The key role of muscle spindles in the pathogenesis of myofascial trigger points according to ramp-and-hold stretch and drug intervention in a rat model.

This study investigated whether abnormal peak inversion spontaneous potentials (PISPs) recorded at resting myofascial trigger points (MTrPs) stem from the discharge of muscle spindles. Forty-eight male Sprague-Dawley rats were randomly divided into six groups. Five groups underwent MTrP modeling intervention, whereas one group did not receive intervention and was duly designated as the blank control. After model construction, five rat models were randomly subjected to ramp-and-hold stretch tests, succinylcholine injection, eperisone hydrochloride injection, saline injection, and blank drug intervention. By contrast, the rats in the blank control group were subjected to ramp-and-hold stretch tests as a control. Frequencies and amplitudes of PISPs were recorded pre- and post-interventions and compared with those of the blank group. Stretch tests showed that the depolarization time and amplitude of PISPs ranged from 0.4 ms to 0.9 ms and from 80 uV to 140 µV, respectively. However, no PISPs were observed in the control rats. The frequency of PISPs in the ramp and hold phases and the first second after the hold phase was higher than that before stretching (p < 0.01). Succinylcholine and eperisone exerted excitatory and inhibitory effects on PISPs, respectively. In the group injected with 0.9% saline, no considerable differences of the PISPs were observed during the entire observation period. In conclusion, PISPs recorded at resting MTrPs are closely related to muscle spindles. The formation of MTrPs may be an important factor that regulate dysfunctional muscle spindles.

In vitro culture of muscle cells derived from myofascial trigger points.

OBJECTIVE: To examine for the in vitro existence of contractile nodules on the taut band of muscle fibers where myofascial trigger points (MTrPs) are located (using cell culture). METHODS: Sixteen male Sprague-Dawley rats (7 weeks old) were randomly divided into experimental and control groups. A blunt striking injury and eccentric exercise were applied to the gastrocnemius muscle of rats in the experimental group once a week for 8 weeks to establish an MTrP model. Subsequently, the rats were reared normally and rested for 4 weeks. After modeling, the skeletal muscles at the MTrPs (and non-MTrPs at the same anatomical position) were extracted from the two groups of rats for in vitro cell culture experiments of single muscle fibers. Potential contractile nodules in the MTrP group were exposed to different concentrations of acetylcholinesterase, whereas non-MTrP cells were exposed to acetylcholine. The morphological changes of muscle cells in each group were observed. RESULTS: By culturing MTrP cells in vitro, large contractile nodules remained in single MTrP muscle fibers, whereas some contractile nodules were twisted and deformed. After the addition of different acetylcholinesterase concentrations, no obvious morphological changes were observed in the contractile nodules in the MTrP group. After the non-MTrP cells were exposed to different acetylcholine concentrations, no significant morphological changes were observed in the single muscle fibers. CONCLUSION: MTrP cells can continue to maintain contractile morphology in vitro, but whether the recovery of such contractile nodules is related to acetylcholine remains uncertain.

Clinical observations in treatment of lower extremity varicose veins with trigger points acupuncture.

OBJECTIVES: To observe the effect of the acupuncture of myofascial trigger points (MTrPs) in the treatment of lower extremity varicose veins (LEVVs). METHODS: Overall, 260 patients with LEVVs participated in this study. LEVVs were selected based on diagnostic criteria of Clinical, Etiology, Anatomy, and Pathophysiology levels 2-5 and classified into six types on the basis of their anatomical positions. The MTrPs in the lower extremities were localized in accordance with the classification of LEVVs and treated by MTrPs acupuncture combined with self-massage and self-stretching. The interval between each treatment was 2 weeks to 1 month, depending on needling pain tolerance of each patient. An in-house evaluation was used to estimate the proportion of varicose veins in the lower limbs and their accompanying symptoms. The treatment effect was evaluated before each treatment and at 1-year follow-up. RESULTS: The mean evaluation score of LEVVs before the treatment course was 3.66 ± 1.19. After the course, this reduced to 1.18 ± 0.97, with the following response rates: 85% for excellent and good and 15% for medium. After 1-year follow-up, the mean evaluation score of all patients was 1.11 ± 0.92, with the following response rates: 87% for excellent and good, and 13% for medium. CONCLUSIONS: In some patients, MTrP acupuncture could cure LEVVs and its accompanying symptoms. These LEVVs are probably caused by fascia tension as a pre-pathology induced by the MTrPs.

