This study sought to make a biomechanical analysis of the diffuse axonal injury(DAI) animal model caused by nonimpact with half bound head in cats. A three-dimensional finite element model of cat's head was established. The head of an anesthetized cat was scanned in 2 mm section. The nods and element meshes were signed out according to the geometry of every section. The geometric data were put into the computer and the element mesh body of cat's head was established in vizi CAD system. The maximum stress, minimum stress and von Mises stress were calculated by Super SAP (93ed) finite elemental software when the force was loaded on the right or left side of model in zero section. The analysis showed that the maximum stress appeared in the anterior and posterior loaded point and extended to cranial base in the cranial shell. There was high stress in the brain surface also. Because of cerebellar tentorium, cerebral falx, petrosal bone and sellar process, the stress did not decrease equivalently while approaching the deep brain, but it was distributed in cerebral-cerebellar peduncles, brain stem, corpus callosum and basal ganglia area at high values. The results suggest that the stress caused by rotational force is widespreadly and unequivalently distributed in brain tissue, which is mainly effected by the cerebellar tentorium, cerebral falx and the irregular geometric forms of cranial bone.
Animals ; Biomechanical Phenomena ; Brain ; pathology ; Brain Injuries ; pathology ; Cats ; Diffuse Axonal Injury ; pathology ; Finite Element Analysis ; Head ; Models, Animal ; Rotation ; Skull

OBJECTIVES: To establish the imaging mass spectrometry for analysis of differentially expressed proteins distribution in the rat brains with diffuse axonal injury （DAI） based on matrix assisted laser desorption/ionization-time of flight imaging mass spectrometry （MALDI-TOF-IMS）. METHODS: MALDI-TOF-IMS scanning were conducted on the brains of DAI group and control group in the m/z range of 1 000 to 20 000 using AutoflexⅢ MALDI-TOF spectrometer. ClinProTool 2.2 software was used for statistical analysis on the data of two groups, and then the differentially expressed proteins were picked out to conduct imaging. The distribution of the proteins with different m/z in the rat brains was observed. RESULTS: Five proteins with different m/z, including 4 963, 5 634, 6 253, 6 714 and 7 532, differentially expressed in the rat brains with DAI. CONCLUSIONS MALDI-TOF-IMS can be used for studying the differentially expressed proteins in rat brains with DAI and the analysis method is established for exploring the distribution of differentially expressed proteins in the rat brains with DAI using imaging mass spectrometry.
Animals ; Brain/pathology* ; Diffuse Axonal Injury/pathology* ; Proteins/metabolism* ; Proteome/metabolism* ; Proteomics ; Rats ; Software ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

OBJECTIVE: To study the expression of nerve growth factor (NGF) in diffuse axonal injury (DAI) in rat. METHODS: Eighty SD rats were used and samples were taken at 1 h, 3 h, 6 h, 12 h, 24 h, 48 h, 3 d, and 7 d after brain injury. The expressions of NGF in cerebral cortex, thalamus, cerebellum, and hippocampus were studied with immunohistochemistry and compared with normal group and sham operation group. RESULTS: Low expression of NGF was observed in normal group and sham operation group. The expression of NGF increased 1 h after injury, peaked at 12 h, and returned to basal level at day 7. CONCLUSION NGF is involved in repair of DAI. The changes of NGF expression following DAI may be applied to estimate the post-injury time interval of the brain in forensic medicine.
Animals ; Brain Injuries/metabolism* ; Diffuse Axonal Injury/metabolism* ; Forensic Pathology ; Male ; Nerve Growth Factors/metabolism* ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To study the disability identification for cases with clinical diagnosis of diffuse axonal injury (DAI) due to traffic accidents, and to explore the possible effects of DAI on identification results. METHODS: Five hundred and fifty-six cases of cerebral injury due to traffic accidents were collected, including 467 cases diagnosed with cerebral contusion or laceration and 89 cases diagnosed with DAI. The identification results of different groups with diagnosis of DAI diagnosis, diagnosis of DAI with cerebral contusion (laceration), and diagnosis of cerebral contusion or laceration without DAI were compared and statistically analyzed, based on the results of CT and MRI re-review. RESULTS: The disability identification levels in DAI group (20 cases), DAI group (69 cases) with cerebral contusion (laceration) and DAI group (467 cases) not complicated by cerebral contusion (laceration) were 7.72 +/- 1.09, 7.78 +/- 1.11, and 8.86 +/- 0.66, respectively. The disability levels of the two groups diagnosed with DAI were higher than those of the group without DAI diagnosis (P < 0.05). CONCLUSION Patients with DAI diagnosis might have more severe cerebral injury. In the identification process, one should pay attention to the possible missed diagnosis and misdiagnosis, and meanwhile avoid relying on those evidences provided only by CT and MRI.
Accidents, Traffic ; Brain Injuries/diagnosis* ; Diagnostic Errors ; Diffuse Axonal Injury/etiology* ; Disability Evaluation ; Forensic Pathology ; Humans ; Magnetic Resonance Imaging ; Resin Cements ; Tomography, X-Ray Computed

