Mild repetitive head injury is a serious health problem with long-term negative consequences. Changes in brain neurobiology were assessed with MRI in a model of head injury designed to reflect the human experience. Rats were maintained on a reverse light-dark cycle and head impacted daily at 24 h intervals over three days while fully awake under red light illumination. There was no neuroradiological evidence of brain damage. Rats were imaged for changes in blood brain barrier permeability, edema and gray matter microarchitecture, and resting state functional connectivity. Data were registered to a 3D MRI rat atlas with 173 segmented brain areas providing site-specific information on each imaging modality. Changes in BBB permeability were minimal and localized to the hippocampus and cerebellum. There was evidence of cytotoxic edema in the basal ganglia, thalamus, and cerebellum. There was a global decrease in connectivity and an increase in gliosis in the thalamus, cerebellum, and hippocampus. This study shows a sequelae of neuropathology caused by mild repetitive head injury that is commonly observed in clinical practice using MRI in patients. As such, it may serve as a model for testing the efficacy of new therapeutics using any or all of the measures as biomarkers to assess drug efficacy.
Animals ; Magnetic Resonance Imaging/methods* ; Disease Models, Animal ; Brain/physiopathology* ; Male ; Rats ; Rats, Sprague-Dawley ; Blood-Brain Barrier/diagnostic imaging* ; Multimodal Imaging ; Wakefulness/physiology* ; Craniocerebral Trauma/physiopathology*

Traumatic brain injury (TBI) is associated with poor neurological outcome, including necrosis and brain edema. In this study, we investigated whether agmatine treatment reduces edema and apoptotic cell death after TBI. TBI was produced by cold injury to the cerebral primary motor cortex of rats. Agmatine was administered 30 min after injury and once daily until the end of the experiment. Animals were sacrificed for analysis at 1, 2, or 7 days after the injury. Various neurological analyses were performed to investigate disruption of the blood-brain barrier (BBB) and neurological dysfunction after TBI. To examine the extent of brain edema after TBI, the expression of aquaporins (AQPs), phosphorylation of mitogen-activated protein kinases (MAPKs), and nuclear translocation of nuclear factor-kappaB (NF-kappaB) were investigated. Our findings demonstrated that agmatine treatment significantly reduces brain edema after TBI by suppressing the expression of AQP1, 4, and 9. In addition, agmatine treatment significantly reduced apoptotic cell death by suppressing the phosphorylation of MAPKs and by increasing the nuclear translocation of NF-kappaB after TBI. These results suggest that agmatine treatment may have therapeutic potential for brain edema and neural cell death in various central nervous system diseases.
Active Transport, Cell Nucleus/drug effects ; Agmatine/*therapeutic use ; Animals ; Apoptosis/*drug effects ; Aquaporins/metabolism ; Blood-Brain Barrier/physiopathology ; Brain Edema/*drug therapy ; Brain Injuries/*pathology ; Male ; Mitogen-Activated Protein Kinases/metabolism ; Motor Cortex/*pathology ; NF-kappa B/metabolism ; Phosphorylation/drug effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To observe the time-course expression of zonula occludens-1 (ZO-1) in cerebral cortex after traumatic brain injury (TBI). METHODS: The TBI model of mouse was established. The mice were divided in 1 h, 3 h, 6 h, 12 h, 24 h, 3 d, 7 d after TBI, sham and control groups. The permeability of the blood brain barrier was evaluated by measuring the extravasation of Evans blue (EB) dye. The expression of ZO-1 in cerebral cortex in the injured area was detected by Western blotting and immunohistochemistry. RESULTS: The extravasation of EB dye of injured cortex gradually increased from 1 h, peaked at 1-3 d and approximately decreased to normal at 7 d after TBI. Western blotting revealed that the expression of ZO-1 gradually decreased after 1 h, was at the lowest at 1-3 d, and then significantly increased after 7 d but was still lower than that of normal and sham groups. The result of immunohistochemistry showed that ZO-1 had strong expression in vessel of normal cortex, gradually decreased after TBI, and almost disappeared at 3 d after TBI and gradually recovered to normal level later. CONCLUSION The expression of ZO-1 in the injured cortex after TBI initially decreases and then increases. The negative correlation between ZO-1 expression and EB extravasation after TBI could be used as a new indicator for wound age estimation.
Animals ; Blood-Brain Barrier ; Blotting, Western ; Brain Injuries/physiopathology* ; Cerebral Cortex/metabolism* ; Immunohistochemistry ; Mice ; Permeability ; Tight Junctions/metabolism* ; Zonula Occludens-1 Protein/metabolism*

