Neuroprotection by the stable nitroxide Tempol during reperfusion in a rat model of transient focal ischemia

2000 ◽  
Vol 92 (4) ◽  
pp. 646-651 ◽  
Author(s):  
Ramin Rak ◽  
Daniel L. Chao ◽  
Ryszard M. Pluta ◽  
James B. Mitchell ◽  
Edward H. Oldfield ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Rat Model ◽  
Focal Ischemia ◽  
Artery Occlusion ◽  
Sprague Dawley ◽  
Triphenyltetrazolium Chloride ◽  
Content Type ◽  
Physiological Variables ◽  
Transient Focal Ischemia ◽  
Fine Print

Object. The use of thrombolytic agents in the treatment of stroke has yielded surprisingly modest success, possibly because of reperfusion injury mediated by reactive oxygen species (ROS). Therefore, scavenging ROS may be of therapeutic value in the treatment of stroke. Nitroxides are low-weight superoxide dismutase mimics, which allows them to act as cell-permeable antioxidants. In this study the nitroxide 4-hydroxy-2,2,6,6,-tetramethylpiperidine-1-oxyl (Tempol) is investigated to determine its ability to reduce reperfusion injury.Methods. Male Sprague—Dawley rats weighing between 280 g and 350 g underwent middle cerebral artery occlusion with an intraluminal suture for 60 minutes. Regional cerebral blood flow, blood pressure, cerebral temperature, and rectal temperature were monitored during the procedure. After reperfusion, the animals were randomized to groups receiving blinded intravenous administration of either Tempol (10 mg/kg; eight animals) or vehicle (eight animals) over the first 20 minutes of reperfusion (Study I). In a second study to determine dose dependency, animals were randomized to groups receiving Tempol (20 mg/kg; eight animals), low-dose Tempol (5 mg/kg; eight animals), or vehicle (eight animals; Study II). The rats were killed after 4 hours of reperfusion, and brain sections were stained with 2,3,5 triphenyltetrazolium chloride. Infarct volumes were measured using digital imaging.Animals receiving Tempol had significantly reduced infarct volumes at doses of 20 mg/kg and 10 mg/kg compared with controls (49.01 ± 18.22% reduction [p = 0.003] and 47.47 ± 34.57 [p = 0.02], respectively). No significant differences in the physiological variables measured were observed between groups.Conclusions. Tempol provides significant neuroprotection after reperfusion in a rat model of transient focal ischemia. These results support the importance of ROS in reperfusion injury and encourage further study of this molecule as a therapeutic agent following thrombolysis.

No additional neuroprotection provided by barbiturate-induced burst suppression under mild hypothermic conditions in rats subjected to reversible focal ischemia

2000 ◽  
Vol 93 (5) ◽  
pp. 835-844 ◽  
Author(s):  
Thomas Westermaier ◽  
Stefan Zausinger ◽  
Alexander Baethmann ◽  
Hans-Jakob Steiger ◽  
Robert Schmid-Elsaesser
Keyword(s):  
Mild Hypothermia ◽  
Artery Occlusion ◽  
Burst Suppression ◽  
Moderate Hypothermia ◽  
Sprague Dawley ◽  
Doppler Flowmetry ◽  
Content Type ◽  
Treatment Groups ◽  
Cerebral Artery Occlusion ◽  
Fine Print

