Light and electron microscopic assessment of progressive atrophy following moderate traumatic brain injury in the rat

The presence of progressive white matter atrophy following traumatic brain injury (TBI) has been reported in humans as well as in animal models. However, a quantitative analysis of progressive alterations in myelinated axons and other cellular responses to trauma has not been conducted. This study examined quantitative differences in myelinated axons from several white and gray matter structures between non-traumatized and traumatized areas at several time points up to 1 year. We hypothesize that axonal numbers decrease over time within the structures analyzed, based on our previous work demonstrating shrinkage of tissue in these vulnerable areas. Intubated, anesthetized male Sprague-Dawley rats were subjected to moderate (1.8–2.2 atm) parasagittal fluid-percussion brain injury, and perfused at various intervals after surgery. Sections from the fimbria, external capsule, thalamus and cerebral cortex from the ipsilateral hemisphere of traumatized and sham-operated animals were prepared and. estimated total numbers of myelinated axons were determined by systematic random sampling. Electron micrographs were obtained for ultrastructural analysis. A significant (P<0.05) reduction in the number of myelinated axons in the traumatized hemisphere compared to control in all structures was observed. In addition, thalamic and cortical axonal counts decreased significantly (P<0.05) over time. Swollen axons and macrophage/microglia infiltration were present as late as 6 months post-TBI in various structures. This study is the first to describe quantitatively chronic axonal changes in vulnerable brains regions after injury. Based on these data, a time-dependent decrease in the number of myelinated axons is seen to occur in vulnerable gray matter regions including the cerebral cortex and thalamus along with distinct morphological changes within white matter tracts after TBI. Although this progressive axonal response to TBI may include Wallerian degeneration, other potential mechanisms underlying this progressive pathological response within the white matter are discussed.

[1]  P. Kochanek,et al.  One-year study of spatial memory performance, brain morphology, and cholinergic markers after moderate controlled cortical impact in rats. , 1999, Journal of neurotrauma.

[2]  S. Murphy,et al.  Functional receptors for neurotransmitters on astroglial cells , 1987, Neuroscience.

[3]  J. Adams,et al.  Axonal injury: a universal consequence of fatal closed head injury? , 2004, Acta Neuropathologica.

[4]  J Q Trojanowski,et al.  Progressive atrophy and neuron death for one year following brain trauma in the rat. , 1997, Journal of neurotrauma.

[5]  D. Graham,et al.  Axonal cytoskeletal changes after non-disruptive axonal injury , 1997, Journal of neurocytology.

[6]  S. Wisniewski,et al.  Vascular Endothelial Growth Factor Is Increased in Cerebrospinal Fluid after Traumatic Brain Injury in Infants and Children , 2004, Neurosurgery.

[7]  J. Wolf,et al.  Prolonged Activation of NF-?B Following Traumatic Brain Injury in Rats , 1999 .

[8]  Sanford L. Palay,et al.  The fine structure of the nervous system , 1976 .

[9]  J. Povlishock,et al.  Traumatically induced axonal damage: evidence for enduring changes in axolemmal permeability with associated cytoskeletal change. , 1996, Acta neurochirurgica. Supplement.

[10]  R. Colello,et al.  Traumatic brain injury induced cell proliferation in the adult mammalian central nervous system. , 2002, Journal of neurotrauma.

[11]  O. Alonso,et al.  Importance of Posttraumatic Hypothermia and Hyperthermia on the Inflammatory Response after Fluid Percussion Brain Injury: Biochemical and Immunocytochemical Studies , 2000, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[12]  D. Smith,et al.  Inflammatory leukocytic recruitment and diffuse neuronal degeneration are separate pathological processes resulting from traumatic brain injury , 1995, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[13]  F. Sherriff,et al.  Early detection of axonal injury after human head trauma using immunocytochemistry for β-amyloid precursor protein , 2004, Acta Neuropathologica.

[14]  T A Gennarelli,et al.  Focal axonal injury: the early axonal response to stretch , 1991, Journal of neurocytology.

[15]  J. Ellison,et al.  Astrocytic demise precedes delayed neuronal death in focal ischemic rat brain. , 1999, Brain research. Molecular brain research.

