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Yeh CC, Lin YC, Tsai FJ, Huang CY, Yao CH, Chen YS. Timing of applying electrical stimulation is an important factor deciding the success rate and maturity of regenerating rat sciatic nerves. Neurorehabil Neural Repair 2010; 24:730-5. [PMID: 20705804 DOI: 10.1177/1545968310376758] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The timing of electrical stimulation (ES) after peripheral nerve transection may enhance axonal regeneration and functional recovery. OBJECTIVE The authors examined whether percutaneous ES at 1 mA and 2 Hz affects regeneration between the proximal and distal nerve stumps. METHODS Four groups of adult rats were subjected to sciatic nerve section followed by repair using silicone rubber conduits across a 10-mm gap. All groups received ES for 15 minutes every other day for 2 weeks. Stimulation was initiated on day 1 following the nerve repair for group A, day 8 for group B, and day 15 for group C. The control group D received no ES. RESULTS At 6 weeks after surgery in groups B and C, histological evaluations showed a significantly higher number of regenerated myelinated fibers in the sciatic nerve, and the electrophysiological results showed higher levels of reinnervation with relatively larger mean values of amplitudes, durations, and areas of compound muscle action potentials compared with A and D. CONCLUSION A short delay in the onset of ES may improve the recovery of a severe peripheral nerve injury, which should be considered as a way of augmenting rehabilitative approaches.
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252
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Jinghui Huang, Lei Lu, Xueyu Hu, Zhengxu Ye, Ye Peng, Xiaodong Yan, Dan Geng, Zhuojing Luo. Electrical Stimulation Accelerates Motor Functional Recovery in the Rat Model of 15-mm Sciatic Nerve Gap Bridged by Scaffolds With Longitudinally Oriented Microchannels. Neurorehabil Neural Repair 2010; 24:736-45. [DOI: 10.1177/1545968310368686] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background. Electrical stimulation (ES) can enhance the regenerative capacity of axotomized motor and sensory neurons. However, the impact of ES on axonal regeneration and functional recovery has not been investigated in an animal model of a lengthy peripheral nerve defect. Objective. To determine whether ES accelerates axonal regeneration and functional recovery of a 15-mm sciatic nerve defect in rats. Methods. A 15-mm excision of the sciatic nerve was bridged with a chitosan scaffold with longitudinally or randomly oriented pores or with autologous grafting of the segment. In half of the animals with chitosan grafts, the proximal nerve stump was electrically stimulated for 1 hour at 20 Hz immediately after the nerve repair with the scaffolds. Axonal regeneration was investigated by retrograde labeling and morphometric analysis. The rate of motor functional recovery was evaluated by electrical nerve stimulation, behavioral tests of stepping, and histological appearance of the target muscles. Results. Axonal regeneration and motor functional recovery were improved by ES in animals that received longitudinal pore grafts as compared with others. The maximal number of axons that regenerated across the longitudinal graft was achieved 2 to 4 weeks earlier in rats with ES. In addition, the latency of compound muscle action potentials (CMAPs), the peak amplitude of CMAPs, and nerve conduction velocity were improved by ES. Stepping indices were better, with less atrophy of target muscle in ES rats managed with longitudinal pores. Conclusion. Brief ES may accelerate axonal regeneration and motor recovery after focal peripheral nerve transection when repaired with optimally tissue-engineered grafts.
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Affiliation(s)
- Jinghui Huang
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Lei Lu
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xueyu Hu
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zhengxu Ye
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ye Peng
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiaodong Yan
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Dan Geng
- Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zhuojing Luo
- Fourth Military Medical University, Xi'an, Shaanxi, China,
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253
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Gordon T, Gordon K. Nerve regeneration in the peripheral nervous system versus the central nervous system and the relevance to speech and hearing after nerve injuries. JOURNAL OF COMMUNICATION DISORDERS 2010; 43:274-285. [PMID: 20510423 DOI: 10.1016/j.jcomdis.2010.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 01/26/2010] [Accepted: 02/01/2010] [Indexed: 05/29/2023]
Abstract
UNLABELLED Schwann cells normally form myelin sheaths around axons in the peripheral nervous system (PNS) and support nerve regeneration after nerve injury. In contrast, nerve regeneration in the central nervous system (CNS) is not supported by the myelinating cells known as oligodendrocytes. We have found that: 1) low frequency electrical stimulation can be used to elevate cAMP thereby promoting regeneration of CNS axons and 2) a conditioning lesion, created by a crush of the peripheral branch of the dorsal root ganglion sensory neurons along with a simultaneous cut of these axons in the CNS, promotes even greater neural outgrowth than electrical stimulation. The effectiveness of the lesion results from both an acceleration of axon outgrowth and an increase in the rate of axon growth. However, electrical stimulation remains a more viable treatment of nerve injuries to stimulate regeneration and has been successfully used to promote development of the auditory pathways in children with severe to profound deafness who use cochlear implants. Without nerve regeneration, there is only a random reinnervation of affected muscles. An example occurs when the laryngeal nerve attempts to reinnervate the vocal cords after injury, causing deficits in speech. Synkinesis occurs when reinnervation of antagonistic muscles effectively paralyze the vocal cords and, in turn, severely compromises speech. The misdirection of laryngeal nerve reinnervation can be alleviated surgically by strategies favoring inspiratory abduction. LEARNING OUTCOMES Readers of this article will gain an understanding of (1) the potential for axon regeneration in the central nervous system and (2) problems and possible solutions for random reinnervation of laryngeal muscles for speech.
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Affiliation(s)
- Tessa Gordon
- Centre for Neuroscience, Division of Physical Medicine and Rehabilitation, Faculty of Medicine, University of Alberta, Edmonton, Alberta, T6H 2S2, Canada.
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254
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Gordon T. The physiology of neural injury and regeneration: The role of neurotrophic factors. JOURNAL OF COMMUNICATION DISORDERS 2010; 43:265-273. [PMID: 20451212 DOI: 10.1016/j.jcomdis.2010.04.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 01/26/2010] [Accepted: 02/01/2010] [Indexed: 05/29/2023]
Abstract
UNLABELLED Injured nerves regenerate slowly and often over long distances. Prolonged periods for regenerating nerves to make functional connections with denervated targets prolong the period of isolation of the neurons from the target (chronic axotomy) and of the denervation of Schwann cells in the distal nerve pathways (chronic denervation). In an animal model, we demonstrated that prolonged axotomy and chronic denervation severely reduce the regenerative capacity of neurons to less to 10%. Concurrent reduction in neurotrophic factors, including brain- and glial-derived neurotrophic factors (BDNF and GDNF) in axotomized neurons and denervated Schwann cells, suggest that these factors are required to sustain nerve regeneration. Findings that exogenous BDNF and GDNF did not increase numbers of neurons that regenerate their axons in freshly cut and repaired rat nerves, but did increase the numbers significantly after chronic axotomy, are consistent with the view that there is sufficient endogenous neurotrophic factor supply in axotomized motoneurons and denervated Schwann cells to support nerve regeneration but that the reduced supply must be supplemented when target reinnervation is delayed. In addition, findings that BDNF is essential for the effectiveness of brief low frequency electrical stimulation in promoting nerve growth, provides further support for a central role of BNDF in motor nerve regeneration. LEARNING OUTCOMES Readers of this article will gain an understanding of the basis for poor functional outcomes of peripheral nerve injuries, even when surgical repair is possible.
