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Allevi F, Abate N, Bolognesi F, Tarabbia F, Rabbiosi D, Bellasio MM, Lozza A, Biglioli F. Is pre-operative electromyography a reliable tool in differentiating acute and chronic facial palsy? A preliminary evaluation in patients treated with triple innervation facial reanimation. J Craniomaxillofac Surg 2024:S1010-5182(24)00139-2. [PMID: 38734508 DOI: 10.1016/j.jcms.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/01/2024] [Indexed: 05/13/2024] Open
Abstract
Electromyographic evaluation is a reliable tool for confirming facial palsy and assessing its severity. It allows differentiating facial paresis and paralysis, and further distinguishes acute palsies, still showing muscle fibrillations, from chronic cases. This article aims to show that EMG fibrillations might represent a better criterion to differentiate acute and chronic palsies than the standard 18-24 months' cut-off usually employed for classification and treatment purposes. We performed a cohort study using the eFACE tool for comparing triple innervation facial reanimation results in patients with EMG fibrillation treated <12 months, 12-18 months, and >18 months from paralysis onset. Patients showed a statistically significant post-operative improvement in all eFACE items, both in the whole sample and in the three groups. Only the deviation from the optimal score for the gentle eye closure item in group 2 didn't reach statistical significance (p = 0.173). The post-operative results were comparable in the three groups, as the Kruskal-Wallis test showed a difference only for the platysmal synkinesis item scores, which were significantly lower in group 3 (p = 0.025).
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Affiliation(s)
- Fabiana Allevi
- Maxillo-Facial Surgery Department, San Paolo Hospital, University of Milan, Milan, Italy.
| | - Nicole Abate
- Maxillo-Facial Surgery Department, San Paolo Hospital, University of Milan, Milan, Italy
| | - Federico Bolognesi
- Maxillo-Facial Surgery Department, San Paolo Hospital, University of Milan, Milan, Italy
| | - Filippo Tarabbia
- Maxillo-Facial Surgery Department, San Paolo Hospital, University of Milan, Milan, Italy
| | - Dimitri Rabbiosi
- Department of Otorhinolaryngology, University of Insubria, Ospedale di Circolo e Fondazione Macchi, Varese, Italy
| | | | | | - Federico Biglioli
- Maxillo-Facial Surgery Department, San Paolo Hospital, University of Milan, Milan, Italy
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Freeberg MJ, Pinault GCJ, Tyler DJ, Triolo RJ, Ansari R. Chronic nerve health following implantation of femoral nerve cuff electrodes. J Neuroeng Rehabil 2020; 17:95. [PMID: 32664972 PMCID: PMC7362538 DOI: 10.1186/s12984-020-00720-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 07/06/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Peripheral nerve stimulation with implanted nerve cuff electrodes can restore standing, stepping and other functions to individuals with spinal cord injury (SCI). We performed the first study to evaluate the clinical electrodiagnostic changes due to electrode implantation acutely, chronic presence on the nerve peri- and post-operatively, and long-term delivery of electrical stimulation. METHODS A man with bilateral lower extremity paralysis secondary to cervical SCI sustained 5 years prior to enrollment received an implanted standing neuroprosthesis including composite flat interface nerve electrodes (C-FINEs) electrodes implanted around the proximal femoral nerves near the inguinal ligaments. Electromyography quantified neurophysiology preoperatively, intraoperatively, and through 1 year postoperatively. Stimulation charge thresholds, evoked knee extension moments, and weight distribution during standing quantified neuroprosthesis function over the same interval. RESULTS Femoral compound motor unit action potentials increased 31% in amplitude and 34% in area while evoked knee extension moments increased significantly (p < 0.01) by 79% over 1 year of rehabilitation with standing and quadriceps exercises. Charge thresholds were low and stable, averaging 19.7 nC ± 6.2 (SEM). Changes in saphenous nerve action potentials and needle electromyography suggested minor nerve irritation perioperatively. CONCLUSIONS This is the first human trial reporting acute and chronic neurophysiologic changes due to application of and stimulation through nerve cuff electrodes. Electrodiagnostics indicated preserved nerve health with strengthened responses following stimulated exercise. Temporary electrodiagnostic changes suggest minor nerve irritation only intra- and peri-operatively, not continuing chronically nor impacting function. These outcomes follow implantation of a neuroprosthesis enabling standing and demonstrate the ability to safely implant electrodes on the proximal femoral nerve close to the inguinal ligament. We demonstrate the electrodiagnostic findings that can be expected from implanting nerve cuff electrodes and their time-course for resolution, potentially applicable to prostheses modulating other peripheral nerves and functions. TRIAL REGISTRATION ClinicalTrials.gov NCT01923662 , retrospectively registered August 15, 2013.
