Effect of belt electrode-skeletal muscle electrical stimulation on immobilization-induced muscle fibrosis

Effectiveness of passive mobilization on the deleterious effects of immobilization in patients with musculoskeletal problems: a systematic review

INTRODUCTION

Joint immobilization may be necessary in some situations, such as in cases of fractures and osteomyoarticular injuries. However, it is known that there are several harmful effects of immobilization, which can cause muscle weakness, loss of motor function, reduced range of motion and increased local pain, and it is important to understand the possible forms of treatment to alleviate the effects of immobilization, focusing on passive mobilization.

OBJECTIVE

To address articles that evaluate the effects of passive mobilization on immobilized patients.

METHODOLOGY

The search was carried out in national and international electronic databases (PubMed, Pedro, Web of Science, Scopus, Embase, Lilacs and Cochrane), in addition to gray literature (Google Scholar, Open Gray and Livivo), using the following descriptors: PASSIVE MOBILIZATION and IMMOBILIZATION, being carried out blindly, by two main researchers, concluding the selection with 6 articles on the subject.

RESULTS

The studies indicate that passive mobilization was able to reverse the negative aspects of immobilization in relation to the recovery of strength, range of movement, local pain and motor function, as its action provides tissue sliding, increasing circulation and the repair process tissue.

CONCLUSION

Although the effects are smaller compared to active exercises, it can be considered that passive mobilization can mitigate the harmful effects of immobilization.

Frequent Tetanic Exercise Through Electrical Muscle Stimulation May Reduce Immobilization-Induced Muscle Fibrosis by Suppressing Myonuclear Apoptosis

INTRODUCTION/AIMS

Immobilization-induced fibrosis is the primary pathogenesis of muscle contracture, and its trigger is myonuclear apoptosis. Tetanic exercise through electrical muscle stimulation may be able to mitigate myonuclear apoptosis; this could be an intervention strategy for Immobilization-induced fibrosis. In the present study, this was tested using rat skeletal muscles.

METHODS

Rats were divided into the control, immobilization, low-contraction frequency (LCF), and high-contraction frequency (HCF) groups. The soleus muscles were used as specimens.

RESULTS

The number of TUNEL-positive myonuclei was 0.36 ± 0.11, 4.66 ± 0.90, 4.25 ± 0.99, and 1.90 ± 0.46 in the control, immobilization, LCF, and HCF groups, respectively. The HCF group was lower than the immobilization and LCF groups (all p < 0.001). The number of myonuclei and cross-sectional area (CSA) in the HCF group was higher than in the immobilization and LCF groups (all p < 0.001). The number of macrophages, mRNA expression of IL-1β, TGF-β1, and α-SMA, and hydroxyproline contents in the HCF group was lower than in the immobilization and LCF groups (all p < 0.001). There were moderate to strong negative correlations between the number of TUNEL-positive myonuclei and the number of myonuclei and between the CSA and the number of macrophages. Moderate to strong positive correlations were found between the number of myonuclei and the CSA, the number of macrophages and IL-1β, IL-1β and TGF-β1, TGF-β1 and α-SMA, and α-SMA and hydroxyproline contents.

DISCUSSION

Frequent tetanic exercise might mitigate macrophage accumulation caused by myonuclear apoptosis and suppress immobilization-induced muscle fibrosis due to fibrosis-associated molecule overexpression.

Targeted Therapy for Skeletal Muscle Fibrosis: Regulation of Myostatin, TGF-β, MMP, and TIMP to Maintain Extracellular Matrix Homeostasis

