Transcutaneous auricular vagus nerve stimulation mitigates gouty inflammation by reducing neutrophil infiltration in BALB/c mice

Abstract Gouty inflammation, caused by uric acid crystal deposition, primarily affects tissues around the toe joints and triggers potent inflammatory responses. Current treatments focus on alleviating inflammation and pain using pharmaceutical agents, which can lead to side effects and complications. This has generated interest in non-pharmacological interventions, such as non-invasive vagus nerve stimulation (VNS). In this study, we explored the anti-inflammatory mechanisms of transcutaneous auricular vagus nerve stimulation (taVNS) in a mouse model of acute gout. Gouty inflammation was induced by injecting monosodium urate (MSU) crystals into the ankle joints of BALB/c mice. The effects of taVNS on the expression of inflammatory cytokines and chemokines in the ankle joint tissue were assessed using real-time quantitative PCR (qPCR), western blotting, histological assessments (H&E staining), and immunohistochemistry (IHC). The role of α7 nicotinic acetylcholine receptors (α7nAChR) was also evaluated by signal blocking. Our findings revealed that MSU significantly elevated gout-associated inflammatory cascades and mediators in the ankle joint. Notably, taVNS at 200 µA and 25 Hz effectively reduced these inflammatory responses, decreasing neutrophil infiltration and chemoattraction within the tissue. taVNS showed significant anti-inflammatory properties by suppressing neutrophil activity, offering a novel therapeutic approach for gout beyond conventional pharmacological methods. Additionally, taVNS holds potential for managing various chronic joint diseases. These results highlight taVNS as a promising non-pharmacological therapy for chronic inflammation.