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Chronic nerve compression alters schwann cell myelin architecture in a murine model

Authors

  • Ranjan Gupta MD,

    Corresponding author
    1. Department of Orthopaedic Surgery, University of California at Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA
    • Department of Orthopaedic Surgery, University of California at Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA
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  • Nima Nassiri BS,

    1. Department of Biomedical Engineering, University of California at Irvine, Irvine, California, USA
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  • Antony Hazel MD,

    1. Department of Orthopaedic Surgery, University of California at Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA
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  • Mary Bathen BS,

    1. Department of Orthopaedic Surgery, University of California at Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA
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  • Tahseen Mozaffar MD

    1. Department of Orthopaedic Surgery, University of California at Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA
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Abstract

Introduction: Myelinating Schwann cells compartmentalize their outermost layer to form actin-rich channels known as Cajal bands. Herein we investigate changes in Schwann cell architecture and cytoplasmic morphology in a novel mouse model of carpal tunnel syndrome. Methods: Chronic nerve compression (CNC) injury was created in wild-type and slow-Wallerian degeneration (WldS) mice. Over 12 weeks, nerves were electrodiagnostically assessed, and Schwann cell morphology was thoroughly evaluated. Results: A decline in nerve conduction velocity and increase in g-ratio is observed without early axonal damage. Schwann cells display shortened internodal lengths and severely disrupted Cajal bands. Quite surprisingly, the latter is reconstituted without improvements to nerve conduction velocity. Conclusions: Chronic entrapment injuries like carpal tunnel syndrome are primarily mediated by the Schwann cell response, where decreases in internodal length and myelin thickness disrupt the efficiency of impulse propagation. Restitution of Cajal bands is not sufficient for remyelination after CNC injury. Muscle Nerve, 2012

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