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Pan X, Li J, Li W, Wang H, Durisic N, Li Z, Feng Y, Liu Y, Zhao CX, Wang T. Axons-on-a-chip for mimicking non-disruptive diffuse axonal injury underlying traumatic brain injury. LAB ON A CHIP 2022; 22:4541-4555. [PMID: 36318066 DOI: 10.1039/d2lc00730d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Diffuse axonal injury (DAI) is the most severe pathological feature of traumatic brain injury (TBI). However, how primary axonal injury is induced by transient mechanical impacts remains unknown, mainly due to the low temporal and spatial resolution of medical imaging approaches. Here we established an axon-on-a-chip (AoC) model for mimicking DAI and monitoring instant cellular responses. Integrating computational fluid dynamics and microfluidic techniques, DAI was induced by injecting a precisely controlled micro-flux in the transverse direction. The clear correlation between the flow speed of injecting flux and the severity of DAI was elucidated. We next used the AoC to investigate the instant intracellular responses underlying DAI and found that the dynamic formation of focal axonal swellings (FAS) accompanied by Ca2+ surge occurs during the flux. Surprisingly, periodic axonal cytoskeleton disruption also occurs rapidly after the flux. These instant injury responses are spatially restricted to the fluxed axon, not affecting the overall viability of the neuron in the acute stage. Compatible with high-resolution live microscopy, the AoC provides a versatile system to identify early mechanisms underlying DAI, offering a platform for screening effective treatments to alleviate TBI.
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Affiliation(s)
- Xiaorong Pan
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Jie Li
- Division of Chemistry and Physical Biology, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wei Li
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Haofei Wang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nela Durisic
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zhenyu Li
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Yu Feng
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Yifan Liu
- Division of Chemistry and Physical Biology, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chun-Xia Zhao
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia.
| | - Tong Wang
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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2
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Axonal injury is detected by βAPP immunohistochemistry in rapid death from head injury following road traffic collision. Int J Legal Med 2022; 136:1321-1339. [PMID: 35488928 PMCID: PMC9375765 DOI: 10.1007/s00414-022-02807-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/21/2022] [Indexed: 11/23/2022]
Abstract
The accumulation of βAPP caused by axonal injury is an active energy-dependent process thought to require blood circulation; therefore, it is closely related to the post-injury survival time. Currently, the earliest reported time at which axonal injury can be detected in post-mortem traumatic brain injury (TBI) tissue by βAPP (Beta Amyloid Precursor Protein) immunohistochemistry is 35 min. The aim of this study is to investigate whether βAPP staining for axonal injury can be detected in patients who died rapidly after TBI in road traffic collision (RTC), in a period of less than 30 min. We retrospectively studied thirty-seven patients (group 1) died very rapidly at the scene; evidenced by forensic assessment of injuries short survival, four patients died after a survival period of between 31 min and 12 h (group 2) and eight patients between 2 and 31 days (group 3). The brains were comprehensively examined and sampled at the time of the autopsy, and βAPP immunohistochemistry carried out on sections from a number of brain areas. βAPP immunoreactivity was demonstrated in 35/37 brains in group 1, albeit with a low frequency and in a variable pattern, and with more intensity and frequency in all brains of group 2 and 7/8 brains from group 3, compared with no similar βAPP immunoreactivity in the control group. The results suggest axonal injury can be detected in those who died rapidly after RTC in a period of less than 30 min, which can help in the diagnosis of severe TBI with short survival time.
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Makino Y, Arai N, Hoshioka Y, Yoshida M, Kojima M, Horikoshi T, Mukai H, Iwase H. Traumatic axonal injury revealed by postmortem magnetic resonance imaging: A case report. Leg Med (Tokyo) 2018; 36:9-16. [PMID: 30312836 DOI: 10.1016/j.legalmed.2018.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 09/03/2018] [Accepted: 09/30/2018] [Indexed: 11/26/2022]
Abstract
In forensic investigations, it is important to detect traumatic axonal injuries (TAIs) to reveal head trauma that might otherwise remain occult. These lesions are subtle and frequently ambiguous on macroscopic evaluations. We present a case of TAI revealed by pre-autopsy postmortem magnetic resonance imaging (PMMR). A man in his sixties was rendered unconscious in a motor vehicle accident. CT scans revealed traumatic mild subarachnoid hemorrhage. Two weeks after the accident he regained consciousness, but displayed an altered mental state. Seven weeks after the accident, he suddenly died in hospital. Postmortem computed tomography (PMCT) and PMMR were followed by a forensic autopsy. PMMR showed low-intensity lesions in parasagittal white matter, deep white matter, and corpus callosum on three-dimensional gradient-echo T1-weighted imaging (3D-GRE T1WI). In some of these lesions, T2∗-weighted imaging also showed low-intensity foci suggesting hemorrhagic axonal injury. The lesions were difficult to find on PMCT and macroscopic evaluation, but were visible on antemortem MRI and confirmed as TAIs on histopathology. From this case, it can be said that PMMR can detect subtle TAIs missed by PMCT and macroscopic evaluation. Hence, pre-autopsy PMMR scanning could be useful for identifying TAIs during forensic investigations.
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Affiliation(s)
- Yohsuke Makino
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
| | - Nobutaka Arai
- Laboratory of Neuropathology, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Yumi Hoshioka
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Maiko Yoshida
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Masatoshi Kojima
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Takuro Horikoshi
- Department of Radiology, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba 260-8677, Japan
| | - Hiroki Mukai
- Department of Radiology, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba 260-8677, Japan
| | - Hirotaro Iwase
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Legal Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
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4
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Bailey NW, Rogasch NC, Hoy KE, Maller JJ, Segrave RA, Sullivan CM, Fitzgerald PB. Increased gamma connectivity during working memory retention following traumatic brain injury. Brain Inj 2017; 31:379-389. [PMID: 28095052 DOI: 10.1080/02699052.2016.1239273] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PRIMARY OBJECTIVE Alterations to functional connectivity following a traumatic brain injury (TBI) may lead to impaired cognitive performance and major depressive disorder (MDD). In particular, functional gamma band connectivity is thought to reflect information binding important for working memory. The objective of this study was to determine whether altered functional gamma connectivity may be a factor in MDD following TBI (TBI-MDD). RESEARCH DESIGN This study assessed individuals with TBI-MDD, as well as individuals with TBI alone and MDD alone using electroencephalographic recordings while participants performed a working memory task to assess differences in functional connectivity between these groups. METHODS AND PROCEDURES Functional connectivity was compared using the debiased weighted phase lag index (wPLI). wPLI was measured from a group of healthy controls (n = 31), participants with MDD (n = 17), participants with TBI (n = 20) and participants with TBI-MDD (n = 15). MAIN OUTCOMES AND RESULTS Contrary to the predictions, this study found both the groups with TBI and TBI-MDD showed higher gamma connectivity from posterior regions during WM retention. CONCLUSIONS This may reflect dysfunctional functional connectivity in these groups, as a result of maladaptive neuroplastic reorganization.
