dizocilpine-maleate and Brain-Infarction

Ischemic stroke is the most frequent cause of persistent neurological disability in Western societies. New treatment strategies are required and effective in vivo models are crucial to their development.. The current study establishes a novel in vivo rat model of focal striatal ischemia using the vasoconstrictive agent N5-(1-iminoethyl)-L-ornithine (L-NIO). Adult male Sprague Dawley rats received a unilateral intrastriatal infusion of L-NIO in combination with jugular vein occlusion.. L-NIO infusion was associated with zero mortality, low surgical complexity and a reproducible infarct, providing advantages over established models of focal ischemia. The mean infarct volume of 8.5±5.3% of the volume of the contralateral striatum resulted in blood-brain barrier dysfunction, neuronal hypoxia and ongoing neurodegeneration. Further characteristics of ischemic stroke were exhibited, including robust microglia/macrophage and astroglial responses lasting at least 35 days post-ischemia, in addition to chronic motor function impairment.. When compared to other models such as the MCAo models, the consistency in regions affected, high success rate, zero mortality, reduced surgical complexity and minimal welfare requirements of the L-NIO model make it ideal for initial high-throughput investigations into preclinical efficacy and proof of principle studies of acute ischemic stroke interventions.. We propose that the L-NIO rat model of focal striatal ischemia does not replace the use of other ischemic stroke models. Rather it provides a new, complementary tool for initial preclinical investigations into the treatment of ischemic stroke.

Topics: Animals; Blood-Brain Barrier; Brain Infarction; Brain Ischemia; Corpus Striatum; Disease Models, Animal; Dizocilpine Maleate; Dose-Response Relationship, Drug; Enzyme Inhibitors; Gene Expression Regulation; Jugular Veins; Male; Movement Disorders; Nerve Degeneration; Nerve Tissue Proteins; Neurons; Neuroprotective Agents; Ornithine; Rats; Rats, Sprague-Dawley; Time Factors

Microinfarctions are present in the aged and injured human brain. Their clinical relevance is controversial, with postulated sequelae ranging from cognitive sparing to vascular dementia. To address the consequences of microinfarcts, we used controlled optical methods to create occlusions of individual penetrating arterioles or venules in rat cortex. Single microinfarcts, targeted to encompass all or part of a cortical column, impaired performance in a macrovibrissa-based behavioral task. Furthermore, the targeting of multiple vessels resulted in tissue damage that coalesced across cortex, even though the intervening penetrating vessels were acutely patent. Post-occlusion administration of memantine, a glutamate receptor antagonist that reduces cognitive decline in Alzheimer's disease, ameliorated tissue damage and perceptual deficits. Collectively, these data imply that microinfarcts likely contribute to cognitive decline. Strategies that have received limited success in the treatment of ischemic injury, which include therapeutics against excitotoxicity, may be successful against the progressive nature of vascular dementia.

Topics: Animals; Brain Infarction; Brain Mapping; Calcium; Cognition Disorders; Disease Models, Animal; Dizocilpine Maleate; Glial Fibrillary Acidic Protein; Humans; Imaging, Three-Dimensional; Infarction, Middle Cerebral Artery; Male; Memantine; Microscopy, Confocal; Microvessels; Models, Biological; Neural Pathways; Neuroprotective Agents; Phosphopyruvate Hydratase; Psychomotor Performance; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Somatosensory Cortex; Vibrissae

Topics: Animals; Brain Infarction; Brain Ischemia; Depressive Disorder; Dizocilpine Maleate; Eliminative Behavior, Animal; Neuroprotective Agents; Rats; Rats, Wistar

