A New Acupuncture Mechanism for Pain Management

A New Acupuncture Mechanism for Pain Management

Muscle pain is a common medical problem that is difficult to treat. One nonpharmacological treatment used is acupuncture, a procedure in which fine needles are inserted into body points with the intent of relieving pain and other symptoms. Here we investigated the effects of manual acupuncture (MA) on modulating macrophage phenotype and interleukin-10 (IL-10) concentrations in animals with muscle inflammation. Carrageenan, injected in the gastrocnemius muscle of mice, induces an inflammatory response characterized by mechanical hyperalgesia and edema. The inflammation is initially a neutrophilic infiltration that converts to a macrophage-dominated inflammation by 48 h. MA of Sanyinjiao (SP6) acupoint reduces nociceptive behaviors, heat, and mechanical hyperalgesia and enhanced escape/avoidance and the accompanying edema. Sanyinjiao (SP6) MA increased muscle IL-10 levels and was ineffective in reducing pain behaviors and edema in IL-10 knockout (IL-10^-/-) mice. Repeated daily treatments with Sanyinjiao (SP6) MA induced a phenotypic switch of muscle macrophages with reduced M1 macrophages (pro-inflammatory cells) and an increase of M2 macrophages (anti-inflammatory cells and important IL-10 source). These findings provide new evidence that MA produces a phenotypic switch in macrophages and increases IL-10 concentrations in muscle to reduce pain and inflammation.

da Silva MD, Bobinski F, Sato KL, Kolker SJ, Sluka KA, Santos AR. IL-10 Cytokine Released from M2 Macrophages Is Crucial for Analgesic and Anti-inflammatory Effects of Acupuncture in a Model of Inflammatory Muscle Pain. Mol Neurobiol. 2014 Jun 25.