Object. Mild-to-moderate hypothermia is increasingly used for neuroprotection in humans. However, it is unknown whether administration of barbiturate medications in burst-suppressive doses—the gold standard of neuroprotection during neurovascular procedures—provides an additional protective effect under hypothermic conditions. The authors conducted the present study to answer this question.Methods. Thirty-two Sprague—Dawley rats were subjected to 90 minutes of middle cerebral artery occlusion and randomly assigned to one of four treatment groups: 1) normothermic controls; 2) methohexital treatment (burst suppression); 3) induction of mild hypothermia (33°C); and 4) induction of mild hypothermia plus methohexital treatment (burst suppression). Local cerebral blood flow was continuously monitored using bilateral laser Doppler flowmetry and electroencephalography. Functional deficits were quantified and recorded during daily neurological examinations. Infarct volumes were assessed histologically after 7 days. Methohexital treatment, mild hypothermia, and mild hypothermia plus methohexital treatment reduced infarct volumes by 32%, 71%, and 66%, respectively, compared with normothermic controls. Furthermore, mild hypothermia therapy provided the best functional outcome, which was not improved by additional barbiturate therapy.Conclusions. The results of this study indicate that barbiturate-induced burst suppression is not required to achieve maximum neuroprotection under mild hypothermic conditions. The magnitude of protection afforded by barbiturates alone appears to be modest compared with that provided by mild hypothermia.

Delayed treatment with magnesium: reduction of brain infarction and improvement of electrophysiological recovery following transient focal cerebral ischemia in rats

2005 ◽  
Vol 102 (6) ◽  
pp. 1085-1093 ◽  
Author(s):  
E-Jian Lee ◽  
Ming-Yang Lee ◽  
Guan-Liang Chang ◽  
Li-Hsuan Chen ◽  
Yu-Ling Hu ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Brain Infarction ◽  
Artery Occlusion ◽  
Sprague Dawley ◽  
Content Type ◽  
Delayed Treatment ◽  
Cerebral Ischemia Reperfusion ◽  
Fine Print

Object. The authors examined whether delayed treatment with Mg++ would reduce brain infarction and improve electrophysiological and neurobehavioral recovery following cerebral ischemia—reperfusion. Methods. Male Sprague—Dawley rats were subjected to right middle cerebral artery occlusion for 90 minutes followed by 72 hours of reperfusion. Magnesium sulfate (750 µmol/kg) or vehicle was given via intracarotid infusion at the beginning of reperfusion. Neurobehavioral outcome and somatosensory evoked potentials (SSEPs) were examined before and 72 hours after ischemia—reperfusion. Brain infarction was assessed after the rats had died. Before ischemia—reperfusion, stable SSEP waveforms were recorded after individual fore- and hindpaw stimulations. At 72 hours of perfusion the SSEPs recorded from ischemic fore- and hindpaw cortical fields were depressed in vehicle-injected animals and the amplitudes decreased to 19 and 27% of baseline, respectively (p < 0.001). Relative to controls, the amplitudes of SSEPs recorded from both ischemic fore- and hindpaw cortical field in the Mg++-treated animals were significantly improved by 23% (p < 0.005) and 39% (p < 0.001) of baselines, respectively. In addition, Mg++ improved sensory and motor neurobehavioral outcomes by 34% (p < 0.01) and 24% (p < 0.05), respectively, and reduced cortical (p < 0.05) and striatal (p < 0.05) infarct sizes by 42 and 36%, respectively. Conclusions. Administration of Mg++ at the commencement of reperfusion enhances electrophysiological and neurobehavioral recovery and reduces brain infarction after cerebral ischemia—reperfusion. Because Mg++ has already been used clinically, it may be worthwhile to investigate it further to see if it holds potential benefits for patients with ischemic stroke and for those who will undergo carotid endarterectomy.

Atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide in ischemic stroke

2006 ◽  
Vol 291 (5) ◽  
pp. H2210-H2215 ◽  
Author(s):  
Hua Hong ◽  
Jin-Sheng Zeng ◽  
David L. Kreulen ◽  
David I. Kaufman ◽  
Alex F. Chen
Keyword(s):  
Ischemic Stroke ◽  
Nadph Oxidase ◽  
Cerebral Infarction ◽  
Infarct Volume ◽  
Focal Ischemia ◽  
Small Gtpase ◽  
Sprague Dawley ◽  
Triphenyltetrazolium Chloride ◽  
Ischemic Core ◽  
Transient Focal Ischemia

