Protective effects of dl-3n-butylphthalide against diffuse brain injury

DI-3n-butyiphthalide can effectively treat cerebral ischemia; however, the mechanisms underlying the effects of dl-3n-butylphthalide on microcirculation disorders following diffuse brain injury remain unclear. In this study, models of diffuse brain injury were established in Sprague-Dawley rats with the vertical impact method. DI-3n-butylphthalide at 80 and 160 mg/kg was given via intraperitoneal injection immediately after diffuse brain injury. Ultrastructural changes in the cerebral cortex were observed using electron microscopy. Cerebral blood flow was measured by laser Doppler flowmetry, vascular density was marked by tannic acid-ferric chloride staining, vascular permeability was es- timated by the Evans blue method, brain water content was measured using the dry-wet method, and rat behavior was measured by motor function and sensory function tests. At 6, 24, 48, and 72 hours after administration of dl-3n-butylphthalide, reduced cerebral ultrastructure damage, in- creased vascular density and cerebral blood flow, and improved motor and sensory functions were observed. Our findings demonstrate that dl-3n-butylphthalide may have protective effects against diffuse brain injury by ameliorating microcirculation disorder and reducing blood-brain barrier dam- age and cerebral edema.

Aquaporin-4 and ischemic brain edema

OBJECTIVE： To investigate the relationship of aquaporin 4 （AQP4） and brain edema. DATA SOURCES： Using the terms of ＂aquaporin-4, brain edema＂, we searched PubMed database to identify studies published from January 1997 to April 2006 in the English languages. Meanwhile, we also searched China National Knowledge Infrastructure （CNKI） for related studies. STUDY SELECTION： The collected data were selected firstly. Studies on AQP4 and brain edema were chosen and their full-texts were searched for, and those with repetitive or review studies were excluded. DATA EXTRACTION： Totally 146 related studies were collected, 42 of them were involved and the other 104 studies were used for reading reference data. DATA SYNTHESIS： AQP4 is a selective water permeable integral membrane protein. It is mainly expressed in astrocytes and ependymocyte, and is the important structural basis for water regulation and transportation between glial cells and cerebrospinal fluid or vessels. Phosphorylation is involved in the regulation of AQP4. AQP4 participates in the formation of brain edema caused by various factors. Studies on the structure and pathological changes of AQP4 are still in the initial stage, and the role and mechanism of AQP4 in the formation of brain edema is very unclear. CONCLUSION： AQP4 plays a critical regulating role in the formation of ischemic brain edema, but whether it is regulated by drugs lacks reliable evidence.

The occurrence of diffuse axonal injury in the brain:associated with the accumulation and clearance of myelin debris

The accumulation of myelin debris may be a major contributor to the inlfammatory response after diffuse axonal injury. In this study, we examined the accumulation and clearance of myelin debris in a rat model of diffuse axonal injury. Oil Red O staining was performed on sections from the cerebral cortex, hippocampus and brain stem to identify the myelin debris. Seven days after diffuse axonal injury, many Oil Red O-stained particles were observed in the cerebral cortex, hippocampus and brain stem. In the cerebral cortex and hippocampus, the amount of myelin debris peaked at 14 days after injury, and decreased signiifcantly at 28 days. In the brain stem, the amount of myelin debris peaked at 7 days after injury, and decreased signiifcantly at 14 and 28 days. In the cortex and hippocampus, some myelin debris could still be observed at 28 days after diffuse axonal injury. Our ifndings suggest that myelin debris may persist in the rat central ner-vous system after diffuse axonal injury, which would hinder recovery.

Enhanced Expression of Aquaporin-9 in Rat Brain Edema Induced by Bacterial Lipopolysaccharides

To investigate the role of AQP9 in brain edema, the expression of AQP9 in an infectious rat brain edema model induced by the injection of lipopolysaccharide （LPS） was examined. Immuno- histochemistry and reverse transcription-polymerase chain reaction （RT-PCR） analysis demonstrated that the expressions of AQP9 mRNA and protein at all observed intervals were significantly increased in LPS-treated animals in comparison with the control animals. Time-course analysis showed that the first signs of blood-brain barrier disruption and the increase of brain water content in LPS-treated animals were evident 6 h after LPS injection, with maximum value appearing at 12 h, which coincided with the expression profiles of AQP9 mRNA and protein in LPS-treated animals. The further correlation analysis revealed strong positive correlations among the brain water content, the disruption of the blood-brain barrier and the enhanced expressions of AQP9 mRNA and protein in LPS-treated animals. These results suggested that the regulation of AQP9 expression may play im- portant roles in water movement and in brain metabolic homeostasis associated with the pathophysi- ology of brain edema induced by LPS injection.

