AIMTo observe the effect of nonselective nitro oxide synthase inhibitor N(G)-nitro-L-arginine(L-NA) on mitochondria injury in focal cerebral ischemia rats.

METHODSThe rats were randomly divided into sham, ischemia and L-NA treatment group. The model of focal cerebral ischemia was prepared with thread embolism in rats. L-NA was administrated respectively at 2 h, 6 h, 12 h after middle cerebral artery occlusion (MCAO). Rats were killed and the mitochondria of cerebral tissue were isolated by differential centrifugation after L-NA treatment for 3 days. The swelling and the activity of mitochondria, and the activities of ATPase, SOD, GSH-Px in mitochondria and the contents of NO, MDA in mitochondria were measured. Ultrastructure changes of neuronal mitochondria were examined by electronic microscope in ischemia and L-NA treatment group.

RESULTSThe swelling of mitochondria was markedly increased and the activity of mitochondria was decreased, and the contents of mitochondria NO and MDA were markedly increased, the activity of ATPase, SOD and GSH-Px in mitochondria were decreased significantly after MCAO. Compared with ischemia group, the contents of NO were decreased after ischemia 2h, 6h, 12h administered by L-NA, and the swelling of mitochondria was decreased and the activity of mitochondria was increased, and the activities of ATPase, SOD, GSH-Px in mitochondria were enhanced and the contents of MDA in mitochondria were decreased after ischemia 12 h administered by L-NA. The neuronal cytoplasm and the mitochondria swelled, the cristae were disrupted, dissolved or disappeared in MCAO rats. Administration of L-NA could reduce these changes induced by cerebral ischemia in rats.

CONCLUSIONIt could be concluded that L-NA could beneficially inhibit NO production. But it could't protect brain against damage in ischemia acute stage. It could improve mitochondria energy pump, ameliorate oxidative injury and increase the activities of mitochondria during postischemia, and then could effectively protect brain against damage induced by focal cerebral ischemia.

Animals ; Arginine ; pharmacology ; Brain ; metabolism ; Brain Ischemia ; metabolism ; pathology ; Male ; Mitochondria ; metabolism ; pathology ; Rats ; Rats, Wistar

Immunohistochemistry and double immunofluorescent labeling techniques combined with confocal laser scanning microscope analysis were used to investigate the characteristic spatial induction profile of nestin following a transient middle cerebral artery occlusion in adult rat brain. The results showed that nestin was induced in ischemic core at 1 day after reperfusion. In addition to ischemic core, the expression of nestin increased in peri-ischemic I, II and III regions at 3 days and 1 week, then it decreased and narrowed along the rim of ischemic core 2 weeks after reperfusion. Double immunofluorescent labeling showed that nestin positive cells were mostly co-stained with GFAP,a astrocyte marker, in peri-ischemic I region 3 days after reperfusion. At 2 weeks, however nestin cells showed a long process and the cells double stained with nestin and NSE,a neuonal specific marker,increased in the ischemic brain. The results suggest that cerebral ischemia induces nestin expression in damaged neurons which might favor the neuroprotection against ischemic damage.
Animals ; Brain ; metabolism ; pathology ; Brain Ischemia ; metabolism ; pathology ; Immunohistochemistry ; Infarction, Middle Cerebral Artery ; metabolism ; pathology ; Nestin ; metabolism ; Neurons ; metabolism ; Rats

Mitochondria play a key role in various cell processes including ATP production, Ca homeostasis, reactive oxygen species (ROS) generation, and apoptosis. The selective removal of impaired mitochondria by autophagosome is known as mitophagy. Cerebral ischemia is a common form of stroke caused by insufficient blood supply to the brain. Emerging evidence suggests that mitophagy plays important roles in the pathophysiological process of cerebral ischemia. This review focuses on the relationship between ischemic brain injury and mitophagy. Based on the latest research, it describes how the signaling pathways of mitophagy appear to be involved in cerebral ischemia.
Animals ; Brain Ischemia ; metabolism ; pathology ; Humans ; Mitochondrial Degradation ; Reactive Oxygen Species ; metabolism ; Stroke ; metabolism ; pathology

AIMTo make approach to the relationship between the changes of free zinc and ischemic neuronal damage in hippocampus after forebrain ischemia/reperfusion.

METHODSThe models of forebrain ischemia/reperfusion were established in rats. The contents of free Zn2+ were measured by TSQ fluorescence method. The Zn2+ chelator (CaEDTA) was injected into lateral ventricles in order to evaluate the effect of free Zn2+ on ischemic neuronal damage.

RESULTS(1) Zn2+ fluorescence in the hilus of dentate gyrus, CA3 region and the stratum radiatum and stratum oriens of CA1 decreased slightly at forty-eight hours after reperfusion. From seventy-two hours to ninety-six hour after reperfusion, the decreased fluorescence gradually returned to the normal level, but some fluorescence dots were found in pyramidal neurons of CA1 and the hilus of dentate gyrus. Seven days after reperfusion, all the changes of the fluorescence almost recovered. (2) The cell membrane-impermeable Zn2+ chelator CaEDTA could reduce the intracellular concentration of free Zn2+ and reduced neuronal damage after forebrain ischemia/reperfusion.

CONCLUSION(1) The synaptic vesicle Zn2+ released and then translocated into postsynaptic neurons after forebrain ischemia/reperfusion and played a role in ischemic neuronal damage. (2) The cell membrane-impermeable chelator CaEDTA could provide neuroprotection.