OBJECT: To investigate the changes in the expression_level of synaptophysin following diffuse brain injury (DBI) in rats and to correlate the changes of the synaptophysin expression_level with the post injury time interval. METHODS: Wister rats were used as a DBI model induced by Marmarou method. The changes of synaptophysin immunoreactivity on coronal sections of the rats sampled at different post-injury time intervals were used as a marker. The densitometry of the synaptophysin immunoreactivity was documented by imaging technique and analyzed by SPSS software. RESULTS: The expression level of synaptophysin in DBI rats showed dynamic changes following DBI as well as during the repairing period. CONCLUSION The changes of synaptophysin level may be used as a marker for estimation of the post injury time interval in DBI.
Animals ; Brain/pathology* ; Brain Injuries/pathology* ; Cerebral Cortex/pathology* ; Diffuse Axonal Injury/pathology* ; Disease Models, Animal ; Immunohistochemistry ; Intracranial Hemorrhage, Traumatic/pathology* ; Neurons/pathology* ; Rats ; Rats, Sprague-Dawley ; Staining and Labeling ; Synapses/pathology* ; Synaptophysin/metabolism* ; Time Factors

Mild traumatic brain injury (mTBI) is a common type of brain disorders among young adults. The dysfunction of the brain is often exacerbated due to diffuse axonal injury (DAI) which based on the injury of white matter fibers and axons. Since mild and moderate brain injury or DAI are diffuse and subtle, conventional CT and MRI are difficult to make a positive diagnosis. Recent clinical study indicated that functional magnetic resonance imaging has a high detection rate in the diagnosis of acute mild and moderate brain injury, especially the diffusion tensor imaging (DTI) and 1H-magnetic resonance spectroscopy (1H-MRS). This paper has reviewed the principles and characteristics of DTI and 1H-MRS, and recent research in the clinical and animal experiments on brain injury.
Animals ; Axons/pathology* ; Brain/pathology* ; Brain Concussion/pathology* ; Brain Injuries/pathology* ; Diagnosis, Differential ; Diffuse Axonal Injury/pathology* ; Diffusion Tensor Imaging ; Humans ; Magnetic Resonance Spectroscopy/methods* ; Nerve Fibers, Myelinated/pathology* ; Severity of Illness Index

OBJECTIVE: To investigate the relationship between the diffuse axonal injury (DAI) and cerebral contusion, primary brain stem injury and brain concussion. METHODS: One hundred and twelve cases with DAI were analyzed according to the characteristics of clinical signs and imaging features. RESULTS: Of 112 cases of DAI, 70.5% injured in traffic accident, 60.7% injured with blunt trauma more than one time and 71.4% injured with cerebral contusion. And 90 cases with brain with hemorrhage were found in CT or MRI imaging. CONCLUSION DAI may be associated with cortical contusion and primary brain stem injury. The CT or MRI is useful to investigate the cause of death and to evaluate the personal disability.
Accidents, Traffic ; Adolescent ; Adult ; Aged ; Brain Concussion/pathology* ; Brain Injuries/diagnosis* ; Brain Stem/pathology* ; Child ; Child, Preschool ; Diagnosis, Differential ; Diffuse Axonal Injury/pathology* ; Female ; Forensic Pathology ; Humans ; Intracranial Hemorrhages/etiology* ; Male ; Middle Aged ; Tomography, X-Ray Computed ; Young Adult

OBJECTIVETo investigate the effect of moderate hypothermia on responses of axonal cytoskeleton to axonal injury in the acute stage of injury.

METHODSOf fifteen adult guinea pigs, twelve animals were subjected to stretch injury to the right optic nerves and divided into the normothermic group (n = 6) in which the animal's core temperature was maintained at 36.0-37.5 degrees C and the hypothermia group (n = 6) in which the core temperature was reduced to 32.0-32.5 degrees C after stretch injury. Remaining three animals sustained no injury to the right optic nerves and served as control group. Half of injured animals (n = 3) of either normothermic group or hypothermic group were killed at either 2 hours or 4 hours after injury. The ultrastructural changes of axonal cytoskeleton of the right optic nerve fibers from the animals were examined under a transmission electron microscope and analyzed by quantitative analysis with a computer image analysis system.