Recombinant tissue plasminogen activator (rt-PA) treatment improves functional outcome after acute ischemic stroke, inducing reperfusion by its thrombolytic activity. Conversely, there is evidence that rt-PA can mediate neuronal damage after ischemic brain injury in vivo. In addition to other mechanisms, enhancement of N-methyl-D-aspartate (NMDA) receptor signalling has been proposed to underlie rt-PA-mediated neurotoxicity. However, the role of poly(ADP-ribose) polymerase-1 (PARP-1) activation, which mediates postischemic excitotoxic cell death, in rt-PA-mediated aggravation of ischemic brain injury has not been established and was therefore addressed in this study. After permanent focal cerebral ischemia, intravenous rt-PA application significantly increased early postischemic PARP-1 activation within ischemic hemispheres and infarct volumes compared with control mice without affecting cerebral blood flow. Rt-PA induced increase in PARP-1 activation, and infarct volumes could be blocked by the PARP inhibitor 3-aminobenzamide. Moreover, the rt-PA-induced increase in PARP-1 activation was also prevented by the NMDA antagonist MK-801. In summary, we demonstrate that rt-PA treatment enhances postischemic PARP-1 activation, which contributes to rt-PA induced aggravation of ischemic brain injury in vivo. Furthermore, we provide evidence that NMDA receptor activation is required for rt-PA-mediated effects on postischemic PARP-1 activation.

Topics: Animals; Benzamides; Blood Gas Analysis; Blood Pressure; Blood-Brain Barrier; Brain; Brain Infarction; Brain Ischemia; Dizocilpine Maleate; Enzyme Activation; Ischemic Attack, Transient; Male; Mice; Mice, Inbred C57BL; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Receptors, N-Methyl-D-Aspartate; Recombinant Proteins; Tissue Plasminogen Activator

Transient focal ischemia produced by local infusion of endothelin-1 (ET1) in the territory of the middle cerebral artery has been proposed as a potentially useful model for the screening of drugs developed for the treatment of thrombo-embolic stroke. However, most of the data rely exclusively on the assessment of the infarct volume, which is only a partial predictor of the neurological outcome of stroke. Here, we have validated the model using a multimodal approach for the assessment of neuroprotection, which includes (i) determination of the infarct volume by 2,3,5-triphenyltetrazolium chloride staining; (ii) an in-depth behavioral analysis of the neurological deficit; and (iii) an EEG analysis of electrophysiological abnormalities in the peri-infarct somatosensory forelimb cortical area, S1FL. The non-competitive NMDA receptor antagonist, MK-801 (3 mg/kg, injected i.p. 20 min after ET1 infusion in conscious rats) could reduce the infarct volume, reverse the EEG changes occurring at early times post-ET1, and markedly improve the neurological deficit in ischemic animals. The latter effect, however, was visible at day 3 post-ET1, because the drug itself produced substantial behavioral abnormalities at earlier times. We conclude that a multimodal approach can be applied to the ET1 model of focal ischemia, and that MK-801 can be used as a reference compound to which the activity of safer neuroprotective drugs should be compared.

Topics: Analysis of Variance; Animals; Behavior, Animal; Brain Infarction; Disease Models, Animal; Dizocilpine Maleate; Electroencephalography; Endothelin-1; Functional Laterality; Ischemic Attack, Transient; Male; Neuroprotective Agents; Rats; Rats, Wistar; Severity of Illness Index; Somatosensory Cortex; Tetrazolium Salts

In recent years, serum S100B has been used as a secondary endpoint in some clinical trials in which serum S100B has successfully indicated the benefits or harm done by tested agents. However, few reports describe serum S100B as an indicator of the efficiency of neuroprotective treatment in experimental stroke models, although serum S100B may be as useful for histological and functional evaluations of neuroprotective treatments as in clinical trials. The present study seeks to investigate the possibility that serum S100B reflects successful combined treatment with rt-PA and MK-801 in an embolic stroke rat model. An embolic stroke model of rats was produced via intra-arterial autologous clot injection, after which serum S100B levels were measured 24 h after embolism and the association of serum S100B levels with brain edema volume and infarct volume investigated. Combination treatment with rt-PA and MK-801 significantly attenuated the elevation of serum S100B, which correlated significantly with reductions in brain edema resulting from combination treatment. These findings suggest that serum S100B is a simple and objective indicator for successful neuroprotective therapy and would help seeking partners for combination treatments with rt-PA in an embolic stroke rat model. Assessments of the efficacy of combination treatments with rt-PA and neuroprotectants using serum S100B would facilitate translational research bridging laboratory and bedsides because serum S100B functions as a common marker in both rats and human patients suffering from ischemic stroke.