Effectiveness of ischemic compression on myofascial trigger points in relieving neck pain: A systematic review and meta-analysis.

BACKGROUND: Ischemic compression is widely used to clinically treat neck pain. However, no meta-analysis has been conducted to evaluate the effects of this process on neck pain. OBJECTIVE: This study aimed to evaluate the effects of ischemic compression on the myofascial trigger points for improving neck pain-related symptoms (mainly pain, joint mobility limitation and function limitation) and to compare ischemic compression with other therapies. METHODS: Electronic searches were conducted in PubMed, OVID, Web of Science, EBSCO, SCOUPS, Cochrane Library, PEDro, Wanfang, CNKI and Chinese VIP Database in June 2021. Only randomised controlled trials on the effects of ischemic compression on neck pain were included. The major outcomes were pain intensity, pressure pain threshold, pain-related disability and range of motion. RESULTS: Fifteen studies involving 725 participants were included. Significant differences were observed between ischemic compression and sham/no treatment group in pain intensity, pressure pain threshold and range of motion immediately and in the short term. Significant effect sizes of dry needling were observed over ischemic compression in terms of improving pain intensity (SMD = 0.62; 95% CI: 0.08 to 1.16; P= 0.02), pain-related disability (SMD = 0.68; 95% CI: 0.19 to 1.17; P= 0.007) and range of motion (MD =-2.12; 95% CI: -2.59 to -1.65; P< 0.001) immediately after treatment. Dry needling also showed a significant small effect size for the short-term reduction of pain (SMD = 0.44; 95% CI: 0.04 to 0.85; P= 0.03). CONCLUSION: Ischemic compression can be recommended in the immediate and short-term pain relief and increase in the pressure pain threshold and range of motion. Dry needling is superior to ischemic compression in relieving pain and improving pain-related disability and range of motion immediately after treatment.

Dry needling on latent and active myofascial trigger points versus oral diclofenac in patients with knee osteoarthritis: a randomized controlled trial.

BACKGROUND: Latent and active myofascial trigger points (MTrPs) in knee-associated muscles may play a key role in pain management among patients with knee osteoarthritis (KOA). The aim of this study was to investigate the effect of dry needling treatment on pain intensity, disability, and range of motion (ROM) in patients with KOA. METHODS: This randomized, single-blinded, clinical trial was carried out for 6 weeks of treatment and 6-month follow-up. A total of 98 patients met the entry criteria and were randomly assigned to the dry needling latent and active myofascial trigger point (MTrPs) with the stretching group or the oral diclofenacwith the stretching group. Numeric Pain Rating Scale (NPRS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and ROM were statistically analyzed before and after treatment and at the 6-month follow-up. RESULTS: A total of 42 patients in the dry needling group (DNG) and 35 patients in the diclofenac group (DG), respectively, completed the study, and there was no significant difference in the general data between the two groups. After treatments, both the groups showed a good effect in knee pain, function, and ROM, However, the DNG showed a significantly better result than the DG. Especially in the results of the 6-month follow-up, the DNG showed much better results than the DG. CONCLUSIONS: Dry needling on latent and active MTrPs combined with stretching and oral diclofenac combined with stretching can effectively relieve pain, improve function, and restore knee ROM affected by KOA. However, the effects of dry needling and stretching are better and longer lasting than those of oral diclofenac and stretching for at least 6 months. TRIAL REGISTRATION: Registered in the Chinese Clinical Trial Registry ( www.chictr.org.cn ) in 17/11/2017 with the following code: ChiCTR-INR-17013432.