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Affiliation(s)
- Max J Freeberg
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Advanced Platform Technology (APT) Center, Cleveland, OH, USA.
| | - Gilles C J Pinault
- Advanced Platform Technology (APT) Center, Cleveland, OH, USA
- Department of Surgery, Case Western Reserve University, Cleveland, OH, USA
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Dustin J Tyler
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology (APT) Center, Cleveland, OH, USA
| | - Ronald J Triolo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology (APT) Center, Cleveland, OH, USA
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Rahila Ansari
- Advanced Platform Technology (APT) Center, Cleveland, OH, USA
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
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Vajtay TJ, Bandi A, Upadhyay A, Swerdel MR, Hart RP, Lee CR, Margolis DJ. Optogenetic and transcriptomic interrogation of enhanced muscle function in the paralyzed mouse whisker pad. J Neurophysiol 2019; 121:1491-1500. [PMID: 30785807 PMCID: PMC6485730 DOI: 10.1152/jn.00837.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The functional state of denervated muscle is a critical factor in the ability to restore movement after injury- or disease-related paralysis. Here we used peripheral optogenetic stimulation and transcriptome profiling in the mouse whisker system to investigate the time course of changes in neuromuscular function following complete unilateral facial nerve transection. While most skeletal muscles rapidly lose functionality after lower motor neuron denervation, optogenetic muscle stimulation of the paralyzed whisker pad revealed sustained increases in the sensitivity, velocity, and amplitude of whisker movements, and reduced fatigability, starting 48 h after denervation. RNA-seq analysis showed distinct regulation of multiple gene families in denervated whisker pad muscles compared with the atrophy-prone soleus, including prominent changes in ion channels and contractile fibers. Together, our results define the unique functional and transcriptomic landscape of denervated facial muscles and have general implications for restoring movement after neuromuscular injury or disease. NEW & NOTEWORTHY Optogenetic activation of muscle can be used to noninvasively induce movements and probe muscle function. We used this technique in mice to investigate changes in whisker movements following facial nerve transection. We found unexpectedly enhanced functional properties of whisker pad muscle following denervation, accompanied by unique transcriptomic changes. Our findings highlight the utility of the mouse whisker pad for investigating the restoration of movement after paralysis.
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Affiliation(s)
- Thomas J Vajtay
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
| | - Akhil Bandi
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
| | - Aman Upadhyay
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
| | - Mavis R Swerdel
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
| | - Christian R Lee
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
| | - David J Margolis
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey , Piscataway, New Jersey
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Electrodiagnostic Evaluation of Individuals Implanted With Extracellular Matrix for the Treatment of Volumetric Muscle Injury: Case Series. Phys Ther 2016; 96:540-9. [PMID: 26564252 PMCID: PMC4817212 DOI: 10.2522/ptj.20150133] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 11/03/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Electrodiagnosis can reveal the nerve and muscle changes following surgical placement of an extracellular matrix (ECM) bioscaffold for treatment of volumetric muscle loss (VML). OBJECTIVE The purpose of this study was to characterize nerve conduction study (NCS) and electromyography (EMG) changes following ECM bioscaffold placement in individuals with VML. The ability of presurgical NCS and EMG to be used as a tool to help identify candidates who are likely to display improvements postsurgically also was explored. DESIGN A longitudinal case series design was used. METHODS The study was conducted at the McGowan Institute for Regenerative Medicine at the University of Pittsburgh. Eight individuals with a history of chronic VML participated. The intervention was surgical placement of an ECM bioscaffold at the site of VML. The strength of the affected region was measured using a handheld dynamometer, and electrophysiologic evaluation was conducted on the affected limb with standard method of NCS and EMG. All measurements were obtained the day before surgery and repeated 6 months after surgery. RESULTS Seven of the 8 participants had a preoperative electrodiagnosis of incomplete mononeuropathy within the site of VML. After ECM treatment, 5 of the 8 participants showed improvements in NCS amplitude or needle EMG parameters. The presence of electrical activity within the scaffold remodeling site was concomitant with clinical improvement in muscle strength. LIMITATIONS This study had a small sample size, and participants served as their own controls. The electromyographers and physical therapists performing the evaluation were not blinded. CONCLUSIONS Electrodiagnostic data provide objective evidence of physiological improvements in muscle function following ECM placement at sites of VML. Future studies are warranted to further investigate the potential of needle EMG as a predictor of successful outcomes following ECM treatment for VML.
