AIMTo study the expression of leptin receptor (OB-R) and neuronal damage following focal ischemia/reperfusion in rats.

METHODS20 adult male Wistar rats were divided into four groups randomly: sham-operated 24 h,72 h control group and ischemic/reperfusion 24 h, 72 h experiment group. Focal ischemia/reperfusion model was made with MCAO. Immunohistochemistry and immunoelectron microscope were used to observe the expression of OB-R of the cortex and neuronal damage.

RESULTSThe positive cells of OB-R were found in pyramidal cells of the parietal cortex, choroid plexus and blood vessel endothelium. Compared with sham-operated group, significant reduction of OB-R positive cells in the pyramidal cells was observed in the ischemia/reperfusion rats 24 hours after cerebral ischemia (P < 0.05). The positive cells of OB-R of sham-operated 72 h group reduced further (P < 0.01). Histochemistry and electron microscope showed neuronal damage in the core area of cerebral ischemia in the late period was more obvious than in the early period.

CONCLUSIONThe early and delayed ischemia/reperfusion neuronal damage were accompanied with reduction of OB-R expression. Thus, it is worth to study the effect of OB-R in cerebral ischemia.

Animals ; Brain Ischemia ; genetics ; metabolism ; pathology ; Cerebral Cortex ; metabolism ; pathology ; Disease Models, Animal ; Gene Expression ; Male ; Neurons ; pathology ; Rats ; Rats, Wistar ; Receptors, Leptin ; metabolism ; Reperfusion Injury ; metabolism ; pathology

OBJECTIVEHypoxic-ischemic encephalopathy (HIE) is an important cause of morbidity and mortality in the neonates. Early and accurate diagnosis is helpful not only for assessing prognosis but also for making treatment decisions. The aim of this study was to explore the value of early assessment of HIE by applying the diffusion-weighted imaging (DWI) in acute (within 72 hours), subacute or chronic stages of HIE in comparison to conventional magnetic resonance imaging (MRI) in clinical practice.

METHODSImages and clinical charts of fourteen term neonates with clinically diagnosed severe hypoxic-ischemic encephalopathy treated in the NICU from January 2006 to February 2007 were retrospectively reviewed. Inclusion criteria were: term infant (37 approximately 42 weeks) and high clinical suspicion of severe HIE (low Apgar scores, need for resuscitation, metabolic acidosis, acute encephalopathy (eg, hypotonia, coma, seizures). All examinations were performed on a 3.0-T MRI system (Philips Intera Acheva Magnetom Vision) with echo-planar imaging capability with the use of a standard protocol. The imaging protocol for all the patients contained diffuse weighted images (EPI-SE, TR = 2144 ms, TE = 56 ms), T1-weighted images (TR = 389 ms; TE = 15 ms; slice thickness = 4 mm) as well as T2-weighted images (TR = 3035 ms; TE = 100 ms; slice thickness = 4 mm). The studies were first performed within 72 hours of life in these 14 consecutive patients, including both standard T1, T2-weighted image and DWI; follow-up MR studies were performed for 4 patients at the ages of 7 days, for 4 at 14 days, for another 3 at ages of both 21 days and 8 months.

RESULTSFirst inspection (on an average of 48 hours after birth): routine T1, T2-weighted images showed normal images in all patients, while diffusion images showed symmetric high intensity signal in the lateral thalami and posterior limbs of internal capsules (PLIC). Following up: on day 7, routine MRI showed both symmetric T1 prolongation and T2 slightly shortening in lateral thalami, DWI showed abnormal high signal intensity in bilateral basal ganglion (mainly in the back site of lentiform nuclei, putamen) and the cortex around central sulcus, but the previous hyperintensity in lateral thalami and PLIC disappeared. On day 14, routine MRI showed symmetric T1 prolongation, T2 shortening in bilateral thalami, lentiform nuclei and cortex around central sulus. On day 21, routine MRI showed T1 prolongation, T2 shortening in bilateral thalami and basal ganglion while previously obvious PLIC disappeared, whereas DWI showed normal images. Eight months later, deeper cerebral sulus, dilation of ventricles and widening of extracerebral space were shown.

