scholarly journals The Contribution of Reoxygenation to Ischemic Brain Damage

1991 ◽  
Vol 11 (6) ◽  
pp. 994-1000 ◽  
Author(s):  
James H. Halsey ◽  
Karl A. Conger ◽  
Julio H. Garcia ◽  
Eniko Sarvary

This study examined the hypothesis that the level of postischemic reperfusion affects the severity of the resulting neuronal necrosis. In rats, tissue Po2% was monitored as an index of flow (reoxygenation) at four cortical sites by chronically implanted platinum electrodes. Twenty minutes of total global cerebral ischemia was followed by 30 min of reoxygenation. The level of reoxygenation was controlled to maintain the Po2 nearly constant at one or more of the cortical electrodes. Tissue from within 400 μm of each of 19 electrode sites among seven rats was evaluated histologically. There was a positive correlation between reoxygenation level and severity of neuronal damage. Perineuronal lucent halo formation, probably representing astrocyte foot process swelling, was negatively correlated with reoxygenation level. This study demonstrates that ischemic neuronal damage was aggravated by increased reoxygenation but that perineuronal swelling, as evidenced by halo formation, was somewhat ameliorated.

1986 ◽  
Vol 6 (5) ◽  
pp. 559-565 ◽  
Author(s):  
Tohru Koide ◽  
Tadeusz W. Wieloch ◽  
Bo K. Siesjö

In search of factors influencing the outcome of an ischemic insult, we induced 10 min of forebrain ischemia in rats and assessed neuronal necrosis by quantitative histopathology after 1 week of recovery. Procedures for inducing ischemia included bilateral carotid artery clamping and reduction of blood pressure to 40–50 mm Hg by bleeding. To facilitate rapid lowering of blood pressure, a ganglionic blocker, trimethaphan (TMP), was administered at the onset of ischemia. Omission of the ganglionic blocker proved to markedly ameliorate neuronal damage. Similarly favorable effects were obtained when a mixture of adrenaline and noradrenaline (1 μg kg−1 min−1 each) was infused during the early recirculation period in animals previously given TMP. Infusion of noradrenaline alone also ameliorated the damage, though the efficacy was somewhat less. The results suggest that catecholamines, released as a response to stress, ameliorate ischemic brain damage.


1991 ◽  
Vol 74 (6) ◽  
pp. 944-950 ◽  
Author(s):  
Min-Hsiung Chen ◽  
Ross Bullock ◽  
David I. Graham ◽  
Jimmy D. Miller ◽  
James McCulloch

✓ The ability of a competitive N-methyl-D-aspartate (NMDA) receptor antagonist (D-CPP-ene) to reduce irreversible brain damage has been examined in a rodent model of acute subdural hematoma. Acute subdural hematoma was produced by the slow injection of 400 µl homologous blood into the subdural space overlying the parietal cortex in halothane-anesthetized rats. Brain damage was assessed histologically in sections at multiple coronal planes in animals sacrificed 4 hours after induction of the subdural hematoma. Pretreatment with D-CPP-ene (15 mg/kg) significantly reduced the volume of ischemic brain damage produced by the subdural hematoma from 62 ± 8 cu mm (mean ± standard error of the mean) in vehicle-treated control rats to 29 ± 7 cu mm in drug-treated animals. These data demonstrate the anti-ischemic efficacy of NMDA antagonists in an animal model of intracranial hemorrhage in which intracranial pressure is elevated, and suggest that excitotoxic mechanisms (which are susceptible to antagonism by D-CPP-ene) may play a role in the ischemic brain damage which is observed in patients who die after acute subdural hematoma.


2004 ◽  
Vol 24 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Ichiro Yonekura ◽  
Nobutaka Kawahara ◽  
Hirofumi Nakatomi ◽  
Kazuhide Furuya ◽  
Takaaki Kirino

A reproducible model of global cerebral ischemia in mice is essential for elucidating the molecular mechanism of ischemic neuronal injury. Such a model is particularly important in the mouse because many genetically engineered mutant animals are available. In C57BL/6 and SV129/EMS mice, we evaluated a three-vessel occlusion model. Occlusion of the basilar artery with a miniature clip was followed by bilateral carotid occlusion. The mean cortical cerebral blood flow was reduced to less than 10% of the preischemic value, and the mean anoxic depolarization was attained within 1 minute. In C57BL/6 mice, there was CA1 hippocampal neuronal degeneration 4 days after ischemia. Neuronal damage depended upon ischemic duration: the surviving neuronal count was 78.5 ± 8.5% after 8-minute ischemia and 8.4 ± 12.7% after 14-minute ischemia. In SV129/EMS mice, similar neuronal degeneration was not observed after 14-minute ischemia. The global ischemia model in C57BL/6 mice showed high reproducibility and consistent neuronal injury in the CA1 sector, indicating that comparison of ischemic outcome between wild-type and mutant mice could provide meaningful data using the C57BL/6 genetic background. Strain differences in this study highlight the need for consideration of genetic background when evaluating ischemia experiments in mice.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Claudia Di Giacomo ◽  
Rosaria Acquaviva ◽  
Rosa Santangelo ◽  
Valeria Sorrenti ◽  
Luca Vanella ◽  
...  