Muscle fibrosis, defined by the excessive deposition of extracellular matrix (ECM) components, is a key pathological process that hinders muscle regeneration following injury. Despite muscle's inherent regenerative potential, severe or chronic injuries often result in fibrosis, which compromises muscle function and impedes healing. This review explores a range of therapeutic strategies aimed at modulating the molecular pathways involved in muscle fibrosis, with a focus on the inhibition of myostatin and transforming growth factor-β (TGF-β), as well as the regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Some therapy modalities, including physiotherapy and exercise therapy, which are commonly used, have demonstrated the ability to regulate extracellular matrix (ECM) components and promote muscle repair. In addition, the use of TGF-β inhibitors, herbal plants, and other biochemically relevant compounds, holds promise in controlling fibrosis by targeting key signaling pathways that drive ECM accumulation as well as having anti-fibrotic and anti-inflammatory properties. Regenerative medicine, including therapies using stem cell, secretome, and platelet-rich plasma (PRP), have also been used as single or adjuvant treatment for muscle fibrosis, and represents a novel and minimally invasive approach. Although these therapeutic strategies show considerable promise, translating preclinical findings to clinical practice remains challenging owing to variability in patient responses and the complexity of human muscle injuries. In conclusion, a multifaceted approach targeting ECM regulation, either as single treatment or combined treatment, offers a promising avenue for the treatment of muscle fibrosis.

Belt Electrode-Skeletal Muscle Electrical Stimulation Prevents Muscle Atrophy in the Soleus of Collagen-Induced Arthritis Rats

We investigated the effects of belt electrode-skeletal muscle electrical stimulation (B-SES) on muscle atrophy in collagen-induced arthritis (CIA) rats. Twenty-eight 8-week-old male Dark Agouti rats were immunized with type II collagen and Freund's incomplete adjuvant (day 0). From days 14 to 28, 18 rats received B-SES (50 Hz) four times only on the right hindlimb (STIM), while the contralateral left hindlimb remained unstimulated. Both hindlimbs of 10 untreated CIA rats were defined as controls (CONT). Paw volume was measured every other day. On day 28, the muscle weight, histology, and gene expression of the soleus and extensor digitorum longus (EDL) were analyzed. B-SES did not worsen paw volume throughout the experimental period. Compared with CONT, the muscle weight and fiber cross-sectional area of the soleus were higher in STIM. The expression of muscle degradation markers (atrogin-1 and MuRF-1) in the soleus and EDL was lower in the STIM group than that in the CONT group. In contrast, B-SES did not significantly affect the expression of muscle synthesis (Eif4e and p70S6K) and mitochondrial (PGC-1α) markers. B-SES prevents muscle atrophy in CIA rats by reducing muscle degradation without exacerbating arthritis, demonstrating its promising potential as an intervention for RA-induced muscle atrophy.

Stochastic electrical stimulation of the thoracic or cervical regions with surface electrodes facilitates swallow in rats

Introduction

Aspiration pneumonia, a leading cause of mortality, poses an urgent challenge in contemporary society. Neuromuscular electrical stimulation (NMES) has been commonly used in dysphagia rehabilitation. However, given that NMES at motor threshold targets only specific muscles, it carries a potential risk of further compromising functions related to swallowing, respiration, and airway protection. Considering that the swallow motor pattern is orchestrated by the entire swallow pattern generator (the neural mechanism governing a sequence of swallow actions), a rehabilitation approach that centrally facilitates the entire circuit through sensory nerve stimulation is desirable. In this context, we propose a novel stimulation method using surface electrodes placed on the back to promote swallowing.

Methods

The efficacy of the proposed method in promoting swallowing was evaluated by electrically stimulating sensory nerves in the back or neck. Probabilistic stimulus was applied to either the back or neck of male and female rats. Swallows were evoked by an oral water stimulus, and electromyographic (EMG) activity of the mylohyoid, thyroarytenoid, and thyropharyngeus muscles served as the primary outcome measure.

Results

Gaussian frequency stimulation applied to the skin surface of the thoracic back elicited significant increases in EMG amplitude of all three swallow-related muscles. Neck stimulation elicited a significant increase in EMG amplitude of the thyroarytenoid during swallow, but not the mylohyoid or thyropharyngeus muscles.

Discussion

While the targeted thoracic spinal segments T9-T10 have been investigated for enhancing respiration, the promotion of swallowing through back stimulation has not been previously studied. Furthermore, this study introduces a new probabilistic stimulus based on Gaussian distribution. Probabilistic stimuli have been reported to excel in nerve stimulation in previous research. The results demonstrate that back stimulation effectively facilitated swallow more than neck stimulation and suggest potential applications for swallowing rehabilitation.