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Affiliation(s)
- Neil W Bailey
- a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia
| | - Nigel C Rogasch
- b Monash Clinical and Imaging Neuroscience, School of Psychological Science and Monash Biomedical Imaging , Monash University , Melbourne , Australia
| | - Kate E Hoy
- a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia
| | - Jerome J Maller
- a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia
| | - Rebecca A Segrave
- a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia
| | - Caley M Sullivan
- a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia
| | - Paul B Fitzgerald
- a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia
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5
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Gennarelli TA, Thibault LE, Graham DI. Diffuse Axonal Injury: An Important Form of Traumatic Brain Damage. Neuroscientist 2016. [DOI: 10.1177/107385849800400316] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Diffuse axonal injury (DAI) is a frequent form of traumatic brain injury in which a clinical spectrum of in creasing injury severity is paralleled by progressively increasing amounts of axonal damage in the brain. When less severe, DAI is associated with concussive syndromes; when most severe, it causes prolonged traumatic coma that is not related to mass lesions, increased intracranial pressure, or ischemia. Pathological investigations of DAI demonstrate widespread but heterogeneous microscopic damage to axons throughout the white matter of the cerebral and cerebellar hemispheres and brainstem. There is a propensity for injury to occur in the central third of the brain, and the corpus callosum and brain stem are especially prone to injury. In these locations, traumatic axonal damage can occur in several degrees of severity, ranging from transient disturbances of ionic homeostasis to swelling, impairment of axoplasmic transport with secondary (delayed) axotomy and primary axotomy (tearing). A more detailed understanding of the processes involved in axonal damage is crucial to the development of effective treatment for the clinical syndromes of DAI. NEUROSCIENTIST 4:202-215, 1998
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Affiliation(s)
- Thomas A. Gennarelli
- Department of Neurosurgery and Center for Neurosciences
Allegheny University of the Health Sciences Philadelphia, Pennsylvania
| | - Lawrence E. Thibault
- Department of Neurosurgery and Center for Neurosciences
Allegheny University of the Health Sciences Philadelphia, Pennsylvania
| | - David I. Graham
- Department of Neuropathology University of Glasgow Glasgow,
Scotland, United Kingdom
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6
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Sosa I, Stemberga V. Letter to the Editor: Role of subconcussion and repetitive TBI. J Neurosurg 2014; 120:789-90. [DOI: 10.3171/2013.10.jns132097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Diffuse axonal injury (DAI) remains a prominent feature of human traumatic brain injury (TBI) and a major player in its subsequent morbidity. The importance of this widespread axonal damage has been confirmed by multiple approaches including routine postmortem neuropathology as well as advanced imaging, which is now capable of detecting the signatures of traumatically induced axonal injury across a spectrum of traumatically brain-injured persons. Despite the increased interest in DAI and its overall implications for brain-injured patients, many questions remain about this component of TBI and its potential therapeutic targeting. To address these deficiencies and to identify future directions needed to fill critical gaps in our understanding of this component of TBI, the National Institute of Neurological Disorders and Stroke hosted a workshop in May 2011. This workshop sought to determine what is known regarding the pathogenesis of DAI in animal models of injury as well as in the human clinical setting. The workshop also addressed new tools to aid in the identification of this axonal injury while also identifying more rational therapeutic targets linked to DAI for continued preclinical investigation and, ultimately, clinical translation. This report encapsulates the oral and written components of this workshop addressing key features regarding the pathobiology of DAI, the biomechanics implicated in its initiating pathology, and those experimental animal modeling considerations that bear relevance to the biomechanical features of human TBI. Parallel considerations of alternate forms of DAI detection including, but not limited to, advanced neuroimaging, electrophysiological, biomarker, and neurobehavioral evaluations are included, together with recommendations for how these technologies can be better used and integrated for a more comprehensive appreciation of the pathobiology of DAI and its overall structural and functional implications. Lastly, the document closes with a thorough review of the targets linked to the pathogenesis of DAI, while also presenting a detailed report of those target-based therapies that have been used, to date, with a consideration of their overall implications for future preclinical discovery and subsequent translation to the clinic. Although all participants realize that various research gaps remained in our understanding and treatment of this complex component of TBI, this workshop refines these issues providing, for the first time, a comprehensive appreciation of what has been done and what critical needs remain unfulfilled.
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Affiliation(s)
- Douglas H. Smith
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ramona Hicks
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - John T. Povlishock
- Department of Anatomy and Neurobiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
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8
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Dollé JP, Morrison B, Schloss RR, Yarmush ML. An organotypic uniaxial strain model using microfluidics. LAB ON A CHIP 2013; 13:432-42. [PMID: 23233120 PMCID: PMC3546521 DOI: 10.1039/c2lc41063j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Traumatic brain injuries are the leading cause of disability each year in the US. The most common and devastating consequence is the stretching of axons caused by shear deformation that occurs during rotational acceleration of the brain during injury. The injury effects on axonal molecular and functional events are not fully characterized. We have developed a strain injury model that maintains the three dimensional cell architecture and neuronal networks found in vivo with the ability to visualize individual axons and their response to a mechanical injury. The advantage of this model is that it can apply uniaxial strains to axons that make functional connections between two organotypic slices and injury responses can be observed in real-time and over long term. This uniaxial strain model was designed to be capable of applying an array of mechanical strains at various rates of strain, thus replicating a range of modes of axonal injury. Long term culture, preservation of slice and cell orientation, and slice-slice connection on the device was demonstrated. The device has the ability to strain either individual axons or bundles of axons through the control of microchannel dimensions. The fidelity of the model was verified by observing characteristic responses to various strain injuries which included axonal beading, delayed elastic effects and breakdown in microtubules. Microtubule breakdown was shown to be dependent on the degree of the applied strain field, where maximal breakdown was observed at peak strain and minimal breakdown is observed at low strain. This strain injury model could be a powerful tool in assessing strain injury effects on functional axonal connections.