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Affiliation(s)
- Tessa Gordon
- Division of Neuroscience, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2S2 Canada.
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255
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Hsieh HY, Robertson CL, Vermehren-Schmaedick A, Balkowiec A. Nitric oxide regulates BDNF release from nodose ganglion neurons in a pattern-dependent and cGMP-independent manner. J Neurosci Res 2010; 88:1285-97. [PMID: 19937808 DOI: 10.1002/jnr.22291] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Activity of arterial baroreceptors is modulated by neurohumoral factors, including nitric oxide (NO), released from endothelial cells. Baroreceptor reflex responses can also be modulated by NO signaling in the brainstem nucleus tractus solitarius (NTS), the primary central target of cardiovascular afferents. Our recent studies indicate that brain-derived neurotrophic factor (BDNF) is abundantly expressed by developing and adult baroreceptor afferents in vivo, and released from cultured nodose ganglion (NG) neurons by patterns of baroreceptor activity. Using electrical field stimulation and ELISA in situ, we show that exogenous NO nearly abolishes BDNF release from newborn rat NG neurons in vitro stimulated with single pulses delivered at 6 Hz, but not 2-pulse bursts delivered at the same 6-Hz frequency, that corresponds to a rat heart rate. Application of L-NAME, a specific inhibitor of endogenous NO synthases, does not have any significant effect on activity-dependent BDNF release, but leads to upregulation of BDNF expression in an activity-dependent manner. The latter effect suggests a novel mechanism of homeostatic regulation of activity-dependent BDNF expression with endogenous NO as a key player. The exogenous NO-mediated effect does not involve the cGMP-protein kinase G (PKG) pathway, but is largely inhibited by N-ethylmaleimide and TEMPOL that are known to prevent S-nitrosylation. Together, our current data identify previously unknown mechanisms regulating BDNF availability, and point to NO as a likely regulator of BDNF at baroafferent synapses in the NTS.
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Affiliation(s)
- Hui-ya Hsieh
- Department of Integrative Biosciences, Oregon Health and Science University, Portland, Oregon 97239, USA
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256
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Hill CE, Harrison BJ, Rau KK, Hougland MT, Bunge MB, Mendell LM, Petruska JC. Skin incision induces expression of axonal regeneration-related genes in adult rat spinal sensory neurons. THE JOURNAL OF PAIN 2010; 11:1066-73. [PMID: 20627820 DOI: 10.1016/j.jpain.2010.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 01/26/2010] [Accepted: 02/01/2010] [Indexed: 12/31/2022]
Abstract
UNLABELLED Skin incision and nerve injury both induce painful conditions. Incisional and postsurgical pain is believed to arise primarily from inflammation of tissue and the subsequent sensitization of peripheral and central neurons. The role of axonal regeneration-related processes in development of pain has only been considered when there has been injury to the peripheral nerve itself, even though tissue damage likely induces injury of resident axons. We sought to determine if skin incision would affect expression of regeneration-related genes such as activating transcription factor 3 (ATF3) in dorsal root ganglion (DRG) neurons. ATF3 is absent from DRG neurons of the normal adult rodent, but is induced by injury of peripheral nerves and modulates the regenerative capacity of axons. Image analysis of immunolabeled DRG sections revealed that skin incision led to an increase in the number of DRG neurons expressing ATF3. RT-PCR indicated that other regeneration-associated genes (galanin, GAP-43, Gadd45a) were also increased, further suggesting an injury-like response in DRG neurons. Our finding that injury of skin can induce expression of neuronal injury/regeneration-associated genes may impact how clinical postsurgical pain is investigated and treated. PERSPECTIVE Tissue injury, even without direct nerve injury, may induce a state of enhanced growth capacity in sensory neurons. Axonal regeneration-associated processes should be considered alongside nerve signal conduction and inflammatory/sensitization processes as possible mechanisms contributing to pain, particularly the transition from acute to chronic pain.
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Affiliation(s)
- Caitlin E Hill
- University of Miami, The Miami Project to Cure Paralysis, Miami, Florida, USA
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257
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Runge MB, Dadsetan M, Baltrusaitis J, Knight AM, Ruesink T, Lazcano EA, Lu L, Windebank AJ, Yaszemski MJ. The development of electrically conductive polycaprolactone fumarate-polypyrrole composite materials for nerve regeneration. Biomaterials 2010; 31:5916-26. [PMID: 20483452 DOI: 10.1016/j.biomaterials.2010.04.012] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 04/05/2010] [Indexed: 01/19/2023]
Abstract
Electrically conductive polymer composites composed of polycaprolactone fumarate and polypyrrole (PCLF-PPy) have been developed for nerve regeneration applications. Here we report the synthesis and characterization of PCLF-PPy and in vitro studies showing PCLF-PPy materials support both PC12 cell and dorsal root ganglia (DRG) neurite extension. PCLF-PPy composite materials were synthesized by polymerizing pyrrole in preformed PCLF scaffolds (M(n) 7,000 or 18,000 g mol(-1)) resulting in interpenetrating networks of PCLF-PPy. Chemical compositions and thermal properties were characterized by ATR-FTIR, XPS, DSC, and TGA. PCLF-PPy materials were synthesized with five different anions (naphthalene-2-sulfonic acid sodium salt (NSA), dodecylbenzenesulfonic acid sodium salt (DBSA), dioctyl sulfosuccinate sodium salt (DOSS), potassium iodide (I), and lysine) to investigate effects on electrical conductivity and to optimize chemical composition for cellular compatibility. PCLF-PPy materials have variable electrical conductivity up to 6 mS cm(-1) with bulk compositions ranging from 5 to 13.5 percent polypyrrole. AFM and SEM characterization show microstructures with a root mean squared (RMS) roughness of 1195 nm and nanostructures with RMS roughness of 8 nm. In vitro studies using PC12 cells and DRG show PCLF-PPy materials synthesized with NSA or DBSA support cell attachment, proliferation, neurite extension, and are promising materials for future studies involving electrical stimulation.
