Therapeutic ultrasound suppresses neuropathic pain and upregulation of substance P and neurokinin-1 receptor in rats after peripheral nerve injury

Ultrasound Med Biol. 2015 Jan;41(1):143-50. doi: 10.1016/j.ultrasmedbio.2014.07.022. Epub 2014 Oct 22.

Abstract

We studied the mechanisms and impact of therapeutic ultrasound (TU) for pain caused by nerve injury. TU began on post-operative day 5 (POD5) and then continued daily for the next 22 d. Sensitivity to thermal and mechanical stimuli and levels of neurokinin-1 receptor, substance P, tumor necrosis factor-α and interleukin-6 in the sciatic nerve were examined. On POD7, chronic constriction injury rats undergoing TU at an intensity of 1 W/cm(2), but not 0.25 or 0.5 W/cm(2), had increases in both the mechanical withdrawal threshold and the thermal withdrawal latency compared with the chronic constriction injury group. Moreover, chronic constriction injury rats exhibited upregulation of neurokinin-1 receptor, substance P, tumor necrosis factor-α and interleukin-6 in the sciatic nerve on PODs 14 and 28, whereas TU inhibited their increased expression. We suggest that the efficacy of TU is dependent on its ability to limit the upregulation of neurokinin-1 receptor, substance P, tumor necrosis factor-α and interleukin-6 around the injured sciatic nerve.

Keywords: Interleukin-6; Neurokinin-1 receptor; Neuropathic pain; Substance P; Therapeutic ultrasound; Tumor necrosis factor α.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Male
  • Neuralgia / etiology
  • Neuralgia / metabolism*
  • Neuralgia / prevention & control*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Neurokinin-1 / metabolism*
  • Sciatic Neuropathy / complications
  • Sciatic Neuropathy / metabolism*
  • Sciatic Neuropathy / therapy*
  • Substance P / metabolism*
  • Treatment Outcome
  • Ultrasonic Therapy / methods*
  • Up-Regulation

Substances

  • Receptors, Neurokinin-1
  • Substance P