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Pain Research and Management
Volume 2017 (2017), Article ID 4792489, 9 pages
Research Article

The Antinociceptive Effect of Light-Emitting Diode Irradiation on Incised Wounds Is Correlated with Changes in Cyclooxygenase 2 Activity, Prostaglandin E2, and Proinflammatory Cytokines

1Department of Anesthesiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
2Department of Anesthesiology, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan
3Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
4Department of Plastic & Reconstructive Surgery, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan
5Department of Anesthesiology, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan
6School of Medicine, I-Shou University, Kaohsiung, Taiwan

Correspondence should be addressed to Chih-Chieh Chen and Ping-Heng Tan

Received 2 December 2016; Accepted 2 March 2017; Published 2 April 2017

Academic Editor: Bülent S. Yurtlu

Copyright © 2017 Yuan-Yi Chia et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Light-emitting diode (LED) phototherapy has been reported to relieve pain and enhance tissue repair through several mechanisms. However, the analgesic effect of LED on incised wounds has never been examined. Objectives. We examined the analgesic effect of LED therapy on incision pain and the changes in cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and the proinflammatory cytokines interleukin 6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α). Methods. Rats received LED therapy on incised skin 6 days before incision (L-I group) or 6 days after incision (I-L group) or from 3 days before incision to 3 days after incision (L-I-L group). Behavioral tests and analysis of skin tissue were performed after LED therapy. Results. LED therapy attenuated the decrease in thermal withdrawal latency in all the irradiated groups and the decrease in the mechanical withdrawal threshold in the L-I group only. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the three LED-treated groups, whereas IL-1β and TNF-α were significantly decreased only in the L-I group compared with their levels in the I groups (). Conclusions. LED therapy provides an analgesic effect and modifies the expression of COX-2, PGE2, and proinflammatory cytokines in incised skin.