Electroacupuncture at Baliao Points Alleviates Ulcerative Colitis via α7nAChR-Mediated Macrophage Polarization and Gut Microbiota Modulation

Ulcerative colitis (UC) is a chronic inflammatory disorder characterized by a significant unmet clinical need for more effective and tolerable therapies. This study explores the therapeutic potential and underlying mechanisms of electroacupuncture (EA) at the Baliao acupoints in a dextran sulfate sodium (DSS)-induced UC rat model. EA treatment significantly alleviated colitis symptoms, restored colon length, and enhanced gut barrier integrity by upregulating tight junction proteins (ZO-1/occludin). Mechanistically, EA activated cholinergic neurons in the dorsal root ganglion (DRG), increased the prevalence of α7nAChR (alpha 7 nicotinic acetylcholine receptor)-positive M2 macrophages in the colon, and elevated local acetylcholine levels. These effects were abolished by the α7nAChR antagonist methyllycaconitine (MLA), confirming the critical role of α7nAChR-mediated cholinergic signaling. Additionally, EA modulated gut microbiota composition, promoting beneficial bacteria (eg Lactobacillus) and suppressing pathogenic species. Heart rate variability analysis indicated enhanced vagal activity post-EA. Collectively, these findings demonstrate that EA at the Baliao acupoints alleviates experimental UC via α7nAChR-dependent facilitation of M2 macrophage polarization and restoration of a healthy gut microbiota, highlighting a promising neuromodulation-based approach for UC treatment.