RESULTSAt 2 hours after stretch injury, there was a significant reduction in the mean number of microtubules (P < 0.001), and a significant increase in the mean intermicrotubule spacing (P < 0.05 or P < 0.01) in axons of all sizes in normothermic animals. The mean number of neurofilaments also decreased statistically (P < 0.01) in large and medium subgroups of axons in the same experimental group at 2 hours. By 4 hours, the large subgroup of axons in normothermic animals still demonstrated a significant decline in the mean number of microtubules (P < 0.01) and an increase in the mean intermicrotubule spacing (P < 0.05), while the medium and small subgroups of axons displayed a significant increase in the mean number of neurofilaments (P < 0.05) and reduction in the mean interneurofilament spacing (P < 0.05). On the contrary, either the mean number of microtubules and the mean intermicrotubule spacing, or the mean number of neurofilaments and interneurofilament spacing in axons of all sizes in hypothermic stretch-injured animals was not significant different from the mean values of sham-operated animals.

CONCLUSIONSPosttraumatic moderate hypothermia induced immediately after axonal injury results in substantial protection of axonal cytoskeleton and ameliorates axonal damage.

Animals ; Axons ; pathology ; ultrastructure ; Culture Techniques ; Diffuse Axonal Injury ; pathology ; prevention & control ; therapy ; Disease Models, Animal ; Guinea Pigs ; Hypothermia, Induced ; methods ; Male ; Microscopy, Electron ; Optic Nerve ; pathology ; ultrastructure ; Optic Nerve Injuries ; prevention & control ; therapy ; Probability ; Random Allocation ; Reference Values

OBJECTIVE: To explore the changes of expression of heat-shock proteins (HSP) 70 mRNA in hippocampus of rats after diffuse axonal injury (DAI). METHODS: RT-PCR products of HSP70 mRNA were tested by agarose gel electrophoresis after RT-PCR amplification. The changes of HSP70 mRNA expression were observed in rat hippocampus after DAI. RESULTS: The expression of HSP70 mRNA in the hippocampus could be detected 4 h after DAI. It reached maximum at 24 h and declined after 48 h. CONCLUSION HSP70 mRNA in hippocampus of rats could be useful for diagnosis of DAI.
Animals ; Axons/pathology* ; Diffuse Axonal Injury/pathology* ; Disease Models, Animal ; Forensic Pathology ; HSP70 Heat-Shock Proteins/metabolism* ; Hippocampus/metabolism* ; Male ; RNA, Messenger/metabolism* ; Random Allocation ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors

OBJECTIVE: To explore an method for diffuse axonal injury (DAI) diagnosis and injury time estimation, the changes of beta-APP immunoreactivity and to observe the morphology of axonal in different parts of brain after experimental DAI injury. METHODS: The animal models of DAI was established according to the Marmarou's method. Immunohistochemistry and Gless staining were performed to observe the changes of beta-APP expression and the morphology of axon with the time elapsed after the DAI injury. RESULTS: In the brain injury group, the morphologic changes of axon in brain stem were showed as twisted, broken and swellen at 0.5 h, and the myelin sheaths broken could be observed, the retraction ball was found at 12 h. Those morphology changes further progressed at 12h, reached to peack up to 1 d, then repaired at 3 d, and recovered at 10 d; Meanwhile the analysis of beta-APP immunoreactivity was also showed a time-dependent difference as fellows: beta-APP expression begin at 3h, increased its immunoreactivity at 12h, reached to maximize at 1 d, decreased after 3 d, returned to basal level at 10 d. CONCLUSIONS The results suggest that beta-APP immunohistochemistry combine with Gless staining be sensitive methods for DAI diagnosis, they could discover the time-dependent changes of the axonal morphology.The changes beta-APP are quite regular and could be used for timing DAI injury.
Amyloid beta-Protein Precursor/metabolism* ; Animals ; Axons/pathology* ; Brain Stem/pathology* ; Diffuse Axonal Injury/pathology* ; Disease Models, Animal ; Female ; Immunohistochemistry/methods* ; Male ; Rats ; Rats, Sprague-Dawley ; Staining and Labeling ; Time Factors