Occludin and connexin 43 expression contribute to the pathogenesis of traumatic brain edema

The experimental model of traumatic brain injury was established in Sprague-Dawley rats according to Feeney＇s free falling method. The brains were harvested at 2, 6 and 24 hours, and at 3 and 5 days after injury. Changes in brain water content were determined using the wet and dry weights. Our results showed that water content of tissue significantly increased after traumatic brain injury, and reached minimum at 24 hours. Hematoxylin-eosin staining revealed pathological impairment of brain tissue at each time point after injury, particularly at 3 days, with nerve cell edema, degenera- tion, and necrosis observed, and the apoptotic rate significantly increased. Immunohistochemistry and western blot analysis revealed that the expression of occludin at the injured site gradually de- creased as injury time advanced and reached a minimum at 3 days after injury; the expression of connexin 43 gradually increased as injury time advanced and reached a peak at 24 hours after in-jury. The experimental findings indicate that changes in occludin and connexin 43 expression were consistent with the development of brain edema, and may reflect the pathogenesis of brain injury.

Apolipoprotein E mimetic peptide protects against diffuse brain injury

Apolipoprotein E plays a crucial role in inhibiting chronic neurodegenerative processes. Howev-er, its impact on neurological function following diffuse brain injury is still unclear. This study was designed to evaluate the therapeutic effects and mechanisms of action of apolipoprotein E mimetic peptide on diffuse brain injury. Apolipoprotein E mimetic peptide was administered into the caudal vein of rats with diffuse brain injury before and after injury. We found that apo-lipoprotein E mimetic peptide signiifcantly decreased the number of apoptotic neurons, reduced extracellular signal-regulated kinase1/2 phosphorylation, down-regulated Bax and cytochrome c expression, decreased malondialdehyde content, and increased superoxide dismutase activity in a dose-dependent manner. These experimental ifndings demonstrate that apolipoprotein E mimetic peptide improves learning and memory function and protects against diffuse brain injury-induced apoptosis by inhibiting the extracellular signal-regulated kinase1/2-Bax mito-chondrial apoptotic pathway.

Brain-derived neurotrophic factor gene transfection promotes neuronal repair and neurite regeneration after diffuse axonal injury

This study sought to assess the potential of brain-derived neurotrophic factor （BDNF） to promote neuronal repair and regeneration in rats with diffuse axonal injury, and to examine the accompanying neurobiological changes. BDNF gene transfection reduced the severity of the pathological changes associated with diffuse axonal injury in cortical neurons of the frontal lobe and increased neurofilament protein expression. These findings demonstrate that BDNF can effectively promote neuronal repair and neurite regeneration after diffuse axonal injury.

The quantitative analysis of S100 in the brain tissue and serum following diffusebrain injury in rats

Objective To investigate the dynamics of the level of S100 in cerebrum,brainstem,and serum following the diffuse brain injury in rats and provide the experimental evidences for estimating injury time.Methods ELISA was used to determine whether S100 protein is changed after diffuse brain injury in rats.Forty rats were sacrificed at 0.5 hour, 2 hours,4 hours,12 hours,24 hours,3d and 7d after diffuse brain injury and normal rats as control.Results The level of S100 in cerebrum,brainstem,and serum increased,followed by a decrease,and then further increased.The level of S100 could be detected to increase at 30 minutes and reached the peak at 4 hours after DBI.The level decreased gradually to the normal at 1d and till 3d formed the second peak.The level returned to the normal at 7d following injury again.In the postmortem injury groups,there were no significant changes compared to the control group.Conclusion The present study showed that the time-dependent expression of S100 is obvious following diffuse brain injury in rats and suggested that S100 will be a suitable marker for diffuse brain injury age determination.

Altered expression of metabotropic glutamate receptor 1 alpha after acute diffuse brain injury Effect of the competitive antagonist 1-aminoindan-1, 5-dicarboxylic acid

The diffuse brain injury model was conducted in Sprague-Dawley rats, according to Marmarou＇s free-fall attack. The water content in brain tissue, expression of metabotropic glutamate receptor la mRNA and protein were significantly increased after injury, reached a peak at 24 hours, and then gradually decreased. After treatment with the competitive antagonist of metabotropic glutamate receptor la, （RS）-l-aminoindan-1,5-dicarboxylic acid, the water content of brain tissues decreased between 12-72 hours after injury, and neurological behaviors improved at 2 weeks. These experimental findings suggest that the 1-aminoindan-1, 5-dicarboxylic acid may result in marked neuroprotection against diffuse brain injury.

