Functional outcome is impaired following traumatic brain injury in aging Nogo-A/B-deficient mice

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Increasing age is associated with a poor prognosis following traumatic brain injury (TBI). CNS axons may recover poorly following TBI due to expression of myelin-derived inhibitors to axonal outgrowth such as Nogo-A. To study the role of Nogo-A/B in the pathophysiological response of the elderly to TBI, 1-year-old mice deficient in Nogo-A/B (Nogo-A/B homozygous(-/-) mice), Nogo-A/B heterozygous(-/+) mice, and age-matched wild-type (WT) littermate controls were subjected to a controlled cortical impact (CCI) TBI. Sham-injured WT mice (7 months old) and 12 month old naïve Nogo-A/B(-/-) and Nogo-A/B(-/+) served as controls. Neurological motor function was evaluated up to 3 weeks, and cognitive function, hemispheric tissue loss, myelin staining and hippocampal beta-amyloid (A beta) immunohistochemistry were evaluated at 4 weeks post-injury. In WT littermates, TBI significantly impaired learning ability at 4 weeks and neurological motor function up to 2 weeks post-injury and caused a significant loss of hemispheric tissue. Following TBI, Nogo-A/B(-/-) mice showed significantly less recovery from neurological motor and cognitive deficits compared to brain-injured WT mice. Naïve Nogo-A/B(-/-) and Nogo-A/B(-/+) mice quickly learned the MWM task in contrast to brain-injured Nogo-A/B(-/-) mice who failed to learn the MWM task at 4 weeks post-injury. Hemispheric tissue loss and cortical lesion volume were similar among the brain-injured genotypes. Neither TBI nor the absence of NogoA/B caused an increased A beta expression. Myelin staining showed a reduced area and density in the corpus callosum in brain-injured Nogo-A/B(-/-) animals compared to their littermate controls. These novel and unexpected behavioral results demonstrate that the absence of Nogo-A/B may negatively influence outcome, possibly related to hypomyelination, following TBI in mice and suggest a complex role for this myelin-associated axonal growth inhibitor following TBI.

Detaljer

Författare
  • N Marklund
  • D Morales
  • F Clausen
  • A Hånell
  • O Kiwanuka
  • A Pitkänen
  • D A Gimbel
  • O Philipson
  • L Lannfelt
  • L Hillered
  • S M Strittmatter
  • T K McIntosh
Externa organisationer
  • University of Pennsylvania
Forskningsområden

Nyckelord

Originalspråkengelska
Sidor (från-till)540-51
Antal sidor12
TidskriftNeuroscience
Volym163
Utgåva nummer2
StatusPublished - 2009 okt 6
PublikationskategoriForskning
Peer review utfördJa
Externt publiceradJa