BACKGROUND: Postoperative cognitive dysfunction (POCD), a common neurological complication in elderly patients, significantly impairs recovery. Emerging evidence suggests the gut microbiota is involved in its pathogenesis. This study aimed to determine whether acupoint catgut embedding (ACE) could alleviate POCD by modulating the gut microbiota in aged mice after laparotomy.
METHODS: Eighteen-month-old male C57BL/6J mice underwent laparotomy on day 8 (excluding the Sham group). The ACE group received ACE treatment, while the anesthesia and surgery group served as surgical controls. The fecal microbiota transplantation (FMT)-ACE and FMT-AS groups received FMT from corresponding donors. Additional groups received oral indole-3-propionic acid (IPA) or vehicle-treated surgery. Hippocampal inflammation and blood-brain barrier proteins were assessed on day 9; cognitive function and intestinal markers on day 15.
RESULTS: Cognitive function was significantly improved in the ACE, FMT-ACE, and IPA groups. ACE and FMT-ACE treatments specifically elevated fecal g-Clostridia_UCG-014 abundance and serum IPA levels. These changes were accompanied by suppressed hippocampal toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling and proinflammatory cytokines [tumor necrosis factor alpha, interleukin (IL)-1β], together with elevated tight junction proteins (occludin, claudin-5). Furthermore, colonic aryl hydrocarbon receptor (AhR) and IL-22 were upregulated, while serum lipopolysaccharide and diamine oxidase were reduced. Accordingly, IPA treatment mirrored the key anti-inflammatory and barrier-protective effects.
CONCLUSION: ACE alleviates POCD probably by modulating gut microbiota, specifically increasing g-Clostridia_UCG-014 abundance and metabolite IPA. These effects are potentially mediated by dual pathways: (a) suppression of neuroinflammation via TLR4/NF-κB signaling, and (b) enhancement of gut barrier integrity via AhR/IL-22 axis. Our findings highlight the therapeutic potential of ACE in targeting the gut-brain axis for POCD management.