THERAPEUTIC EFFECT OF CYPROHEPTADINE ON TRAUMATIC BRAIN EDEMA IN RATS

Acute traumatic brain edema models were established in SD rats by dropping weight methods.We observed the therapeutic effect of Cyproheptadine(Cyp)on traumatic brain edema.It was shown that Cyp could obviously reduce the brain water content,decrease the releae or LDH,reduce the seventy of the pathological changes at the injury areas,increase the SOD activity and decrease the production of MDA in SD rats.The results suggest that Cyp has obvious.therapeutic effect on traumatic brain edema.The mechanism may be that it can increase the activity or clearance enzyme of free radical,inhibit lipid peroxldation and reduce intracellular Ca2+-overload.

Research on the relationship between reduced scattering coefficient and intracranial pressure in brain edema model

Intracranial hypertension is a serious threat to the health of neurosurgical patients.At present,there is a lack of a safe and e®ective technology to monitor intracranial pressure(ICP)accurately and nondestructively.In this paper,based on near infrared technology,the continuous nonde-structive monitoring of ICP change caused by brain edema was studied.The rat brain edema models were constructed by lipopolysaccharide.The ICP monitor and the self-made near infrared tissue parameter measuring instrument were used to monitor the invasive intracranial pressure and the reduced scattering coe±cient of brain tissue during the brain edema development.The results showed that there was a negative correlation between the reduced scattering coe±cient(690nm and 834nm)and ICP,and then the mathematical model was established.The experimental results promoted the development of nondestructive ICP monitoring based on near infrared technology.

Study of the AQP4 expression in traumatic brain edema and multimodal MRI imaging

The aquaporin-4(AQP4)is a highly selective membrane protein.It is important for the body to maintain the water balance between internal and external environment of cells,the studies have found that the abnormal expression of AQP4 is related to the occurrence of many diseases.The cerebral edema is the most common and serious complication of brain trauma,and its pathogenesis is closely related to AQP4.The development of multimodal magnetic resonance imaging(M-MRI)could been provided imaging basis for accurate diagnosis of traumatic brain edema.In recent years,the correlation between AQP4 and M-MRI has become a hotspot of research.This paper reviews the research progress on the correlation between AQP4 expression in traumatic cerebral edema and M-MRI.

ERBB1 Is Amplified and Overexpressed in High-grade Diffusely Infiltrative Pediatric Brain Stem Glioma

PURPOSE:This study was conducted to investigate the incidence of ERBB1 amplification and overexpression in samples of diffusely infiltrative (WHO grades Ⅱ-Ⅳ) pediatric brain stem glioma (BSG) and determine the relationship of these abnormalities to expression and mutation of TP53 and tumor grade. Experimental Design: After central pathology review, the incidence of ERBB1 amplification and overexpression was determined in 28 samples (18 surgical biopsy and 10 postmortem specimens) of BSG using quantitative PCR and immunohistochemistry,

Suppressive effect of dexamethasone on the neutrophil expression of CD18 in rats with radiation induced brain edema

BACKGROUND： Stereo-tactic radiation therapy （SRT） is widely used to treat intracranial diseases, but some patients suffered from radiation induced brain edema after SRT. Once radiation induced brain edema occurs, the treatment is quite difficult, and it always leads to a poor outcome. Dexamethasone has certain therapeutic effect on traumatic brain edema, but the biological mechanism is still unclear. OBJECTIVE ： To observe the effect of dexamethasone on the neutrophil expression of CD18.DESIGN ： A randomized control observation.SETTING： Changhai Hospital of the Second Military Medical University of Chinese PLA. MATERIALS ： The experiment was carried out in Changhai Hospital of the Second Military Medical University of Chinese PLA from January 1999 to December 1999. Twenty SD rats （male and female each in half） weighing （250±50） g were used. METHODS： Twenty SD rats were divided into four groups at random. ① Blank control group （n=5）： The rats were not treated without dexamethasone or irradiation;② Irradiation group （n=5）： The rats were given irradiation but no dexamethasone treatment; ③ Irradiation＋1 mg/kg dexamethasone group （n=5）; The rats were treated with irradiation and dexamethasone of 1 mg/kg; ④Irradiation＋5 mg/kg dexamethasone group （n=5）： The rats were treated with irradiation and dexamethasone of 5 mg/kg. The heads of the rats were irradiated with 10 MeV X-ray （30 Gy）, and brain tissue was removed after 2 weeks to observe the pathological changes. Blood samples were taken from the carotid artery, gradient centrifugation was used, and neutrophile layer was obtained, the level of neutrophile expression of CD18 mRNA and quantity of membrane proteins in blood were detected with Northern blot and flow cytometry respectively. MAIN OUTCOME MEASURES： ① Blood cell count; ② Pathological results; ③ level of neutrophile expression of CD18 mRNA and quantity of membrane proteins. RESULTS ： All the 20 SD rats were involved in the analysis of results without deletion. At 2 weeks after irradiation, obvious cell injury could be observed under light microscope. The level of neutrophile expression of CD18 mRNA and quantity of membrane proteins in blood were obviously increased, but the severity of cell injury was relieved in the irradiation＋1 and 5 mg/kg dexamethasone groups, and the CD18 expression was markedly suppressed （P 〈 0.05）, and the suppression was more obvious in the irradiation＋5 mg/kg dexamethasone group than in the irradiation＋1 mg/kg dexamethasone group （P 〈 0.01 ）. CONCLUSION： Dexamethasone can reduce the radiation induced brain edema by inhibiting the expression of CD18.