Intramuscular botulinum toxin-A in complex regional pain syndrome resistant to standard treatment: a case report

OBJECTIVE

To present a patient with complex regional pain syndrome type 1 (CRPS-I) and improvement of contracture of hand muscles and grip strength after successful treatment with botulinum neurotoxin‑A (BoNT-A).

CASE

A 53-year-old woman with CRPS‑I experienced severe allodynia, swelling and autonomic changes in the left hand after a distal radius fracture. Over the succeeding months, she developed contracture of the left hand muscles which was treated with injection of BoNT‑A into the hand muscles (10 points).

RESULTS

In the patient treatment with BoNT‑A an improvement was seen in the hand range of motion (ROM) and grip strength.

CONCLUSION

Successful results can be obtained with BoNT‑A injection in treatment-resistant CRPS‑I cases which may develop joint contracture.

Development of an electrical stimulator for swallow facilitation through action on spinal circuits

This paper studies a rehabilitation method to centrally facilitate swallowing by stimulating the peripheral sensory nervous system. We developed an electrical device using surface electrodes to promote swallowing through activation of spinal afferent pathways by effectively stimulating the sensory nerves of the back using a Gaussian frequency biphasic burst waveform, which differs from the conventional electrical stimulation method targeting the neck muscles. To validate its effectiveness, the Gaussian frequency biphasic burst waveform was generated in a Gaussian distribution with a mean of 30 Hz, and randomly applied as a burst to either the back or neck of adult rats. Experiments using a Gaussian frequency monophasic pulse waveform were conducted as a comparative reference. Swallow related electromyographic (EMG) activity from three upper airway muscles before and after a series of three electrical stimulation trials were compared. The current increased with the Gaussian biphasic waveform at 2V compared to the Gaussian monophasic waveform at 5V, suggesting the potential to reduce impedance between the skin and electrodes. Both the Gaussian frequency monophasic and biphasic burst waveforms increased the EMG amplitude of swallow related muscles, suggesting effective activation of the swallow reflex circuit. Furthermore, stimulation near the T9-T10 region of the back resulted in increased amplitude of the thyropharyngeus muscle early in the stimulation protocol for both waveform types, demonstrating the potential for improvement in swallowing dysfunction by electrical stimulation of the T9-T10 region of the back using surface electrodes.

Sialyllactose preserves residual hearing after cochlear implantation

In individuals with hearing loss, protection of residual hearing is essential following cochlear implantation to facilitate acoustic and electric hearing. Hearing preservation requires slow insertion, atraumatic electrode and delivery of the optimal quantity of a pharmacological agent. Several studies have reported variable hearing outcomes with osmotic pump-mediated steroid delivery. New drugs, such as sialyllactose (SL) which have anti-inflammatory effect in many body parts, can prevent tissue overgrowth. In the present study, the positive effects of the pharmacological agent SL against insults were evaluated in vitro using HEI-OC1 cells. An animal model to simulate the damage due to electrode insertion during cochlear implantation was used. SL was delivered using osmotic pumps to prevent loss of the residual hearing in this animal model. Hearing deterioration, tissue fibrosis and ossification were confirmed in this animal model. Increased gene expressions of inflammatory cytokines were identified in the cochleae following dummy electrode insertion. Following the administration of SL, insertion led to a decrease in hearing threshold shifts, tissue reactions, and inflammatory markers. These results emphasize the possible role of SL in hearing preservation and improve our understanding of the mechanism underlying hearing loss after cochlear implantation.

Electrical Stimulation-Based Twitch Exercise Suppresses Progression of Immobilization-Induced Muscle Fibrosis via Downregulation of PGC-1?/VEGF Pathway