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Affiliation(s)
- M Brett Runge
- Department of Orthopedic Surgery, Mayo Clinic College of Medicine, Rochester MN 55905, USA
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258
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Gordon T, Amirjani N, Edwards DC, Chan KM. Brief post-surgical electrical stimulation accelerates axon regeneration and muscle reinnervation without affecting the functional measures in carpal tunnel syndrome patients. Exp Neurol 2010; 223:192-202. [DOI: 10.1016/j.expneurol.2009.09.020] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 09/23/2009] [Accepted: 09/25/2009] [Indexed: 11/26/2022]
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259
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Udina E, Ladak A, Furey M, Brushart T, Tyreman N, Gordon T. Rolipram-induced elevation of cAMP or chondroitinase ABC breakdown of inhibitory proteoglycans in the extracellular matrix promotes peripheral nerve regeneration. Exp Neurol 2010; 223:143-52. [PMID: 19733561 PMCID: PMC3071985 DOI: 10.1016/j.expneurol.2009.08.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 08/25/2009] [Accepted: 08/26/2009] [Indexed: 11/24/2022]
Abstract
The inhibitory growth environment of myelin and extracellular matrix proteoglycans in the central nervous system may be overcome by elevating neuronal cAMP or degrading inhibitory proteoglycans with chondroitinase ABC (ChABC). In this study, we asked whether similar mechanisms operate in peripheral nerve regeneration where effective Wallerian degeneration removes myelin and extracellular proteoglycans slowly. We repaired transected common peroneal (CP) nerve in rats and either elevated cAMP in the axotomized neurons by subcutaneous rolipram, a specific inhibitor of phosphodiesterase IV, and/or promoted degradation of proteoglycans in the distal nerve stump by local ChABC administration. Rolipram treatment significantly increased the number of motoneurons that regenerated axons across the repair site at 1 and 2 weeks, and increased the number of sensory neurons that regenerated axons across the repair site at 2 weeks. Local application of ChABC had a similar effect to rolipram treatment in promoting motor axon regeneration, the effect being no greater when rolipram and ChABC were administered simultaneously. We conclude that blocking inhibitors of axon regeneration by elevating cAMP or degrading proteoglycans in the distal nerve stump promotes peripheral axon regeneration after surgical repair of a transected nerve. It is likely that elevated cAMP is sufficient to encourage axon outgrowth despite the inhibitory growth environment such that simultaneous enzymatic proteoglycan degradation does not promote more axon regeneration than either elevated cAMP or proteoglycan degradation alone.
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Affiliation(s)
- E Udina
- Division of Physical Medicine and Rehabilitation, Faculty of Medicine and Dentistry, Center for Neurosciences, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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260
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Electrical stimulation and testosterone differentially enhance expression of regeneration-associated genes. Exp Neurol 2010; 223:183-91. [DOI: 10.1016/j.expneurol.2009.04.031] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 04/26/2009] [Accepted: 04/28/2009] [Indexed: 02/04/2023]
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261
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Li S, Li H, Wang Z. Orientation of spiral ganglion neurite extension in electrical fields of charge-balanced biphasic pulses and direct current in vitro. Hear Res 2010; 267:111-8. [PMID: 20430073 DOI: 10.1016/j.heares.2010.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 04/04/2010] [Accepted: 04/12/2010] [Indexed: 12/15/2022]
Abstract
Cochlear implants function by stimulating residual spiral ganglion neurons (SGNs) with electric current. Promoting the neurites of SGNs to grow towards an electrode array could improve the outcome of cochlear implantation. Several studies have suggested that DC electrical fields (EFs) can affect the direction of neurite extension. To investigate the impact of steady DC EFs, pulsed DC EFs and charge-balanced biphasic pulsed EFs on the direction of SGN neurite extension, we established an SGN culturing and imaging system. SGN explants of newborn Sprague-Dawley rats were cultured on slides. Slides were positioned into the monitoring system with neurite terminals in a certain orientation and location, while the migration of SGN growth cones was monitored by taking serial photos. Deflection angles of neurites at a certain period were measured. In steady or pulsed DC EFs, neurites on laminin-coated slides turned towards the cathode, while those on PDL-coated slides turned towards the anode. The neurites in charge-balanced biphasic pulsed EFs had an obvious orientation of turning away from the electrode rings. This orientation diminished with increasing distance from the electrode rings and followed the nonuniform characteristics of charge-balanced biphasic pulsed EFs.
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Affiliation(s)
- Shufeng Li
- Department of Otolaryngology, Eye & ENT Hospital of Fudan University, 83 Fenyang Road, 200031 Shanghai, China.
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262
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Huang J, Ye Z, Hu X, Lu L, Luo Z. Electrical stimulation induces calcium-dependent release of NGF from cultured Schwann cells. Glia 2010; 58:622-31. [PMID: 19998481 DOI: 10.1002/glia.20951] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Production of nerve growth factor (NGF) from Schwann cells (SCs) progressively declines in the distal stump, if axonal regeneration is staggered across the suture site after peripheral nerve injuries. This may be an important factor limiting the outcome of nerve injury repair. Thus far, extensive efforts are devoted to modulating NGF production in cultured SCs, but little has been achieved. In the present in vitro study, electrical stimulation (ES) was attempted to stimulate cultured SCs to release NGF. Our data showed that ES was capable of enhancing NGF release from cultured SCs. An electrical field (1 Hz, 5 V/cm) caused a 4.1-fold increase in NGF release from cultured SCs. The ES-induced NGF release is calcium dependent. Depletion of extracellular or/and intracellular calcium partially/ completely abolished the ES-induced NGF release. Further pharmacological interventions showed that ES induces calcium influx through T-type voltage-gated calcium channels and mobilizes calcium from 1, 4, 5-trisphosphate-sensitive stores and caffeine/ryanodine-sensitive stores, both of which contributed to the enhanced NGF release induced by ES. In addition, a calcium-triggered exocytosis mechanism was involved in the ES-induced NGF release from cultured SCs. These findings show the feasibility of using ES in stimulating SCs to release NGF, which holds great potential in promoting nerve regeneration by enhancing survival and outgrowth of damaged nerves, and is of great significance in nerve injury repair and neuronal tissue engineering.