Statins have recently been shown to exert neuronal protection in ischemic stroke. Reactive oxygen species, specifically superoxide formed during the early phase of reperfusion, augment neuronal injury. NADPH oxidase is a key enzyme for superoxide production. The present study tested the hypothesis that atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide in transient focal ischemia. Transient focal ischemia was created in halothane-anesthetized adult male Sprague-Dawley rats (250–300 g) by middle cerebral artery occlusion (MCAO). Atorvastatin (Lipitor, 10 mg/kg sc) was administered three times before MCAO. Infarct volume was measured by triphenyltetrazolium chloride staining. NADPH oxidase enzymatic activity and superoxide levels were quantified in the ischemic core and penumbral regions by lucigenin (5 μM)-enhanced chemiluminescence. Expression of NADPH oxidase membrane subunit gp91phox and membrane-translocated subunit p47phox and small GTPase Rac-1 was analyzed by Western blot. NADPH oxidase activity and superoxide levels increased after reperfusion and peaked within 2 h of reperfusion in the penumbra, but not in the ischemic core, in MCAO rats. Atorvastatin pretreatment prevented these increases, blunted expression of membrane subunit gp91phox, and prevented translocation of cytoplasmic subunit p47phox to the membrane in the penumbra 2 h after reperfusion. Consequently, cerebral infarct volume was significantly reduced in atorvastatin-treated compared with nontreated MCAO rats 24 h after reperfusion. These results indicate that atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide in transient focal ischemia.

Influence of age on stroke outcome following transient focal ischemia

2005 ◽  
Vol 103 (4) ◽  
pp. 687-694 ◽  
Author(s):  
Charles L. Rosen ◽  
Vincent A. Dinapoli ◽  
Tomoaki Nagamine ◽  
Todd Crocco
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Animal Models ◽  
Young Animal ◽  
The Elderly ◽  
Female Rats ◽  
Sprague Dawley ◽  
Content Type ◽  
Transient Focal Ischemia ◽  
Fine Print

Object. More than 100 clinical trials based on animal models have failed to identify a clinically effective neuroprotectant for stroke. Current models of stroke do not account adequately for aging nor do they incorporate the use of female animals. The authors evaluated the pathological and physiological differences in stroke in young, adult, and elderly female rats. Methods. Three groups of female Sprague—Dawley rats were studied. Nine rats were divided into three groups: young (3 months); adult (9 months); and elderly (18 months). Intraluminal filament occlusion was performed for 120 minutes while cerebral blood flow was monitored. Physiological parameters were assessed. Infarction volumes were quantified at 24 hours. The mean arterial pressure increased in the young animals (103 ± 3.51 mm Hg; p < 0.001) during occlusion and decreased in the elderly group (65.56 ± 3.03 mm Hg; p < 0.01). Cortical and striatal infarction volumes in the elderly animals were substantially larger (p < 0.05). Young animals exhibited a lesser decrement in cerebral blood flow (p < 0.05) during ischemia. Conclusions. This study reinforces the importance of using older animals for the researching and treatment of stroke. Elderly animals show differences in response mechanisms, ischemic consequences, and histological changes. These differences may partially explain the current lack of success involved in using young-animal models to predict the clinical efficacy of neuroprotective agents.

Neuroprotective activity of tamoxifen in permanent focal ischemia

2003 ◽  
Vol 99 (1) ◽  
pp. 138-142 ◽  
Author(s):  
Harold K. Kimelberg ◽  
Yiqiang Jin ◽  
Carol Charniga ◽  
Paul J. Feustel
Keyword(s):  
Rat Model ◽  
Infarct Volume ◽  
Focal Ischemia ◽  
Neuroprotective Activity ◽  
Therapeutic Window ◽  
Protective Effects ◽  
Content Type ◽  
Mca Occlusion ◽  
Fine Print ◽  
Permanent Focal Ischemia

