Researchers at China Medical University and China Medical University Hospital in Taiwan recently published in the journal PLoS One new findings that electroacupuncture, through specific molecular pathways, can suppress pain in a fibromyalgia mouse model. The study is entitled “Analgesic Effect of Electroacupuncture in a Mouse Fibromyalgia Model: Roles of TRPV1, TRPV4, and pERK.”
Fibromyalgia is a medical disorder characterized by a set of symptoms that includes widespread chronic musculoskeletal pain, incapacitating fatigue, stiffness and numbness in certain parts of the body, painful response to pressure, headaches, unrefreshing sleep (poor sleep quality), anxiety or depression and mood alterations. Fibromyalgia can affect people’s ability to conduct simple daily tasks, compromising their quality of life. It is estimated that 5 to 15 million Americans are affected by the disorder, especially women. The causes of fibromyalgia are unclear, but it is thought that genetic, neurophysiological and psychosocial mechanisms are involved.
The activation of acid-sensitive ion channels has been previously suggested to contribute to muscle pain in fibromyalgia patients. The protein pERK (phosphorylated extracellular signals regulated kinase) and members of the transient receptor potential vanilloid (TRPV) family of channels have been implicated in physiological pain and suggested to be altered in chronic pain conditions such as fibromyalgia.
Acupuncture is considered a highly effective therapy for certain pain symptoms. Pain reduction through acupuncture is thought to be mediated by the release of endogenous opiates that ultimately block the transmission of inflammatory and neuropathic pain. Electroacupuncture is a type of acupuncture where a small electric current is conducted between acupuncture needles; this method is particularly effective in treating pain. Interestingly, it has been previously suggested that TRPV1 and TRPV4 channels can contribute to the electroacupuncture-mediated analgesia in a mouse model of inflammatory pain.
In the study, researchers assessed the contribution of TRPV1 and TRPV4 channels to chronic pain in a mouse model of fibromyalgia, and analyzed the potential therapeutic effect of electroacupuncture.
Researchers found that specific dorsal root ganglion (DRG; an important structure related to pain) neurons in fibromyalgia mouse models are hyperexcitable, exhibit an increase mechanical hyperalgesia (increased sensitivity to pain) and a upregulation of TRPV1 expression and activation of pERK. The team found that the blockade of TRPV1 and pERK suppressed pain development. Electroacupuncture therapy was found to reduce mechanical hyperalgesia and DRG hyperexcitability in the fibromyalgia mice. In the spinal cord of the animals, both TRPV1 and TRPV4 protein expression were found to be increased.
The research team concluded that electroacupuncture can decrease mechanical hyperalgesia in a fibromyalgia mouse model, possibly by reducing hyperexcitability, TRPV1 overexpression and pERK activation in DRG neurons, as well as by reducing the overexpression of TRPV1 and TRPV4 in the spinal cord. Electroacupuncture can therefore decrease pain through peripheral and central effects. The findings suggest that electroacupuncture might have a potential therapeutic effect in relieving fibromyalgia symptoms in humans. Further studies should, however, be conducted to test this hypothesis.
Glossary of Terms:
[wikibox lang=”en”]Extracellular signal-regulated kinases[/wikibox]