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

OBJECTIVETo study the effect of telomerase reverse transcriptase (TERT) on cell apoptosis in neonatal rat brains after hypoxic-ischemic brain injury (HIBD).

METHODSA total of 72 neonatal rats were divided into sham, vehicle, HIBD and TERT groups. HIBD was induced by Rice method in the later three groups. The neonatal rats in the vehicle and TERT groups were injected with plasmids containing mock or full length TERT by an intracerebroventricular injection 30 minutes after hypoxic-ischemic (HI) injury. Pathological changes of brain tissue were observed by hematoxylin and eosin (HE) staining. Western blot was used to detect the protein expression of TERT, apoptosis-inducing factor (AIF) and cleaved caspase 3 (CC3). Apoptotic cells were detected by TUNEL staining.

RESULTSWestern blot showed that TERT protein was dramatically increased in the vehicle, HIBD and TERT groups compared with the sham group. Compared with the vehicle and HIBD groups, TERT protein in the TERT group was significantly upregulated. Compared with the sham group, there was a significant increase in apoptotic index and expression of AIF and CC3 proteins in the vehicle and HIBD groups (p<0.01). The TERT group showed decreased expression of AIF and CC3 proteins and apoptotic index compared with the vehicle and HIBD groups (p<0.01).

CONCLUSIONSTERT can inhibit cell apoptosis induced by HI and might have a neuroprotective role in developing brain with HIBD.

Animals ; Animals, Newborn ; Apoptosis ; Caspase 3 ; metabolism ; Hypoxia-Ischemia, Brain ; pathology ; therapy ; Male ; Rats ; Rats, Sprague-Dawley ; Telomerase ; genetics

OBJECTIVETo investigate the effect of graded hypothermia on neuropathologic alterations of neonatal rat brain after exposed to hypoxic-ischemic insult at 37°C, 33°C, 31°C, and 28°C, respectively, and to observe the effect of hypothermia on 72-kDa heat shock protein (HSP72) expression after hypoxic-ischemic insult.

METHODSSeven days old Wistar rats were subjected to unilateral common carotid artery ligation followed by exposure to hypoxia in 8% oxygen for 2 hours at 37°C, 33°C, 31°C, and 28°C, respectively. The brain temperature was monitored indirectly by inserting a mini-thermocouple probe into the temporal muscle during hypoxia. After hypoxia-ischemia their mortality was assessed. Neuronal damage was assessed with HE staining 72 hours after hypoxia. HSP72 expression at 0.5, 24, and 72 hours of recovery was immunohistochemically assessed using a monoclonal antibody to HSP72.

RESULTSHypoxia-ischemia caused 10.5% (2/19) of mortality in rat of 37°C group, but no death occurred in 33°C, 31°C or 28°C groups. HE staining showed neuropathologic damage was extensive in rats exposed to hypoxia-ischemia at 37°C (more than 80.0%). The incidence of severe brain damage was significantly decreased in 33°C (53.3%) and 31°C groups (44.4%), and no histologic injury was seen in the 28°C group of rats. Expression of HSP72 was manifest and persistent in the rat brain of 37°C group, but minimum in the rat brain of 28°C group.

CONCLUSIONMild and moderate hypothermia might prevent cerebral visible neuropathologic damage associated with hypoxic-ischemic injury by decreasing stress response.

Animals ; Animals, Newborn ; Body Temperature ; Female ; HSP72 Heat-Shock Proteins ; metabolism ; Hypothermia ; Hypoxia-Ischemia, Brain ; pathology ; Pregnancy ; Rats ; Rats, Wistar

OBJECTIVETo observe the effects of hyperbaric oxygen (HBO) on synaptic ultrastructure and the synaptophysin expression (p38) in hippocampal CA3 after hypoxia-ischemic brain damage (HIBD) in neonatal rats.