CONCLUSIONDiffusion-weighted imaging has proved more sensitive than conventional MR imaging sequences in detecting acute cerebral infarction in adult subjects. DWI is proposed as a method for early detection of hypoxic-ischemic brain injury. In this study, DWI showed the same focus (lateral thalami and PLIC) and similar extent of the injury in these severe HIE patients in the early stage after birth (in 72 hours). The sites which showed hyperintensive signals in DWI were consistent with the foci in subsequent follow-up by routine MRI. Thus, DWI is supposed to be a technique for early assessment of the extent of hypoxic-ischemic brain injury and the prognosis in clinic. Though DWI is superior to the other imaging modalities in detecting ischemia, diffusion restriction is not necessarily indicative of permanent damage. The abnormal image on DWI may not last long. However, in chronic stage, the follow-up conventional MRI may compensate the inadequacy of DWI.

Brain ; pathology ; Cerebral Cortex ; metabolism ; Cerebral Infarction ; metabolism ; Diffusion ; Humans ; Hypoxia-Ischemia, Brain ; metabolism ; Infant ; Infant, Newborn ; Magnetic Resonance Imaging ; methods ; Stroke ; metabolism

OBJECTIVES: To observe the changes of expression of α-synuclein （α-syn） and neuronal apoptosis in brain cortex of acute alcoholism rats and to explore the mechanism of the damage caused by ethanol to the neurons. METHODS: The model of acute alcoholism rat was established by 50% alcohol gavage. The α-syn and caspase-3 were detected by immunohistochemical staining and imaging analysis at 1 h, 3 h, 6 h and 12 h after acute alcoholism. The number of positive cell and mean of optical density were detected and the trend change was analyzed. The variance analysis and t-test were also performed. RESULTS: The number of α-syn positive cell and average optical density in brain cortex of acute alcoholism rat increased significantly and peaked at 6 hour with a following slight decrease at 12 h, but still higher than the groups at 1 h and 3 h. Within 12 hours after poisoning, the number of caspase-3 positive cell and average optical density in brain cortex of rats gradually increased. CONCLUSIONS The abnormal aggregation of α-syn caused by brain edema and hypoxia may participate the early stage of neuronal apoptosis in brain cortex after acute alcoholism.
Alcoholism/pathology* ; Animals ; Apoptosis ; Brain Edema/pathology* ; Caspase 3/metabolism* ; Cerebral Cortex/pathology* ; Ethanol ; Hypoxia/pathology* ; Neurons/pathology* ; Rats ; alpha-Synuclein/metabolism*

OBJECTIVETo observe the effects of electroacupuncture (EA) on the expressions of Nogo-A and the ultrastructure in the cerebral cortex at different time points after the cerebral ischemia-reperfusion in rats.

METHODSOne hundred and thirty male Sprague Dawley (SD) rats were randomly divided into the EA group (n = 30), the sham-EA group (n = 30), the model group (n = 30), the sham-operation group (n = 30), and the blank group (n = 10). The modified ZeaLonga method was used to prepare the left middle cerebral artery occlusion (MCAO) model in the first three groups. After the operation Baihui (DU20) and Dazhui (DU14) were daily needled in the EA group. One inch beside Baihui (DU20) and Dazhui (DU14) were daily needled in the sham-EA group. Rats in the model group were only treated with MCAO ischemia/reperfusion. Rats in the sham-operation group only received surgical wound. No treatment was given to rats in the blank group. The ultrastructures of ischemic cells and the intervention of the Nogo-A expressions were observed using the immunohistochemical staining and the transmission electron microscope 1, 7, and 28 days after EA.

RESULTS(1) In the EA group, the damage of ultrastructures of neurons, gliocytes, and blood brain barrier in the ischemic region was alleviated when compared with that of the sham-EA group and the model group. (2) On the 1st, 7th and 28th day after the cerebral ischemia-reperfusion, the expressions of Nogo-A in the ischemic cortex in the EA group was lower when compared with those in the sham-EA group and the model group at the corresponding time points, showing significant difference (P < 0.05). But there was no statistical difference between the sham-EA group and the model group at the same time point (P > 0.05).

CONCLUSIONThe mechanism of EA for protecting cerebral ischemia/reperfusion might be closely associated with alleviating the damage on the ultrastructures of brain cells, and down-regulating the expressions of Nogo-A.

Acupuncture Points ; Animals ; Brain Ischemia ; metabolism ; pathology ; therapy ; Cerebral Cortex ; metabolism ; ultrastructure ; Electroacupuncture ; Male ; Myelin Proteins ; metabolism ; Nogo Proteins ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism ; pathology ; therapy

OBJECTIVETo investigate the changes of endoplasmic reticulum stress (ERS)- and apoptosis-related factors in rat cerebral cortex following controlled hypotension.

