Neural Pathway Involving the Remote Effects of Dry Needling on the Irritability of Myofascial Trigger Spots in Rabbit Skeletal Muscle

• Main Authors: Yie-San Joe, 卓裕森
• Other Authors: Chi-Mei Hsueh
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/78103728111869650885

碩士 === 國立中興大學 === 生命科學院碩士在職專班 === 100 === Previous clinical study has demonstrated remote effects of acupuncture on alleviating chronic myofascial pain. Myofascial trigger point (MTrP) is the major cause of myofascial pain in clinical practice. In the MTrP region, electromyographic (EMG) activity of endplate noise (EPN) can be recorded. The prevalence and amplitude of EPN is highly correlated with the irritability of an MTrP, and can be indicators to assess the effectiveness of MTrP therapy. Recent human studies have indicated that the irritability of an MTrP can be suppressed after dry needling of a remote MTrP. However, its underlying neural pathway is still unclear and needs to be further investigated. This pathway is probably also similar to that of remote effects of acupuncture. This study is designed to investigate the remote effects of dry needling to distal myofascial trigger spots (MTrS – similar to human MTrP) of gastrocnemius muscle on the irritability of a proximal MTrS of biceps femoris muscle in rabbit skeletal muscle. The purposes of this study are to: (1) investigate the remote influence of dry needling on the irritability (assessed with the change in the amplitude of EPN) in the MTrS of rabbit skeletal muscle, (2) investigate the influence of the peripheral nerve transaction on the effectiveness of dry needling of MTrS, and (3) investigate the influence of the spinal cord transection on the effectiveness of dry needling of MTrS. Ninety six adult male New Zealand rabbits will be investigated. The animals in the treatment group will be treated with dry needling on the distal MTrSs of the gastrocnemius muscles. Very slow needle insertion (sham needling) with minimal local twitch response elicitation will conducted to the MTrSs of same muscles for the control group. The electromyographic changes of endplate noise (EPN) at biceps femoris elicited before, during and 3 minutes after dry needling treatments were collected for evaluating the irritability of the proximal MTrS. Animals were divided four group: no intervention for neural interruption in group I, transection of the tibial nerve in group II, transection of L5 and L6 spinal cord in group III, and transection of the T1 and T2 spinal cord in group IV. Each group was further divided into 4 subgroups: animals received ipsilateral dry needling, contralateral dry needling, ipsilateral sham needling, or contralateral sham needling of gastrocnemius MTrSs. Mean EPN amplitudes of Biceps femoris MTrS significantly increased (P<0.05) initially after gastrocnemius needling but reduced to a level significantly lower (P<0.05) than the preneedling level in groups I and IV with ipsilateral dry needling or contralateral dry needling, and in group II with contralateral dry needling (but not ipsilateral dry needling). No significant EPN amplitude changes were observed in group III or in the control animals receiving superficial sham needling. This remote effect of dry needling depends on an intact afferent pathway from the stimulating site to the spinal cord and a normal spinal cord function at the levels corresponding to the innervation of the proximally affected muscle. Finally, the neural pathways of the dry needling to influence the remote MTrS activity may be clarified.