METHODSThe rat model of HIBD was made by the method of Bjelke and divided randomly into two groups (n = 10)--HIBD group and HBO-treated HIBD group. Another 20 rats underwent sham-operation and were also divided randomly into HBO-treated control group and the control group. After 24 h of the operation, the rats of the HBO-treated groups received HBO (2ATA, 1 h/d) for 14 days. When rats were 4 weeks old, the learning-memory ability of rats in every group was evaluated through water-maze test. Their hippocampal ultrastructure was observed with electron microscope and the p38 expression was detected immunohistochemically.

RESULTSCompared with the control group [(10.6 +/- 3.4) times], the water-maze learning ability of the rats in HIBD group [(15.5 +/- 4.9) times] was significantly decreased (P < 0.01), while the learning-memory ability of the HBO-treated HIBD group [(11.3 +/- 2.6) times] was significantly improved. There was no significant difference in the water-maze test between the HBO-treated HIBD group and the control group (P > 0.05). Compared with the control group, the ultrastructure of pyramidal neuron of hippocampal CA3 was distorted in HIBD group under the electron microscope. Compared with that in HBO-treated HIBD group (0.77 +/- 0.17, 0.67 +/- 0.16, 0.46 +/- 0.13, 0.86 +/- 0.14) and the control group (0.82 +/- 0.16, 0.70 +/- 0.16, 0.53 +/- 0.15, 0.91 +/- 0.17), the corrected optical densities (COD) of immunoreactive products of the hippocampal CA3 p38 were significantly decreased in HIBD group (0.41 +/- 0.19, 0.21 +/- 0.11, 0.08 +/- 0.03, 0.38 +/- 0.16) (P < 0.01). There was no significant difference in either ultrastructure or immunohistochemically reactive COD of p38 between the HBO-treated HIBD group and the control group (P > 0.05).

CONCLUSIONUnderlying the induction of synaptic plasticity and reducing the ultrastructural damage may be involved in the mechanism of HBO in the brain rehabilitation in perinatal brain damage with hypoxia-ischemia.

Animals ; Animals, Newborn ; Female ; Hippocampus ; metabolism ; pathology ; Hyperbaric Oxygenation ; Hypoxia-Ischemia, Brain ; metabolism ; pathology ; therapy ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Synapses ; metabolism ; ultrastructure ; Synaptophysin ; metabolism

Animals ; Apoptosis ; Hypoxia-Inducible Factor 1, alpha Subunit ; Hypoxia-Ischemia, Brain ; genetics ; pathology ; Neurons ; cytology ; metabolism ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Transcription Factors ; genetics

OBJECTIVETo investigate the effect of adenosine A2A receptor knockout (A(2A)RKO) on relationship between continuous activation of phospho-c-Jun N-terminal kinase (P-JNK) and expression of nerve cell apoptosis in hippocampus CA1 domain of newborn mice after hypoxia/ischemia brain damage(HIBD) and its potential mechanism.

METHODSA(2A)RKO mice and adenosine A2A receptor wildtype (A(2A)RWT) littermates (n = 80) were divided into Sham operation group (S) and model group (M), 1, 3 and 7 day after HIBD, totally 8 groups. HIBD was developed with 7 day-old neonatal mice according classical Rice-Vannucci method. It was tested the effect of A(2A)RKO on short-term neurofunctional outcomes consisted of three developmental reflexes (righting, geotaxis and cliff aversion), the changes of brain pathology with hematoxylin-eosin (HE) staining and Nissl staining, the expressions of nerve cell apoptosis with terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeling(TUNEL) staining and P-JNK were observed by immunohistochemistry.

RESULTSThe neurological behavior injuries and brain histopathological damages and nerve apoptosis cells were aggravated in A(2A)RKO newborn mice after HIBD. The positive expressions of P-JNK were significantly higher in the ischemic hippocampus CA1 domain after HIBD than ones in group S respectively (P < 0.01), reaching to peak at 1 day and then began gradually decreasing. P-JNK expression in model knockout(MKO) at 1, 3 and 7 day increased greatly compared to those in the previous time point of corresponding model wildtype (MWT) (P < 0.01, P < 0.05, P > 0.05); there was a positive correlation between the expressions of P-JNK and nerve cell apoptosis after HIBD in newborn mice(r = 0.837, P < 0.01).