[16]  L. S. Murray,et al.  Simple morphometry of axonal swellings cannot be used in isolation for dating lesions after traumatic brain injury. , 2002, Journal of neurotrauma.

[17]  K. Ikematsu,et al.  Induction of nitric oxide synthase by traumatic brain injury. , 2001, Forensic science international.

[18]  G. Paxinos,et al.  The Rat Brain in Stereotaxic Coordinates , 1983 .

[19]  D. Graham,et al.  Recent Advances in Neurotrauma , 2000, Journal of neuropathology and experimental neurology.

[20]  F. Barone,et al.  Cytokines, inflammation, and brain injury: role of tumor necrosis factor-alpha. , 1994, Cerebrovascular and brain metabolism reviews.

[21]  E. J. Green,et al.  Chronic histopathological consequences of fluid-percussion brain injury in rats: effects of post-traumatic hypothermia , 1997, Acta Neuropathologica.

[22]  E. Ling,et al.  Nitric oxide induces macrophage apoptosis following traumatic brain injury in rats , 2003, Neuroscience Letters.

[23]  Mark J. West,et al.  New stereological methods for counting neurons , 1993, Neurobiology of Aging.

[24]  P. Kochanek,et al.  Assessment of posttraumatic polymorphonuclear leukocyte accumulation in rat brain using tissue myeloperoxidase assay and vinblastine treatment. , 1992, Journal of neurotrauma.

[25]  F. Barone,et al.  The Role of Inflammation and Cytokines in Brain Injury , 1996, Neuroscience & Biobehavioral Reviews.

[26]  J. Adams,et al.  Diffuse axonal injury in non-missile head injury. , 1982, Injury.

[27]  J. Povlishock,et al.  Characterization of a distinct set of intra-axonal ultrastructural changes associated with traumatically induced alteration in axolemmal permeability , 1996, Brain Research.

[28]  J. Trojanowski,et al.  Immunohistochemical characterization of alterations in the distribution of amyloid precursor proteins and beta-amyloid peptide after experimental brain injury in the rat , 1996, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[29]  T. Mathiesen,et al.  Temporal profiles and cellular sources of three nitric oxide synthase isoforms in the brain after experimental contusion. , 2000, Neurosurgery.

[30]  D. Graham,et al.  Axonal injury is accentuated in the caudal corpus callosum of head-injured patients. , 2001, Journal of neurotrauma.

[31]  W. D. Dietrich,et al.  Interleukin-1β Messenger Ribonucleic Acid and Protein Levels after Fluid-Percussion Brain Injury in Rats: Importance of Injury Severity and Brain Temperature. , 2002, Neurosurgery.

[32]  J. Schwab,et al.  Traumatic brain injury induces prolonged accumulation of cyclooxygenase-1 expressing microglia/brain macrophages in rats. , 2001, Journal of neurotrauma.

[33]  S. Furukawa,et al.  Synthesis and secretion of nerve growth factor by mouse astroglial cells in culture. , 1986, Biochemical and biophysical research communications.

[34]  J. Adams,et al.  Diffuse axonal injury in head injury: Definition, diagnosis and grading , 1989, Histopathology.

[35]  M. Morganti-Kossmann,et al.  Inflammatory response in acute traumatic brain injury: a double-edged sword , 2002, Current opinion in critical care.

[36]  J. van der Naalt,et al.  Computed tomography and magnetic resonance imaging in mild to moderate head injury: Early and late imaging related to outcome , 1999, Annals of neurology.

[37]  P. Lantos,et al.  A morphometric study of blood vessel, neuron and glial cell distribution in young and old rat brain , 1987, Journal of the Neurological Sciences.

[38]  D. Graham,et al.  Loss of axonal microtubules and neurofilaments after stretch-injury to guinea pig optic nerve fibers. , 1997, Journal of neurotrauma.

[39]  J. Povlishock,et al.  The pathobiology of traumatically induced axonal injury in animals and humans: a review of current thoughts. , 1995, Journal of neurotrauma.

[40]  S. Levison,et al.  Mini review , 2004 .

[41]  O. Alonso,et al.  Interleukin-1beta messenger ribonucleic acid and protein levels after fluid-percussion brain injury in rats: importance of injury severity and brain temperature. , 2002, Neurosurgery.