OBJECTIVETo establish a method for detecting circulating brain microvascular endothelial cells (cBMECs), a novel biomarker of blood-brain barrier (BBB) injury.

METHODSBlood samples were collected from 33 patients with AIDS encephalitis and 13 healthy subjects for detection of cBMECs, cECs and EPCs using magnetic affinity isolation and immune identification technology.

RESULTSThe numbers of cBMECs, cECs and EPCs were significantly higher in the AIDS patients than in the control subjects (t=4.298, P<0.01; t=4.886, P<0.01; t=4.889, P<0.01). An significant association was also noted between HIV load and cBMEC number (r=0.928, P<0.01).

CONCLUSIONWe have successfully established a method for detecting peripheral blood cBMECs, which can be of important value in non-invasive assessment of BBB injury.

Acquired Immunodeficiency Syndrome ; physiopathology ; Biomarkers ; Blood-Brain Barrier ; pathology ; Cell Separation ; methods ; Cells, Cultured ; Endothelial Progenitor Cells ; cytology ; Humans

Integrins such as αvβ3, α5β1 play a key role in angiogenesis regulation, invasion and metastasis, inflammation, wound healing, etc. The up-regulation of integrin αvβ3 after cerebral ischemic stroke can promote angiogenesis, which in turn improves functional recovery. In addition, the integrin αvβ3 inhibitor can block the blood-brain barrier (BBB) leakage induced by vascular endothelial growth factor (VEGF) and also can reduce inflammatory reaction, decrease the deposition of fibrinogen. Other studies showed that integrin αvβ3 is not essential in revascularization. Therefore, the effect of integrin αvβ3 in the whole process of brain function recovery merits further study.
Animals ; Blood Vessels ; drug effects ; physiopathology ; Blood-Brain Barrier ; drug effects ; metabolism ; physiopathology ; Humans ; Integrin alphaVbeta3 ; antagonists & inhibitors ; metabolism ; Integrins ; metabolism ; Models, Biological ; Peptides, Cyclic ; pharmacology ; Stroke ; metabolism ; physiopathology ; Vascular Endothelial Growth Factor A ; metabolism

BACKGROUNDEndothelin-1 (ET-1) has deleterious effects on water homeostasis, cerebral edema, and blood-brain barrier (BBB) integrity. Highly expressed ET-1 was observed after intracerebral hemorrhage (ICH); however, ET-1 changes and their relationship with BBB disruption within 24 hours of ICH have not been thoroughly investigated. The aim of the present study was to observe the changes in perihematomal ET-1 levels in various phases of ICH and their correlation with the BBB integrity in a rabbit model of ICH.

METHODSTwenty-five rabbits (3.2-4.3 kg body weight) were randomly divided into a normal control group (five rabbits) and a model group (20 rabbits). Animals in the model group were equally divided into four subgroups (five rabbits each to be sacrificed at 6, 12, 18, and 24 hours following ICH establishment). An ICH model was prepared in the model group by infusing autologous arterial blood into the rabbit brain. ET-1 expression in perihematomal brain tissues was determined using immunohistochemistry and color image analysis, and the permeability of the BBB was assayed using the Evan's Blue (EB) method. A repeated measures analysis of variance was used to make comparisons of the ET-1 and EB content across the entire time series.

