Research Article Remote Dose-Dependent Effects of Dry Needling at Distant Myofascial Trigger Spots of Rabbit Skeletal Muscles on Reduction of Substance P Levels of Proximal Muscle and Spinal Cords Yueh-Ling Hsieh, 1 Chen-Chia Yang, 2 Szu-Yu Liu, 1 Li-Wei Chou, 3,4,5 and Chang-Zern Hong 6 1 Department of Physical herapy, Graduate Institute of Rehabilitation Science, China Medical University, Taichung 40402, Taiwan 2 Department of Physical Medicine and Rehabilitation, Cheng Ching General Hospital, Taichung 40407, Taiwan 3 School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung 40402, Taiwan 4 Department of Physical Medicine and Rehabilitation, China Medical University Hospital, Taichung 40402, Taiwan 5 Research Center for Chinese Medicine and Acupuncture, China Medical University, Taichung 40402, Taiwan 6 Department of Physical herapy, Hungkuang University, Taichung 43302, Taiwan Correspondence should be addressed to Li-Wei Chou; chouliwe@gmail.com and Chang-Zern Hong; cczzhhoonngg@yahoo.com.tw Received 13 February 2014; Accepted 15 August 2014; Published 3 September 2014 Academic Editor: Katarzyna Starowicz Copyright © 2014 Yueh-Ling Hsieh et al. his 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. Dry needling at distant myofascial trigger points is an efective pain management in patients with myofascial pain. However, the biochemical efects of remote dry needling are not well understood. his study evaluates the remote efects of dry needling with diferent dosages on the expressions of substance P (SP) in the proximal muscle, spinal dorsal horns of rabbits. Methods. Male New Zealand rabbits (2.5–3.0kg) received dry needling at myofascial trigger spots of a gastrocnemius (distant muscle) in one (1D) or ive sessions (5D). Bilateral biceps femoris (proximal muscles) and supericial laminaes of L5-S2, T2-T5, and C2-C5 were sampled immediately and 5 days ater dry needling to determine the levels of SP using immunohistochemistry and western blot. Results. Immediately ater dry needling for 1D and 5D, the expressions of SP were signiicantly decreased in ipsilateral biceps femoris and bilateral spinal supericial laminaes ( < .05). Five days ater dry needling, these reduced immunoactivities of SP were found only in animals receiving 5D dry needling ( < .05). Conclusions. his remote efect of dry needling involves the reduction of SP levels in proximal muscle and spinal supericial laminaes, which may be closely associated with the control of myofascial pain. 1. Introduction Myofascial trigger points (MTrPs), a source of musculoskele- tal pain, has been deined as a hyperirritable (hypersensitive) spot in a taut band of skeletal muscle ibers and may play a key role in the pathophysiology of myofascial pain syndrome [1]. Dry needling targeting directly the primary MTrP, if performed appropriately, is one of the efective therapies for inactivating MTrPs and alleviating pain [2–10]. How- ever, repetitive and intensive needling manipulation may cause excess damage and increase inlammatory nociception in skeletal muscle ibers [11]. herefore, acupuncture-like needling at a region some distance away from the painful MTrPs can provide an alternative approach to remote pain relief [12–16]. In an electrophysiological study investigating the neural mechanism of remote efects of dry needling, it has found that these efects are mediated via intact aferent neural pathways from the stimulated site to the spinal cord segments of the proximally responded afected muscle [17] and may also involve the possible efects from extrasegments of the spinal cord, such as descending pain inhibitory systems [17]. Hindawi Publishing Corporation BioMed Research International Volume 2014, Article ID 982121, 11 pages http://dx.doi.org/10.1155/2014/982121