[42]  F. Amenta,et al.  Expression of neurofilament proteins in the rat cerebellar cortex as a function of age: an immunohistochemical study , 1994, Mechanisms of Ageing and Development.

[43]  J. Adams,et al.  Diffuse axonal injury and traumatic coma in the primate , 1982, Annals of neurology.

[44]  V. Hans,et al.  Cell activation and inflammatory response following traumatic axonal injury in the rat , 2000, Neuroreport.

[45]  A J McLean,et al.  Staining of amyloid precursor protein to study axonal damage in mild head injury. , 1994, Lancet.

[46]  D. Graham,et al.  Is β-APP a marker of axonal damage in short-surviving head injury? , 1996, Acta Neuropathologica.

[47]  J. Adams,et al.  Glial swelling following human cerebral contusion: an ultrastructural study. , 1991, Journal of neurology, neurosurgery, and psychiatry.

[48]  Helen M. Bramlett,et al.  Quantitative structural changes in white and gray matter 1 year following traumatic brain injury in rats , 2002, Acta Neuropathologica.

[49]  D. Graham,et al.  Axonal cytoskeletal changes after nondisruptive axonal injury. II. Intermediate sized axons. , 1998, Journal of neurotrauma.

[50]  D. Graham,et al.  Freeze-fracture and cytochemical evidence for structural and functional alteration in the axolemma and myelin sheath of adult guinea pig optic nerve fibers after stretch injury. , 1999, Journal of neurotrauma.

[51]  E. Bigler,et al.  Ventricular dilation, cortical atrophy, and neuropsychological outcome following traumatic brain injury. , 1995, The Journal of neuropsychiatry and clinical neurosciences.

[52]  E. J. Green,et al.  Temporal and Regional Patterns of Axonal Damage following Traumatic Brain Injury: A Beta‐amyloid Precursor Protein Immunocytochemical Study in Rats , 1997, Journal of neuropathology and experimental neurology.

[53]  E. Shohami,et al.  Closed Head Injury Triggers Early Production of TNFα and IL-6 by Brain Tissue , 1994 .

[54]  W. Maxwell.  Histopathological changes at central nodes of Ranvier after stretch‐injury , 1996, Microscopy research and technique.

[55]  P. Kochanek,et al.  Expression of endothelial adhesion molecules and recruitment of neutrophils after traumatic brain injury in rats , 1997, Journal of leukocyte biology.

[56]  J. Wrathall,et al.  Quantitative analysis of acute axonal pathology in experimental spinal cord contusion. , 1997, Journal of neurotrauma.

[57]  V. Tennyson.  The Fine Structure of the Nervous System. , 1970 .

[58]  R. Busto,et al.  Inducible nitric oxide synthase expression after traumatic brain injury and neuroprotection with aminoguanidine treatment in rats. , 1998, Neurosurgery.

[59]  E. Shohami,et al.  Closed head injury triggers early production of TNF alpha and IL-6 by brain tissue. , 1994, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[60]  J. Wolf,et al.  Prolonged activation of NF-kappaB following traumatic brain injury in rats. , 1999, Journal of neurotrauma.

[61]  R. Narayan,et al.  Prolonged cyclooxygenase-2 induction in neurons and glia following traumatic brain injury in the rat. , 2000, Journal of neurotrauma.

[62]  D. Graham,et al.  Is beta-APP a marker of axonal damage in short-surviving head injury? , 1996, Acta neuropathologica.

[63]  D. Graham,et al.  Post-acute alterations in the axonal cytoskeleton after traumatic axonal injury. , 2003, Journal of neurotrauma.

[64]  Shigeaki Suzuki,et al.  Upregulation of oligodendrocyte progenitor cells associated with restoration of mature oligodendrocytes and myelination in peri-infarct area in the rat brain , 2003, Brain Research.

[65]  A. Hamberger,et al.  Redistribution of neurofilaments and accumulation of beta-amyloid protein after brain injury by rotational acceleration of the head. , 2003, Journal of neurotrauma.

[66]  R. Kucherlapati,et al.  GFAP Is Necessary for the Integrity of CNS White Matter Architecture and Long-Term Maintenance of Myelination , 1996, Neuron.

[67]  V. Höllt,et al.  BetaIII tubulin-expressing neurons reveal enhanced neurogenesis in hippocampal and cortical structures after a contusion trauma in rats. , 2002, Journal of neurotrauma.