This study aimed to determine whether electrical stimulation-based twitch exercise is effective in inhibiting the progression of immobilization-induced muscle fibrosis. 19 Wistar rats were randomly divided into a control group (n=6), an immobilization group (n=6; with immobilization only), and a Belt group (n=7; with immobilization and twitch exercise through the belt electrode device, beginning 2 weeks after immobilization). The bilateral soleus muscles were harvested after the experimental period. The right soleus muscles were used for histological analysis, and the left soleus muscles were used for biochemical and molecular biological analysis. As a result, in the picrosirius red images, the perimysium and endomysium were thicker in both the immobilization and Belt groups compared to the control group. However, the perimysium and endomysium thickening were suppressed in the Belt group. The hydroxyproline content and alpha-SMA, TGF-beta1, and HIF-1alpha mRNA expressions were significantly higher in the immobilization and belt groups than in the control group. These expressions were significantly lower in the Belt group than in the immobilization group. The capillary-to-myofiber ratio and the mRNA expressions of VEGF and PGC-1alpha were significantly lower in the immobilization and belt groups than in the control group, these were significantly higher in the Belt group than in the immobilization group. From these results, Electrical stimulation-based twitch exercise using the belt electrode device may prevent the progression of immobilization-induced muscle fibrosis caused by downregulating PGC-1alpha/VEGF pathway, we surmised that this intervention strategy might be effective against the progression of muscle contracture. Keywords: Immobilization, Skeletal muscle, Fibrosis, Electrical stimulation-based twitch exercise, PGC-1alpha/VEGF pathway.

Effects of Neuromuscular Electrical Stimulation and Therapeutic Ultrasound on Quadriceps Contracture of Immobilized Rats

Quadriceps contracture is a condition where the muscle-tendon unit is abnormally shortened. The treatment prognosis is guarded to poor depending on the progress of the disease. To improve the prognosis, we investigated the effectiveness of therapeutic ultrasound and NMES in treating quadriceps contracture in an immobilized rat model. Thirty-six Wistar rats were randomized into control, immobilization alone, immobilization and spontaneous recovery, immobilization and therapeutic ultrasound, immobilization and NMES, and immobilization and therapeutic ultrasound and NMES combination groups. The continuous therapeutic ultrasound (frequency, 3 MHz, intensity 1 W/cm2) and NMES (TENS mode, frequency 50 Hz; intensity 5.0 ± 0.8 mA) were performed on the quadriceps muscle. On Day 15, immobilization-induced quadriceps contracture resulted in a decreased ROM of the stifle joint, reduction in the sarcomere length, muscle atrophy, and muscle fibrosis. On Day 43, therapeutic ultrasound, NMES, and combining both methods improved muscle atrophy and shortening and decreased collagen type I and III and α-SMA protein. The combination of therapeutic ultrasound and NMES significantly reduced the mRNA expression of IL-1β, TGF-β1, and HIF-1α and increased TGF-β3. Therefore, the combination of therapeutic ultrasound and NMES is the most potent rehabilitation program for treating quadriceps contracture.

Skeletal Muscle Electrical Stimulation Prevents Progression of Disuse Muscle Atrophy via Forkhead Box O Dynamics Mediated by Phosphorylated Protein Kinase B and Peroxisome Proliferator-Activated Receptor gamma Coactivator-1alpha

Although electrical muscle stimulation (EMS) of skeletal muscle effectively prevents muscle atrophy, its effect on the breakdown of muscle component proteins is unknown. In this study, we investigated the biological mechanisms by which EMS-induced muscle contraction inhibits disuse muscle atrophy progression. Experimental animals were divided into a control group and three experimental groups: immobilized (Im; immobilization treatment), low-frequency (LF; immobilization treatment and low-frequency muscle contraction exercise), and high-frequency (HF; immobilization treatment and high-frequency muscle contraction exercise). Following the experimental period, bilateral soleus muscles were collected and analyzed. Atrogin-1 and Muscle RING finger 1 (MuRF-1) mRNA expression levels were significantly higher for the experimental groups than for the control group but were significantly lower for the HF group than for the Im group. Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) mRNA and protein expression levels in the HF group were significantly higher than those in the Im group, with no significant differences compared to the Con group. Both the Forkhead box O (FoxO)/phosphorylated FoxO and protein kinase B (AKT)/phosphorylated AKT ratios were significantly lower for the Im group than for the control group and significantly higher for the HF group than for the Im group. These results, the suppression of atrogin-1 and MuRF-1 expression for the HF group may be due to decreased nuclear expression of FoxO by AKT phosphorylation and suppression of FoxO transcriptional activity by PGC-1alpha. Furthermore, the number of muscle contractions might be important for effective EMS.

