Focal damage to the adult rat neocortex induces wound healing accompanied by axonal sprouting and dendritic structural plasticity.
Accumulating evidence indicates that damage to the adult mammalian brain evokes an array of adaptive cellular responses and may retain a capacity for structural plasticity. We have investigated the cellular and architectural alterations following focal experimental brain injury, as well as the specific capacity for structural remodeling of neuronal processes in a subset of cortical interneurons. Focal acute injury was induced by transient insertion of a needle into the neocortex of anesthetized adult male Hooded-Wistar rats and thy1 green fluorescent protein (GFP) mice. Immunohistochemical, electron microscopy, and bromodeoxyuridine cell proliferation studies demonstrated an active and evolving response of the brain to injury, indicating astrocytic but not neuronal proliferation. Immunolabeling for the neuron-specific markers phosphorylated neurofilaments, α-internexin and calretinin at 7 days post injury (DPI) indicated phosphorylated neurofilaments and α-internexin but not calretinin immunopositive axonal sprouts within the injury site. However, quantitative studies indicated a significant realignment of horizontally projecting dendrites of calretinin-labeled interneurons at 14 DPI. This remodeling was specific to calretinin immunopositive interneurons and did not occur in a subpopulation of pyramidal neurons expressing GFP in the injured mouse cortex. These data show that subclasses of cortical interneurons are capable of adaptive structural remodeling.
Wicking Dementia Research and Education Centre, Menzies Research Institute, Hobart Tasmania 7000, Australia.
Catherine A
CA
Blizzard
Jyoti A
JA
Chuckowree
Anna E
AE
King
Katherine A
KA
Hosie
Graeme H
GH
McCormack
Jamie A
JA
Chapman
James C
JC
Vickers
Tracey C
TC
Dickson
D053687:Adult Stem Cells / Q000502:physiology; D000818:Animals; D001369:Axons / Q000473:pathology* / Q000648:ultrastructure; D001930:Brain Injuries / Q000473:pathology*; D001973:Bromodeoxyuridine / Q000378:metabolism; D049109:Cell Proliferation; D003712:Dendrites / Q000473:pathology / Q000648:ultrastructure; D004195:Disease Models, Animal; D049452:Green Fluorescent Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D019579:Neocortex / Q000473:pathology* / Q000503:physiopathology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D017966:Pyramidal Cells / Q000473:pathology / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000502:physiology*
D009419:Nerve Tissue Proteins; D049452:Green Fluorescent Proteins; D001973:Bromodeoxyuridine