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Wu P, Chawla A, Spinner RJ, Yu C, Yaszemski MJ, Windebank AJ, Wang H. Key changes in denervated muscles and their impact on regeneration and reinnervation. Neural Regen Res 2014; 9:1796-809. [PMID: 25422641 PMCID: PMC4239769 DOI: 10.4103/1673-5374.143424] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2014] [Indexed: 11/29/2022] Open
Abstract
The neuromuscular junction becomes progressively less receptive to regenerating axons if nerve repair is delayed for a long period of time. It is difficult to ascertain the denervated muscle's residual receptivity by time alone. Other sensitive markers that closely correlate with the extent of denervation should be found. After a denervated muscle develops a fibrillation potential, muscle fiber conduction velocity, muscle fiber diameter, muscle wet weight, and maximal isometric force all decrease; remodeling increases neuromuscular junction fragmentation and plantar area, and expression of myogenesis-related genes is initially up-regulated and then down-regulated. All these changes correlate with both the time course and degree of denervation. The nature and time course of these denervation changes in muscle are reviewed from the literature to explore their roles in assessing both the degree of detrimental changes and the potential success of a nerve repair. Fibrillation potential amplitude, muscle fiber conduction velocity, muscle fiber diameter, mRNA expression levels of myogenic regulatory factors and nicotinic acetylcholine receptor could all reflect the severity and length of denervation and the receptiveness of denervated muscle to regenerating axons, which could possibly offer an important clue for surgical choices and predict the outcomes of delayed nerve repair.
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Affiliation(s)
- Peng Wu
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA ; Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, China ; Department of Orthopedic Surgery, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Aditya Chawla
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA ; Department of Orthopedic Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Robert J Spinner
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Cong Yu
- Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Michael J Yaszemski
- Departments of Orthopedic Surgery and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | | | - Huan Wang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA ; Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, China
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Pond A, Marcante A, Zanato R, Martino L, Stramare R, Vindigni V, Zampieri S, Hofer C, Kern H, Masiero S, Piccione F. History, Mechanisms and Clinical Value of Fibrillation Analyses in Muscle Denervation and Reinnervation by Single Fiber Electromyography and Dynamic Echomyography. Eur J Transl Myol 2014; 24:3297. [PMID: 26913128 PMCID: PMC4749004 DOI: 10.4081/ejtm.2014.3297] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This work reviews history, current clinical relevance and future of fibrillation, a functional marker of skeletal muscle denervated fibers. Fibrillations, i.e., spontaneous contraction, in denervated muscle were first described during the nineteenth century. It is known that alterations in membrane potential are responsible for the phenomenon and that they are related to changes in electrophysiological factors, cellular metabolism, cell turnover and gene expression. They are known to inhibit muscle atrophy to some degree and are used to diagnose neural injury and reinnervation that are occurring in patients. Electromyography (EMG) is useful in determining progress, prognosis and efficacy of therapeutic interventions and their eventual change. For patients with peripheral nerve injury, and thus without the option of volitional contractions, electrical muscle stimulation may be helpful in preserving the contractility and extensibility of denervated muscle tissue and in retarding/counteracting muscle atrophy. It is obvious from the paucity of recent literature that research in this area has declined over the years. This is likely a consequence of the decrease in funding available for research and the fact that the fibrillations do not appear to cause serious health issues. Nonetheless, further exploration of them as diagnostic tools in long-term denervation is merited, in particular if Single Fiber EMG (SFEMG) is combined with Dynamic Echomyography (DyEM), an Ultra Sound muscle approach we recently designed and developed to explore denervated and reinnervating muscles.