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Affiliation(s)
- Jinghui Huang
- Department of Spine Surgery, Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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263
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Becker D, Gary DS, Rosenzweig ES, Grill WM, McDonald JW. Functional electrical stimulation helps replenish progenitor cells in the injured spinal cord of adult rats. Exp Neurol 2010; 222:211-8. [PMID: 20059998 DOI: 10.1016/j.expneurol.2009.12.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/19/2009] [Accepted: 12/29/2009] [Indexed: 12/21/2022]
Abstract
Functional electrical stimulation (FES) can restore control and offset atrophy to muscles after neurological injury. However, FES has not been considered as a method for enhancing CNS regeneration. This paper demonstrates that FES dramatically enhanced progenitor cell birth in the spinal cord of rats with a chronic spinal cord injury (SCI). A complete SCI at thoracic level 8/9 was performed on 12 rats. Three weeks later, a FES device to stimulate hindlimb movement was implanted into these rats. Twelve identically-injured rats received inactive FES implants. An additional control group of uninjured rats were also examined. Ten days after FES implantation, dividing cells were marked with bromodeoxyuridine (BrdU). The "cell birth" subgroup (half the animals in each group) was sacrificed immediately after completion of BrdU administration, and the "cell survival" subgroup was sacrificed 7 days later. In the injured "cell birth" subgroup, FES induced an 82-86% increase in cell birth in the lumbar spinal cord. In the injured "cell survival" subgroup, the increased lumbar newborn cell counts persisted. FES doubled the proportion of the newly-born cells which expressed nestin and other markers suggestive of tripotential progenitors. In uninjured rats, FES had no effect on cell birth/survival. This report suggests that controlled electrical activation of the CNS may enhance spontaneous regeneration after neurological injuries.
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Affiliation(s)
- Daniel Becker
- International Center, for Spinal Cord Injury, Hugo Moser Research Institute, Department of Neurology, Johns Hopkins School of Medicine and Kennedy Krieger Institute, Baltimore, MD 21205, USA
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264
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Mao HQ, Lim SH, Zhang S, Christopherson G, Kam K, Fischer S. The Nanofiber Matrix as an Artificial Stem Cell Niche. STUDIES IN MECHANOBIOLOGY, TISSUE ENGINEERING AND BIOMATERIALS 2010. [DOI: 10.1007/8415_2010_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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265
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Use of Electrical Stimulation at Different Current Levels to Promote Recovery After Peripheral Nerve Injury in Rats. ACTA ACUST UNITED AC 2009; 67:1066-72. [DOI: 10.1097/ta.0b013e318182351a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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266
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Huang J, Hu X, Lu L, Ye Z, Wang Y, Luo Z. Electrical Stimulation Accelerates Motor Functional Recovery in Autograft-Repaired 10 mm Femoral Nerve Gap in Rats. J Neurotrauma 2009; 26:1805-13. [PMID: 19226192 DOI: 10.1089/neu.2008.0732] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jinghui Huang
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Xueyu Hu
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Lei Lu
- Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Zhengxu Ye
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yuqing Wang
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Zhuojing Luo
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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267
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Jung R, Belanger A, Kanchiku T, Fairchild M, Abbas JJ. Neuromuscular stimulation therapy after incomplete spinal cord injury promotes recovery of interlimb coordination during locomotion. J Neural Eng 2009; 6:055010. [PMID: 19721184 DOI: 10.1088/1741-2560/6/5/055010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The mechanisms underlying the effects of neuromuscular electrical stimulation (NMES) induced repetitive limb movement therapy after incomplete spinal cord injury (iSCI) are unknown. This study establishes the capability of using therapeutic NMES in rodents with iSCI and evaluates its ability to promote recovery of interlimb control during locomotion. Ten adult female Long Evans rats received thoracic spinal contusion injuries (T9; 156 +/- 9.52 Kdyne). 7 days post-recovery, 6/10 animals received NMES therapy for 15 min/day for 5 days, via electrodes implanted bilaterally into hip flexors and extensors. Six intact animals served as controls. Motor function was evaluated using the BBB locomotor scale for the first 6 days and on 14th day post-injury. 3D kinematic analysis of treadmill walking was performed on day 14 post-injury. Rodents receiving NMES therapy exhibited improved interlimb coordination in control of the hip joint, which was the specific NMES target. Symmetry indices improved significantly in the therapy group. Additionally, injured rodents receiving therapy more consistently displayed a high percentage of 1:1 coordinated steps, and more consistently achieved proper hindlimb touchdown timing. These results suggest that NMES techniques could provide an effective therapeutic tool for neuromotor treatment following iSCI.
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Affiliation(s)
- R Jung
- Center for Adaptive Neural Systems, Arizona State University, Tempe, 85287-4404, USA.
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268
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269
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Geremia NM, Pettersson LME, Hasmatali JC, Hryciw T, Danielsen N, Schreyer DJ, Verge VMK. Endogenous BDNF regulates induction of intrinsic neuronal growth programs in injured sensory neurons. Exp Neurol 2009; 223:128-42. [PMID: 19646438 DOI: 10.1016/j.expneurol.2009.07.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 07/11/2009] [Accepted: 07/15/2009] [Indexed: 12/21/2022]
Abstract
Identification of the molecule(s) that globally induce a robust regenerative state in sensory neurons following peripheral nerve injury remains elusive. A potential candidate is brain-derived neurotrophic factor (BDNF), the sole neurotrophin upregulated in sensory neurons after peripheral nerve injury. Here we tested the hypothesis that BDNF plays a critical role in the regenerative response of mature rat sensory neurons following peripheral nerve lesion. Neutralization of endogenous BDNF was performed by infusing BDNF antibodies intrathecally via a mini-osmotic pump for 3 days at the level of the fifth lumbar dorsal root ganglion, immediately following unilateral spinal nerve injury. This resulted in decreased expression of the injury/regeneration-associated genes growth-associated protein-43 and Talpha1 tubulin in the injured sensory neurons as compared to injury plus control IgG infused or injury alone animals. Similar results were observed following inhibition of BDNF expression by intrathecal delivery of small interfering RNAs (siRNA) targeting BDNF starting 3 days prior to injury. The reduced injury/regeneration-associated gene expression correlated with a significantly reduced intrinsic capacity of these neurons to extend neurites when assayed in vitro. In contrast, delayed infusion of BDNF antibody for 3 days beginning 1 week post-lesion had no discernible influence on the elevated expression of these regeneration-associated markers. These results support an important role for endogenous BDNF in induction of the cell body response in injured sensory neurons and their intrinsic ability to extend neurites, but BDNF does not appear to be necessary for maintaining the response once it is induced.