THE RELATIONSHIP BETWEEN PERITUMORAL BRAIN EDEMA AND VASCULAR ENDOTHELIAL GROWTH FACTOR EXPRESSION IN PATIENTS WITH MENINGIOMA

Objective: To determine whether VEGF plays a role in the development of peritumoral brain edema. Methods 50 meningioma patients and their VEGF expression were studied. We took a monoclonal antibody from mouse to VEGF to stain the tumor cells, the vascular endothelial cells and the interstitial cells. The severity of brain edema was evaluated according to CT or MR scans by the following equation: edema index= V tumor +edema /Vtumor. The relationship between VEGF expression and edema index was analyzed statistically. Results VEGF was expressed in meningioma tumor cells, which is usually concentrated at the peripheral sites of the tumor. There was a positive linear correlation between the expression and the brain edema index. Conclusion VEGF may play a role in the development of peritumoral brain edema in meningioma patient.

Brain edema and intracranial hypertension in fulminant hepatic failure:Pathophysiology and management

Intracranial hypertension is a major cause of morbidity and mortality of patients suffering from fulminant hepatic failure. The etiology of this intracranial hypertension is not fully determined, and is probably multifactorial, combining a cytotoxic brain edema due to the astrocytic accumulation of glutamine, and an increase in cerebral blood volume and cerebral blood flow, in part due to inflammation, to glutamine and to toxic products of the diseased liver. Validated methods to control intracranial hypertension in fulminant hepatic failure patients mainly include mannitol, hypertonic saline, indomethacin, thiopental, and hyperventilation. However all these measures are often not sufficient in absence of liver transplantation, the only curative treatment of intracranial hypertension in fulminant hepatic failure to date. Induced moderate hypothermia seems very promising in this setting, but has to be validated by a controlled, randomized study. Artificial liver support systems have been under investigation for many decades. The bioartificial liver, based on both detoxification and swine liver cells, has shown some efficacy on reduction of intracranial pressure but did not show survival benefit in a controlled, randomized study. The Molecular Adsorbents Recirculating System has shown some efficacy in decreasing intracranial pressure in an animal model of liver failure, but has still to be evaluated in a phase Ⅲ trial.

Rifaximin,but not growth factor 1,reduces brain edema in cirrhotic rats

AIM:To compare rifaximin and insulin-like growth factor(IGF)-1 treatment of hyperammonemia and brain edema in cirrhotic rats with portal occlusion.METHODS:Rats with CCl4-induced cirrhosis with ascites plus portal vein occlusion and controls were randomized into six groups:Cirrhosis;Cirrhosis + IGF-1;Cirrhosis + rifaximin;Controls;Controls + IGF-1;and Controls + rifaximin.An oral glutamine-challenge test was performed,and plasma and cerebral ammonia,glucose,bilirubin,transaminases,endotoxemia,brain water content and ileocecal cultures were measured and liver histology was assessed.RESULTS:Rifaximin treatment significantly reduced bacterial overgrowth and endotoxemia compared with cirrhosis groups,and improved some liver function parameters(bilirubin,alanine aminotransferase and aspartate aminotransferase).These effects were associated with a significant reduction in cerebral water content.Blood and cerebral ammonia levels,and area-underthe-curve values for oral glutamine-challenge tests were similar in rifaximin-treated cirrhotic rats and control group animals.By contrast,IGF-1 administration failed to improve most alterations observed in cirrhosis.CONCLUSION:By reducing gut bacterial overgrowth,only rifaximin was capable of normalizing plasma and brain ammonia and thereby abolishing low-grade brain edema,alterations associated with hepatic encephalopathy.

