From mechanosensing to immune regulation: mechanisms of acupuncture signal initiation and amplification mediated by macrophages.

Scientists are beginning to understand exactly how acupuncture needles create healing effects throughout the body. This review study explains that the process starts when an acupuncture practitioner inserts and manipulates needles at specific points on your body. When the practitioner twists or moves the needle up and down, it creates physical stress in the tissue by pulling on collagen fibers. This mechanical signal is picked up by special cells called macrophages, which act like sensors and coordinators in your immune system. These macrophages detect the physical pressure through channels and receptors on their surface, triggering calcium changes inside the cells and activating important proteins. Once activated, macrophages recruit other immune cells to the area, help reduce inflammation, and start tissue repair processes. They do this by switching between different functional states and working with other cells like fibroblasts to rebuild the tissue matrix. The macrophages also communicate with T cells to regulate broader immune responses throughout your body. This research provides a scientific explanation for how a local needle insertion can create widespread therapeutic effects, helping resolve inflammation and promote healing. Understanding these mechanisms helps explain why acupuncture can be effective for various health conditions involving pain and inflammation. If you're considering acupuncture treatment, be sure to seek care from a licensed acupuncturist who has proper training in needle manipulation techniques.

This review examines the mechanotransduction mechanisms underlying acupuncture's therapeutic effects, with emphasis on macrophage-mediated signal initiation and amplification. The authors propose that needle manipulation techniques (lifting-thrusting, twisting) generate mechanical stress at acupoints through collagen fiber entanglement and traction. This mechanical signal propagates through the extracellular matrix to mechanosensitive cells, particularly macrophages and fibroblasts. Macrophages perceive mechanical stimuli via Piezo1, TRPV4 channels, integrin receptors, and podosomes, triggering intracellular Ca2+ fluctuations and YAP/TAZ nuclear translocation. Activated macrophages subsequently orchestrate immune responses by recruiting neutrophils and monocytes, dynamically polarizing between M1/M2 phenotypes to resolve inflammation, regulating T cell-mediated adaptive immunity through antigen presentation, and collaborating with fibroblasts for ECM remodeling. Fibroblasts concurrently release alarmin proteins like IL-33 to further modulate macrophage activity. Clinical relevance: This mechanistic framework supports the biological plausibility of acupuncture's local-to-systemic effects and suggests needle manipulation quality directly influences therapeutic outcomes through macrophage-centered immunomodulation.