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Affiliation(s)
- Nicole M Geremia
- Department of Anatomy and Cell Biology, Cameco MS Neuroscience Research Center University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E5
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Jung R, Ichihara K, Venkatasubramanian G, Abbas JJ. Chronic neuromuscular electrical stimulation of paralyzed hindlimbs in a rodent model. J Neurosci Methods 2009; 183:241-54. [PMID: 19596376 DOI: 10.1016/j.jneumeth.2009.06.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 06/07/2009] [Accepted: 06/29/2009] [Indexed: 11/15/2022]
Abstract
Neuromuscular electrical stimulation (NMES) can be used to activate paralyzed or paretic muscles to generate functional or therapeutic movements. The goal of this research was to develop a rodent model of NMES-assisted movement therapy after spinal cord injury (SCI) that will enable investigation of mechanisms of NMES-induced plasticity, from the molecular to systems level. Development of the model requires accurate mapping of electrode and muscle stimulation sites, the capability to selectively activate muscles to produce graded contractions of sufficient strength, stable anchoring of the implanted electrode within the muscles and stable performance with functional reliability over several weeks of the therapy window. Custom designed electrodes were implanted chronically in hindlimb muscles of spinal cord transected rats. Mechanical and electrical stability of electrodes and the ability to achieve appropriate muscle recruitment and joint angle excursion were assessed by characterizing the strength duration curves, isometric torque recruitment curves and kinematics of joint angle excursion over 6-8 weeks post implantation. Results indicate that the custom designed electrodes and implantation techniques provided sufficient anchoring and produced stable and reliable recruitment of muscles both in the absence of daily NMES (for 8 weeks) as well as with daily NMES that is initiated 3 weeks post implantation (for 6 weeks). The completed work establishes a rodent model that can be used to investigate mechanisms of neuroplasticity that underlie NMES-based movement therapy after spinal cord injury and to optimize the timing of its delivery.
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Affiliation(s)
- Ranu Jung
- Center for Adaptive Neural Systems, Tempe, Arizona State University, AZ 85287-4404, USA.
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271
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Ni YQ, Gan DK, Xu HD, Xu GZ, Da CD. Neuroprotective effect of transcorneal electrical stimulation on light-induced photoreceptor degeneration. Exp Neurol 2009; 219:439-52. [PMID: 19576889 DOI: 10.1016/j.expneurol.2009.06.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 06/17/2009] [Accepted: 06/20/2009] [Indexed: 10/20/2022]
Abstract
Direct electrical stimulation of neural tissues is a strategic approach to treat injured axons by accelerating their outgrowth [Al-Majed, A.A., Neumann, C.M., Brushart, T.M., Gordon, T., 2000. Brief electrical stimulation promotes the speed and accuracy of motor axonal regeneration. J. Neurosci. 20, 2602-2608] and promoting their regeneration [Geremia, N.M., Gordon, T., Brushart, T.M., Al-Majed, A.A., Verge, V.M.K., 2007. Electrical stimulation promotes sensory neuron regeneration and growth-associated gene expression. Exp. Neurol. 205, 347-359]. Recently, transcorneal electrical stimulation (TCES), a novel less invasive method, has been shown to rescue axotomized and damaged retinal ganglion cells [Morimoto, T., Miyoshi, T., Matsuda, S., Tano, Y., Fujikado, T., Fukuda, Y., 2005. Transcorneal electrical stimulation rescues axotomized retinal ganglion cells by activating endogenous retinal IGF-1 system. Invest. Ophthalmol. Vis. Sci. 46(6), 2147-2155]. Here, we investigated the neuroprotection of TCES on light-induced photoreceptor degeneration and the underlying mechanism. Adult male Sprague-Dawley (SD) rats received TCES before (pre-TCES) or after (post-TCES) intense light exposure. After fourteen days of light exposure, retinal histology and electroretinography were performed to evaluate the neuroprotective effect of TCES. The mRNA and protein levels of apoptotic-associated genes including Bcl-2, Bax, Caspase-3 as well as ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in the retinas were determined by real-time PCR and Western blot analysis. The localization of these gene products in the retinas was examined by immunohistochemistry. Both pre- and post-TCES ameliorated the progressive photoreceptor degeneration. The degree of rescue depended on the strength of the electric charge. Post-TCES showed a relatively better and longer-term protective effect than pre-TCES. Real-time PCR and Western blot analysis revealed an upregulation of Bcl-2, CNTF, and BDNF and a downregulation of Bax in the retinas after TCES. Immunohistochemical studies showed that Bcl-2 and CNTF were selectively upregulated in Müller cells. These findings provide a new therapeutic method to prevent or delay photoreceptor degeneration through activating the intrinsic survival system.
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Affiliation(s)
- Ying-qin Ni
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fen Yang Road, Shanghai 200031, People's Republic of China
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272
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Jiao H, Yao J, Yang Y, Chen X, Lin W, Li Y, Gu X, Wang X. Chitosan/polyglycolic acid nerve grafts for axon regeneration from prolonged axotomized neurons to chronically denervated segments. Biomaterials 2009; 30:5004-18. [PMID: 19540584 DOI: 10.1016/j.biomaterials.2009.05.059] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Accepted: 05/22/2009] [Indexed: 12/27/2022]
Abstract
Peripheral nerve regeneration for long-term delayed injuries is usually unsatisfied. Here we attempted to use a chitosan/polyglycolic acid (PGA) artificial nerve graft to bridge a long-term delayed 10-mm defect in SD rats based on the previous studies on the graft used for immediate repair of 30-mm-long dog sciatic nerve defects and for clinical treatment of a 35-mm-long median nerve defect at elbow of a human patient. In this study, for experimental groups, the rat sciatic nerve had been transected leaving a 10-mm defect, which was maintained for 3 or 6 months before implantation with the chitosan/PGA artificial nerve graft. The animals non-grafted or grafted with autograft served as negative or positive control group. In experiment groups, nerve regeneration with functional recovery was achieved as measured by electrophysiological and histological techniques, although differences in the quantity and the quality of the regenerated nerve were observed between the 3- and 6-month delayed subgroups. The results showed that: (1) a few denervated Schwann cells survived and sustained their ability to myelinate axons at least 6 months, and (2) the atrophic denervated muscle could be reinnervated by regenerated axons through new muscle-nerve connections. These observations provide the possibility of guiding regenerated axons from survived axotomized neurons to distal nerve stump by the chitosan/PGA artificial nerve graft.