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Affiliation(s)
- Jean-Pierre Dollé
- Department of Biomedical Engineering, Rutgers, the State University of New Jersey, 599 Taylor Road, Piscataway, New Jersey 08854. Fax: 732-445-3753, Phone: 732-445-4500
| | - Barclay Morrison
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, New York, NY 10027. Fax: 212-854-8725, Phone: 212-854-6277
| | - Rene R. Schloss
- Department of Biomedical Engineering, Rutgers, the State University of New Jersey, 599 Taylor Road, Piscataway, New Jersey 08854. Fax: 732-445-3753, Phone: 732-445-4500
| | - Martin L. Yarmush
- Department of Biomedical Engineering, Rutgers, the State University of New Jersey, 599 Taylor Road, Piscataway, New Jersey 08854. Fax: 732-445-3753, Phone: 732-445-4500
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9
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Bigler ED, Maxwell WL. Neuropathology of mild traumatic brain injury: relationship to neuroimaging findings. Brain Imaging Behav 2012; 6:108-36. [PMID: 22434552 DOI: 10.1007/s11682-011-9145-0] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neuroimaging identified abnormalities associated with traumatic brain injury (TBI) are but gross indicators that reflect underlying trauma-induced neuropathology at the cellular level. This review examines how cellular pathology relates to neuroimaging findings with the objective of more closely relating how neuroimaging findings reveal underlying neuropathology. Throughout this review an attempt will be made to relate what is directly known from post-mortem microscopic and gross anatomical studies of TBI of all severity levels to the types of lesions and abnormalities observed in contemporary neuroimaging of TBI, with an emphasis on mild traumatic brain injury (mTBI). However, it is impossible to discuss the neuropathology of mTBI without discussing what occurs with more severe injury and viewing pathological changes on some continuum from the mildest to the most severe. Historical milestones in understanding the neuropathology of mTBI are reviewed along with implications for future directions in the examination of neuroimaging and neuropathological correlates of TBI.
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Affiliation(s)
- Erin D Bigler
- Department of Psychology, Brigham Young University, Provo, UT, USA.
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10
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Maxwell WL. Traumatic brain injury in the neonate, child and adolescent human: An overview of pathology. Int J Dev Neurosci 2011; 30:167-83. [DOI: 10.1016/j.ijdevneu.2011.12.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 10/27/2011] [Accepted: 12/16/2011] [Indexed: 01/14/2023] Open
Affiliation(s)
- William L. Maxwell
- Anatomy, Thomson BuildingSchool of Medicine Veterinary Medicine and Life SciencesUniversity of GlasgowGlasgowG12 8QQScotlandUnited Kingdom
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11
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Wang W, Zhang P, Yan J, Han N, Kou Y, Zhang H, Jiang B. Histological analysis of single peripheral nerve fiber in acute nerve elongation process. ACTA ACUST UNITED AC 2010; 38:165-8. [PMID: 20491608 DOI: 10.3109/10731191003670558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To observe the histological alterations of single nerve fiber structures after nerve elongation by employing a rabbit peroneal nerve stretching model. 14 rabbits weighing mean 3. 0 kg (2.02-3.31 kg.) were used in the experiment. Two rabbits were used as control when only a sham operation was done (group one, 0% stretch). Acute stretching of the peroneal nerves to elongate them by 10% was done in 6 rabbits (group two, 10% elongation) and by 20% (group three, 20% elongation) in another 6 rabbits. All animals were evaluated by tissue staining technology in a teased-fiber study. The internodal lengths were measured, and nodes of Ranvier and Schmidt-Lanterman notch were observed. The nerve fiber length was increased after stretching. The mean internodal length was 1208.31 microm in group one, 1347.26 microm in group two, and 1411.35 microm in group three. Compared with the control group, mean internodal length was elongated by 11.50% in group two and 16.80% in group three. The difference was statistically significant. The node of Ranvier and Schmidt-Lanterman notch was wider in both group two and group three. Rupture of nerve fiber at the node of Ranvier was observed in group three. The peroneal nerve in rabbits can adapt to mild stretching by internodal length elongation. Elongation by 20% will cause structural rupture and therefore is the limit for nerve elongation.
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Affiliation(s)
- Weibin Wang
- Department of Trauma and Orthopedics, Peking University People's Hospital, Beijing, China
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12
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Kallakuri S, Singh A, Lu Y, Chen C, Patwardhan A, Cavanaugh JM. Tensile stretching of cervical facet joint capsule and related axonal changes. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2007; 17:556-63. [PMID: 18080147 DOI: 10.1007/s00586-007-0562-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 10/10/2007] [Accepted: 11/21/2007] [Indexed: 12/13/2022]
Abstract
This study examines axonal changes in goat cervical facet joint capsules (FJC) subjected to low rate loading. Left C5-C6 FJC was subjected to a series of tensile tests from 2 mm to failure using a computer-controlled actuator. The FJC strain on the dorsal aspect was monitored by a stereo-imaging system. Stretched (n = 10) and unstretched (n = 7) capsules were harvested and serial sections were processed by a silver impregnation method. The mean peak actuator displacement was 21.3 mm (range: 12-30 mm). The average peak strain encompassing various regions of the capsule was 72.9 +/- 7.1%. Complete failure of the capsule was observed in 70% of the stretched capsules. Silver impregnation of the sections revealed nerve fibers and bundles in all the regions of the capsule. A blinded analysis of digital photomicrographs of axons revealed a statistically significant number of swollen axons with non-uniform caliber in stretched FJCs. Axons with terminal retraction balls, with occasional beaded appearance or with vacuolations were also observed. Stretching the FJC beyond physiological range could result in altered axonal morphology that may be related to secondary or delayed axotomy changes similar to those seen in central nervous system injuries where axons are subjected to stretching and shearing. These may contribute to neuropathic pain and are potentially related to neck pain after whiplash events.
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Affiliation(s)
- Srinivasu Kallakuri
- Biomedical Engineering, Bioengineering Center, Wayne State University, 818 W Hancock, Detroit, MI 48201, USA.
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13
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Biasca N, Maxwell WL. Minor traumatic brain injury in sports: a review in order to prevent neurological sequelae. PROGRESS IN BRAIN RESEARCH 2007; 161:263-91. [PMID: 17618984 DOI: 10.1016/s0079-6123(06)61019-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Minor traumatic brain injury (mTBI) is caused by inertial effects, which induce sudden rotation and acceleration forces to and within the brain. At less severe levels of injury, for example in mTBI, there is probably only transient disturbance of ionic homeostasis with short-term, temporary disturbance of brain function. With increased levels of severity, however, studies in animal models of TBI and in humans have demonstrated focal intra-axonal alterations within the subaxolemmal, neurofilament and microtubular cytoskeletal network together with impairment of axoplasmic transport. These changes have, until very recently, been thought to lead to progressive axonal swelling, axonal detachment or even cell death over a period of hours or days, the so-called process of "secondary axotomy". However, recent evidence has suggested that there may be two discrete pathologies that may develop in injured nerve fibers. In the TBI scenario, disturbances of ionic homeostasis, acute metabolic changes and alterations in cerebral blood flow compromise the ability of neurons to function and render cells of the brain increasingly vulnerable to the development of pathology. In ice hockey, current return-to-play guidelines do not take into account these new findings appropriately, for example allow returning to play in the same game. It has recently been hypothesized that the processes summarized above may predispose brain cells to assume a vulnerable state for an unknown period after mild injury (mTBI). Therefore, we recommend that any confused player with or without amnesia should be taken off the ice and not be permitted to play again for at least 72h.
