Article

Concussive brain trauma in the mouse results in acute cognitive deficits and sustained impairment of axonal function.

Program in Neuroscience, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA.
Journal of neurotrauma (Impact Factor: 3.97). 02/2011; 28(4):547-63. DOI: 10.1089/neu.2010.1729
Source: PubMed

ABSTRACT Concussive brain injury (CBI) accounts for approximately 75% of all brain-injured people in the United States each year and is particularly prevalent in contact sports. Concussion is the mildest form of diffuse traumatic brain injury (TBI) and results in transient cognitive dysfunction, the neuropathologic basis for which is traumatic axonal injury (TAI). To evaluate the structural and functional changes associated with concussion-induced cognitive deficits, adult mice were subjected to an impact on the intact skull over the midline suture that resulted in a brief apneic period and loss of the righting reflex. Closed head injury also resulted in an increase in the wet weight:dry weight ratio in the cortex suggestive of edema in the first 24 h, and the appearance of Fluoro-Jade-B-labeled degenerating neurons in the cortex and dentate gyrus of the hippocampus within the first 3 days post-injury. Compared to sham-injured mice, brain-injured mice exhibited significant deficits in spatial acquisition and working memory as measured using the Morris water maze over the first 3 days (p<0.001), but not after the fourth day post-injury. At 1 and 3 days post-injury, intra-axonal accumulation of amyloid precursor protein in the corpus callosum and cingulum was accompanied by neurofilament dephosphorylation, impaired transport of Fluoro-Gold and synaptophysin, and deficits in axonal conductance. Importantly, deficits in retrograde transport and in action potential of myelinated axons continued to be observed until 14 days post-injury, at which time axonal degeneration was apparent. These data suggest that despite recovery from acute cognitive deficits, concussive brain trauma leads to axonal degeneration and a sustained perturbation of axonal function.

0 Followers
 · 
87 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: : Mild traumatic brain injury (TBI) has become a rising epidemic, affecting millions of people each year. Even though it is the most common type of brain injury, our understanding of the science underlying mild TBI is just in its infancy. There has been an explosion of basic science research interest in mild TBI, as emerging clinical evidence is suggestive that concussion and subconcussion may result in detrimental long-term neurological sequelae, particularly when occurring repetitively. Many animal models have been developed to study the different pathological mechanisms implicated in TBI, and more recently there has been a heightened focus on modeling mild TBI in the laboratory as well. The most widely used models of TBI have been adapted for experimental mild TBI research, although more work still remains. The ability to create improved diagnostic measures and treatment approaches for concussion depend on the development and characterization of clinically relevant models of mild TBI. This review aims to provide a broad general overview of the current efforts to model mild TBI in animals and the challenges and limitations that exist in translating this behavioral, physiological, and anatomic knowledge from the bench to the clinical arena.
    Neurosurgery 10/2014; 75 Suppl 4:S34-S49. DOI:10.1227/NEU.0000000000000472 · 3.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Traumatic brain injury (TBI) from penetrating or closed forces to the cranium can result in a range of forms of neural damage, which culminate in mortality or impart mild to significant neurological disability. In this regard, diffuse axonal injury (DAI) is a major neuronal pathophenotype of TBI and is associated with a complex set of cytoskeletal changes. The neurofilament triplet proteins are key structural cytoskeletal elements, which may also be important contributors to the tensile strength of axons. This has significant implications with respect to how axons may respond to TBI. It is not known, however, whether neurofilament compaction and the cytoskeletal changes that evolve following axonal injury represent a component of a protective mechanism following damage, or whether they serve to augment degeneration and progression to secondary axotomy. Here we review the structure and role of neurofilament proteins in normal neuronal function. We also discuss the processes that characterize DAI and the resultant alterations in neurofilaments, highlighting potential clues to a possible protective or degenerative influence of specific neurofilament alterations within injured neurons. The potential utility of neurofilament assays as biomarkers for axonal injury is also discussed. Insights into the complex alterations in neurofilaments will contribute to future efforts in developing therapeutic strategies to prevent, ameliorate or reverse neuronal degeneration in the central nervous system (CNS) following traumatic injury.
    Frontiers in Cellular Neuroscience 12/2014; 8:429. DOI:10.3389/fncel.2014.00429 · 4.18 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Axonal injury is a key feature of several types of brain trauma and neurological disease. However, in mice and humans, many axons are less than 500 nanometers in diameter which is at or below the resolution of most conventional light microscopic imaging methods. In moderate to severe forms of axon injury, damaged axons become dilated and therefore readily detectible by light microscopy. However, in more subtle forms of injury, the damaged axons may remain undilated and therefore difficult to detect.
    Journal of Neuroscience Methods 02/2015; DOI:10.1016/j.jneumeth.2015.02.005 · 1.96 Impact Factor

Full-text (2 Sources)

Download
4 Downloads
Available from
Jan 20, 2015