Mechanical Stress Via Muscle Contractile Exercise Suppresses Atrophic Alterations of Bone-microstructure in Immobilized Rat Femurs

OBJECTIVES

This study aimed to determine whether mechanical stress via muscle contractile exercise with belt electrode-skeletal muscle electrical stimulation (B-SES) device effectively prevents immobilization-induced bone atrophy.

METHODS

Wistar rats were randomly divided into the control (CON) group, immobilization (IM) group (immobilized treatment only), HES and LES groups (immobilized treatment and high or low-intensity electrical muscular stimulation through B-SES device). Bilateral femurs were used for X-ray micro-CT and biomechanical tests.

RESULTS

The maximum load value was significantly lower in the IM and HES groups than in the CON group and significantly higher in the LES group than in the IM group. The maximum crushing load was significantly lower in the IM, HES, and LES groups than in the CON group, and significantly higher in the HES and LES groups than that in the IM group. In micro-CT, the mechanical stress by B-SES device did not affect degenerative microstructural changes in the cortical bone, but prevented those changes in the cancellous bone.

CONCLUSIONS

Applying mechanical stress via B-SES device suppressed the loss of cancellous bone density and degenerative microstructural changes caused by immobilization, which in turn suppressed the reduction of bone strength. From these findings, muscle contractile exercise may be effective in preventing immobilization-induced bone atrophy.

Eight-week neuromuscular electrical stimulation training produces muscle strength gains and hypertrophy, and partial muscle quality improvement in the knee extensors

This study investigated the effect of an 8-week neuromuscular electrical stimulation (NMES) training programme (3 days/week) on muscle quantity and quality and single-joint performance in the knee extensors. Thirty-nine untrained young male participants were randomly assigned to NMES training (n = 21) and control (n = 18) groups. The 8-week NMES training induced significant increase in the isometric maximal voluntary contraction (MVC) torque of the knee extensors (≈9.3%), muscle volume of the individual and entire quadriceps muscles determined by magnetic resonance imaging (≈3.3%-6.4%), and a significant decrease in the ultrasound echo intensity of the vastus lateralis (≈-4.0%); however, hypertrophy of the vastus intermedius (i.e., the deep muscle) was limited (≈3.3%). In the NMES training group, the repeated measures correlations of the isometric MVC torque with the muscle volume of the entire quadriceps muscle and each quadriceps muscle were significant (rrm (20) = 0.551-0.776), whereas that of the isometric MVC torque with the ultrasound echo intensity of the vastus lateralis was not significant. These findings suggest that NMES training produces muscle strength gains, muscle hypertrophy, and partial muscle quality improvement and that the NMES training-induced muscle strength gains is caused by muscle hypertrophy in the knee extensors.

Muscle contractile exercise through a belt electrode device prevents myofiber atrophy, muscle contracture, and muscular pain in immobilized rat gastrocnemius muscle

Purpose

Immobilization of skeletal muscles causes muscle atrophy, muscle contracture, and muscle pain, the mechanisms of which are related to macrophage accumulation. However, muscle contractile exercise through a belt electrode device may mitigate macrophage accumulation. We hypothesized that such exercise would be effective in preventing myofiber atrophy, muscle contracture, and muscular pain. This study tested this hypothesis in immobilized rat gastrocnemius muscle.

Materials and methods

A total of 32 rats were divided into the following control and experimental groups: immobilization (immobilized treatment only), low-frequency (LF; immobilized treatment and muscle contractile exercise with a 2 s (do) /6 s (rest) duty cycle), and high-frequency (HF; immobilized treatment and muscle contractile exercise with a 2 s (do)/2 s (rest) duty cycle). Electrical stimulation was performed at 50 Hz and 4.7 mA, and muscle contractile exercise was applied to the lower limb muscles for 15 or 20 min/session (once daily) for 2 weeks (6 times/week). After the behavioral tests, the bilateral gastrocnemius muscles were collected for analysis.