RESULTSThe number of perihematomal endothelial cells with ET-1 positive expressions following 6, 12, 18, and 24 hours ICH model establishment was 9.32, 13.05, 15.90, and 20.44, respectively, but as low as 6.67 in the control group. The average transmittance of ET-1-positive cell bodies at 6, 12, 18, and 24 hours after ICH was 99.10, 97.40, 85.70, and 80.80, respectively, but 100.12 in the control group. These data reveal that the expression of ET-1 was significantly increased at 6, 12, 18, and 24 hours after ICH compared with the control group, and a marked decrease in the average transmittance of ET-1-positive cell bodies was noted (P < 0.05). Similarly, the perihematomal EB content at 6, 12, 18, and 24 hours after ICH was 29.39 ± 1.16, 32.20 ± 0.73, 33.63 ± 1.08, and 35.26 ± 1.12, respectively, in the model group and 28.06 ± 0.80 in the control group. The results indicate that a significant increase in the EB content in the model group was observed compared with that of the control group (P < 0.05). Moreover, a positive correlation between the number of ET-1-positive endothelial cells and BBB permeability was observed (r = 0.883, P < 0.05).

CONCLUSIONSHigh levels of ET-1 are closely associated with BBB disruption. ET-1 may play an important role in the pathogenesis of secondary brain injury after ICH.

Animals ; Blood-Brain Barrier ; metabolism ; physiopathology ; Brain ; metabolism ; physiopathology ; Cerebral Hemorrhage ; metabolism ; physiopathology ; Disease Models, Animal ; Endothelin-1 ; metabolism ; Immunohistochemistry ; Male ; Rabbits

OBJECTIVETo observe the effect and mechanism of Huatuo Zaizao extractum (HTZZ) on focal ischemia/reperfusion (I/R) blood-brain barrier injury induced by middle cerebral artery occlusion.

METHODSixty healthy male adult Sprague-Dawley rats was randomly divided into the sham operation group, the MCAO model group, the Tanakan (20 mg x kg(-1)) group, and high, middle and low-dose HTZZ groups (5, 2.5, 1.25 g x kg(-1)), with 10 in each group and single-dose duodenal administration. Middle cerebral artery occlusion was adopted to establish the rat focal I/R model. After ischemia for 90 min and reperfusion for 24 h, the pathological injury at the ischemia side was observed by HE staining. The blood-brain barrier structure was observed under transmission electron microscope. Expressions of G protein-coupled receptor kinases 2 (GRK2), matrix metalloproteinases 2 (MMP-2) and MMP-9 were detected by western blotting technique.

RESULTAfter 90 min MCAO/24 h reperfusion, penumbra cerebral cortical micro-vessels showed edema, mitochondrial injury, vacuolation, membrane injury and reduction. Along with the changes, sub-cells of G protein-coupled receptor kinase 2 (GRK2) in cortical penumbra brain tissues transferred from cytoplasm to membrane, with increase in expressions of MMP-2 and MMP-9. HTZZ could effectively recover cerebral micro-vascular endothelial edemaand blood-brain barrier ultrastructure injury induced by I/R, reduce expression of functional (membrane coupling) GRK2, and inhibit expressions of MMP-2 and MMP-9.

CONCLUSIONCell membrane coupling GRK2 may be the effective target of Huatuo Zaizao extractum.