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Affiliation(s)
- Haishan Jiao
- Department of Histology and Embryology, Medical College, Nantong University, Nantong, Jiangsu 226001, China
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273
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Asensio-Pinilla E, Udina E, Jaramillo J, Navarro X. Electrical stimulation combined with exercise increase axonal regeneration after peripheral nerve injury. Exp Neurol 2009; 219:258-65. [PMID: 19500575 DOI: 10.1016/j.expneurol.2009.05.034] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 04/24/2009] [Accepted: 05/22/2009] [Indexed: 12/11/2022]
Abstract
Although injured peripheral axons are able to regenerate, functional recovery is usually poor after nerve transection. In this study we aim to elucidate the role of neuronal activity, induced by nerve electrical stimulation and by exercise, in promoting axonal regeneration and modulating plasticity in the spinal cord after nerve injury. Four groups of adult rats were subjected to sciatic nerve transection and suture repair. Two groups received electrical stimulation (3 V, 0.1 ms at 20 Hz) for 1 h, immediately after injury (ESa) or during 4 weeks (1 h daily; ESc). A third group (ES+TR) received 1 h electrical stimulation and was submitted to treadmill running during 4 weeks (5 m/min, 2 h daily). A fourth group performed only exercise (TR), whereas an untreated group served as control (C). Nerve conduction, H reflex and algesimetry tests were performed at 1, 3, 5, 7 and 9 weeks after surgery, to assess muscle reinnervation and changes in excitability of spinal cord circuitry. Histological analysis was made at the end of the follow-up. Groups that received acute ES and/or were forced to exercise in the treadmill showed higher levels of muscle reinnervation and increased numbers of regenerated myelinated axons when compared to control animals or animals that received chronic ES. Combining ESa with treadmill training significantly improved muscle reinnervation during the initial phase. The facilitation of the monosynaptic H reflex in the injured limb was reduced in all treated groups, suggesting that the maintenance of activity helps to prevent the development of hyperreflexia.
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Affiliation(s)
- Elena Asensio-Pinilla
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
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274
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Wood MD, Willits RK. Applied electric field enhances DRG neurite growth: influence of stimulation media, surface coating and growth supplements. J Neural Eng 2009; 6:046003. [PMID: 19494423 DOI: 10.1088/1741-2560/6/4/046003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Electrical therapies have been found to aid repair of nerve injuries and have been shown to increase and direct neurite outgrowth during stimulation. This enhanced neural growth existed even after the electric field (EF) or stimulation was removed, but the factors that may influence the enhanced growth, such as stimulation media or surface coating, have not been fully investigated. This study characterized neurite outgrowth and branching under various conditions: EF magnitude and application time, ECM surface coating, medium during EF application and growth supplements. A uniform, low-magnitude EF (24 or 44 V m(-1)) was applied to dissociated chick embryo dorsal root ganglia seeded on collagen or laminin-coated surfaces. During the growth period, cells were either exposed to NGF or N2, and during stimulation cells were exposed to either unsupplemented media (Ca(2+)) or PBS (no Ca(2+)). Parallel controls for each experiment included cells exposed to the chamber with no stimulation and cells remaining outside the chamber. After brief electrical stimulation (10 min), neurite length significantly increased 24 h after application for all conditions studied. Of particular interest, increased stimulation time (10-100 min) further enhanced neurite length on laminin but not on collagen surfaces. Neurite branching was not affected by stimulation on any surface, and no preferential growth of neurites was noted after stimulation. Overall, the results of this report suggest that short-duration electric stimulation is sufficient to enhance neurite length under a variety of conditions. While further data are needed to fully elucidate a mechanism for this increased growth, these data suggest that one focus of those investigations should be the interaction between the growth cone and the substrata.
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Affiliation(s)
- Matthew D Wood
- Department of Biomedical Engineering, Saint Louis University, St Louis, MO, USA
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275
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Ghaffariyeh A, Peyman A, Puyan S, Honarpisheh N, Bagheri B, Peyman M. Evaluation of transcutaneous electrical simulation to improve recovery from corneal hypoesthesia after LASIK. Graefes Arch Clin Exp Ophthalmol 2009; 247:1133-8. [DOI: 10.1007/s00417-009-1079-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 03/20/2009] [Accepted: 04/06/2009] [Indexed: 10/20/2022] Open
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276
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Electrical stimulation of paralyzed vibrissal muscles reduces endplate reinnervation and does not promote motor recovery after facial nerve repair in rats. Ann Anat 2009; 191:356-70. [PMID: 19481914 DOI: 10.1016/j.aanat.2009.03.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/24/2009] [Accepted: 03/24/2009] [Indexed: 01/26/2023]
Abstract
The outcome of peripheral nerve injuries requiring surgical repair is poor. Recent work has suggested that electrical stimulation (ES) of denervated muscles could be beneficial. Here we tested whether ES has a positive influence on functional recovery after injury and surgical repair of the facial nerve. Outcomes at 2 months were compared to animals receiving sham stimulation (SS). Starting on the first day after end-to-end suture (facial-facial anastomosis), electrical stimulation (square 0.1 ms pulses at 5 Hz at an ex tempore established threshold amplitude of between 3.0 and 5.0V) was delivered to the vibrissal muscles for 5 min a day, 3 times a week. Restoration of vibrissal motor performance following ES or SS was evaluated using the video-based motion analysis and correlated with the degree of collateral axonal branching at the lesion site, the number of motor endplates in the target musculature and the quality of their reinnervation, i.e. the degree of mono- versus poly-innervation. Neither protocol reduced collateral branching. ES did not improve functional outcome, but rather reduced the number of innervated motor endplates to approximately one-fifth of normal values and failed to reduce the proportion of poly-innervated motor endplates. We conclude that ES is not beneficial for recovery of whisker function after facial nerve repair in rats.
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277
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Maeda Y, Ikeuchi M, Wacnik P, Sluka KA. Increased c-fos immunoreactivity in the spinal cord and brain following spinal cord stimulation is frequency-dependent. Brain Res 2009; 1259:40-50. [DOI: 10.1016/j.brainres.2008.12.060] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 12/23/2008] [Accepted: 12/24/2008] [Indexed: 10/21/2022]
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278
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Gordon T, Sulaiman OAR, Ladak A. Chapter 24: Electrical stimulation for improving nerve regeneration: where do we stand? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:433-44. [PMID: 19682653 DOI: 10.1016/s0074-7742(09)87024-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
While injured neurons regenerate their axons in the peripheral nervous system, it is well recognized that functional recovery is frequently poor. Animal experiments in which injured motoneurons remain without peripheral targets (chronic axotomy) and Schwann cells in distal nerve stumps remain without innervation (chronic denervation) revealed that it is the duration of chronic axotomy and Schwann cell denervation that accounts for this poor functional recovery and not irreversible muscle atrophy that has been so commonly thought to be the reason. More recently, we demonstrated that axon outgrowth across lesion sites is a major contributing factor to the long delays incurred between the injury and the reinnervation of denervated targets. In the rat, a period of 1 month transpires before all motoneurons regenerate their axons across a lesion site. We have developed a technique of 1 h low-frequency electrical stimulation (ES) of the proximal nerve stump just after surgical repair of a transected peripheral nerve that greatly accelerates axon outgrowth. This technique has been applied in patients after carpal tunnel release surgery where the ES promoted the regeneration of all median nerves to reinnervate thenar muscles within 6-8 months, which contrasted with failure of any injured nerves to reinnervate muscles in the same time frame without ES. These findings are very promising such that the ES method could become a clinically viable tool for accelerating axon regeneration and muscle reinnervation.
