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Delayed oligodendrocyte degeneration induced by brief exposure to hydrogen peroxide
Author(s) -
Laszkiewicz Iwona,
Mouzannar Raymond,
Wiggins Richard C.,
Konat Gregory W.
Publication year - 1999
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19990201)55:3<303::aid-jnr5>3.0.co;2-c
Subject(s) - hydrogen peroxide , degeneration (medical) , oligodendrocyte , medicine , chemistry , pathology , biochemistry , myelin , central nervous system
An in vitro model system of cultured oligodendrocytes was used to determine the susceptibility of these cells to oxidative stress induced by 15 min exposure to millimolar concentrations of hydrogen peroxide (H 2 O 2 ). Following the exposure, the cells were incubated in normal growth medium, and analyzed at different time points. Although no cell loss was observed during the exposure period, there was a progressive depletion of adherent cells during the postexposure period as seen from either the number of recoverable nuclei, or from total RNA content of the cultures. Both the rate and the extent of cell deletion was directly dependent on H 2 O 2 concentration. Cell death was preceded by structural alterations in the nuclear envelope resulting in “fragile” nuclei which disintegrated during isolation. Northern blot analysis showed that the expression of myelin‐specific genes was rapidly downregulated in H 2 O 2 ‐treated cells. On the other hand, the expression of antiapoptotic gene, bcl‐2 featured massive but transient upregulation. Oligodendrocyte degeneration also featured genomic DNA degradation into high molecular weight fragments, which are likely to represent cleaved chromosomal loops. The results demonstrate vulnerability of oligodendrocytes to oxidative stress that induces rapid degeneration and ultimately leads to delayed cell death. This feature is highly relevant to oligodendrocyte damage and depletion following ischemic, traumatic, or inflammatory insults to the central nervous system (CNS). J. Neurosci. Res. 55:303–310, 1999. © 1999 Wiley‐Liss, Inc.