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Affiliation(s)
- Amber Pond
- Anatomy Department, Southern Illinois University School of Medicine, Carbondale, IL USA
| | - Andrea Marcante
- CIR-Myo, Rehabilitation and Physical Medicine Unit, Department of Neurosciences, University of Padova, Italy
| | - Riccardo Zanato
- CIR-Myo, Radiology, Department of Medicine, University of Padova, Italy
| | - Leonora Martino
- CIR-Myo, Radiology, Department of Medicine, University of Padova, Italy
| | - Roberto Stramare
- CIR-Myo, Radiology, Department of Medicine, University of Padova, Italy
| | - Vincenzo Vindigni
- CIR-Myo, Plastic Surgery, Department of Neuroscience, University of Padova, Italy
| | | | - Christian Hofer
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | | | - Stefano Masiero
- CIR-Myo, Rehabilitation and Physical Medicine Unit, Department of Neurosciences, University of Padova, Italy
| | - Francesco Piccione
- Clinical Neurophysiology, San Camillo Hospital I.R.C.C.S., Venezia-Lido, Italy
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Heaton JT, Sheu SH, Hohman MH, Knox CJ, Weinberg JS, Kleiss IJ, Hadlock TA. Rat whisker movement after facial nerve lesion: evidence for autonomic contraction of skeletal muscle. Neuroscience 2014; 265:9-20. [PMID: 24480367 DOI: 10.1016/j.neuroscience.2014.01.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 01/03/2014] [Accepted: 01/19/2014] [Indexed: 11/25/2022]
Abstract
Vibrissal whisking is often employed to track facial nerve regeneration in rats; however, we have observed similar degrees of whisking recovery after facial nerve transection with or without repair. We hypothesized that the source of non-facial nerve-mediated whisker movement after chronic denervation was from autonomic, cholinergic axons traveling within the infraorbital branch of the trigeminal nerve (ION). Rats underwent unilateral facial nerve transection with repair (N=7) or resection without repair (N=11). Post-operative whisking amplitude was measured weekly across 10weeks, and during intraoperative stimulation of the ION and facial nerves at ⩾18weeks. Whisking was also measured after subsequent ION transection (N=6) or pharmacologic blocking of the autonomic ganglia using hexamethonium (N=3), and after snout cooling intended to elicit a vasodilation reflex (N=3). Whisking recovered more quickly and with greater amplitude in rats that underwent facial nerve repair compared to resection (P<0.05), but individual rats overlapped in whisking amplitude across both groups. In the resected rats, non-facial-nerve-mediated whisking was elicited by electrical stimulation of the ION, temporarily diminished following hexamethonium injection, abolished by transection of the ION, and rapidly and significantly (P<0.05) increased by snout cooling. Moreover, fibrillation-related whisker movements decreased in all rats during the initial recovery period (indicative of reinnervation), but re-appeared in the resected rats after undergoing ION transection (indicative of motor denervation). Cholinergic, parasympathetic axons traveling within the ION innervate whisker pad vasculature, and immunohistochemistry for vasoactive intestinal peptide revealed these axons branching extensively over whisker pad muscles and contacting neuromuscular junctions after facial nerve resection. This study provides the first behavioral and anatomical evidence of spontaneous autonomic innervation of skeletal muscle after motor nerve lesion, which not only has implications for interpreting facial nerve reinnervation results, but also calls into question whether autonomic-mediated innervation of striated muscle occurs naturally in other forms of neuropathy.
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Affiliation(s)
- James T Heaton
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, United States.