METHODSTwenty-four healthy male SD rats were randomly divided into 4 equal groups, including a sham hypotension group (group A) and 3 hypotension groups with the mean arterial pressure maintained for 60 min at 70 mmHg (group B), 50 mmHg (group) and 30 mmHg (group D) with sodium nitroprusside and esmolol. All the rats received an equal volume of fluid infusion. Twelve hours after controlled hypotension, the rats were sacrificed to examine the protein expressions of Bax, Bcl-2, glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP) and caspase-12 in the cortex with Western blotting. GRP78 mRNA expression was measured by RT-PCR, and the cell apoptosis was evaluated by TUNEL staining.

RESULTSCompared with those in group A, GRP78 mRNA and protein expressions of GRP78, CHOP, caspase-12 related with ERS increased significantly in groups C and D (P<0.05), especially in group D (P<0.05), but not in group B (P>0.05). Apoptotic cells and Bax expression increased and Bcl-2 expression decreased significantly in groups C and D (P<0.05), but not in group B (P>0.05); such changes were more prominent in group D than in group C (P<0.05).

CONCLUSIONMild controlled hypotension (70 mmHg) does not induce neuronal injury in rat cerebral cortex, but severe hypertension (lower than 50 mmHg) can cause neuronal ERS and apoptosis.

Animals ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Cerebral Cortex ; pathology ; Endoplasmic Reticulum Stress ; Hypotension, Controlled ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To observe the alteration of nestin intervals in the experimental traumatic brain injury and investigate its relation to the injury intervals. METHODS: The rat brain contusion was conducted by falling impact injury. After various survival interval (0.5, 6, 12 h and 1, 3, 7, 14, 28 d), immunohistochemical SP method was used for observing the expression of nestin in the cortex, hippocampal dentate gyrus and the corpus callosum on injury side. RESULTS: Expression of nestin positive cells increased at 0.5 h and reached the maximum level in 7 d after brain contusion, then the expression decreased gradually. The intensity of nestin staining in the the cortex and the hippocampal dentate gyrus decreased to normal on 28 d. As to the corpus callosum of injury side it remained weak on 28 d. CONCLUSION The changes of nestin immunohistochemical staining can be used as an index for forensic estimation of early injury time.
Animals ; Brain/metabolism* ; Brain Injuries/pathology* ; Cerebral Cortex/metabolism* ; Immunohistochemistry ; Intermediate Filament Proteins/metabolism* ; Male ; Nerve Tissue Proteins/metabolism* ; Nestin ; Rats ; Rats, Sprague-Dawley ; Staining and Labeling ; Time Factors

OBJECTIVETo observe the change of nitric oxide (NO) and expression of nuclear factor-kappa B (NF-kappaB) in the cortex of cerebral infarction rat induced by photochemical reaction, and study the effect of extract from Cornus officinalis (whose main ingredient is iridoid glycoside) in the course of disease.

METHODAfter rats were fed with experimental drugs for 7 days, the model of cerebral infarction was induced. Spectrophotography and immunohistochemistry were used to detect the change of the content of NO, NOS and the expression of NF-kappaB in the cortex.

RESULTCompared with control group, distinct infarction was visible in the model group, and the content of NO, the activity of NOS and the positive cell number of NF-kappaB were increased obviously. Compared with model group, the extract of C. officeinalis decreased the area of infarction, the content of NO, the activity of NOS and the positive cell number of NF-kappaB.

CONCLUSIONThe iridoid glycoside of C. officinalis may have therapeutical effect on cerebral infarction through regulating the content of NO and NF-kappaB.

Animals ; Cerebral Cortex ; metabolism ; pathology ; Cerebral Infarction ; metabolism ; pathology ; Cornus ; chemistry ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Male ; NF-kappa B ; metabolism ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Plants, Medicinal ; chemistry ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo determine the role of extracellular signal-regulated kinase (ERK)1/2 during focal cerebral ischemia.

METHODSLeft middle cerebral artery occlusion (MCAO) was undergone after the introduction of a nylon suture to the left internal carotid artery in 70 male adult CD-1 mice. ERK 1/2 phosphorylation was detected using Western blot analysis, and the morphological feature was determined by immunohistochemistry. An ERK pathway inhibitor, 1,4-diamino-2,3-dicyano-1,4-bis[2-amino-phenylthio] butadiene (U0126), was administered intravenously 20 minutes before MCAO, and the neurological deficit levels and the infarct volumes were measured 24 hours after MCAO.