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Affiliation(s)
- Nicola Biasca
- Clinic of Orthopaedic, Sports Medicine and Traumatology, Department of Surgery, Spital Oberengadin, CH-7503 Samedan/St. Moritz, Switzerland.
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14
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Staal JA, Dickson TC, Chung RS, Vickers JC. Cyclosporin-A treatment attenuates delayed cytoskeletal alterations and secondary axotomy following mild axonal stretch injury. Dev Neurobiol 2007; 67:1831-42. [PMID: 17702000 DOI: 10.1002/dneu.20552] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Following central nervous system trauma, diffuse axonal injury and secondary axotomy result from a cascade of cellular alterations including cytoskeletal and mitochondrial disruption. We have examined the link between intracellular changes following mild/moderate axonal stretch injury and secondary axotomy in rat cortical neurons cultured to relative maturity (21 days in vitro). Axon bundles were transiently stretched to a strain level between 103% and 106% using controlled pressurized fluid. Double-immunohistochemical analysis of neurofilaments, neuronal spectrin, alpha-internexin, cytochrome-c, and ubiquitin was conducted at 24-, 48-, 72-, and 96-h postinjury. Stretch injury resulted in delayed cytoskeletal damage, maximal at 48-h postinjury. Accumulation of cytochrome-c and ubiquitin was also evident at 48 h following injury and colocalized to axonal regions of cytoskeletal disruption. Pretreatment of cultures with cyclosporin-A, an inhibitor of calcineurin and the mitochondrial membrane transitional pore, reduced the degree of cytoskeletal damage in stretch-injured axonal bundles. At 48-h postinjury, 20% of untreated cultures demonstrated secondary axotomy, whereas cyclosporin A-treated axon bundles remained intact. By 72-h postinjury, 50% of control preparations and 7% of cyclosporin A-treated axonal bundles had progressed to secondary axotomy, respectively. Statistical analyses demonstrated a significant (p < 0.05) reduction in secondary axotomy between treated and untreated cultures. In summary, these results suggest that cyclosporin-A reduces progressive cytoskeletal damage and secondary axotomy following transient axonal stretch injury in vitro.
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Affiliation(s)
- J A Staal
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
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Morales DM, Marklund N, Lebold D, Thompson HJ, Pitkanen A, Maxwell WL, Longhi L, Laurer H, Maegele M, Neugebauer E, Graham DI, Stocchetti N, McIntosh TK. Experimental models of traumatic brain injury: do we really need to build a better mousetrap? Neuroscience 2005; 136:971-89. [PMID: 16242846 DOI: 10.1016/j.neuroscience.2005.08.030] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Revised: 06/08/2005] [Accepted: 08/04/2005] [Indexed: 11/19/2022]
Abstract
Approximately 4000 human beings experience a traumatic brain injury each day in the United States ranging in severity from mild to fatal. Improvements in initial management, surgical treatment, and neurointensive care have resulted in a better prognosis for traumatic brain injury patients but, to date, there is no available pharmaceutical treatment with proven efficacy, and prevention is the major protective strategy. Many patients are left with disabling changes in cognition, motor function, and personality. Over the past two decades, a number of experimental laboratories have attempted to develop novel and innovative ways to replicate, in animal models, the different aspects of this heterogenous clinical paradigm to better understand and treat patients after traumatic brain injury. Although several clinically-relevant but different experimental models have been developed to reproduce specific characteristics of human traumatic brain injury, its heterogeneity does not allow one single model to reproduce the entire spectrum of events that may occur. The use of these models has resulted in an increased understanding of the pathophysiology of traumatic brain injury, including changes in molecular and cellular pathways and neurobehavioral outcomes. This review provides an up-to-date and critical analysis of the existing models of traumatic brain injury with a view toward guiding and improving future research endeavors.
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Affiliation(s)
- D M Morales
- Traumatic Brain Injury Laboratory, Department of Neurosurgery, University of Pennsylvania, 3320 Smith Walk, 105C Hayden Hall, Philadelphia, PA 19104, USA.
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Lea PM, Custer SJ, Stoica BA, Faden AI. Modulation of stretch-induced enhancement of neuronal NMDA receptor current by mGluR1 depends upon presence of glia. J Neurotrauma 2004; 20:1233-49. [PMID: 14651810 DOI: 10.1089/089771503770802907] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Stretching of cultured neurons has been used to model diffuse axonal injury associated with brain trauma. N-Methyl-D-aspartate receptor (NMDAR) activation and group I metabotropic glutamate receptors (mGluRs) are implicated in the pathophysiology of such injury. Here we detail the effects of culture condition and mGluR1 modulation on stretch-enhanced NMDA receptor activity, and show the presence of mGluR1 in addition to mGluR5 in glia. In cortical neurons grown in the absence (PN) or presence (NG) of a glial monolayer, stretch injury (5.7 mm) enhances NMDAR activity by increasing maximal NMDAR current, decreasing the voltage-dependent Mg(2+) block, and altering the kinetic behavior of these receptors. In PN cultures, activation of mGluR1 increases stretch-enhanced NMDAR activity, whereas in NG cultures, such activity is reduced. In contrast, inhibition of mGluR1 in PN cultures limits stretch-enhanced NMDAR activity, whereas in NG cultures activity is increased. MGluR1 modulate stretch-enhanced NMDAR activity through multiple mechanisms including: altering peak or steady state current, affecting Mg(2+) blockade of the NMDAR, or by changing NMDAR kinetics. The presence of glia significantly alters the nature of mGluR1-mediated modulation of NMDAR activity and stretch-induced injury. Together these data indicate a significant neuronal/glial interaction between glial mGluR1 and neuronal NMDA receptor activity.
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Affiliation(s)
- Paul M Lea
- Department of Neuroscience, Georgetown University, Washington, D.C. 20057-1464, USA
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17
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Asamura H, Yamazaki K, Mukai T, Ito M, Takayanagi K, Ota M, Fukushima H. Case of shaken baby syndrome in Japan caused by shaking alone. Pediatr Int 2003; 45:117-9. [PMID: 12654085 DOI: 10.1046/j.1442-200x.2003.01653.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Hideki Asamura
- Department of Legal Medicine, Shinshu University School of Medicine, Nagano, Japan.
