Role of Neuroimmune Crosstalk in Mediating the Anti-inflammatory and Analgesic Effects of Acupuncture on Inflammatory Pain

Inflammatory pain is a complex condition that affects millions of people around the world, caused by injuries to peripheral tissues and inflammatory processes that can lead to chronic pain and progressive functional limitations. This scientific review examines how acupuncture may help in the treatment of inflammatory pain through specific mechanisms of communication between the nervous system and the immune system, offering a scientific perspective on this ancient therapy.

The study of inflammatory pain reveals that it develops through a complex process whereby tissue injuries activate immune system cells, which then release inflammatory substances. These substances not only cause local inflammation but also sensitize the nerves that detect pain, making them more sensitive to stimuli. In addition, prolonged stimulation may cause changes in the central nervous system, creating a cycle in which pain is perpetuated even after the initial injury has been repaired. The World Health Organization officially recognizes acupuncture as an effective treatment for sixteen diseases related to inflammatory pain, including rheumatoid arthritis, gastritis, and shoulder bursitis.

This research consisted of a comprehensive review of the scientific literature, analyzing studies published between 2010 and 2020. The researchers initially examined more than three thousand scientific articles, refining the selection to 97 experimental studies that investigated the mechanisms by which acupuncture relieves inflammatory pain. Most studies used well-established animal models of inflammatory pain, primarily the complete Freund's adjuvant-induced arthritis model, which simulates features of human rheumatoid arthritis. The most frequently studied acupuncture points were ST-36 (Zusanli) and other points traditionally used in the treatment of arthritic conditions.

The results revealed that acupuncture acts through three main levels of interaction between nerves and immune cells. At the site of the acupuncture points, needle insertion activates specific channels in cells, particularly TRPV1 and TRPV2 channels, promoting the release of substances such as adenosine and histamine. These substances interact with receptors on nerve terminals, initiating the therapeutic signals of acupuncture. At the sites of inflammation, acupuncture demonstrated the ability to recruit immune cells that release natural opioid peptides, providing pain relief, while also regulating the balance between pro-inflammatory and anti-inflammatory immune cells.

In the central nervous system, acupuncture inhibits communication between glial cells and neurons, reducing the release of excitatory neurotransmitters and promoting the release of pain-inhibiting substances.

For patients suffering from chronic inflammatory pain, these findings are particularly relevant because they demonstrate that acupuncture does not merely mask pain, but acts on the fundamental mechanisms that perpetuate it. The therapy has proven effective in reducing inflammatory markers such as interleukin-1β, tumor necrosis factor-α, and interleukin-6, while simultaneously increasing anti-inflammatory mediators such as interleukin-10. For health care professionals, the results provide solid scientific evidence that acupuncture can be safely integrated into conventional treatment protocols, potentially reducing dependence on anti-inflammatory medications and analgesics that may have significant side effects with prolonged use.

The research also identified several important limitations that should be considered. Most studies used animal models of acute pain rather than chronic inflammatory conditions that are more representative of human clinical conditions. Additionally, the brain mechanisms that regulate neuroimmune interactions during acupuncture treatment are not yet as well understood as the peripheral and spinal mechanisms. Another significant limitation is that many studies examined only the protective effects of acupuncture in the early phases of inflammatory pain, and more studies are needed on its efficacy in chronic inflammatory conditions.

The scientific evidence compiled in this review demonstrates that acupuncture acts through multiple integrated mechanisms that modulate both inflammation and pain transmission. By regulating communication between nerve and immune cells at different levels of the nervous system, acupuncture offers a therapeutic approach that goes beyond mere symptomatic relief, acting on the underlying causes of inflammatory pain. These findings pave the way for future research that may develop more specific and effective protocols, potentially combining acupuncture with conventional therapies for optimal pain management. For patients and professionals interested in integrative approaches to pain treatment, this research provides a robust scientific basis for considering acupuncture as a valid and evidence-based therapeutic option.