Adrenal sympathetic nerve mediated the anti-inflammatory effect of electroacupuncture at ST25 acupoint on a rat model of sepsis

Abstract

Acupuncture plays a vital anti-inflammatory action on sepsis through activating autonomic nerve anti-inflammatory pathways, such as sympathoadrenal medullary pathway, but the mechanism remains unclear. This study aims to explore the optimum parameter of electroacupuncture (EA) stimulation in regulating sympathoadrenal medullary pathway and evaluate EA anti-inflammatory effect on sepsis. To explore the optimum parameter of EA at homosegmental acupoint on adrenal sympathetic activity, the left adrenal sympathetic nerve firing rate evoked by different intensities of single shock electrical stimulation (ES) at ST25 in healthy male Sprague-Dawley (SD) rats were evaluated by in vivo electrophysiological recording, and the levels of norepinephrine (NE) and its metabolites were also examined using mass spectrometry. To verify the role of EA at ST25 in sepsis, the rat was given intraperitoneal injection lipopolysaccharide to induce sepsis model, and survival rate, clinical score, and the level of interleukin (IL)-6, IL-1β, and IL-10 were evaluated after EA application. We observed that 3 mA is the optimal intensity on activating adrenal sympathetic nerve, which significantly elevated the level of NE in the peripheral blood. For LPS-treated rats, EA at the ST25 apparently increased the survival rate and improved the clinical score compared to the control group. Furthermore, 3 mA EA at ST25 significantly decreased pro-inflammatory cytokines IL-6 and IL-1β and upregulated anti-inflammatory cytokine IL-10 compared to the Lipopolysaccharide (LPS)-treated group. Overall, these data suggest that 3 mA is the optimal EA intensity at ST25 to activate the sympathoadrenal medullary pathway and exert an anti-inflammatory effect on sepsis.

Revealing the biological mechanism of acupuncture in alleviating excessive inflammatory responses and organ damage in sepsis: a systematic review

“…The sympathetic nervous system plays a dual role in regulating inflammatory responses and mediates both proinflammatory and anti-inflammatory effects. A previous study found that stimulating the homosegmental acupoint ST25 with 3 mA EA can drive the release of peripheral NE from the sympathoadrenal medullary axis ( 108 ). Unlike low-intensity EA, high-intensity EA activates the sympathetic nervous system and inhibits sepsis-induced inflammation.…”