Article

Transcutaneous electrical nerve stimulation (TENS) is often used for
management of chronic pain.
The purpose of this study was to
investigate whether TENS altered postincisional allodynia, substance P, and
proinflammatory cytokines in a rat model of skin-muscle incision and retraction (SMIR).
This was an experimental study. METHODS: High-frequency (100-Hz)
TENS therapy began on postoperative day 3 and was administered for 20 minutes
daily to SMIR-operated rats by self-adhesive electrodes delivered to skin
innervated via the ipsilateral dorsal rami of lumbar spinal nerves L1-L6 for the
next 27 days. The expressions of substance P, tumor necrosis factor alpha
(TNF-alpha), interleukin-6 (IL-6), and interleukin-1beta (IL-1beta) in the spinal
cord and mechanical sensitivity to von Frey stimuli (4g and 10g) were evaluated.
RESULTS: The SMIR-operated rats displayed a marked hypersensitivity to von Frey
stimuli on postoperative day 3. In contrast to the SMIR-operated rats,
SMIR-operated rats after TENS administration showed a quick recovery of
mechanical hypersensitivity. On postoperative days 3, 16, and 30, SMIR-operated
rats exhibited an upregulation of substance P and cytokines (TNF-alpha, IL-6, and
IL-1beta) in the spinal cord, whereas SMIR-operated rats after TENS therapy
inhibited that upregulation. By contrast, the placebo TENS following SMIR surgery
did not alter mechanical hypersensitivity and the levels of spinal substance P,
TNF-alpha, IL-6, and IL-1beta. LIMITATIONS: The experimental data are limited to
animal models and cannot be generalized to postoperative pain in humans.
CONCLUSIONS: The results revealed that TENS attenuates prolonged postoperative
allodynia following SMIR surgery. Increased levels of spinal substance P and
proinflammatory cytokines, activated after SMIR surgery, are important in the
processing of persistent postsurgical allodynia. The protective effect of TENS
may be related to the suppression of spinal substance P and proinflammatory
cytokines in SMIR-operated rats.
CI - (c) 2015 American Physical Therapy Association.

Langue : ANGLAIS