Effects of sling exercise on the core endurance and performance of basketball players / Efectos del ejercicio con sling en la resistencia del core y rendimiento de los jugadores de baloncesto / Efeitos do exercício com sling na resistência do core e desempenho de jogadores de basquetebol

ABSTRACT Introduction Strong core stability and strength enable the trunk to transfer the maximum amount of torque to the terminal segments, which is conducive to improving athletic performance. Because sling training is a new core exercise method, its effect on trunk endurance relative to basketball performance has rarely been studied. Objective To investigate whether a core exercise program in a specific sports group can improve core and sports-specific performance. Methods A total of 40 college students majoring in basketball were randomly assigned to training and control groups. A standardized set of core endurance and basketball-specific performance tests were used to determine and assess the effects of sling training on trunk strength, endurance, and control. Results Flexor, extensor, and right and left lateral trunk flexor muscles endurance were significantly greater in the training group than in the control group, and the time to complete the layup obstacle course was shorter than in the control group at the end of the training program, p<0.01. No differences between the two groups were found in the penalty shot, the fixed position shot, or the vertical jump and reach at the end of the training program. Conclusions Sling exercises can improve the core endurance and strength of basketball players and increase the speed of lay-ups over obstructions. Level of evidence I; Randomized clinical trial.

RESUMEN Introducción La sólida estabilidad y fuerza del core permiten que el tronco transfiera el torque máximo a los segmentos terminales, lo que conduce a mejorar el rendimiento deportivo. Como método novedoso de ejercicio para el core, se ha estudiado poco el efecto del entrenamiento con ejercicios con sling sobre la resistencia del tronco en relación con el rendimiento en el baloncesto. Objetivo Investigar si un programa de ejercicios para el core en un grupo deportivo específico puede mejorar el rendimiento del core y específico del deporte. Métodos Un total de 40 estudiantes universitarios con especialización en baloncesto fueron asignados aleatoriamente a grupos de entrenamiento y de control. Se utilizó una serie estandarizada de pruebas de resistencia del core y rendimiento específico del baloncesto para determinar y evaluar los efectos de los ejercicios con sling en la fuerza, la resistencia y el control del tronco. Resultados La resistencia de los músculos flexores, extensores y flexores laterales derecho e izquierdo del tronco fue significativamente mayor en el grupo de entrenamiento en comparación con el grupo de control, y el tiempo para completar la prueba de tiro con obstáculos fue menor que el del grupo de control al final del programa de entrenamiento, p<0,01. No hubo diferencias entre los dos grupos en lo que respecta a: tiro libre, lanzamiento en posición fija y salto vertical y alcance al final del programa de entrenamiento. Conclusiones Los ejercicios con sling pueden mejorar la resistencia y la fuerza del core en jugadores de baloncesto y aumentar la velocidad de los tiros con dribling. Nivel de evidencia I; Ensayo clínico aleatorizado.

RESUMO Introdução A sólida estabilidade e a força do core permitem que o tronco transfira o torque máximo para os segmentos terminais, o que é propício para melhorar o desempenho atlético. Como um novo método de exercício para o core, o efeito do treinamento com sling na resistência do tronco com relação ao desempenho no basquete tem sido pouco estudado. Objetivo Investigar se um programa de exercícios para o core em um grupo esportivo específico pode melhorar o desempenho do core e específico do esporte. Métodos Um total de 40 estudantes universitários formados em basquete foram aleatoriamente designados para grupos de treinamento e controle. Uma série padronizada de testes de resistência do core e desempenho específico do basquete foi usada para determinar e avaliar os efeitos dos exercícios com sling na força, resistência e controle do tronco. Resultados A resistência dos músculos flexores, extensores e flexores laterais direito e esquerdo do tronco foi significativamente maior no grupo treinamento em comparação ao grupo controle e o tempo para concluir o teste de bandeja com obstáculos foi menor que o do grupo controle no final do programa de treinamento, p < 0,01. Não houve diferenças entre os dois grupos quanto ao lance livre, arremesso em posição fixa e salto vertical e alcance no final do programa de treinamento. Conclusões Os exercícios com sling podem melhorar a resistência e a força do core em jogadores de basquete e aumentar a velocidade das bandejas com drible. Nível de evidência I; Estudo clínico randomizado.

Effects of dry needling intervention on lower limb dysfunction after stroke: study protocol for a randomised controlled trial.