Object. The authors have previously shown that tamoxifen is effective in protecting brain tissue from ischemic injury in a rat model of reversible focal ischemia. In this study the authors tested whether similar protective effects are found in a rat model of permanent focal ischemia (permanent middle cerebral artery [MCA] occlusion). Methods. Tamoxifen (20 mg/kg) was given either before or at 1, 3, or 6 hours after permanent MCA occlusion in rats, with sustaining doses given every 12 hours thereafter. The median infarct volume measured after 72 hours was 113 mm3 for the vehicle (dimethyl sulfoxide) groups, compared with 31 mm3 for pretreatment, and 14, 27, and 98 mm3 for treatment beginning at 1, 3, and 6 hours, respectively, after permanent MCA occlusion. The infarct reductions in the pretreated and 1- and 3-hour post—MCA occlusion treatment groups were statistically significant (p < 0.05). At 3 hours after permanent MCA occlusion, tamoxifen also significantly reduced the infarct size at a lower dose of 5 mg/kg but not at 1 mg/kg; the same sustaining doses of 5 and 1 mg/kg were given every 12 hours. Conclusions. Tamoxifen is as effective in a permanent model of focal ischemia as it is in the reversible model, and the therapeutic window of 3 hours after initiation of ischemia is identical. This effectiveness is likely due to several properties of the drug, including its known ability to cross the blood—brain barrier. Because tamoxifen has been administered safely in humans for treatment of gliomas at similarly high doses to those used in this study, it may be clinically useful as a treatment for ischemic stroke.

Insulin reduction of cerebral infarction due to transient focal ischemia

1995 ◽  
Vol 82 (2) ◽  
pp. 262-268 ◽  
Author(s):  
Mark G. Hamilton ◽  
Bruce I. Tranmer ◽  
Roland N. Auer
Keyword(s):  
Blood Glucose ◽  
Focal Ischemia ◽  
Artery Occlusion ◽  
Content Type ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
The Mean ◽  
Transient Focal Ischemia ◽  
Cerebral Artery Occlusion ◽  
Total Damage

✓ Insulin has recently been shown to ameliorate damage in models of global brain ischemia. To determine whether insulin is also neuroprotective in focal ischemia, 20 rats were given 2 to 3 IU/kg insulin and 10 did not receive treatment prior to normothermic transient middle cerebral artery occlusion for 2 hours at a blood pressure of 60 mm Hg. To further elucidate whether infarction volume is influenced by variations in blood glucose levels within the physiological range, blood glucose was raised in 10 of the insulin-treated animals to levels comparable with the untreated controls. At 1-week survival, damage was assessed using quantitative neuropathological examination of 25 coronal planes. It was found that preischemic insulin lowered the mean intraischemic blood glucose level from 8.4 ± 0.2 mM (µ ± standard error of the mean) in the control group to 3.4 ± 0.2 mM and reduced total damage (atrophy plus cortical and striatal necrosis), expressed as the percentage of the normal hemisphere, from a control of 28.5% ± 2.9% to 14.5% ± 1.6% (p < 0.005). Coadministration of glucose and insulin resulted in a mean intraischemic blood glucose level of 10.1 ± 0.5 mM, with 27.0% ± 2.4% total damage (p = 0.96, compared with control). Total ischemic damage showed an independent correlation with blood glucose levels (r = 0.67, p = 0.0018). The findings indicate that insulin benefits transient focal ischemia and that reducing the blood glucose from 8 to 9 mM to the low-normal range of 3 to 4 mM with insulin dramatically reduces subsequent infarction. The data suggest that the neuroprotective mechanism of insulin action in focal middle cerebral artery occlusion is mediated predominantly via alterations in blood glucose levels. In comparison to global ischemia, focal ischemia appears to show only a minor direct central nervous system effect of insulin. In clinical situations in which transient focal ischemia to the hemisphere can be anticipated, insulin-induced hypoglycemia of a mild degree may be beneficial.