CONCLUSIONEarly continuous activation of P-JNK might be involved in the aggravated nerve apoptosis cells and brain damage induced by A(2A) RKO newborn mice after HIBD.

Animals ; Animals, Newborn ; Apoptosis ; Hypoxia-Ischemia, Brain ; metabolism ; pathology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Mice ; Mice, Knockout ; Neurons ; drug effects ; metabolism ; pathology ; Receptor, Adenosine A2A ; genetics

OBJECTIVE: To investigate the expression of hypoxia-inducible factor 1-alpha (HIF1-alpha) in the heart, lung, liver and kidney in rats died of two typical models of asphyxia. METHODS: Two asphyxia models were made and tissue samples of the dead rats were collected from different groups at various postmortem duration. The expression and the changes of HIF1-alpha in various tissues were examined by immunohistochemistry and image analysis techniques. Results Significant expression of HIF1-alpha was observed in the myocardial fibers, kidney cells, liver cells and lung cells in both asphyxia models, but not in the control group. The expression of HIF1-alpha in various tissues in the rat died of nitrogen gas breathing was found in the nuclei at 0 hour and the expression level decreased gradually thereafter. The HIF1-alpha expression level and duration in various tissues of the rat died of hanging were higher and longer than that of the former group, with a peak of the expression level observed 6 hours after death, and then started to decline in all tissues except the heart where the expression still showed an increase 24 hours after death. The control groups showed a steady expression in the cytoplasm but not in the nuclei. CONCLUSION HIF1-alpha appears to be a valuable biomarker in the diagnosis of asphyxia within 24 hours after death.
Animals ; Asphyxia/metabolism* ; Disease Models, Animal ; Female ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Hypoxia-Ischemia, Brain/metabolism* ; Immunohistochemistry ; Kidney/pathology* ; Liver/pathology* ; Lung/pathology* ; Male ; Myocardium/pathology* ; Nitrogen/poisoning* ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVETo investigate the effects of mild hypothermia on sequential events of neuronal apoptosis following hypoxic-ischemic brain damage (HIBD) in neonatal rats.

METHODSA model of HIBD was prepared by ligating the left common carotid artery in 7-day-old rats, followed by 8% hypoxia exposure. HIBD rats were randomly assigned into a hypothermia group (rectal temperature = 33 centi-degrees) and a normothermia group (rectal temperature = 36 centi-degrees). TUNEL, Haematoxylin and Eosin, and Nissl staining were used to detect neuronal apoptosis. Western blotting, RT-PCR and enzyme activity measurement were used to evaluate the changes of plasma and mitochondrial cytochrome c (Cyt c), caspase-3 mRNA expression and caspase-3 enzyme activity, respectively.

RESULTSThe number of apoptotic cells in the ipsilateral hemisphere of the hypothermia group was significantly reduced compared with that of the normothermia group at 72 hrs post-HI (6.4 +/- 1.7% vs 25.3 +/- 1.5%) (P < 0.01). Analysis of Western blotting showed that Cyt c levels increased in the cytosolic fraction, but decreased significantly in the mitochondrial fraction in the ipsilateral hemisphere of the hypothermia group at 24, 48 and 72 hrs of HI insult compared with the normothermia group (P < 0.05). Caspase-3 mRNA increased significantly after 24 hrs post-HI in the normothermia group, and this change became more pronounced with time. Mild hypothermia treatment decreased significantly caspase-3 mRNA expression at 24, 48 and 72 hrs post-HI (P < 0.05). Caspase-3 activity gradually increased 2 hrs after HI insult and peaked at 24 hrs in the normothermia group. Mild hypothermia treatment resulted in a significant reduction in caspase-3 activity in the ipsilateral hemisphere, with an optimal effect produced at 24 hrs post-HI (2.42 +/- 0.5 RFU vs 34.7 +/- 3.2 RFU; P < 0.01).

CONCLUSIONSMild hypothermia treatment attenuates neuronal apoptosis following HIBD, possibly through a reduction in Cyt c release from mitochondria and an inhibition of caspase-3 mRNA expression and its enzyme activity.