INTRODUCTION: Lower limb dysfunction is among the common sequelae of patients who had a poststroke and often results in the reduction of the quality of life. This study aims to assess the short and interim-term efficacy of dry needling (DN) intervention on lower extremity function, balance and gait in lower limb dysfunction after stroke. METHODS AND ANALYSIS: This protocol entails an assessor and statistician-blinded, single-centre study with a randomised controlled trial. Forty-four patients who had a poststroke will be randomly allocated (1:1) to either the conventional treatment group (n=22) or the DN group (n=22). The conventional treatment group will receive conventional rehabilitation treatment once a day for 40 min each time. The treatment will be performed five times a week for 2 weeks. In the DN group, participants will be treated with DN on the basis of the conventional treatment. The intervention will be performed thrice a week for 2 weeks. The primary outcome that determines the efficacy of lower limb dysfunction will be the change in the Fugl-Meyer Assessment of Lower Extremity scale. The secondary indicators include the range of motion of knee and ankle joints, limits of stability, modified Clinical Test of Sensory Interaction on Balance, Timed Up and Go test, Modified Ashworth Scale and Barthel Index. Results will be evaluated at baseline, at 24 hours after intervention, at 2 weeks after intervention and at 3-month follow-up. Data will be released after the completion of the study. Adverse events will be reported. ETHICS AND DISSEMINATION: The experiment was approved by the Ethical Committee of Shanghai Tong Ren Hospital in October 2021 (approval number: 202105702). The results of this study will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR2000040754.

Efficacy of Dry Needling Under EMG Guidance for Myofascial Neck and Shoulder Pain: A Randomized Clinical Trial.

Purpose: To determine the difference in maintenance of improvement of pain and disability for dry needling (DN) under needle electromyography (EMG) guidance technique in myofascial neck and shoulder pain patients, compared with DN alone. Patients and Methods: In this randomized single-blind clinical trial, 30 participants with myofascial pain in the neck and shoulder were randomly allocated to two groups: myofascial trigger points (MTrPs) DN with EMG guided (DN-EMG) group and MTrPs DN without EMG (DN) group. Needling treatment lasted for 2 weeks, twice a week. The primary outcome was pain intensity as assessed by visual analogue scale (VAS) and neck disability index (NDI). A number of mappings referred to pain and spontaneous muscle activity (SEA) were considered secondary outcomes. VAS and NDI were measured before treatment, after 2 weeks of intervention and at 4-, 6- and 12-week follow-up periods after the intervention. Secondary outcomes were assessed before each treatment (T1-T4). Data were analysed using mixed-model analyses of variance (ANOVA) with time as a within-subject variable and groups as between-subject variables followed by Bonferroni's post-hoc test. Results: Mixed-model ANOVA revealed significant time-by-group interaction effects (F = 3.49, P = 0.01) for VAS. Post-hoc analysis showed a significant decrease in VAS and NDI after 2 weeks of intervention and at all follow-up periods compared with baseline in both groups (p < 0.01). The DN-EMG group exhibited higher improvements in VAS at 6- and 12-week follow-up period than the DN group (p < 0.05). In the SEA of MTrPs, we found positive sharp waves, fibrillation and fascicular potentials. DN-EMG group exhibited lower amplitudes at T2-T4 and frequencies at T2 and T3. Conclusion: DN under needle EMG guidance technique exhibited greater improvements in maintenance of improvement of pain and lower SEA value than the DN group due to sufficient MTrPs inactivation.

[Essence of acupoints and meridians based on the studies of myofascial trigger points].

Based on the modern anatomy and physiology, the referred pain of myofascial trigger points of each muscle is integrated; compared with the twelve meridians as well as conception vessel and governor vessel, the similarity of their position and running course is observed. With the current research progress of myofascial trigger points and fasciology, based on the running course of referred pain of trigger points, combined with fascia mechanics, nerve and vascular, the location of acupoints and meridians, as well as the relationship between acupoints and meridians, are discussed.

Criteria Used for the Diagnosis of Myofascial Trigger Points in Clinical Trials on Physical Therapy: Updated Systematic Review.

