Electroacupuncture Attenuates CFA-induced Inflammatory Pain by suppressing Nav1.8 through S100B, TRPV1, Opioid, and Adenosine Pathways in Mice

Sci Rep. 2017 Feb 13:7:42531. doi: 10.1038/srep42531.

Abstract

Pain is associated with several conditions, such as inflammation, that result from altered peripheral nerve properties. Electroacupuncture (EA) is a common Chinese clinical medical technology used for pain management. Using an inflammatory pain mouse model, we investigated the effects of EA on the regulation of neurons, microglia, and related molecules. Complete Freund's adjuvant (CFA) injections produced a significant mechanical and thermal hyperalgesia that was reversed by EA or a transient receptor potential V1 (TRPV1) gene deletion. The expression of the astrocytic marker glial fibrillary acidic protein (GFAP), the microglial marker Iba-1, S100B, receptor for advanced glycation end-products (RAGE), TRPV1, and other related molecules was dramatically increased in the dorsal root ganglion (DRG) and spinal cord dorsal horn (SCDH) of CFA-treated mice. This effect was reversed by EA and TRPV1 gene deletion. In addition, endomorphin (EM) and N6-cyclopentyladenosine (CPA) administration reliably reduced mechanical and thermal hyperalgesia, thereby suggesting the involvement of opioid and adenosine receptors. Furthermore, blocking of opioid and adenosine A1 receptors reversed the analgesic effects of EA. Our study illustrates the substantial therapeutic effects of EA against inflammatory pain and provides a novel and detailed mechanism underlying EA-mediated analgesia via neuronal and non-neuronal pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acupuncture Analgesia
  • Adenosine / metabolism
  • Analgesics, Opioid / metabolism
  • Analgesics, Opioid / pharmacology
  • Animals
  • Behavior, Animal
  • Biomarkers
  • Chromones / pharmacology
  • Disease Models, Animal
  • Electroacupuncture*
  • Freund's Adjuvant / adverse effects*
  • Gene Deletion
  • Gene Expression
  • Gene Knockout Techniques
  • Glial Fibrillary Acidic Protein / genetics
  • Glial Fibrillary Acidic Protein / metabolism
  • Male
  • Mice
  • Morpholines / pharmacology
  • NAV1.8 Voltage-Gated Sodium Channel / metabolism*
  • Neurons / metabolism
  • Pain / etiology*
  • Pain / metabolism*
  • Pain Management* / methods
  • Proto-Oncogene Proteins c-akt / metabolism
  • S100 Calcium Binding Protein beta Subunit / metabolism*
  • Signal Transduction*
  • Spinal Cord Dorsal Horn / cytology
  • Spinal Cord Dorsal Horn / metabolism
  • TOR Serine-Threonine Kinases / metabolism
  • TRPV Cation Channels / genetics
  • TRPV Cation Channels / metabolism*
  • Xanthines / pharmacology

Substances

  • Analgesics, Opioid
  • Biomarkers
  • Chromones
  • Glial Fibrillary Acidic Protein
  • Morpholines
  • NAV1.8 Voltage-Gated Sodium Channel
  • S100 Calcium Binding Protein beta Subunit
  • S100b protein, mouse
  • TRPV Cation Channels
  • TRPV1 protein, mouse
  • Xanthines
  • glial fibrillary astrocytic protein, mouse
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • rolofylline
  • Freund's Adjuvant
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • Adenosine