Results

The number of macrophages, the Atrogin-1 and MuRF-1 mRNA expression, and the hydroxyproline content in the HF group were lower than those in the immobilization and LF groups. The cross-sectional area (CSA) of type IIb myofibers in the superficial region, the PGC-1α mRNA expression, and the range of motion of dorsiflexion in the HF group were significantly higher than those in the immobilization and LF groups. The pressure pain thresholds in the LF and HF groups were significantly higher than that in the immobilization group, and the nerve growth factor (NGF) content in the LF and HF groups was significantly lower than that in the immobilization group.

Conclusion

Muscle contractile exercise through the belt electrode device may be effective in preventing immobilization-induced myofiber atrophy, muscle contracture, and muscular pain in the immobilized rat gastrocnemius muscle.

Dysregulation of dopamine neurotransmission in the nucleus accumbens in immobilization-induced hypersensitivity

Cast immobilization causes sensory hypersensitivity, which is also a symptom of neuropathic pain and chronic pain. However, the mechanisms underlying immobilization-induced hypersensitivity remain unclear. The present study investigated the role of dopamine neurotransmission in the nucleus accumbens shell (NAcSh) of rats with cast immobilization-induced mechanical hypersensitivity using in vivo microdialysis. Cast immobilization of the hind limb decreased the paw withdrawal threshold (PWT). Mechanical stimulation of the cast-immobilized hind limb induced a decrease in dopamine in the NAcSh, and this decrease was associated with the upregulation of presynaptic D2-like receptors. A D2-like receptor antagonist infused into the NAcSh reversed the decrease in PWT in rats with cast immobilization, whereas a D2-like receptor agonist infused into the NAcSh induced a decrease in PWT in control rats. In addition, the expression of the D2 receptor (Drd2) mRNA in the NAcSh was increased by cast immobilization. Importantly, systemic administration of the D2-like receptor antagonist reversed the decrease in PWT in rats with cast immobilization. As dopamine levels regulated by presynaptic D2-like receptors did not correlate with the PWT, it is presumed that the D2-like receptor antagonist or agonist acts on postsynaptic D2-like receptors. These results suggest that immobilization-induced mechanical hypersensitivity is attributable to the upregulation of postsynaptic D2-like receptors in the NAc. Blockade of D2-like receptors in the NAcSh is a potential therapeutic strategy for immobilization-induced hypersensitivity.

Percutaneous electrical stimulation-induced muscle contraction prevents the decrease in ribosome RNA and ribosome protein during pelvic hindlimb suspension

Skeletal muscle unloading leads to muscle atrophy. Ribosome synthesis has been implicated as an important skeletal muscle mass regulator owing to its translational capacity. Muscle unloading induces a reduction in ribosome synthesis and content, with muscle atrophy. Percutaneous electrical muscle stimulation (pEMS)-induced muscle contraction is widely used in clinics to improve muscle mass. However, its efficacy in rescuing the reduction in ribosomal synthesis has not been addressed thus far. We examined the effects of daily pEMS treatment on ribosome synthesis and content during mouse hindlimb unloading. Male C57BL/6J mice were randomly assigned to sedentary (SED) and hindlimb unloading by pelvic suspension (HU) groups. Muscle contraction was triggered by pEMS treatment of the right gastrocnemius muscle of a subset of the HU group (HU+pEMS). Hindlimb unloading for 6 days significantly lowered 28S rRNA, rpL10, and rpS3 expression, which was rescued by daily pEMS treatment. The protein expression of phospho-p70S6K and UBF was significantly higher in the HU+pEMS than in the HU group. The mRNA expression of ribophagy receptor Nufip1 increased in both the HU and HU+pEMS groups. Protein light chain 3 (LC3)-II expression and the LC3-II/LC3-I ratio were increased by HU, but pEMS attenuated this increase. Our findings indicate that during HU, daily pEMS treatment prevents the reduction in the levels of some proteins associated with ribosome synthesis. Additionally, the HU-induced activation of ribosome degradation may be attenuated. These data provide insights into ribosome content regulation and the mechanism of attenuation of muscle atrophy by pEMS treatment during muscle disuse.