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Affiliation(s)
- Tessa Gordon
- Division of Neuroscience, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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279
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Induction of fibroblast growth factor-2 by electrical stimulation in cultured retinal Mueller cells. Neuroreport 2008; 19:1617-21. [PMID: 18815585 DOI: 10.1097/wnr.0b013e3283140f25] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It has been demonstrated that retinal Mueller cells, the predominant glial cells, produce neurotrophic factors including basic fibroblast growth factor (FGF-2), and that electrical stimulation enhances the transcription of FGF-2 in the central nervous system. In this study, the effect of electrical stimulation on the induction of FGF-2 in cultured rat Mueller cells was investigated by quantitative real-time polymerase chain reaction and western blotting. Both the messenger RNA and protein of FGF-2 were significantly upregulated after electrical stimulation compared with that of controls. These results suggest that electrical stimulation may directly induce the production of FGF-2 in the retina.
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280
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Abstract
Cortical mapping and relearning are key factors in optimizing patient outcome following motor nerve transfers. To maximize function following nerve transfers, the rehabilitation program must include motor reeducation to initiate recruitment of the weak reinnervated muscles and to establish new motor patterns and cortical mapping. Patient education and a home program are essential to obtain the optimal functional result.
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Affiliation(s)
- Christine B Novak
- University Health Network, 8N-875, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada.
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281
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Neuromuscular electrical stimulation of the hindlimb muscles for movement therapy in a rodent model. J Neurosci Methods 2008; 176:213-24. [PMID: 18848960 DOI: 10.1016/j.jneumeth.2008.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2008] [Revised: 08/16/2008] [Accepted: 09/05/2008] [Indexed: 11/21/2022]
Abstract
Neuromuscular electrical stimulation (NMES) can provide functional movements in people after central nervous system injury. The neuroplastic effects of long-term NMES-induced repetitive limb movement are not well understood. A rodent model of neurotrauma in which NMES can be implemented may be effective for such investigations. We present a rodent model for NMES of the flexor and extensor muscles of the hip, knee, and ankle hindlimb muscles. Custom fabricated intramuscular stimulating electrodes for rodents were implanted near identified motor points of targeted muscles in ten adult, female Long Evans rats. The effects of altering NMES pulse stimulation parameters were characterized using strength duration curves, isometric joint torque recruitment curves and joint angle measures. The data indicate that short pulse widths have the advantage of producing graded torque recruitment curves when current is used as the control parameter. A stimulus frequency of 75 Hz or more produces fused contractions. The data demonstrate ability to accurately implant the electrodes and obtain selective, graded, repeatable, strong muscle contractions. Knee and ankle angular excursions comparable to those obtained in normal treadmill walking in the same rodent species can be obtained by stimulating the target muscles. Joint torques (normalized to body weight) obtained were larger than those reported in the literature for small tailed therian mammals and for peak isometric ankle plantarflexion in a different rodent species. This model system could be used for investigations of NMES assisted hindlimb movement therapy.
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282
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Lu MC, Ho CY, Hsu SF, Lee HC, Lin JH, Yao CH, Chen YS. Effects of electrical stimulation at different frequencies on regeneration of transected peripheral nerve. Neurorehabil Neural Repair 2008; 22:367-73. [PMID: 18663248 DOI: 10.1177/1545968307313507] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Electrical stimulation of damaged peripheral nerve may aid regeneration. OBJECTIVE The purpose of this study was to determine whether 1 mA of percutaneous electrical stimulation at 1, 2, 20, or 200 Hz augments regeneration between the proximal and distal nerve stumps. METHODS A10-mm gap was made in rat sciatic nerve by suturing the stumps into silicone rubber tubes. A control group received no stimulation. Starting 1 week after transection, electrical stimulation was applied between the cathode placed at the distal stump and the anode at the proximal stump every other day for 6 weeks. RESULTS Higher frequency stimulation led to less regeneration compared to lower frequencies. Quantitative histology of the successfully regenerated nerves revealed that the groups receiving electrical treatment, especially at 2 Hz, had a more mature structure with a smaller cross-sectional area, more myelinated fibers, higher axon density, and higher ratio of blood vessel to total nerve area compared with the controls. Electrophysiology showed significantly shorter latency, longer duration, and faster conduction velocity. CONCLUSION Electrical stimulation can have either a positive or negative impact on peripheral nerve regeneration. Clinical trials that combine stimulation with rehabilitation must determine the parameters that are most likely to be safe and effective.
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Affiliation(s)
- Ming-Chin Lu
- School of Post Baccalaureate Chinese Medicine, China Medical University, Taichung, Taiwan
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283
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284
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Campbell WW. Evaluation and management of peripheral nerve injury. Clin Neurophysiol 2008; 119:1951-65. [PMID: 18482862 DOI: 10.1016/j.clinph.2008.03.018] [Citation(s) in RCA: 436] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2006] [Revised: 01/27/2008] [Accepted: 03/07/2008] [Indexed: 01/08/2023]
Abstract
Common etiologies of acute traumatic peripheral nerve injury (TPNI) include penetrating injury, crush, stretch, and ischemia. Management of TPNI requires familiarity with the relevant anatomy, pathology, pathophysiology, and the surgical principles, approaches and concerns. Surgical repair of TPNI is done at varying time intervals after the injury, and there are a number of considerations in deciding whether and when to operate. In neurapraxia, the compound muscle and nerve action potentials on stimulating distal to the lesion are maintained indefinitely; stimulation above the lesion reveals partial or complete conduction block. The picture in axonotmesis and neurotmesis depends on the time since injury. The optimal timing for an electrodiagnostic study depends upon the clinical question being asked. Although conventional teaching usually holds that an electrodiagnostic study should not be done until about 3 weeks after the injury, in fact a great deal of important information can be obtained by studies done in the first week. Proximal nerve injuries are problematic because the long distance makes it difficult to reinnervate distal muscles before irreversible changes occur. Decision making regarding exploration must occur more quickly, and exploration using intraoperative nerve action potential recording to guide the choice of surgical procedure is often useful.