Hyperammonemia,brain edema and blood-brain barrier alterations in prehepatic portal hypertensive rats and paracetamol intoxication

AIM: To study the blood-brain barrier integrity, brain edema,animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication.METHODS: Adults male Wistar rats were divided into four groups. Group I: sham operation; II: Prehepatic portal hypertension, produced by partial portal vein ligation; III:Acetaminophen intoxication and IV: Prehepatic portal hypertension plus acetaminophen. Acetaminophen was administered to produce acute hepatic injury. Portal pressure, liver serum enzymes and ammonia plasma levels were determined. Brain cortex water content was registered and trypan blue was utilized to study blood brain barrier integrity. Reflexes and behavioral tests were recorded.RESULTS: Portal hypertension was significantly elevated in groups II and IV. Liver enzymes and ammonia plasma levels were increased in groups II, III and IV. Prehepatic portal hypertension (group II), acetaminophen intoxication (group III) and both (group IV) had changes in the blood brain-barrier integrity (trypan blue) and hyperammonemia. Cortical edema was present in rats with acute hepatic injury in groups III and IV. Behavioral test (rota rod) was altered in group IV.CONCLUSION: These results suggest the possibility of another pathway for cortical edema production because blood brain barrier was altered (vasogenic) and hyperammonemia was registered (cytotoxic). Group IV, with behavioral altered test, can be considered as a model for study at an early stage of portal-systemic encephalopathy.

Study on glucocorticoid receptor of brain cytosol in rats with traumatic brain edema

The high-affinity glucocorticoid binding sites（HAGS）and the low-affinity glucocor-ticoid binding sites（LAGS）with steroid specificity were demonstrated in cerebral cytosol ofrats by using the radioligand binding assay.The equilibrium dissocation constant（Kd）of HAGSand LAGS were（2.78+0.71）×10-8mol/L and（2.12±1.06）×10-6mol/L respectively as esti-mated by Scatchard and Pseudoseatchard analysis.Glucocorticoid receptors（GR）in the trau-matized（left）hemisphere cytosol were decreased more significantly than those in both the con-trol（right）hemisphere cytosol at 6 h postinjury and normal brain tissue（P【0.05）,but Kd ofGR showed no significant changes.GR of liver cytosol at 6h postinjury were more markedly de-creased than normal hepatic cytosol,but Kd of GR underwent no significant changes.These da-ta demonstrate that high-dose glucocorticoid（GC）used in the treatment of traumatic brain ede-ma might maintain target-cell reactions by increasing the production of GC receptor complexesand is most likely to be mediated by LAGS.

Correlation between aquaporin-4 and brain edema in an animal model of astrocytic oxygen-glucose deprivation and reintroduction

BACKGROUND：Previous studies have demonstrated that aquaporin-4 （AQP4） plays a key role in the formation and resolution of brain edema.However,the molecular mechanisms and role of AQP4 in hypoxia-ischemia-induced brain edema remain poorly understood.OBJECTIVE：To establish a newborn animal model of astrocytic oxygen-glucose deprivation and reintroduction,to observe the correlation between AQP4 and cellular volume,and to investigate the role of AQP4 in the development of brain edema following oxygen deprivation and reintroduction.DESIGN,TIME AND SETTING：A comparative experiment was performed at the Experimental Center of West China Second University Hospital between October 2007 and April 2009.MATERIALS：Astrocytes were derived from the neocortex of Sprague Dawley rats aged 3 days.METHODS：Astrocytes were incubated in glucose/serum-free Dulbecco＇s modified Eagle＇s medium,followed by 1% oxygen for 6 hours.Finally,oxygen-glucose deprivation and reintroduction models were successfully established.MAIN OUTCOME MEASURES：Real-time polymerase chain reaction and Western blot analysis were used to measure expression of AQP4 mRNA and protein in cultured rat astrocytes following oxygen-glucose deprivation and reintroduction.Astrocytic cellular volume,as determined by [3H]-3-O-methyl-D-glucose,was used to represent the extent of astrocytic swelling.RESULTS：During oxygen-glucose deprivation,AQP4 mRNA and protein expression gradually decreased in astrocytes,whereas cellular volume increased in a time-dependent manner （P〈 0.01）.Following oxygen-glucose reintroduction,AQP4 mRNAand protein expression was upregulated,peaked at day 7,and then gradually decreased,but still higher than normal levels （P 〈 0.05）.However,cellular volume gradually decreased （P 〈 0.01）,and then reached normal levels at day 7.CONCLUSION：AQP4 expression highly correlated with cellular volume changes,suggesting that AQP4 played an important role in modulating brain water transport in an astrocytic oxygen-glucose deprivation and reintroduction model.