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18
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Saatman KE, Abai B, Grosvenor A, Vorwerk CK, Smith DH, Meaney DF. Traumatic axonal injury results in biphasic calpain activation and retrograde transport impairment in mice. J Cereb Blood Flow Metab 2003; 23:34-42. [PMID: 12500089 DOI: 10.1097/01.wcb.0000035040.10031.b0] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Traumatic axonal injury (TAI) is one of the most important pathologies associated with closed head injury, and contributes to ensuing morbidity. The authors evaluated the potential role of calpains in TAI using a new model of optic nerve stretch injury in mice. Male C57BL/6 mice were anesthetized, surgically prepared, and subjected to a 2.0-mm optic nerve stretch injury (n = 34) or sham injury (n = 18). At various intervals up to 2 weeks after injury, optic nerves were examined for neurofilament proteins and calpain-mediated spectrin breakdown products using immunohistochemistry. In addition, fluorescent tracer was injected into the superior colliculi of mice 1 day before they were killed, to investigate the integrity of retrograde axonal transport to the retina. Optic nerve stretch injury resulted in persistent disruption of retrograde axonal transport by day 1, progressive accumulation and dephosphorylation of neurofilament protein in swollen and disconnected axons, and subsequent loss of neurofilament protein in degenerating axons at day 14. Calpains were transiently activated in intact axons in the first minutes to hours after stretch injury. A second stage of calpain-mediated proteolysis was observed at 4 days in axonal swellings, bulbs, and fragments. These data suggest that early calpain activation may contribute to progressive intraaxonal structural damage, whereas delayed calpain activation may be associated with axonal degeneration.
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Affiliation(s)
- Kathryn E Saatman
- Department of Neurosurgery, University of Pennsylvania, Philadelphia 19104, USA.
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19
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Affiliation(s)
- J Sahuquillo
- Department of Neurosurgery, Vall d'Hebron University Hospital, Barcelona, Spain
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20
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Baker AJ, Phan N, Moulton RJ, Fehlings MG, Yucel Y, Zhao M, Liu E, Tian GF. Attenuation of the electrophysiological function of the corpus callosum after fluid percussion injury in the rat. J Neurotrauma 2002; 19:587-99. [PMID: 12042094 DOI: 10.1089/089771502753754064] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study describes a new method used to evaluate axonal physiological dysfunction following fluid percussion induced traumatic brain injury (TBI) that may facilitate the study of the mechanisms and novel therapeutic strategies of posttraumatic diffuse axonal injury (DAI). Stimulated compound action potentials (CAP) were recorded extracellularly in the corpus callosum of superfused brain slices at 3 h, and 1, 3, and 7 days following central fluid percussion injury and demonstrated a temporal pattern of functional deterioration. The maximal CAP amplitude (CAPA) covaried with the intensity of impact 1 day following sham, mild (1.0-1.2 atm), and moderate (1.8-2.0 atm) injury (p < 0.05; 1.11 +/- 0.10, 0.82 +/- 0.11, and 0.49 +/- 0.08 mV, respectively). The CAPA in sham animals were approximately 1.1 mV and did not vary with survival interval (3 h, and 1, 3, and 7 days); however, they were significantly decreased at each time point following moderate injury (p < 0.05; 0.51 +/- 0.11, 0.49 +/- 0.08, 0.46 +/- 0.10, and 0.75 +/- 0.13 mV, respectively). The CAPA at 7 days in the injured group were higher than at 3 h, and 1 and 3 days. H&E and amyloid precursor protein (APP) light microscopic analysis confirmed previously reported trauma-induced axonal injury in the corpus callosum seen after fluid percussion injury. Increased APP expression was confirmed using Western blotting showing significant accumulation at 1 day (IOD 913.0 +/- 252.7; n = 3; p = 0.05), 3 days (IOD 753.1 +/- 159.1; n = 3; p = 0.03), and at 7 days (IOD 1093.8 = 105.0; n = 3; p = 0.001) compared to shams (IOD 217.6 +/- 20.4; n = 3). Thus, we report the characterization of white matter axonal dysfunction in the corpus callosum following TBI. This novel method was easily applied, and the results were consistent and reproducible. The electrophysiological changes were sensitive to the early effects of impact intensity, as well as to delayed changes occurring several days following injury. They also indicated a greater degree of attenuation than predicted by APP expression changes alone.
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Affiliation(s)
- A J Baker
- Department of Anaesthesia, University of Toronto, Toronto, Canada.
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21
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Geddes JF, Whitwell HL. Head injury in routine and forensic pathological practice. CURRENT TOPICS IN PATHOLOGY. ERGEBNISSE DER PATHOLOGIE 2001; 95:101-24. [PMID: 11545051 DOI: 10.1007/978-3-642-59554-7_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- J F Geddes
- Department of Morbid Anatomy, Royal London Hospital, Whitechapel, London E1 1BB, UK
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22
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Bain AC, Raghupathi R, Meaney DF. Dynamic stretch correlates to both morphological abnormalities and electrophysiological impairment in a model of traumatic axonal injury. J Neurotrauma 2001; 18:499-511. [PMID: 11393253 DOI: 10.1089/089771501300227305] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this investigation, the relationships between stretch and both morphological and electrophysiological signs of axonal injury were examined in the guinea pig optic nerve stretch model. Additionally, the relationship between axonal morphology and electrophysiological impairment was assessed. Axonal injury was produced in vivo by elongating the guinea pig optic nerve between 0 and 8 mm (Ntotal = 70). Morphological damage was detected using neurofilament immunohistochemistry (SMI 32). Electrophysiological impairment was determined using changes in visual evoked potentials (VEPs) measured prior to injury, every 5 min for 40 min following injury, and at sacrifice (72 h). All nerves subjected to ocular displacements greater than 6 mm demonstrated axonal swellings and retraction bulbs, while nerves subjected to displacements below 4 mm did not show any signs of morphological injury. Planned comparisons of latency shifts of the N35 peak in the VEPs showed that ocular displacements greater than 5 mm produced electrophysiological impairment that was significantly different from sham animals. Logit analysis demonstrated that less stretch was required to elicit electrophysiological changes (5.5 mm) than morphological signs of damage (6.8 mm). Moreover, Student t tests indicated that the mean latency shift measured in animals exhibiting morphological injury was significantly greater than that calculated from animals lacking morphological injury (p < 0.01). These data show that distinct mechanical thresholds exist for both morphological and electrophysiological damage to the white matter. In a larger context, the distinct injury thresholds presented in the report will aid in the biomechanical assessment of animate models of head injury, as well as assist in extending these findings to predict the conditions that cause white matter injury in humans.
