Anti-Inflammatory Effects of Acupuncture Stimulation via the Vagus Nerve.

Hee-Don Lim,Min-Hee Kim,Uk Namgung,Chan-Yong Lee

doi:10.1371/journal.pone.0151882

Abstract

Although acupuncture therapy is widely used in traditional Asian medicine for the treatment of diverse internal organ disorders, its underlying biological mechanisms are largely unknown. Here, we investigated the functional involvement of acupuncture stimulation (AS) in the regulation of inflammatory responses. TNF-α production in mouse serum, which was induced by lipopolysaccharide (LPS) administration, was decreased by manual acupuncture (MAC) at the zusanli acupoint (stomach36, ST36). In the spleen, TNF-α mRNA and protein levels were also downregulated by MAC and were recovered by using a splenic neurectomy and a vagotomy. c-Fos, which was induced in the nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus nerve (DMV) by LPS and electroacupuncture (EAC), was further increased by focal administration of the AMPA receptor blocker CNQX and the purinergic receptor antagonist PPADS. TNF-α levels in the spleen were decreased by CNQX and PPADS treatments, implying the involvement of inhibitory neuronal activity in the DVC. In unanesthetized animals, both MAC and EAC generated c-Fos induction in the DVC neurons. However, MAC, but not EAC, was effective in decreasing splenic TNF-α production. These results suggest that the therapeutic effects of acupuncture may be mediated through vagal modulation of inflammatory responses in internal organs.

Highlights

Acupuncture therapy has been used to treat diverse disorders of the internal organ in several Asian countries, and its use is increasing in Western countries as well [1]
To examine whether the reduction in the tumor necrosis factor-α (TNF-α) production in animals given acupuncture stimulation (AS) under anesthesia was caused by the AS, we investigated the effects of acupuncture therapy on c-Fos and TNF-α productions in unanesthetized animals. c-Fos was clearly induced in the dorsal vagal complex (DVC) by LPS administration and further increased by manual acupuncture (MAC) and EAC, though EAC was more effective than MAC (Fig 6A)
The present study provides evidence that AS transmits signals into the vagus nerve and mediates anti-inflammatory responses in the spleen

Summary

Introduction

Acupuncture therapy has been used to treat diverse disorders of the internal organ in several Asian countries, and its use is increasing in Western countries as well [1]. AS at the abdomen acupoint ST25 has been shown to induce c-Fos signals in neurons at the rostroventrolateral medulla (RVLM), a brain center that sends out axons to the spinal cord for sympathetic regulation of cardiovascular functions [10]. Some RVLM neurons have been observed to respond to electrical stimulations on both the vagus nerve and the sciatic nerve [11]. While these and other reports imply that the signals from diverse acupoints may be transmitted into the vagus nerve and affect the function of ANS, systematic studies on the neuronal circuits in the brainstem, which connect somatosensory afferents and the vagal efferent, have not been reported so far

Methods

Results

Conclusion