| | - Shu Hsien Sheu
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02114, United States
| | - Marc H Hohman
- Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, United States
| | - Christopher J Knox
- Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, United States
| | - Julie S Weinberg
- Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, United States
| | - Ingrid J Kleiss
- Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, United States; Department of Otorhinolaryngology and Head & Neck Surgery, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Tessa A Hadlock
- Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, United States
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Salomone R, Costa HJZR, Rodrigues JRF, Reis e Silva SM, Ovando PC, Orando PC, Bento RF. Assessment of a neurophysiological model of the mandibular branch of the facial nerve in rats by electromyography. Ann Otol Rhinol Laryngol 2012; 121:179-84. [PMID: 22530478 DOI: 10.1177/000348941212100307] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Our objective was to develop an experimental model for the noninvasive and objective evaluation of facial nerve regeneration in rats using a motor nerve conduction test (electromyography). METHODS Twenty-two rats were submitted to neurophysiological evaluation using motor nerve conduction of the mandibular branch of the facial nerve to obtain the compound muscle action potentials (CMAPs). To record the CMAPs, we used two needle electrodes that were inserted into the lower lip muscle of the rat. A supramaximal electrical stimulus was applied, and the values of CMAP latency, amplitude, length, area, and stimulus intensity obtained from each side were compared by use of the Wilcoxon test. RESULTS There was no significant difference (all p > 0.05) in latency, amplitude, duration, area, or intensity of stimuli between the two sides. The amplitudes ranged between 1.61 and 8.30 mV, the latencies between 1.03 and 1.97 ms, and the stimulus intensities between 1.50 and 2.90 mA. CONCLUSIONS This is a noninvasive, easy, and highly reproducible method that contributes to an improvement of the techniques previously described and may contribute to future studies of the degeneration and regeneration of the facial nerve.
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Affiliation(s)
- Raquel Salomone
- Department of Otolaryngology, University of São Paulo School of Medicine, São Paulo, Brazil
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Abstract
Active stretch is necessary for regulating muscle fiber length (ie, the number of series sarcomeres). Elevated cytoplasmic calcium is the proposed component of contractile activity required to activate signaling pathways for sarcomere number regulation. Passive stretch reduces muscle tissue stiffness, most likely by signaling connective tissue remodeling via fibroblasts. Passive stretch may induce sarcomere addition if the muscle fibers are lengthened sufficiently to raise cytoplasmic calcium through stretch-activated calcium channels. The magnitude of stretch in vivo is limited by the physiologic range of movement and stretch pain tolerance. The greatest effect of stretching muscle fibers is expected when the lengthening exceeds the optimum fiber length (Lo).
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Chang HM, Huang YL, Lan CT, Wu UI, Hu ME, Youn SC. Melatonin preserves superoxide dismutase activity in hypoglossal motoneurons of adult rats following peripheral nerve injury. J Pineal Res 2008; 44:172-80. [PMID: 18289169 DOI: 10.1111/j.1600-079x.2007.00505.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Peripheral nerve injury (PNI) produces functional changes in lesioned neurons in which oxidative stress is considered to be the main cause of neuronal damage. As superoxide dismutase (SOD) is an important antioxidative enzyme involved in redox regulation of oxidative stress, the present study determined whether melatonin would exert its beneficial effects by preserving the SOD reactivity following PNI. Adult rats subjected to hypoglossal nerve transection were intraperitoneally injected with melatonin at ones for 3, 7, 14, 30 and 60 days successively. The potential neuroprotective effects of melatonin were quantitatively demonstrated by neuronal nitric oxide synthase (nNOS), mitochondrial manganese SOD (Mn-SOD), and cytosolic copper-zinc SOD (Cu/Zn-SOD) immunohistochemistry. The functional recovery of the lesioned neurons was evaluated by choline acetyltransferase (ChAT) immunohistochemistry along with the electromyographic (EMG) recordings of denervation-induced fibrillation activity. The results indicate that following PNI, the nNOS immunoreactivity was significantly increased in lesioned neurons peaking at 14 days. The up-regulation of nNOS temporally coincided with the reduction of ChAT and SOD in which the Cu/Zn-SOD showed a greater diminution than Mn-SOD. However, following melatonin administration, the nNOS augmentation was successfully suppressed and the activities of Mn-SOD, Cu/Zn-SOD, and ChAT were effectively preserved at all postaxotomy periods. EMG data also showed a decreased fibrillation in melatonin-treated groups, suggesting a potential effect of melatonin in promoting functional recovery. In association with its significant capacity in preserving SOD reactivity, melatonin is suggested to serve as a powerful therapeutic agent for treating PNI-relevant oxidative damage.
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Affiliation(s)
- Hung-Ming Chang
- Department of Anatomy, Faculty of Medicine, Chung Shan Medical University, Taichung, Taiwan.
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