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Affiliation(s)
- A C Bain
- Department of Bioengineering, University of Pennsylvania, Philadelphia 19104-6392, USA
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23
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Bain AC, Meaney DF. Tissue-level thresholds for axonal damage in an experimental model of central nervous system white matter injury. J Biomech Eng 2000; 122:615-22. [PMID: 11192383 DOI: 10.1115/1.1324667] [Citation(s) in RCA: 336] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In vivo, tissue-level, mechanical thresholds for axonal injury were determined by comparing morphological injury and electrophysiological impairment to estimated tissue strain in an in vivo model of axonal injury. Axonal injury was produced by dynamically stretching the right optic nerve of an adult male guinea pig to one of seven levels of ocular displacement (Nlevel = 10; Ntotal = 70). Morphological injury was detected with neurofilament immunohistochemical staining (NF68, SM132). Simultaneously, functional injury was determined by the magnitude of the latency shift of the N35 peak of the visual evoked potentials (VEPs) recorded before and after stretch. A companion set of in situ experiments (Nlevel = 5) was used to determine the empirical relationship between the applied ocular displacement and the magnitude of optic nerve stretch. Logistic regression analysis, combined with sensitivity and specificity measures and receiver operating characteristic (ROC) curves were used to predict strain thresholds for axonal injury. From this analysis, we determined three Lagrangian strain-based thresholds for morphological damage to white matter. The liberal threshold, intended to minimize the detection of false positives, was a strain of 0.34, and the conservative threshold strain that minimized the false negative rate was 0.14. The optimal threshold strain criterion that balanced the specificity and sensitivity measures was 0.21. Similar comparisons for electrophysiological impairment produced liberal, conservative, and optimal strain thresholds of 0.28, 0.13, and 0.18, respectively. With these threshold data, it is now possible to predict more accurately the conditions that cause axonal injury in human white matter.
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Affiliation(s)
- A C Bain
- Department of Bioengineering, 120 Hayden Hall, University of Pennsylvania, Philadelphia, PA 19104-6392, USA
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24
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Geddes JF, Whitwell HL, Graham DI. Traumatic axonal injury: practical issues for diagnosis in medicolegal cases. Neuropathol Appl Neurobiol 2000; 26:105-16. [PMID: 10840273 DOI: 10.1046/j.1365-2990.2000.026002105.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the 25 years or so after the first clinicopathological descriptions of diffuse axonal injury (DAI), the criterion for diagnosing recent traumatic white matter damage was the identification of swollen axons ('bulbs') on routine or silver stains, in the appropriate clinical setting. In the last decade, however, experimental work has given us greater understanding of the cellular events initiated by trauma to axons, and this in turn has led to the adoption of immunocytochemical methods to detect markers of axonal damage in both routine and experimental work. These methods have shown that traumatic axonal injury (TAI) is much more common than previously realized, and that what was originally described as DAI occupies only the most severe end of a spectrum of diffuse trauma-induced brain injury. They have also revealed a whole field of previously unrecognized white matter pathology, in which axons are diffusely damaged by processes other than head injury; this in turn has led to some terminological confusion in the literature. Neuropathologists are often asked to assess head injuries in a forensic setting: the diagnostic challenge is to sort out whether the axonal damage detected in a brain is indeed traumatic, and if so, to decide what - if anything - can be inferred from it. The lack of correlation between well-documented histories and neuropathological findings means that in the interpretation of assault cases at least, a diagnosis of 'TAI' or 'DAI' is likely to be of limited use for medicolegal purposes.
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Affiliation(s)
- J F Geddes
- Department of Histopathology and Morbid Anatomy, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK
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25
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Gleckman AM, Evans RJ, Bell MD, Smith TW. Optic nerve damage in shaken baby syndrome: detection by beta-amyloid precursor protein immunohistochemistry. Arch Pathol Lab Med 2000; 124:251-6. [PMID: 10656735 DOI: 10.5858/2000-124-0251-ondisb] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Rapid acceleration-deceleration of an infant's head during intentional shaking should in theory exert stretch or shear forces upon the optic nerves sufficient to cause axonal injury. beta-Amyloid precursor protein (beta-APP) immunohistochemistry recently has been shown to be a highly effective method for identifying diffuse axonal injury in the brains of infants with shaken baby syndrome. In this study, we investigated the utility of beta-APP in identifying optic nerve damage in infants who have sustained fatal whiplash shaking. MATERIALS AND METHODS beta-Amyloid precursor protein immunohistochemistry was performed on formalin-fixed, paraffin-embedded sections of eyes (including optic disc and distal optic nerve) from infants less than 1 year of age with shaken baby syndrome (5 cases), combined shaken baby syndrome/blunt head trauma (3 cases), and "pure" blunt head trauma (1 case). Nontraumatic control cases included infants who died of suffocation (1 case), sudden infant death syndrome (1 case), and positional asphyxia (1 case) and an enucleation from a child with a retinoblastoma (1 case). Matched hematoxylin-eosin-and neurofilament-stained sections were used for comparison. RESULTS Three of the 5 shaken baby cases and all 3 combined shaken baby/blunt head trauma cases had optic nerve axonal injury identified by the presence of strongly beta-APP-immunoreactive beaded or swollen axonal segments. Axonal injury could not be detected in the corresponding hematoxylin-eosin-or neurofilament-stained sections. Optic nerve axonal injury was not seen in the case involving pure blunt head trauma or in the nontraumatic control cases. CONCLUSIONS Optic nerve axonal injury is a prominent feature of intentional fatal whiplash head trauma in infants less than 1 year of age. beta-Amyloid protein precursor immunohistochemistry appears to be the most effective method for demonstrating axonal damage in the optic nerve.
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Affiliation(s)
- A M Gleckman
- Office of the Chief Medical Examiner of Massachusetts, Boston, Massachusetts, USA
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26
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Del Bigio MR, Zhang YW. Cell death, axonal damage, and cell birth in the immature rat brain following induction of hydrocephalus. Exp Neurol 1998; 154:157-69. [PMID: 9875277 DOI: 10.1006/exnr.1998.6922] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesized that hydrocephalus can cause death of brain cells and that generation of new brain cells might compensate for the cell loss. Hydrocephalus was induced in 3-week-old rats by injection of kaolin into the cisterna magna. The brains were studied 1 to 4 weeks later by histochemical, immunochemical, and ultrastructural methods. The ventricles enlarged progressively. Some axons in the corpus callosum were injured as early as 1 week, but axonal damage was not prevalent until 4 weeks when ventriculomegaly became severe. Dying cells detected by DNA end labeling and often identified as oligodendrocytes by electron microscopy were evident in white matter. Late-stage hydrocephalus was associated with a significant increase in the quantity of dying cells. Hydrocephalus was associated with increased Ki67 labeling and bromodeoxyuridine incorporation in the subependymal zone. Reactive changes were identified among astrocytes, oligodendroglia, and microglia. We conclude that hydrocephalus causes, in addition to axonal injury, gradual cell death in the cerebrum, particularly the white matter. The brain response includes production of new glial cells, but whether the new cells play any beneficial role remains unknown.