OBJECTIVE: The objective of this study was to conduct an updated systematic review of diagnostic criteria for myofascial trigger points (MTrPs) used in clinical trials of physical therapy interventions from 2007 to 2019. METHODS: MEDLINE and Physiotherapy Evidence Database (PEDro) were searched using the following MeSH keywords: "trigger points," "trigger point," "myofascial trigger point," "myofascial trigger points," "myofascial pain," and "myofascial pain syndrome." The MeSH keywords were combined by using Boolean operators "OR"/"AND." All physiotherapy clinical trials including patients with musculoskeletal conditions characterized by at least 1 active MTrP or latent MTrP in any body area were selected. We pooled data from an individual criterion and criteria combinations used to diagnose MTrPs. The protocol was developed in accordance with the PRISMA-P guidelines. RESULTS: Of 478 possibly relevant publications, 198 met the inclusion criteria. Of these 198 studies, 129 studies (65.1%) stated specifically the diagnostic criteria used for MTrPs in the main text, 56 studies (28.3%) failed to report any method whereby MTrP was diagnosed, and 13 studies (6.6%) adopted expert-based definitions for MTrPs without specification. Of 129 studies, the 6 criteria applied most commonly were: "spot tenderness" (n=125, 96.9%), "referred pain" (95, 73.6%), "local twitch response" (63, 48.8%), pain recognition (59, 45.7%), limited range of motion" (29, 22.5%), and "jump sign" (10, 7.8%). Twenty-three combinations of diagnostic criteria were identified. The most frequently used combination was "spot tenderness," "referred pain," and "local twitch response" (n=28 studies, 22%). CONCLUSIONS: A number of the included studies failed in properly reporting the MTrP diagnostic criteria. Moreover, high variability in the use of MTrP diagnostic was also observed. Spot tenderness, referred pain, and local twitch response were the 3 most popular criteria (and the most frequently used combination). A lack of transparency in the reporting of MTrP diagnostic criteria is present in the literature. REGISTRY: This systematic review was registered under the Centre for Reviews and Dissemination, PROSPERO number: CRD42018087420.

Effects of Trigger Point Dry Needling on Neuromuscular Performance and Pain of Individuals Affected by Patellofemoral Pain: A Randomized Controlled Trial.

PURPOSE: To investigate the effects of trigger point dry needling (TrP-DN) on exercise-induced patellofemoral pain syndrome (PFPS). PATIENTS AND METHODS: In this randomized, single-blind, parallel-group trial, 50 patients with PFPS were randomly allocated to the following two groups: the TrP-DN group (n = 25) and the Sham needling group (n = 25). Patients in both groups were asked to perform a stretching exercise of the quadriceps daily after needling. The needling group received a single session of TrP-DN to trigger points (TrPs) in the vastus medialis oblique (VMO), vastus lateralis (VL), and rectus femoris muscles (once a week for 6 weeks), and the Sham group received placebo needling. Visual analogue scale (VAS) for pain intensity and Kujala questionnaire for the functional status were assessed before treatment, 3 and 6 weeks after treatment, and at the 3-month follow-up. The ratio of the myoelectric amplitude of the vastus medialis oblique and vastus lateralis muscles (VMO/VL) was assessed before treatment and 6 weeks after treatment. RESULTS: There was no significant difference in the general data between the two groups. The VAS scores and Kujala scores in the TrP-DN group were significantly improved and increased at the 3-week treatment visit, 6-week treatment visit, and 3-month follow-up compared to the scores before treatment; and the scores in the Sham group were only significantly improved at the 3-week treatment visit, and 6-week treatment visit. VAS scores in the TrP-DN group were significantly lower and Kujala scores were significantly higher at the 6-week treatment visit and the 3-month follow-up compared to those in the Sham group. The VMO/VL ratio in the TrP-DN group was significantly increased at the 6-week treatment visit compared to that before treatment. CONCLUSION: TrP-DN at the quadriceps combined with stretch can reduce the pain, and improves the clinical symptoms and function, the VMO/VL ratio, and the coordination of VMO and VL in patients with PFPS.

Compression of Myofascial Trigger Points With a Foam Roller or Ball for Exercise-induced Anterior Knee Pain: A Randomized Controlled Trial.