RESULTSPhosphorylated ERK 1/2 (pERK 1/2) activity increased after 30 minutes of MCAO and peaked at 2 hours. The immunohistochemical study displayed a large number of pERK 1/2 positive cells in the ischemic basal ganglion and surrounding cortex. Double-labeled fluorescent staining identified the pERK1/2 positive cells as neurons or astrocytes. In U0126 treated mice which had undergone 24 hours of MCAO, the neurological deficit levels and the infarct volumes were 44.6% and 45.8% respectively, less than those of the control mice.

CONCLUSIONSERK plays an important role in focal cerebral ischemia and inhibition of the ERK pathway can help protect against ischemic brain injury, which may provide a therapeutic approach for cerebral ischemia.

Animals ; Basal Ganglia ; pathology ; Brain Ischemia ; metabolism ; pathology ; physiopathology ; Butadienes ; pharmacology ; Cerebral Cortex ; pathology ; Immunohistochemistry ; Male ; Mice ; Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; physiology ; Nitriles ; pharmacology ; Phosphorylation

OBJECTIVES: To observe the changes of cystathionine β-synthase （CBS） expression in the cerebral cortex after brain contusion at different times. METHODS: An experimental model of traumatic brain injury （TBI） in mice was established by an improved weight-drop device. Then Western blotting and immunohistochemical examination were used to detect the CBS expression in cerebral cortex around injury at different time points （1 h, 6 h, 12 h, 1 d, 2 d, 3 d, 7 d）. RESULTS: The results of Western blotting revealed that the expression level of CBS was down-regulated and reached its lowest level at the 3rd days after injury, and then restored to normal level after 7 days. The results of immunohistochemistry showed that CBS was present in the normal brain cortex. CBS expression gradually decreased at the 3rd days after injury, and then restored to normal level after 7 days. CONCLUSIONS CBS has the potential to be a reference index for time estimation after brain contusion in forensic practice.
Animals ; Blotting, Western ; Brain ; Brain Contusion/pathology* ; Brain Injuries/pathology* ; Cerebral Cortex/pathology* ; Cystathionine beta-Synthase/metabolism* ; Down-Regulation ; Immunohistochemistry ; Male ; Mice ; Time Factors

OBJECTIVE: To explore the expression profile of Ephrin-B2 in the ischemic penumbra after transient focal cerebral ischemia in rats, and to clarify the mechanism of Ephrin-B2 triggering angiogenesis. METHODS: Sprague-Dawley rats were randomly divided into a normal group, a sham operation group and ischemic-reperfusion 1, 3, 7, 14, and 28 d groups. Suture-occluded method was used to establish the focal middle cerebral artery occlusion model and the ischemic brain was reperfused 2 h after the occlusion. Western blot and quantitative real-time reverse-transcription polymerase chain reaction were used to detect the dynamic expression profile of Ephrin-B2 in the penumbra cortex. Double immunofluorescence was used to speculate the location and the co-expression of Ephrin-B2 in blood vessels, neurons and astrocytes. Microvessel density was quantified by the number of CD31+ cells. Rats were subjected to neurologic functional tests by modified neurological severity scores (mNSS) before sacrifice. RESULTS: Compared with the sham group, Ephrin-B2 protein and mRNA level of the penumbra cortex in the ischemic group increased 3 days (P<0.05) after the reperfusion, peaked at day 7 and 14 (P<0.01), and declined at day 28. Double immunofluorescence indicated that Ehprin-b2 was expressed in the neurons, blood vessels and astrocytes; mNSS peaked at day 7, and gradually declined at day 14. The microvessel density of penumbra cortex in the ischemic group increased 3 days (P<0.05) after the reperfusion, peaked at day 14 (P<0.01), and gradually declined at 48 h. CONCLUSION Cerebral ischemia reperfusion induces the over-expression of Ephrin-B2, with a dynamic trend, suggesting that Ehprin-b2 may improve post-stroke functional recovery by enhancing angiogenesis and neurogenesis.
Animals ; Astrocytes ; metabolism ; Brain ; pathology ; Brain Ischemia ; metabolism ; Cerebral Cortex ; metabolism ; Ephrin-B2 ; metabolism ; Infarction, Middle Cerebral Artery ; Ischemic Attack, Transient ; Neurons ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism