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Evidence-Based Complementary and Alternative Medicine
Volume 2012 (2012), Article ID 671386, 16 pages
http://dx.doi.org/10.1155/2012/671386
Research Article

Effects of Different Electroacupuncture Scheduling Regimens on Murine Bone Tumor-Induced Hyperalgesia: Sex Differences and Role of Inflammation

1Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
2Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
3Department of Veterinary and Biomedical Sciences, University of Minnesota, Room 205 Veterinary Medicine Building, 1971 Commonwealth Avenue, St. Paul, MN 55108, USA

Received 23 August 2012; Revised 21 November 2012; Accepted 28 November 2012

Academic Editor: Chong-Zhi Wang

Copyright © 2012 Branden A. Smeester 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.

Abstract

Previous studies have shown that electroacupuncture (EA) is able to reduce hyperalgesia in rodent models of persistent pain, but very little is known about the analgesic effects and potential sex differences of different EA treatment regimens. In the present study, we examined the effects of five different EA treatments on tumor-induced hyperalgesia in male and female mice. EA applied to the ST-36 acupoint either twice weekly (EA-2X/3) beginning on postimplantation day (PID) 3 or prophylactically three times prior to implantation produced the most robust and longest lasting antinociceptive effects. EA treatment given once per week beginning at PID 7 only produced an antinociceptive effect in female animals. The analgesic effect of EA-2X/3 began earlier in males, but lasted longer in females indicating sex differences in EA. We further demonstrate that EA-2X/3 elicits a marked decrease in tumor-associated inflammation as evidenced by a significant reduction in tumor-associated neutrophils at PID 7. Moreover, EA-2X/3 produced a significant reduction in tumor-associated PGE2 as measured in microperfusate samples. Collectively, these data provide evidence that EA-2X/3 treatment reduces tumor-induced hyperalgesia, which is associated with a decrease in tumor-associated inflammation and PGE2 concentration at the tumor site suggesting possible mechanisms by which EA reduces tumor nociception.