Animals ; Behavior, Animal ; drug effects ; physiology ; Blood-Brain Barrier ; drug effects ; injuries ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; pharmacology ; G-Protein-Coupled Receptor Kinase 2 ; metabolism ; Gene Expression Regulation, Enzymologic ; drug effects ; Infarction, Middle Cerebral Artery ; complications ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Microvessels ; drug effects ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; complications ; metabolism ; physiopathology

Blood cells are transported into the brain and are thought to participate in neurodegenerative processes following hypoxic ischemic injury. We examined the possibility that transient forebrain ischemia (TFI) causes the blood-brain barrier (BBB) to become permeable to blood cells, possibly via dysfunction and degeneration of endothelial cells in rats. Extravasation of Evans blue and immunoglobulin G (IgG) was observed in the hippocampal CA1-2 areas within 8 h after TFI, and peaked at 48 h. This extravasation was accompanied by loss of tight junction proteins, occludin, and zonula occludens-1, and degeneration of endothelial cells in the CA1-2 areas. Iron overload and mitochondrial free radical production were evident in the microvessel endothelium of the hippocampus before endothelial cell damage occurred. Administration of deferoxamine (DFO), an iron chelator, or Neu2000, an antioxidant, blocked free radical production and endothelial cell degeneration. Our findings suggest that iron overload and iron-mediated free radical production cause loss of tight junction proteins and degeneration of endothelial cells, opening of the BBB after TFI.
Animals ; Blood-Brain Barrier/*metabolism ; Capillary Permeability ; Endothelial Cells/*metabolism ; Evans Blue/metabolism ; Free Radicals/metabolism ; Hippocampus/*metabolism/pathology ; Iron/*metabolism ; Ischemic Attack, Transient/pathology/*physiopathology ; Male ; Membrane Proteins/metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the changes of vascular endothelial growth factor(VEGF), aquaporin (AQP) gene and protein expression during hypoxic encephaledema so as to provide the basis for elucidating the brain injury caused by acute hypoxic exposure and pathogenesis of the encephaledema.

METHODSWistar rats were randomly divided into 4 groups, i.e. control group, hypoxia 4 000 m group, hypoxia 6 000 m group and hypoxia 8 000 m group. Rats in hypoxic groups were exposed to hypoxia at simulated altitude of 4 000 m, 6 000 m and 8 000 m above sea level for 8 hours respectively in order to establish hypoxic encephaledema model. The water content in brain was determined by dry-weight method. The changes in morphology of brains were observed under optical microscope. The changes in expression of VEGF, AQP1 and AQP4 genes and protein were determined by RT-PCR and immunohistochemistry.

RESULTS(1) The results determined by dry-weight method indicated that water content of rats brain increased markedly after rats were exposed to a simulated altitude at 6 000 m, 8 000 m. (2) The results determined by microscopy indicated that during the rats exposed to hypoxia, nerve cells, vascular endothelial cells and astrocyte foot processes swelled lightly, transudate occurred in tissues at 4 000 m. The swelling of vascular endothelial cell (VEC) and astrocyte foot processes aggravated, interspace between vessels and tissues enlarged, and transudate in tissue increased at 6 000 m. The swelling of VEC and astrocyte foot processes went from bad to worse, interspace between vessels and tissues enlarged further, and transudate in tissue increased evidently at 8 000 m. (3) During hypoxic encephaledema, the expression of VEGF, AQP1 and AQP4 mRNA increased, AQP1 was abnormally expressed on the surface of VEC, and the expressive level of VEGF and AQP1 on VEC and AQP4 on astrocyte foot processes increased.

CONCLUSIONThe changes in expression and distribution of VEGF, AQP1 and AQP4 during encephaledema caused by hypoxic exposure may induce blood-brain barrier injury, and may be one of the pathogenesis of hypoxic encephaledema.

Animals ; Aquaporin 1 ; genetics ; metabolism ; Aquaporin 4 ; genetics ; metabolism ; Blood-Brain Barrier ; pathology ; Brain ; metabolism ; Brain Edema ; etiology ; metabolism ; physiopathology ; Hypoxia ; complications ; metabolism ; Male ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

Animals ; Aquaporin 4 ; metabolism ; Blood-Brain Barrier ; physiopathology ; Brain Edema ; physiopathology ; Brain Ischemia ; metabolism ; physiopathology ; Capillary Permeability ; physiology ; Male ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism ; physiopathology