Cation dysfunction associated with cerebral ischemia followed by reperfusion: a comparison of microdialysis and ion-selective electrode methods

2002 ◽  
Vol 97 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Michael F. Stiefel ◽  
Anthony Marmarou
Keyword(s):  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Extracellular Potassium ◽  
Sprague Dawley ◽  
Microdialysis Probe ◽  
Content Type ◽  
Minute Period ◽  
Bilateral Carotid ◽  
Extracellular Ions ◽  
Fine Print

Object. Disruption of ionic homeostasis during ischemia is a well-characterized event and is identified by a rise in the concentration of extracellular potassium [K+]e, with a concomitant reduction in the concentration of extracellular sodium [Na+]e. Results of clinical studies in which microdialysis has been used, however, have shown only modest changes in the levels of extracellular ions. The object of this study was to measure [K+]e and [Na+]e by using ion-selective electrodes (ISEs) and to compare these measurements with those obtained using the well-established method of microdialysis. Methods. Fifteen Sprague—Dawley rats were separated into three groups. Five animals were subjected to a 15-minute period of ischemia, and another five animals to a 60-minute period of ischemia; animals in both of these groups received K+-free microdialysis perfusate. The third group of five rats underwent a 60-minute period of ischemia and received a reduced-Na+ microdialysis perfusate. Transient forebrain ischemia was produced by bilateral carotid artery occlusion combined with hypotension. A custom-fabricated glass Na+ electrode and a flexible plastic K+ and reference electrodes were used to monitor extracellular ion transients. Microdialysis samples were obtained with the aid of a 2-mm microdialysis probe that was perfused with K+-free mock cerebrospinal fluid at a rate of 2 µl/minute. Baseline measurements of [K+]e and [Na+]e, obtained using ISEs, were 3.41 ± 0.09 mM and 145 ± 7.75 mM, respectively. Ischemia resulted in a rapid accumulation of [K+]e (in animals subjected to 15 minutes of ischemia, the concentration was 41.9 ± 13.7 mM; and in animals subjected to 60 minutes of ischemia, the concentration was 66.9 ± 11.5 mM), with a concomitant decrease in [Na+]e (in animals subjected to 15 minutes of ischemia, the concentration was 71.7 ± 2.9 mM; and in animals subjected to 60 minutes of ischemia, the concentration was 74.7 ± 1.9 mM). A comparison of microdialysis and ISE methods revealed that microdialysis underestimated the [K+]e changes and was insensitive to concomitant [Na+]e alterations that occur during ischemia. Conclusions. Our results indicate that the flexible ISE is a reliable and accurate tool for monitoring ionic dysfunction that accompanies brain injury.

scholarly journals NEUROPROTECTIVE EFFECTS OF KAPPA OPIOID RECEPTOR AGONIST IN TRANSIENT FOCAL ISCHEMIA

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 355-355
Author(s):  
Anish Bhardwaj ◽  
Thomas Jk Toung ◽  
Jeffrey R Kirsch ◽  
Raymond C Koehler ◽  
Patricia D Hurn ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Receptor Agonist ◽  
Focal Ischemia ◽  
Artery Occlusion ◽  
Kappa Opioid Receptor ◽  
Triphenyltetrazolium Chloride ◽  
Neuroprotective Effects ◽  
Opioid Receptor Agonist ◽  
Infarction Volume ◽  
Transient Focal Ischemia

