Electrical stimulation of the auricular branch of the vagus nerve potentiates analgesia induced by physical exercise in mice with peripheral inflammation

Abstract

ObjectiveThis study evaluated the antihyperalgesic and anti-inflammatory effects of percutaneous vagus nerve electrical stimulation (pVNS) associated with physical exercise, i.e., swimming, in mice with peripheral inflammation.MethodsThe pain model was induced by intraplantar (i.pl.) injection of Freund’s complete adjuvant (CFA). Sixty-four male Swiss mice (35–40 g) received an i.pl. of CFA and underwent behavioral tests, i.e., mechanical hyperalgesia, edema, and paw temperature tests. Additionally, cytokine levels, specifically interleukin-6 (IL-6) and interleukin-10 (IL-10), were determined by enzyme-linked immunosorbent assay. Mice were treated with swimming exercise for 30 min alone or associated with different time protocols (10, 20, or 30 min) of stimulation in the left ear with random frequency during four consecutive days.ResultspVNS for 20 min prolonged the antihyperalgesic effect for up to 2 h, 24 h after CFA injection. pVNS for 30 min prolonged the antihyperalgesic effect for up to 7 h, 96 h after CFA injection. However, it did not alter the edema or temperature at both analyzed times (24 and 96 h). Furthermore, the combination of pVNS plus swimming exercise, but not swimming exercise alone, reduced IL-6 levels in the paw and spinal cord, as well as IL-10 levels in the spinal cord.ConclusionpVNS potentiates the analgesic effect induced by swimming, which may be, at least in part, mediated by the modulation of inflammatory cytokines in the periphery (paw) and central nervous system (spinal cord). Therefore, the combination of these therapies may serve as an important adjunctive treatment for persistent inflammatory pain.

Transcutaneous Auricular Vagus Nerve Stimulation Alleviates Monobenzone-Induced Vitiligo in Mice

“…In our research, we further explored the potential impact of vagus nerve stimulation in a mouse model of vitiligo. We observed a significant decrease in inflammation in vitiligo mice after vagus nerve stimulation, consistent with previous findings in inflammatory diseases, suggesting that the vagus nerve system may alleviate tissue damage and the development of related inflammatory diseases by inhibiting inflammatory reactions [ 9 , 29 , 30 , 31 , 32 ]. However, unlike previous studies that have focused mainly on the regulation of inflammatory processes, our study explored the potential effects of vagus nerve stimulation on skin diseases.…”