Animals ; Apoptosis ; Brain ; pathology ; Caspase 3 ; genetics ; metabolism ; Cytochromes c ; secretion ; Female ; Hypothermia, Induced ; Hypoxia-Ischemia, Brain ; pathology ; therapy ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the effect of progesterone on matrix metalloproteinase-3 (MMP-3) expression in neonatal rat brain after hypoxic-ischemia.

METHODSFollowed the hypoxic-ischemia of neonatal rat brain, Evans blue (EB) staining and transmission electron microscopy were used to detect the blood-brain barrier pathological changes on permeability. MMP-3 protein expression in cerebral cortex was measured with Western blot.

RESULTSTransmission electron microscopy results showed that the blood brain barrier in hypoxic-ischemic group changed significantly compare to progesterone group. EB staining results suggested that the blood-brain barrier permeability of hypoxic-ischemic group was significantly increased compared to sham-operated group (P < 0.01). The blood-brain barrier permeability in progesterone group was also decreased in comparison to that of hypoxic-ischemic group (P < 0.05). Western blot image analysis results indicated that MMP-3 protein expression in the hypoxic-ischemic group increased significantly than that in sham-operated group (P < 0.01), and the progesterone group was decreased significantly than that in hypoxic-ischemic group (P < 0.05).

CONCLUSIONProgesterone may reduce the blood-brain barrier damage by reducing MMP-3 expression. This might be one of the protective mechanisms in the hypoxic-ischemic brain injury.

Animals ; Animals, Newborn ; Blood-Brain Barrier ; physiopathology ; Hypoxia-Ischemia, Brain ; metabolism ; pathology ; physiopathology ; Matrix Metalloproteinase 3 ; metabolism ; Progesterone ; pharmacology ; Rats ; Rats, Sprague-Dawley

BACKGROUNDHypoxic-ischemic brain injury (HIBI) after cardiopulmonary resuscitation is one of the most devastating neurological conditions that causing the impaired consciousness. However, there were few studies investigated the changes of brain metabolism in patients with vegetative state (VS) after post-resuscitated HIBI. This study aimed to analyze the change of overall brain metabolism and elucidated the brain area correlated with the level of consciousness (LOC) in patients with VS after post-resuscitated HIBI.

METHODSWe consecutively enrolled 17 patients with VS after HIBI, who experienced cardiopulmonary resuscitation. Overall brain metabolism was measured by F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) and we compared regional brain metabolic patterns from 17 patients with those from 15 normal controls using voxel-by-voxel based statistical parametric mapping analysis. Additionally, we correlated the LOC measured by the JFK-coma recovery scale-revised of each patient with brain metabolism by covariance analysis.

RESULTSCompared with normal controls, the patients with VS after post-resuscitated HIBI revealed significantly decreased brain metabolism in bilateral precuneus, bilateral posterior cingulate gyrus, bilateral middle frontal gyri, bilateral superior parietal gyri, bilateral middle occipital gyri, bilateral precentral gyri (PFEW correctecd < 0.0001), and increased brain metabolism in bilateral insula, bilateral cerebella, and the brainstem (PFEW correctecd < 0.0001). In covariance analysis, the LOC was significantly correlated with brain metabolism in bilateral fusiform and superior temporal gyri (Puncorrected < 0.005).

CONCLUSIONSOur study demonstrated that the precuneus, the posterior cingulate area and the frontoparietal cortex, which is a component of neural correlate for consciousness, may be relevant structure for impaired consciousness in patient with VS after post-resuscitated HIBI. In post-resuscitated HIBI, measurement of brain metabolism using PET images may be helpful for investigating the brain function that cannot be obtained by morphological imaging and can be used to assess the brain area responsible for consciousness.

Adult ; Brain ; metabolism ; Female ; Fluorodeoxyglucose F18 ; Humans ; Hypoxia-Ischemia, Brain ; metabolism ; Male ; Middle Aged ; Persistent Vegetative State ; pathology ; Positron-Emission Tomography ; methods ; Young Adult