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Affiliation(s)
- M R Del Bigio
- Department of Pathology, University of Manitoba, Winnipeg, Canada
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27
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Gallant PE, Galbraith JA. Axonal structure and function after axolemmal leakage in the squid giant axon. J Neurotrauma 1997; 14:811-22. [PMID: 9421453 DOI: 10.1089/neu.1997.14.811] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Membrane leakage is a common consequence of traumatic nerve injury. In order to measure the early secondary effects of different levels of membrane leakage on axonal structure and function we studied the squid giant axon after electroporation at field strengths of 0.5, 1.0, 1.6, or 3.3 kV/cm. Immediately after mild electroporation at 0.5 kV/cm, 40% of the axons had no action potentials, but by 1 h all of the mildly electroporated axons had recovered their action potentials. Many large organelles (mitochondria) were swollen, however, and their transport was reduced by 62% 1 h after this mild electroporation. One hour after moderate electroporation at 1.0 kV/cm, most of the axons had no action potentials, most large organelles were swollen, and their transport was reduced by 98%, whereas small organelle transport was reduced by 75%. Finally at severe electroporation levels of 1.65-3.0 kV/cm all conduction and transport was lost and the gel-like axoplasmic structure was clumped or liquefied. The structural damage and transport block seen after severe and moderate poration were early secondary injuries that could be prevented by placing the porated axons in an intracellular-type medium (low in Ca2+, Na+, and Cl-) immediately after poration. In moderately, but not severely, porated axons this protection of organelle transport and structure persisted, and action potential conduction returned when the axons were returned to the previously injurious extracellular-type medium. This suggests that the primary damage, the axolemmal leak, was repaired while the moderately porated axons were in the protective intracellular-type medium.
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Affiliation(s)
- P E Gallant
- Laboratory of Neurobiology, NINDS, National Institutes of Health, Bethesda, Maryland 20892-4062, USA
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28
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Maxwell WL, Povlishock JT, Graham DL. A mechanistic analysis of nondisruptive axonal injury: a review. J Neurotrauma 1997; 14:419-40. [PMID: 9257661 DOI: 10.1089/neu.1997.14.419] [Citation(s) in RCA: 432] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Axons are particularly at risk in human diffuse head injury. Use of immunocytochemical labeling techniques has recently demonstrated that axonal injury (AI) and the ensuing reactive axonal change is, probably, more widespread and occurs over a longer posttraumatic time in the injured brain than had previously been appreciated. But the characterization of morphologic or reactive changes occurring after nondisruptive AI has largely been defined from animal models. The comparability of AI in animal models to human diffuse AI (DAI) is discussed and the conclusion drawn that, although animal models allow the analysis of morphologic changes, the spatial distribution within the brain and the time course of reactive axonal change differs to some extent both between species and with the mode of brain injury. Thus, the majority of animal models do not reproduce exactly the extent and time course of AI that occurs in human DAI. Nonetheless, these studies provide good insight into reactive axonal change. In addition, there is developing in the literature considerable variance in the terminology applied to injured axons or nerve fibers. We explain our current understanding of a number of terms now present in the literature and suggest the adoption of a common terminology. Recent work has provided a consensus that reactive axonal change is linked to pertubation of the axolemma resulting in disruption of ionic homeostatic mechanisms within injured nerve fibers. But quantitative data for changes for different ion species is lacking and is required before a better definition of this homeostatic disruption may be provided. Recent studies of responses by the axonal cytoskeleton after nondisruptive AI have demonstrated loss of axonal microtubules over a period up to 24 h after injury. The biochemical mechanisms resulting in loss of microtubules are, hypothetically, mediated both by posttraumatic influx of calcium and activation of calmodulin. This loss results in focal accumulation of membranous organelles in parts of the length of damaged axons where the axonal diameter is greater than normal to form axonal swellings. We distinguish, on morphologic grounds, between axonal swellings and axonal bulbs. There is also a growing consensus regarding responses by neurofilaments after nondisruptive AI. Initially, and rapidly after injury, there is reduced spacing or compaction of neurofilaments. This compaction is stable over at least 6 h and results from the loss or collapse of neurofilament sidearms but retention of the filamentous form of the neurofilaments. We posit that sidearm loss may be mediated either through proteolysis of sidearms via activation of microM calpain or sidearm dephosphorylation via posttraumatic, altered interaction between protein phosphatases and kinase(s), or a combination of these two, after calcium influx, which occurs, at least in part, as a result of changes in the structure and functional state of the axolemma. Evidence for proteolysis of neurofilaments has been obtained recently in the optic nerve stretch injury model and is correlated with disruption of the axolemma. But the earliest posttraumatic interval at which this was obtained was 4 h. Clearly, therefore, no evidence has been obtained to support the hypothesis that there is rapid, posttraumatic proteolysis of the whole axonal cytoskeleton mediated by calpains. Rather, we hypothesize that such proteolysis occurs only when intra-axonal calcium levels allow activation of mM calpain and suggest that such proteolysis, resulting in the loss of the filamentous structure of neurofilaments occurs either when the amount of deformation of the axolemma is so great at the time of injury to result in primary axotomy or, more commonly, is a terminal degenerative change that results in secondary axotomy or disconnection some hours after injury.
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Affiliation(s)
- W L Maxwell
- Laboratory of Human Anatomy, Institute of Biomedical and Life Sciences, University of Glasgow, United Kingdom
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29
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Affiliation(s)
- T A Gennarelli
- Department of Neurosurgery, Allegheny University of the Health Sciences, Philadelphia, USA
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30
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Anthes DL, Theriault E, Tator CH. Characterization of axonal ultrastructural pathology following experimental spinal cord compression injury. Brain Res 1995; 702:1-16. [PMID: 8846063 DOI: 10.1016/0006-8993(95)01028-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present study characterizes axonal pathology associated with traumatic compression injuries of the spinal cord and quantitatively assesses subtypes of axonal pathology in the acute, post-injury period. Eighteen adult female Wistar rats underwent spinal cord compression injury with a 53 g modified aneurysm clip at the C8-T1 segment. Six additional rats served as sham controls. Six experimental animals were sacrificed at each of the three post-injury time points: 15 min, 2 h and 24 h. From all animals, the C8-T1 spinal cord was dissected and processed for both light and electron microscopy. Axonal pathology included periaxonal swelling, organelle accumulation, vesicular myelin, myelin invagination, myelin rupture, and giant axons. Early myelin rupture and the ultrastructural features of giant axons are described here for the first time in the context of spinal cord compression injury. The quantitative analysis characterizes the prevalence of types of axonal pathology over the acute post-injury period and provides evidence for the secondary injury hypothesis regarding the evolution of axonal pathophysiology following trauma.
