Anti-inflammatory effects of acupuncture via the Vagus nerve
Acupuncture is a commonly used modality utilized to treat dysfunction of the musculoskeletal system and internal organs in both eastern and western medicine. The autonomic nervous system (ANS) is frequently considered to be a mediator of acupuncture stimulation (AS), because of its ability to interconnect peripheral somatosensory input with internal organ structures.
Previous studies have shown that specific point stimulation can create measureable molecular change within the activity of specific brain centers responsible for regulating autonomic function. Considering this, the authors hypothesized that acupuncture stimulation may change internal inflammatory responses in organs, such as the spleen, via efferent Vagus nerve activity. Overall, it was shown that stimulation reduced the levels of cytokines in the spleen as well as serum, the effects of which were reversed with de-inervation of the Vagus nerve complex.
Manual acupuncture was applied for thirty minutes to acupoint ST36 in gender and age controlled mice. Cytokine (TNF-α) levels were measuredin thirty minute intervals after an inflammatory reaction was induced. Splenic and Vagus nerves were severed to determine the neural modulation of inflammatory response. Immunofluoresence staining was used to track protein expression and activity in central nervous tissue.
Growing bodies of evidence indicate that the Vagus nerve acts as a bridge between the neural and immune system, homeostatically regulating internal organs and pathological inflammatory reactions. By mechanically stimulating the ANS, the authors were able to show a reduction in both serum and spleen TNF-α, which was then abrogated with a neurectomy of the Splenic and Vagus nerve.
In a follow up experiment, they then showed that AS increased protein expression (c-Fos) levels within the motor nucleus of the vagus nerve (within the CNS). This increase in expression was then further elevated with AMPA and purinergic receptor blockers. This in turn coincided with a decrease in TNF-α as had been previously seen with the severance of the Vagus nerve. The authors speculate that this observation within the CNS indicates that inflammatory reactions by acupuncture could be mediated by disinhibition of synaptic transmission.
The study at hand continues to shed light into the complexity of acupunctures effects on human anatomy. From a clinical perspective, it is hard to ignore the significant effects somatosensory stimulation can have on immunological activity and how that in turn can effect complex cases and chronic disease.
> From: Lim et al., PLoS One 11 (2016) e0151882(Epub ahead of print). All rights reserved to The Author(s). Click here for the Pubmed summary.