This study investigated the effect of cyanidin-3-O-β-glucoside on an experimental model of partial/transient cerebral ischemia in the rats in order to verify the effectiveness of both pre- and posttreatments. Cyanidin-3-O-β-glucoside-pretreated rats were injected with 10 mg/Kg i.p. 1 h before the induction of cerebral ischemia; in posttreated rats, the same dosage was injected during reperfusion (30 min after restoring blood flow). Cerebral ischemia was induced by bilateral clamping of common carotid arteries for 20 min. Ischemic rats were sacrificed immediately after 20 min ischemia; postischemic reperfused animals were sacrificed after 3 or 24 h of restoring blood flow. Results showed that treatment with cyanidin increased the levels of nonproteic thiol groups after 24 h of postischemic reperfusion, significantly reduced the lipid hydroperoxides, and increased the expression of heme oxygenase andγ-glutamyl cysteine synthase; a significant reduction in the expression of neuronal and inducible nitric oxide synthases and the equally significant increase in the endothelial isoform were observed. Significant modifications were also detected in enzymes involved in metabolism of endogenous inhibitors of nitric oxide. Most of the effects were observed with both pre- and posttreatments with cyanidin-3-O-β-glucoside suggesting a role of anthocyanin in both prevention and treatment of postischemic reperfusion brain damage.


1986 ◽  
Vol 6 (4) ◽  
pp. 395-404 ◽  
Author(s):  
Tohru Koide ◽  
Tadeusz W. Wieloch ◽  
Bo K. Siesjö

This study addresses the question of whether the cyclooxygenase inhibitors indomethacin and diclofenac and the glucocorticosteroid dexamethasone ameliorate neuronal necrosis following cerebral ischemia. In addition, since these drugs inhibit the production of prostaglandins and depress phospholipase A2 activity, respectively, the importance of free fatty acids (FFAs) on the development of ischemic neuronal damage was assessed. Neuronal damage was determined in the rat brain at 1 week following 10 min of forebrain ischemia. The cyclooxygenase inhibitors, whether given before or after ischemia, failed to alter the brain damage incurred. Animals given dexamethasone were divided into three groups and the drug was administered at a constant dosage of 2 mg/kg: (a) 2 days, 1 day, and 3 h intraperitoneally before (chronic pretreatment), (b) 3 h intraperitoneally before (acute pretreatment), and (c) 5 min intravenously and 6 h and 1 day intraperitoneally after (chronic posttreatment) induction of ischemia. Acute pretreatment did not affect the histopathological outcome. Chronic posttreatment of animals with dexamethasone ameliorated the damage inflicted on the caudate nucleus, but had no effect on other brain areas investigated. Unexpectedly, the chronic pretreatment aggravated the brain damage and caused seizures following ischemia. Histopathological data showed massive neuronal damage in these brains. The accumulation of FFA levels during ischemia was markedly suppressed, and the decrease in the energy charge was curtailed by chronic pretreatment with dexamethasone. However, brain glucose levels in control animals and lactic acid concentrations following 10 min of ischemia were significantly higher both in the cerebral cortex and in the hippocampus of dexamethasone-treated animals. These results suggest that aggravation of neuronal necrosis by chronic dexamethasone pretreatment could be ascribed to lactic acidosis due to hyperglycemia in combination with an action of dexamethasone on glucocorticoid receptors in the brain.


2018 ◽  
Vol 24 (3) ◽  
pp. 58-64
Author(s):  
O.I. Savchuk ◽  
G.G. Skibo

The stroke-causing problems are extremely important in Ukraine. This makes a heavy burden not only on the health care system, but also on the whole society as a whole. That's why we've studied structural and ultrastructural changes of cortical neurons and striatum of the brain and the development of delayed death of nerve cells after the modeling of the middle cerebral artery occlusion (MCAO) and post ischemic period in rats. We've analyzed the data at different terms after modeling of MCAO. The purpose of the study was to investigate the changes in the nervous tissue in the modeling of focal cerebral ischemia by monofilament occlusion of MCAO in rats at different periods of reperfusion. The statistical processing of primary digital experimental data was carried out using the software Statistica 6.0. It was confirmed that the 60-minute occlusion of the MCAO is an adequate model of focal ischemic brain damage in rats. Changes of locomotor activity and a tactile sensitivity were determined in rats after occlusion and after reperfusion during the post-period period. It was found that in the experimental group with a reperfusion period of 72 hours, a clear increase of the volume of the ischemic area of the brain, accompanied by significant neurological deficiency, was observed. Reduced research activity of the rats was revealed, which was shown in the decrease of the number of squares they crossed, the number of racks, the increase of acts of grooming and the duration of acts of frizings. Following ischemic brain damage, there was also a disbalance of somato-sensory functions, as evidenced by an increase in the time during which the animal took a test stimulus ("Sticky tape") from both the anterior paws when tested for tactile sensitivity (adhesive removal test). An electron microscopic study of the cortex showed that dark wrinkled neurons and enlightened swollen neurons were observed at 72 hours of post-occlusion period, indicating different ways of death of these cells. Changes in striatum were similar to changes in the cortex, which progressed with an increase in the post-occlusion period. The protocol of the serial evaluation of neurological disorders used after MCAO modeling allowed detecting long-term stable functional disorders in laboratory rats. The obtained data indicate significant changes in the structure of the cortex and striatum in the post-ischemic period and the progressive nature of these changes.


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