Combination of electroacupuncture and Liqi Yangyin formula treatment alleviates cognitive impairment and constipation in D-gal-induced mice via modulation of the brain-gut axis

Mild cognitive impairment (MCI), a precursor to Alzheimer's disease, and constipation, a common gastrointestinal complaint in older adults, frequently co-occur and have been increasingly linked through the gut-brain axis. Emerging evidence suggests that disruptions in gut microbiota and intestinal function may contribute to cognitive decline. However, effective therapeutic strategies that simultaneously address both conditions remain limited. This study investigated the effects of electroacupuncture (EA) combined with the Liqi Yangyin (LQYY) formula on cognitive function and constipation in a D-galactose (D-gal)-induced mouse model of MCI. Forty-five C57BL/6 mice were randomized into five groups: control, D-gal model, EA, EA+LQYY, and donepezil groups. Behavioural tests, including the Y-maze and Morris water maze, were used to assess cognitive performance. Meanwhile, gastrointestinal (GI) transit rate, fecal water content, and histological analysis were conducted to evaluate constipation-related parameters. Intestinal barrier function was assessed via Occludin and ZO-1 protein expression, and levels of 5-hydroxytryptamine (5-HT) and amyloid-beta (Aβ42) were measured in the colon, serum, and hippocampus. Results showed that EA+LQYY significantly improved cognitive performance and alleviated constipation compared to the model group, with superior efficacy to EA alone or donepezil. Mechanistically, EA+LQYY restored intestinal barrier integrity (via upregulation of Occludin and ZO-1), increased 5-HT levels in the gut, serum, and hippocampus, and reduced Aβ42 deposition in the colon, serum, and hippocampus across tissues. These findings suggest that EA+LQYY modulates the gut-brain axis through multi-target mechanisms, offering a promising integrative therapy for MCI and associated constipation. Future studies should explore specific molecular pathways and long-term clinical efficacy to further validate its therapeutic potential.