Nerve fibres in spinal cord impact injuries: Part 1. Changes in the myelin sheath during the initial 5 weeks

doi:10.1016/0022-510X(83)90093-X

Journal of the Neurological Sciences

Volume 58, Issue 3, March 1983, Pages 335-349

https://doi.org/10.1016/0022-510X(83)90093-X Get rights and content

Abstract

The spinal cords of cats were subjected to an impact injury using a “weight dropping” technique and sequential changes in the sheaths of non-degenerate myelinated fibres studied over a 3-week period. By $112 h$ after impact fibres showed retraction of some lateral loops from one paranode. The extent and severity of this change increased over the first week so that partial and full thickness demyelination were seen frequently. Partial demyelination most commonly resulted from the internodal termination of the innermost lamellae at an internodal location often associated with a Schmidt-Lantermann incisure. Remyelination by both Schwann cells and oligodendroglia occurred at the end of the second week. Oligodendroglial myelin showed many features of immaturity, similar to those found during development.

It is suggested that the very earliest myelin damage is mechanical but is aggravated by other factor(s) one of which is probably ischaemia. Within the most severely injured areas there is death of oligodendroglia and any surviving axons are remyelinated principally by Schwann cells. In intermediate and minimally damaged areas of white matter oligodendroglial remyelination predominates.

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The altered membrane excitability we observed in short-term SCI animals is also consistent with additional anatomical and structural changes known to occur in the early stages after injury. Demyelination of white matter axons in the vicinity of a lesion begins within 24 h, and peaks at 2–3 wks post injury (Blight, 1985; Blight and Decrescito, 1986; Griffiths and McCulloch, 1983). Additionally, large diameter axons are selectively lost in the short-term after injury (Blight and Decrescito, 1986).
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^☆: This study was supported by the Wellcome Trust.

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Research reportNerve fibres in spinal cord impact injuries: Part 1. Changes in the myelin sheath during the initial 5 weeks☆

Abstract

J. neurol. Sci.

J. neurol. Sci.

J. neurol. Sci.

J. neurol. Sci.

J. neurol. Sci.

J. neurol. Sci.

J. neurol. Sci.

J. neurol. Sci.

Pathology of experimental spinal cord trauma, Part 2 (Ultrastructure of axons and myelin)

Lab. Invest.

Remyelination of CNS axons by Schwann cells transplanted from the sciatic nerve

Nature (Lond.)

Partial demyelination of cat spinal cord after X irradiation and surgical interference, Neuropath

appl. Neurobiol.

Observations on the interactions of Schwann cells and astrocytes following X-irradiation of the neonatal rat spinal cord

J. Neurocytol.

Remodelling during remyelination in the peripheral nervous system, Neuropath

appl. Neurobiol.

Transitory traumatic paraplegia — Electron microscopy of early alterations in myelinated nerve fibres

J. Neurosurg.

Morphological characteristics of central demyelination and remyelination — A single fibre study

Ann. Neurol.

Research report
Nerve fibres in spinal cord impact injuries: Part 1. Changes in the myelin sheath during the initial 5 weeks☆