Mechanism of the "dark" axonal degeneration in the central nervous system

József Pál, Ferenc Gallyas

Research output: Contribution to journalArticle

Abstract

Background and purpose - In the central nervous tissue, two types of transsection-resulted axonal degeneration are generally accepted: "watery" and "dark". The present paper deals with the assumption that the mechanism of this kind of "dark" axonal degeneration has a relationship with that of the "dark" neuronal degeneration.

Methods - A minute stab wound is inflicted in the parietal cortex of the rat brain. From 1 h to 3 months postinjury, the resulted ultrastructural events in two distant regions of the corticospinal tract (internal capsule and C3 region of the corticospinal tract) are studied.

Results - As a novel finding, the first morphological process of "dark" axonal degeneration was found to consists in a striking reduction of the distances between neighboring neurofilaments, which were readily distinguishable and apparently undamaged. This pattern (compacted ultrastructure) persisted for hours. By day 1 postinjury, the compacted axo-plasmic elements aggregated into a homogenous and dense ("dark") mass in which hardly any ultrastructural elements could be distinguished. Surrounded by apparently normal or mildly abnormal myelin sheat, this mass underwent a non-isotropic shrinkage during the next three months. Morphological signs of phagocytosis were insignificant.

Conclusion - The ultrastructural events during the first day post-injury suggest a non-enzymatic mechanism as an alternative to the prevailing molecular-biological mechanism.

Original languageEnglish
Pages (from-to)323-330
Number of pages8
JournalIdeggyogyaszati szemle
Volume67
Issue number9-10
Publication statusPublished - Sep 30 2014

Keywords

  • "dark"
  • Axonal degeneration
  • Cortical stab-wound
  • Corticospinal tract
  • Non-enzymatic mechanism
  • Ultrastructural companion

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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