OBJECTIVE: The study aimed to evaluate the effectiveness of compression of myofascial trigger points (MTrPs) with a foam roller or ball, combined with static stretching of knee muscles, on exercise-induced, anterior knee pain in fitness runners. DESIGN: The research team designed a randomized controlled trial. SETTING: The study took place in the Department of Sports Medicine and Rehabilitation Center of the School of Kinesiology at Shanghai University of Sport in Shanghai, China. PARTICIPANTS: A total of 80 participants, 28 males and 52 females with an average age of 37.2 ± 2.9 years, were recruited at the center. INTERVENTION: The participants were randomly assigned to one of 4 groups, with 20 participants in each group: (1) the MG+SG group, which received compression with a foam roller or ball (MG) and static stretching (SG); (2) the MG group, which received compression only; (3) the SG group static, which received static stretching only; or (4) the control group (CG), which attended a 30-min class about nutrition or exercise once a month and received no intervention. For the MG intervention, participants' MTrPs were compressed with a foam roller or ball for 30 minutes once every 5 days for 2 months. After each compression, the MG+SG group received static stretching immediately. OUTCOME MEASURES: A visual analog scale (VAS) and a participant's range of motion (ROM) of the knee were assessed at baseline, after 4 weeks of the intervention, immediately postintervention, and at a follow-up at 8 weeks postintervention. The effectiveness of the treatment in the different groups was also compared. RESULTS: Immediately postintervention, 18 participants (90%) in MG+SG group, 12 (60%) in MG group, and 8 (40%) in the SG group were pain free. Compared with those at baseline, the VAS scores of the MG+SG group significantly improved between baseline and postintervention and were unchanged at the eight-week follow-up. In all groups, the VAS scores and ROMs of the knee increased, but only the MG+SG group's values increased significantly. CONCLUSIONS: Compression of MTrPs with a foam roller or ball, combined with static stretching, was more effective than either the compression only or static stretching only.

Relationship between muscle spindles and myofascial trigger spots according to Hoffmann reflex pathway and tissue morphology characteristics in a rat model.

OBJECTIVES: To determine how muscle spindles are involved in the pathophysiology of chronic myofascial trigger spots (MTrSs, similar to myofascial trigger points) in a rat injury model according to the characteristics of the Hoffmann reflex (H-reflex) and the anatomical relationship between muscle spindles and MTrSs. METHODS: 16 male Sprague-Dawley rats (7 weeks old) were randomly divided into experimental and control groups. A blunt strike injury and eccentric exercise were applied to the gastrocnemius muscle of rats in the experimental group once a week for 8 weeks as a MTrS modelling intervention. Subsequently, the rats were reared normally and rested for 4 weeks. At the end of the 12th week, the rats were examined for the presence of MTrSs defined by the detection of a palpable taut band exhibiting both a local twitch response and spontaneous electrical activity. After modelling, evocation of the H-reflex and morphological examination of muscle spindles and MTrSs were conducted. RESULTS: The threshold (0.35±0.04 mA) of the H-reflex and latency (1.24±0.18 ms) of the M wave recorded at MTrSs were not significantly different to those at non-MTrSs (P>0.05). Compared with non-MTrSs, a lower Mmax (4.28±1.27 mV), higher Hmax (median (IQR) 0.95 (0.80-1.08) mV) and Hmax/Mmax (median (IQR) 0.21 (0.16-0.40)), and shorter H wave latency (4.60±0.89 ms) were recorded at MTrSs (P<0.05). Morphologically, there was a close anatomical relationship between the MTrS cells and the muscle spindles. DISCUSSION: Compared with normal muscles, the H-reflex myoelectrical activity was enhanced and some muscle spindles might have been influenced by active MTrSs. Thus, muscle spindles may play an important role in the pathological mechanism underlying myofascial trigger points.

Structural and functional abnormalities of motor endplates in rat skeletal model of myofascial trigger spots.