P91 Kappa ( K ) opioid receptors have been implicated in neuroprotection from ischemic neuronal injury. We tested the effects of a selective and specific K -opioid receptor agonist, BRL 52537 and antagonist, norBNI on infarction volume following transient focal ischemia in the rat. Under controlled conditions of normoxia, normocarbia and normothermia, halothane (1–2%)-anesthetized male Wistar rats (250–300 g) were subjected to 2 hr of middle cerebral artery occlusion (MCAO) by the intraluminal occlusion-technique using laser Doppler perfusion to assess intensity of ischemia. In a blinded randomized fashion, rats were treated with either vehicle (saline) or 1 mg/Kg/hr BRL 52537 with continuous iv infusion starting 15 min prior to MCAO. In a second set of experiments, rats were treated with vehicle (saline), 1 mg/Kg/hr BRL 52537 , 1 or 5 mg/Kg/hr norBNI starting at onset of reperfusion. All infusions were at a rate of 0.5 ml/hr and continued until the end of the experiment. Infarction volume was assessed by triphenyltetrazolium chloride (TTC) staining at 22 hr of reperfusion in all rats. TTC-determined infarction volume of ipsilateral caudoputamen (CP) complex in rats pretreated with BRL 52537 (N=7; 29±11 mm 3 ; p<0.05) (mean±SEM) and cortex (61±32 mm 3 ; p<0.05) was smaller than in rats treated with saline (N=7;72±4 mm3 and 174 ±24 mm 3 , respectively). Similarly, rats treated with BRL 52537 at the onset of reperfusion had smaller infarction volume in CP complex (N=10;35±9 mm 3 ) and cortex (73±32 mm 3 ) compared to saline (N=10;64±5 mm 3 and 148±23 mm 3 , respectively). Rats treated with norBNI (N=10) at the onset of reperfusion had similar infraction volumes in the CP complex and the cortex as compared to saline controls. These data demonstrate that K -opioid receptor agonist provides significant neuroprotection when given as a pretreatment as well as following 2 hr of transient focal ischemia.

Role of a synthetic pyrimidine compound, MS-818, in reduction of infarct size and amelioration of sensorimotor dysfunction following permanent focal cerebral ischemia in rats

2002 ◽  
Vol 96 (6) ◽  
pp. 1072-1076 ◽  
Author(s):  
Tetsuryu Mitsuyama ◽  
Takakazu Kawamata ◽  
Fumitaka Yamane ◽  
Akira Awaya ◽  
Tomokatsu Hori
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Biological Activities ◽  
Infarct Volume ◽  
Saline Control ◽  
Control Group ◽  
Sprague Dawley ◽  
Triphenyltetrazolium Chloride ◽  
Content Type ◽  
Fine Print

Object. A synthetic heterocyclic pyrimidine compound, MS-818 (2-piperadino-6-methyl-5-oxo-5,6-dihydro-(7H) pyrrolo-[3,4-d] pyrimidine maleate) is reported to have a variety of biological activities including neurite outgrowth, astrocyte differentiation, suppression of neuronal apoptosis, regeneration of injured peripheral nerves, fracture repairs, angiogenesis, and superovulation. To be able to explicate the neurotrophic effects of MS-818, the authors evaluated its effect on the reduction of infarct volume and amelioration of sensorimotor dysfunction in a rat model of focal ischemia. Methods. Forty male Sprague—Dawley rats were subjected to right middle cerebral artery occlusion and assigned to one of four treatment groups (10 animals in each group). The MS-818 (1, 5, or 10 mg/kg) or phosphate-buffered saline (control group) was administered intraperitoneally at onset of ischemia and again 24 hours later. The rats were killed 48 hours after they underwent surgery to induce stroke, and infarct volume was determined using an image-analysis computer software program following staining with 2,3,5-triphenyltetrazolium chloride. Postischemic neurological deficit and body weight were also assessed. Conclusions. Significant reductions in infarct volume (total and cortical infarction) were found in all the MS-818—treated groups compared with the control group. Furthermore, MS-818 induced significant amelioration of sensorimotor dysfunction, as indicated by the results of forelimb and hindlimb placing tests. The present findings suggest that MS-818, which has a much smaller molecular weight than neurotrophic peptides, represents a new approach to the treatment of focal cerebral ischemia.

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