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.