High-frequency transcutaneous electrical nerve stimulation attenuates postsurgical pain and inhibits excess substance P in rat dorsal root ganglion

Reg Anesth Pain Med. Jul-Aug 2014;39(4):322-8. doi: 10.1097/AAP.0000000000000091.

Abstract

Background: Transcutaneous electrical nerve stimulation (TENS) is a common therapeutic modality for pain management, but its effectiveness in skin/muscle incision and retraction (SMIR)-evoked pain is unknown. We aimed to examine the effects of TENS on postoperative pain and the levels of substance P (SP), N-methyl-D-aspartate receptor 1 (NR1), and interleukin 1β (IL-1β) in rat dorsal root ganglion (DRG).

Methods: High-frequency (100 Hz) TENS was administered daily beginning on postoperative day 1 (POD1) and continued until animal subjects were killed for tissues. Mechanical sensitivity to von Frey stimuli (6g and 15g) and the levels of NR1, SP, and IL-1β in DRG were assessed in the sham-operated, SMIR-operated, TENS after SMIR surgery, and placebo-TENS after SMIR surgery groups.

Results: Skin/muscle incision and retraction rats exhibited a significant hypersensitivity to von Frey stimuli on POD3. In contrast with SMIR rats, SMIR-operated rats receiving TENS therapy demonstrated a rapid recovery of mechanical hypersensitivity. The SMIR-operated rats showed an up-regulation of NR1, SP, and IL-1β in DRG on PODs 14 and 28, whereas the SMIR-operated rats after TENS administration reversed this up-regulation. By contrast, the placebo-TENS after SMIR operation did not alter postsurgical pain nor the levels of NR1, SP, and IL-1β.

Conclusions: Our data demonstrated that TENS intervention reduced persistent postoperative pain caused by SMIR operation. Up-regulation of NR1, SP, and IL-1β in DRG, activated after SMIR surgery, is important in the development of prolonged postincisional pain. The TENS pain relief may be related to the suppression of NR1, SP, and IL-1β in DRG of SMIR rats.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ganglia, Spinal / metabolism*
  • Interleukin-1beta / metabolism
  • Male
  • Pain Measurement
  • Pain, Postoperative / therapy*
  • Physical Stimulation
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / metabolism
  • Substance P / metabolism*
  • Transcutaneous Electric Nerve Stimulation / methods*

Substances

  • Interleukin-1beta
  • Receptors, N-Methyl-D-Aspartate
  • Substance P