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Affiliation(s)
- William W Campbell
- Department of Neurology, Uniformed Services University of Health Sciences, Room A 1036, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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285
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Aglah C, Gordon T, Posse de Chaves EI. cAMP promotes neurite outgrowth and extension through protein kinase A but independently of Erk activation in cultured rat motoneurons. Neuropharmacology 2008; 55:8-17. [PMID: 18502451 DOI: 10.1016/j.neuropharm.2008.04.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 02/19/2008] [Accepted: 04/08/2008] [Indexed: 11/28/2022]
Abstract
It is well established that cAMP counteracts myelin inhibition to permit axon regeneration in the central nervous system. On the other hand, the role of cAMP in axonal growth on permissive substrates remains controversial because the evidence available is contradictory. In view that elevation of cAMP represents an attractive therapeutic target to promote nerve regeneration in vivo, we investigated the effect of cAMP on neurite outgrowth and extension in motoneurons. We manipulated cAMP levels pharmacologically in cultured motoneurons and investigated targets downstream of cAMP of neurite outgrowth and extension on a permissive substrate. Reduction of cAMP by the adenylyl cyclase inhibitor SQ22536 inhibited, and elevation of cAMP by forskolin, dibutyryl cAMP, IBMX and rolipram increased outgrowth and extension of neurites. The cAMP-mediated effects occur via activation of protein kinase A (PKA) and were reduced by the inhibitors, H89 and Rp-cAMP. However, cAMP elevation did not lead to Erk activation that is an essential downstream component of neurotrophin signaling. These findings provide evidence for a key role of cAMP in promoting peripheral nerve regeneration after nerve injuries and indicate that this effect is unusual in not being mediated via Erk phosphorylation.
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Affiliation(s)
- C Aglah
- Division of Physical Medicine and Rehabilitation, Centre for Neuroscience, University of Alberta, 525 Heritage Medical Research Centre, Edmonton, Alberta, Canada T6G 2S2
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286
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Vivó M, Puigdemasa A, Casals L, Asensio E, Udina E, Navarro X. Immediate electrical stimulation enhances regeneration and reinnervation and modulates spinal plastic changes after sciatic nerve injury and repair. Exp Neurol 2008; 211:180-93. [PMID: 18316076 DOI: 10.1016/j.expneurol.2008.01.020] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/19/2008] [Accepted: 01/25/2008] [Indexed: 12/23/2022]
Abstract
We have studied whether electrical stimulation immediately after nerve injury may enhance axonal regeneration and modulate plastic changes at the spinal cord level underlying the appearance of hyperreflexia. Two groups of adult rats were subjected to sciatic nerve section followed by suture repair. One group (ES) received electrical stimulation (3 V, 0.1 ms at 20 Hz) for 1 h after injury. A second group served as control (C). Nerve conduction, H reflex, motor evoked potentials, and algesimetry tests were performed at 1, 3, 5, 7 and 9 weeks after surgery, to assess muscle reinnervation and changes in excitability of spinal cord circuitry. The electrophysiological results showed higher levels of reinnervation, and histological results a significantly higher number of regenerated myelinated fibers in the distal tibial nerve in group ES in comparison with group C. The monosynaptic H reflex was facilitated in the injured limb, to a higher degree in group C than in group ES. The amplitudes of motor evoked potentials were similar in both groups, although the MEP/M ratio was increased in group C compared to group ES, indicating mild central motor hyperexcitability. Immunohistochemical labeling of sensory afferents in the spinal cord dorsal horn showed prevention of the reduction in expression of substance P at one month postlesion in group ES. In conclusion, brief electrical stimulation applied after sciatic nerve injury promotes axonal regeneration over a long distance and reduces facilitation of spinal motor responses.
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Affiliation(s)
- Meritxell Vivó
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
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287
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Franz CK, Rutishauser U, Rafuse VF. Intrinsic neuronal properties control selective targeting of regenerating motoneurons. Brain 2008; 131:1492-505. [PMID: 18334536 DOI: 10.1093/brain/awn039] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Colin K Franz
- Department of Anatomy and Neurobiology, Sir Charles Tupper Medical Building, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1X5
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288
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Udina E, Furey M, Busch S, Silver J, Gordon T, Fouad K. Electrical stimulation of intact peripheral sensory axons in rats promotes outgrowth of their central projections. Exp Neurol 2007; 210:238-47. [PMID: 18164293 DOI: 10.1016/j.expneurol.2007.11.007] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 10/30/2007] [Accepted: 11/02/2007] [Indexed: 01/20/2023]
Abstract
A lesion of a peripheral nerve before a second injury (conditioning lesion, CL), enhances peripheral and central regeneration of dorsal root ganglion (DRG) axons. This effect is mediated by elevated neuronal cAMP. Here we wanted to investigate whether electrical stimulation (ES) of an intact nerve, which has been shown to accelerate peripheral axon outgrowth, is also effective in promoting axon regeneration of injured DRG axons in vitro and of the central DRG axons in vivo and, whether this effect is mediated by elevation of cAMP. For the in vitro assay, the intact sciatic nerve of adult rats was stimulated at 20 Hz for 1 h, 7 days before harvest and primary culture of DRG neurons on a growth permissive substrate. In the in vivo study, the central axons of the lumbosacral DRGs were cut in the Th8 dorsal column, and the sciatic nerve was either cut or left intact, and subjected to 1 h ES at 20 Hz or 200 Hz. In vitro, ES increased neurite outgrowth 4-fold as compared to non-stimulated DRG neurons. In vivo, ES at 20 Hz significantly increased axon outgrowth into the central lesion site as compared to the Sham control. The 20 Hz ES was as effective as the CL in increasing axon outgrowth into the lesion site but not in promoting axonal elongation even though 20 Hz ES increased intracellular cAMP levels in DRG neurons as effectively as the CL. Thus elevation of cAMP may account for the central axonal outgrowth after ES and a CL.
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Affiliation(s)
- Esther Udina
- Division of Physical Medicine and Rehabilitation, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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289
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One hour electrical stimulation accelerates functional recovery after femoral nerve repair. Exp Neurol 2007; 208:137-44. [DOI: 10.1016/j.expneurol.2007.08.005] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 08/04/2007] [Accepted: 08/13/2007] [Indexed: 01/06/2023]
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