Animals ; Brain Ischemia ; metabolism ; pathology ; Hippocampus ; pathology ; Male ; Neurons ; metabolism ; Rats ; Rats, Wistar ; Reperfusion Injury ; metabolism ; pathology ; Zinc ; metabolism

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

OBJECTIVEThe investigated the effects of Dengzhan Xixin on brain water content, blood-brain barrier (BBB) permeability, T2-weighted imaging (T2WI), metabolites and the lesion ratio after cerebral ischemia-reperfusion injuries (IRI).

METHODThe 65 rats were randomly individed into three groups, the sham-operated group, the ischemia-reperfusion group and the Dengzhan Xixin treatment group. The models of ischemia-reperfusion of middle cerebral artery in rats were established by placing an intraluminal suture. The Dengzhan Xixin treatment group were injected 10% Dengzhan Xixin injection 22.5 mg kg(-1) after ischemia 1.5 h. The sh am-operated group (n=5) were sacrificed on 1 to measure brain water content and BBB permeability. The rats of the ischemia-reperfusion group (n=30) and the Dengzhan Xixin treatment group (n=30) were sacrificed at reperfusion for 6 h, 12 h, 1 d, 2 d, 4 d, 7 d, respectively, after ischemia 1.5 h. The additional 35 rats were individed into the same three groups. The changes of T2WI and metabolites in the brain were observed, and rats were sacrificed at reperfusion for 1 d, 2 d, 4 d after ischemia 1.5 h to determine the lesion ratio by TTC.

RESULTIn the ischemia-reperfusion group, brain water content(77.93+/-0.68)% and BBB permeability (3.77+/-0.28) increased after reperfusion for 6 h. The peak time of brain water content was at 4 d (83.82+/-0.49)% and BBB permeability was at 2 d (5.51+/-0.24)%. In the ischemia-reperfusion group and the Dengzhan Xixin treatment group, there were hyperintense signals in the injury region of T2WI. In the ischemia-reperfusion group after reperfusion for 1 d, the ratio of NAA/Cr decreased and Cho/Cr increased. In the Dengzhan Xixin treatment group, the ratio of NAA/Cr increased and Cho/Cr decreased. In the treatment group, the lesion ratio decreased by TTC was 16.78+/-1.45 and in the ischemia-reperfusion group was 21.27+/-1.73 at 2 d.

CONCLUSIONDengzhan Xixin may relieve cerebral ischemia-reperfusion injury by influencing the metabolites of brain, stabilizing BBB and decreasing brain edema.

Animals ; Blood-Brain Barrier ; drug effects ; metabolism ; Brain Ischemia ; complications ; metabolism ; pathology ; Flavonoids ; pharmacology ; Male ; Permeability ; drug effects ; Rats ; Rats, Wistar ; Reperfusion Injury ; complications ; metabolism ; pathology ; Water ; metabolism

Brain Ischemia ; pathology ; physiopathology ; Humans ; Neoplasm Proteins ; metabolism ; Pyroptosis ; physiology ; Signal Transduction ; physiology

Animals ; Brain Ischemia ; metabolism ; pathology ; Male ; Metallothionein ; metabolism ; Nerve Tissue Proteins ; metabolism ; Neurons ; pathology ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Reperfusion Injury ; metabolism ; pathology

OBJECTIVETo observe the protective effect of verapamil pretreatment against cerebral ischemia-reperfusion injury in gerbils.

METHODSThirty-three Mongolian gerbils were randomized into the control group (group A, n=6, with sham operation), ischemia group (group B), and 3 verapamil groups (groups C, D, and E, n=7) with intraperitpneal verapamil injection (2 mg/kg) 48, 24 and 12 h before ischemia, respectively. In group A, the bilateral common carotid arteries were only exposed without clamping, and in the other 4 groups, the arteries were clamped for 20 min followed by reperfusion for 50 min. The gerbils were then decapitated and the forebrain cerebral cortex was removed to determine superoxide dismutase (SOD) and glutathione (GSH) activities and measure the contents of malondial dehyde (MDA), endothelin (ET) and calcitonin gene-related peptide (CGRP). The left forebrain cerebral cortex was sampled in each group to observe the ultrastructural changes under electron microscope.

RESULTSIn groups C and D, SOD activities were significantly higher than those in group B (P<0.05), and in group E, the SOD activity elevation was not statistically significant (P>0.05). In groups C, D and E, GSH activity was significantly higher than that in group B (P<0.05). MDA content was significantly lower in groups C and D than in group B (P<0.05), but comparable between groups E and B (P>0.05). ET content was also significantly lower in the pretreatment groups (P<0.05), but CGRP content higher (not statistically so, however) than those in group B. The more serious ultrastructural damage of the cerebral tissue was observed in group B, but only mild damage was found in the verapamil groups.

CONCLUSIONSVerapamil given 12-48 h before cerebral ischemia may protect the gerbils from cerebral ischemia-reperfusion injury by enhancing SOD, GSH activities and decreasing ET content.

Animals ; Brain ; drug effects ; metabolism ; pathology ; Brain Ischemia ; complications ; metabolism ; pathology ; prevention & control ; Endothelins ; metabolism ; Gerbillinae ; Glutathione ; metabolism ; Malondialdehyde ; metabolism ; Receptors, Calcitonin Gene-Related Peptide ; metabolism ; Reperfusion Injury ; complications ; metabolism ; pathology ; prevention & control ; Superoxide Dismutase ; metabolism ; Verapamil ; pharmacology

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