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Affiliation(s)
- D L Anthes
- Playfair Neuroscience Unit, Toronto Hospital, University of Toronto, Ont., Canada
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31
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Maxwell WL, McCreath BJ, Graham DI, Gennarelli TA. Cytochemical evidence for redistribution of membrane pump calcium-ATPase and ecto-Ca-ATPase activity, and calcium influx in myelinated nerve fibres of the optic nerve after stretch injury. JOURNAL OF NEUROCYTOLOGY 1995; 24:925-42. [PMID: 8719820 DOI: 10.1007/bf01215643] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
There has been controversy for some time as to whether a posttraumatic influx of calcium ions occurs in stretch/nondisruptively injured axons within the central nervous system in both human diffuse axonal injury and a variety of models of such injury. We have used the oxalate/pyroantimonate technique to provide cytochemical evidence in support of such an ionic influx after focal axonal injury to normoxic guinea pig optic nerve axons, a model for human diffuse axonal injury. We present evidence for morphological changes within 15 min of injury where aggregates of pyroantimonate precipitate occur in nodal blebs at nodes of Ranvier, in focal swellings within axonal mitochondria, and at localized sites of separation of myelin lamellae. In parallel with these studies, we have used cytochemical techniques for localization of membrane pump Ca(2+)-ATPase and ecto-Ca-ATPase activity. There is loss of labelling for membrane pump Ca(2+)-ATPase activity on the nodal axolemma, together with loss of ecto-Ca-ATPase from the external aspect of the myelin sheath at sites of focal separation of myelin lamellae. Disruption of myelin lamellae and loss of ecto-Ca-ATPase activity becomes widespread between 1 and 4 h after injury. This is correlated with both infolding and retraction of the axolemma from the internal aspect of the myelin sheath to form periaxonal spaces which are characterized by aggregates of pyroantimonate precipitate, and the development of myelin intrusions into invaginations of the axolemma such that the regular profile of the axon is lost. There is novel labelling of membrane pump Ca(2+)-ATPase on the cytoplasmic aspect of the internodal axolemma between 1 and 4 h after injury. There is loss of an organized axonal cytoskeleton in a proportion of nerve fibres by 4-6 h after injury. We suggest that these changes demonstrate a progressive pathology linked to calcium ion influx after stretch (non-disruptive) axonal injury to optic nerve myelinated fibres. We posit that calcium influx, linked to or correlated with changes in Ca(2+)-ATPase activities, results in dissolution of the axonal cytoskeleton and axotomy between 4 and 6 h after the initial insult to axons.
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Affiliation(s)
- W L Maxwell
- Laboratory of Human Anatomy, University of Glasgow, UK
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32
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Povlishock JT, Christman CW. The pathobiology of traumatically induced axonal injury in animals and humans: a review of current thoughts. J Neurotrauma 1995; 12:555-64. [PMID: 8683606 DOI: 10.1089/neu.1995.12.555] [Citation(s) in RCA: 356] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
This manuscript provides a review of those factors involved in the pathogenesis of traumatically induced axonal injury in both animals and man. The review comments on the issue of primary versus secondary, or delayed, axotomy, pointing to the fact that in cases of experimental traumatic brain injury, secondary, or delayed, axotomy predominates. This review links the process of secondary axotomy to an impairment of axoplasmic transport which is initiated, depending upon the severity of the injury, by either focal cytoskeletal. misalignment or axolemmal permeability change with concomitant cytoskeletal. collapse. Data are provided to show that these focal axonal changes are related to the focal impairment of axoplasmic transport which, in turn, triggers the progression of reactive axonal change, leading to disconnection. In the context of experimental studies, evidence is also provided to explain the damaging consequences of diffuse axonal injury. The implications of diffuse axonal injury and its attendant deafferentation are considered by noting that with mild injury such deafferentation may lead to an adaptive neuroplastic recovery, whereas in more severe injury a disordered and/or maladaptive neuroplastic re-organization occurs, consistent with the enduring morbidity associated with severe injury. In closing, the review focuses on the implications of the findings made in experimental animals for our understanding of those events ongoing in traumatically brain-injured humans. It is noted that the findings made in experimental animals have been confirmed, in large part, in humans, suggesting the relevance of animal models for continued study of human traumatically induced axonal injury.
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Affiliation(s)
- J T Povlishock
- Department of Anatomy, School of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond, USA
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33
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Rango M, Spagnoli D, Tomei G, Bamonti F, Scarlato G, Zetta L. Central nervous system trans-synaptic effects of acute axonal injury: a 1H magnetic resonance spectroscopy study. Magn Reson Med 1995; 33:595-600. [PMID: 7596262 DOI: 10.1002/mrm.1910330503] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
N-acetylaspartate (NAA) has previously been proposed as a neuronal marker. 1H magnetic resonance spectroscopy (MRS) is able to detect NAA in brain, and decreases of NAA have been documented after brain injury. The reason for this decrease is not fully understood and neuron loss damage and "dysfunction" have all been proposed. It is hypothesized that acute central nervous system (CNS) deafferentation causes a trans-synaptic NAA decrease and that high resolution 1H MRS is able to detect such a decrease. To test this hypothesis, an experimental model was used in which axonal lesions were obtained by stretch injury in guinea pig right optic nerve (95-99% crossed fibers). The trans-synaptic concentration of NAA, total creatine (Cr), and the NAA/Cr ratio in lateral geniculate bodies (LGB) and superior colliculi (SC) sample extracts were measured 72 h later by high resolution 1H MRS. In the left LGB/SC, which is where right optic nerve fibers project, reductions of NAA and NAA/Cr were found whereas Cr levels were normal. NAA, NAA/Cr, and Cr values were all normal in the right LGB/SC. Histology and EM findings revealed no abnormalities. At 7 days, left LGB/SC NAA and NAA/Cr values were in the normal range. It was concluded that 1) acute deafferentation in the CNS causes a trans-synaptic decrease of NAA levels that can be detected by 1H MRS and 2) NAA decrease may be due to changes of NAA metabolism caused by functional neuronal inactivity rather than neuronal loss, injury or "dysfunction." 1H MRS is a potential tool for the study of functional effect of CNS lesions in vivo.
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Affiliation(s)
- M Rango
- Università degli Studi di Milano, Istituto di Clinica Neurologica, Italy
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Yamaki T, Murakami N, Iwamoto Y, Nakagawa Y, Ueda S, Irizawa Y, Komura S, Matsuura T. Pathological study of diffuse axonal injury patients who died shortly after impact. Acta Neurochir (Wien) 1992; 119:153-8. [PMID: 1481741 DOI: 10.1007/bf01541800] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It is generally considered that axonal injury is apparent only on electron microscopy in the very early stage after a closed head injury. To clarify the pathological findings in head injury patients dying very shortly after the impact, we analyzed 8 fatal cases of diffuse axonal injury (DAI) who underwent medicolegal autopsy at the Department of Forensic Medicine of Kyoto Prefectural University of Medicine. Seven cases died within one hour after injury and another one case died 3 days after injury. We studied these cases macroscopically, microscopically, and electron microscopically. Macroscopically all cases showed the typical findings of diffuse axonal injury. Microscopical study of the cases who died within one hour revealed no characteristic findings of DAI such as appearance of retraction balls or microglia. On the other hand, in the case who died only 3 days after injury it showed the typical retraction balls. Electron microscopic study showed the remarkable destruction of cytoskeletal structure of axons in all cases. From our results, it is reasonable to speculate that DAI may be common among head injury patients who die very soon after the impact.
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Affiliation(s)
- T Yamaki
- Department of Neurosurgery, Kyoto Prefectural University of Medicine, Japan
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