[68]  H. Bramlett,et al.  Pathophysiology of Cerebral Ischemia and Brain Trauma: Similarities and Differences , 2004, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[69]  E. Lehning,et al.  Mechanism of calcium entry during axon injury and degeneration. , 1997, Toxicology and applied pharmacology.

[70]  D. Graham,et al.  Distribution of beta-amyloid protein in the brain following severe head injury. , 1995, Neuropathology and applied neurobiology.

[71]  D. Graham,et al.  Tissue tears in the white matter after lateral fluid percussion brain injury in the rat: relevance to human brain injury , 2000, Acta Neuropathologica.

[72]  N. Marklund,et al.  Cyclooxygenase-2, prostaglandin synthases, and prostaglandin H2 metabolism in traumatic brain injury in the rat. , 2002, Journal of neurotrauma.

[73]  J. Trojanowski,et al.  Enduring cognitive, neurobehavioral and histopathological changes persist for up to one year following severe experimental brain injury in rats , 1998, Neuroscience.

[74]  Douglas H. Smith,et al.  Neurogenesis and glial proliferation persist for at least one year in the subventricular zone following brain trauma in rats. , 2003, Journal of neurotrauma.

[75]  E. Bigler,et al.  Ventricle size, cortical atrophy and the relationship with neuropsychological status in closed head injury: a quantitative analysis. , 1986, Journal of clinical and experimental neuropsychology.

[76]  M. Schalling,et al.  Delayed cytokine expression in rat brain following experimental contusion. , 1997, Journal of neurosurgery.

[77]  Steven T. DeKosky,et al.  Astrocytes Are the Major Source of Nerve Growth Factor Upregulation Following Traumatic Brain Injury in the Rat , 1998, Experimental Neurology.

[78]  V. Hans,et al.  Production of cytokines following brain injury: beneficial and deleterious for the damaged tissue , 1997, Molecular Psychiatry.

[79]  J. Povlishock,et al.  Are the Pathobiological Changes Evoked by Traumatic Brain Injury Immediate and Irreversible? , 1995, Brain pathology.

[80]  J. Eubanks,et al.  Differential Expression of Vascular Endothelial Growth Factor‐A (VEGF‐A) and VEGF‐B After Brain Injury , 2002, Journal of neuropathology and experimental neurology.

[81]  D. Graham,et al.  Ultrastructural evidence of axonal shearing as a result of lateral acceleration of the head in non-human primates , 2004, Acta Neuropathologica.

[82]  M. Esiri,et al.  Axonal damage: a key predictor of outcome in human CNS diseases. , 2003, Brain : a journal of neurology.

[83]  D. Graham,et al.  Long-term intracerebral inflammatory response after traumatic brain injury. , 2004, Forensic science international.

[84]  P. Stys,et al.  Important role of reverse Na(+)-Ca(2+) exchange in spinal cord white matter injury at physiological temperature. , 2000, Journal of neurophysiology.

[85]  J. Duncan,et al.  Early neutrophilic expression of vascular endothelial growth factor after traumatic brain injury , 2003, Neuroscience.

[86]  A. J. McLean,et al.  Stalning af amyloid percursor protein to study axonal damage in mild head Injury , 1994, The Lancet.

[87]  S. Grad,et al.  Strongly Enhanced Serum Levels of Vascular Endothelial Growth Factor (VEGF) after Poly-trauma and Burn , 1998, Clinical chemistry and laboratory medicine.

[88]  J. Povlishock,et al.  A mechanistic analysis of nondisruptive axonal injury: a review. , 1997, Journal of neurotrauma.

[89]  G. L. Li,et al.  Traumatic brain injury in rat produces changes of beta-amyloid precursor protein immunoreactivity. , 1995, Neuroreport.

[90]  D D Blatter,et al.  Nonspecific white matter degeneration following traumatic brain injury , 1995, Journal of the International Neuropsychological Society.

[91]  S. Gentleman,et al.  Distribution of β‐amyloid protein in the brain following severe head injury , 1995 .

[92]  K. Crutcher.  The regulation of axonal growth in the mature mammalian nervous system. , 1990, Acta neurobiologiae experimentalis.