5% dextran sodium sulfate (DSS) solution for 7 days. Colitis severity was assessed via body weight, colon length, and H&E staining. Proximal colon cytokines were measured by MSD assay. Immunofluorescence evaluated activation of ChAT-positive neurons in the dorsal motor nucleus of the vagus (DMV) and local colon cholinergic markers. Anatomical interactions between ChAT-positive fibers and α7nAChR-positive cells were observed. Vagal efferent fiber activity was recorded electrophysiologically. RESULTS: EA at ST37 significantly reduced body weight loss and proximal colon tissue damage in colitis mice (P < 0.05). These beneficial effects were blocked by the α7nAChR antagonist MLA. Levels of five pro-inflammatory cytokines (TNF-α, IL-6, CXCL1, IL-1β, IL-5) were elevated in the model group but decreased following EA treatment (P < 0.05). Colitis increased activation of ChAT-positive neurons in the DMV, and EA further enhanced this activation (P < 0.05). The reduced α7nAChR content in the proximal colon of model mice was restored to near-normal levels by EA (P < 0.05). EA also significantly increased the activation of cervical vagal efferent fibers (P < 0.05). Anatomical associations between ChAT-positive fibers and α7nAChR-positive cells were observed in the EA group. CONCLUSION: EA at ST37 alleviates inflammation in colitis mice likely by activating ChAT-positive neurons in the DMV. This stimulates vagal efferent nerves, modulates α7nAChR-positive cells in the proximal colon, and engages the vagal cholinergic anti-inflammatory pathway.