Myofascial trigger points (MTrPs) are defined as hyperirritable spots in a palpable taut band (TB) of skeletal muscle fibers. Knowing the formation and location of MTrPs is a great help to prevent their development and inactivate existing MTrPs. This study aimed to obtain new evidence that myofascial trigger spots (MTrSs), which are similar to human MTrPs, are found in dysfunctional motor endplates by observing the morphological characteristics of muscles and changes in biochemical substances. A total of 32 male Sprague Dawley rats were randomly divided into four groups: two control groups (i.e., C1 and C2) and two model groups (i.e., M1 and M2). C1 and M1 were used for acetylcholine (ACh) content measurement, while C2 and M2 were utilized for acetylcholinesterase (AChE) staining. In the model groups, blunt striking injury was induced and eccentric exercise was applied to the left gastrocnemius for 8 weeks. After 1 month, spontaneous electrical activity(SEA), AChE optical density (OD), muscle fiber diameter, and ACh content were measured. The results showed that extensive abnormal endplate noise (aEPN), including positive neurons, fibrillation potentials, fasciculation potential, and high amplitude (endplate spikes [EPS]), is present at MTrSs in M1. Quantitative electromyography results showed that the amplitudes of aEPN and frequency of EPS in M1 were significantly higher than those of C1. The ACh content of MTrSs in M1 was significantly higher than that in C1. The AChE OD value of M2 was significantly lower than that of C2. In addition, the diameter of the muscle fibers in the AChE-stained area was longer in M2 than in C2. In conclusion, MTrSs formed at the motor endplate with a larger diameter of muscle fibers. Excessive ACh release and decreased AChE activity at MTrSs stimulated muscle action potential and muscle contraction.

Proteins and Signaling Pathways Response to Dry Needling Combined with Static Stretching Treatment for Chronic Myofascial Pain in a RAT Model: An Explorative Proteomic Study.

A quantitative proteomic analysis of the response to dry needling combined with static stretching treatment was performed in a rat model of active myofascial trigger points (MTrPs). 36 rats were divided into a model group (MG), a stretching group (SG) and a dry needling combined with stretching group (SDG). We performed three biological replicates to compare large-scale differential protein expression between groups by tandem mass tag (TMT) labeling technology based on nanoscale liquid chromatography mass spectrometry analysis (LC⁻MS/MS). Hierarchical clustering, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and protein-protein interaction network analyses were performed for the general characterization of overall enriched proteins. For validation of the results of TMT, the candidate proteins were verified by parallel reaction monitoring (PRM) analysis. 285 differentially expressed proteins between groups were identified and quantified. Tight junction pathway played a dominant role in dry needling combined with static stretching treatment for the rat model of active MTrPs. Three candidate proteins, namely actinin alpha 3, calsequestrin-1 and parvalbumin alpha, were further validated, consistent with the results of LC⁻MS/MS. This is the first proteomics-based study to report the therapeutic mechanism underlying dry needling and static stretching treatment for MTrPs. Further functional verification of the potential signaling pathways and the enriched proteins is warranted.

Quantitative proteomics analysis to identify biomarkers of chronic myofascial pain and therapeutic targets of dry needling in a rat model of myofascial trigger points.

BACKGROUND: Proteomics analysis may provide important information regarding the pathogenesis of chronic myofascial pain and the mechanisms underlying the treatment effects of dry needling. MATERIALS AND METHODS: This study used a rat model of myofascial trigger points (MTrPs) to perform a proteomics analysis. Three biological replicate experiments were used to compare the proteomes of healthy control rats, a rat model of MTrP, MTrP model rats following dry needling of MTrPs, and MTrP model rats following dry needling of non-MTrPs. Tandem mass tag (TMT) labeling technology based on nanoscale liquid chromatography-tandem mass spectrometry was used. Hierarchical clustering, gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-protein interaction network analysis were performed to characterize the proteins. To validate the TMT results, three candidate biomarker proteins were verified using parallel reaction monitoring and Western blot analysis. RESULTS: A total of 2,635 proteins were identified. GO and KEGG enrichment analyses showed that the glycolysis/gluconeogenesis pathways played dominant roles in the pathogenesis of chronic myofascial pain. The three candidate biomarker proteins were the pyruvate kinase muscle isozyme (encoded by the PKM gene), the muscle isoform of glycogen phosphorylase (encoded by the PYGM gene), and myozenin 2 (encoded by the MYOZ2 gene). The validation results were consistent with the TMT results. CONCLUSION: This is the first proteomics study that has investigated the pathogenesis of chronic myofascial pain and the mechanisms underlying the treatment effects of dry needling in an in vivo rat model of MTrPs, which might promote our understanding of the molecular mechanisms underlying chronic myofascial pain.