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Acupuncture is a traditional Chinese technique that has been used for thousands of years to treat chronic pain and other health problems related to inflammation, but the scientific basis of this technique is still poorly understood

Now, a team of researchers led by neuroscientists at Harvard Medical School has elucidated the underlying neuroanatomical principles of acupuncture activation of specific signaling pathways

In a study on mice published in the journal Nature on October 13, 2021, the team identified a subset of neurons that must exist in acupuncture and moxibustion to trigger resistance through this signaling pathway.

Scientists determined that these neurons only appear in a specific area of ​​the hind limbs, which explains why acupuncture on the hind limbs is effective, but acupuncture on the abdomen is ineffective

"This research touched on one of the most basic questions in the field of acupuncture: What is the neuroanatomical basis for body part or acupoint selection?" said Qiufu Ma, HMS professor of neurobiology and lead researcher at the Dana-Farber Cancer Institute

One area of ​​particular interest to the research team is the so-called cytokine storm—the rapid release of large numbers of cytokines that often leads to severe systemic inflammation and can be triggered by many things, including COVID-19, cancer treatment, or sepsis

Professor Ma said: "This vigorous immune response is a major medical problem, with a mortality rate as high as 15% to 30%

Use ancient techniques to treat abnormal inflammation

In recent decades, acupuncture as a potential method of treating inflammation has gained more and more acceptance in Western medicine

In this technique, acupuncture points on the surface of the body are mechanically stimulated, triggering nerve signals, and affecting the functions of other parts of the body, including organs

In a 2014 study, researchers reported that electroacupuncture (a modern version of traditional acupuncture that uses electrical stimulation) can reduce the reduction by activating the vagus nerve-adrenal axis (the way the vagus nerve sends signals to the adrenal glands to release dopamine).

In a study published in 2020, Ma and his team found that this electroacupuncture effect is region-specific: it is effective in the hind limb area, but has no effect in the abdomen area

In their new study, the researchers conducted a series of experiments on mice to verify this hypothesis

Then, the research team created mice that lost these sensory neurons

This stimulation activates the vagus nerve-adrenal axis in a manner similar to electroacupuncture

In the last experiment, the scientists explored the distribution of neurons in the hind limbs

"Based on the distribution of nerve fibers, we can almost accurately predict where electrical stimulation is effective and where it is not effective," Ma explained
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He added that these results provide "the first specific neuroanatomical explanation for the selectivity and specificity of acupuncture points, telling us the parameters of acupuncture, such as the location, depth, and intensity of acupuncture
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"

He pointed out that although this study was conducted in mice, the basic structure of neurons may be conserved in the evolution of mammals, including humans
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However, the important next step will be to conduct clinical trials of electroacupuncture on humans with inflammation caused by real-world infections such as COVID-19
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Ma is also interested in exploring other signaling pathways that can be stimulated by acupuncture to treat excessive inflammation
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He said: "We still have many difficult chronic diseases that need better treatment, such as inflammatory bowel syndrome and arthritis
.
" He added that another area of ​​need is excessive immune response, which may be cancer immunotherapy.
Side effects
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Professor Ma hopes that his research will eventually promote the scientific understanding of acupuncture and provide practical information that can be used to improve and perfect this technology
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"A neuroanatomical basis for electroacupuncture to drive the vagal–adrenal axis" by Shenbin Liu, Zhifu Wang, Yangshuai Su, Lu Qi, Wei Yang, Mingzhou Fu, Xianghong Jing, Yanqing Wang and Qiufu Ma, 13 October 2021, Nature .

DOI: 10.
1038/s41586-021-04001-4