Topics: Animals; Brain Edema; Brain Infarction; Disease Models, Animal; Dizocilpine Maleate; Drug Therapy, Combination; Fibrinolytic Agents; Laser-Doppler Flowmetry; Male; Nerve Growth Factors; Neuroprotective Agents; Rats; Regional Blood Flow; S100 Calcium Binding Protein beta Subunit; S100 Proteins; Stroke; Thromboembolism; Tissue Plasminogen Activator

Neuregulin-1 (NRG-1) is a growth factor with potent neuroprotective capacity in ischemic stroke. We recently showed that NRG-1 reduced neuronal death following transient middle cerebral artery occlusion (tMCAO) by up to 90% with an extended therapeutic window. Here, we examined the neuroprotective potential of NRG-1 using a permanent MCAO ischemia (pMCAO) rat model. NRG-1 reduced infarction in pMCAO by 50% when administered prior to ischemia. We previously demonstrated using gene expression profiling that pMCAO was associated with an exaggerated excitotoxicity response compared to tMCAO. Therefore, we examined whether co-treatment with an inhibitor of excitotoxicity would augment the effect of NRG-1 following pMCAO. Both NRG-1 and the N-methyl-D-aspartate (NMDA) antagonist MK-801 similarly reduced infarct size following pMCAO. However, combination treatment with both NRG-1 and MK-801 resulted in greater neuroprotection than either compound alone, including a 75% reduction in cortical infarction compared to control. Consistent with these findings, NRG-1 reduced neuronal death using an in vitro ischemia model and this effect was augmented by MK-801. These results demonstrate the efficacy of NRG-1 in pMCAO rat focal ischemia model. Our findings further indicate the potential clinically relevance of NRG-1 alone or as a combination strategy for treating ischemic stroke.

Topics: Animals; Brain Infarction; Brain Ischemia; Cell Death; Cell Line, Tumor; Disease Models, Animal; Dizocilpine Maleate; Glucose; Hypoxia; Male; Neuregulin-1; Neuroblastoma; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Tetrazolium Salts

Ginkgo biloba exerts many pharmacological actions. It possesses antioxidant properties, the ability of neurotransmitter/receptor modulation and antiplatelet activation factor. This research is designed to investigate the neuroprotective effects of long-term treatment with EGb761 (a standard form of the extract of Ginkgo biloba leaf) in combination with MgSO(4), FK506, or MK-801 on the infarct volume of male gerbils' brain induced by unilateral middle cerebral artery occlusion (MCAO). Thirty-five gerbils fed a standard diet were intragastrically given water or EGb761 (100 mg/kg/day) for one week. Five randomized groups were established: control (n = 7), EGb761 (n = 8), EGb761 + MgSO(4) (n = 7), EGb761 + FK506 (n = 7), and EGb761 + MK-801 (n = 6). The three drug-combination groups were injected with MgSO(4) (90 mg/kg), FK506 (0.5 mg/kg), or MK-801 (1 mg/kg), respectively 30 min before MCAO. Gerbils were anesthetized and craniectomized to expose the right middle cerebral artery (MCA). The right MCA was constricted with an 8-0 suture to produce a permanent ligation for 24 hours. Postmortem infarct volumes were determined by quantitative image analysis of 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections. Results showed that the total infarct volumes of the four treated groups either EGb761 alone or in combination with drugs were lower than the control group by 36.1% (EGb761 alone), 40.3% (EGb761 + MgSO(4)), 35.3% (EGb761 + FK506), and 56.4% (EGb761 + MK-801), respectively (p < 0.01). The main affected areas of the brain in the four treated groups were significantly focused between 4 and 6 mm from the frontal pole, when compared to the control group (p < 0.01). All animals in the five groups had infarctions in both cortex and subcortex. These results indicate that long-term pre-treatment of EGb761 administered either alone or in combination with drugs significantly effective neuroprotection on infarct volume in gerbil ischemic brains.

Topics: Animals; Brain Infarction; Brain Ischemia; Dizocilpine Maleate; Drug Therapy, Combination; Gerbillinae; Ginkgo biloba; Infarction, Middle Cerebral Artery; Magnesium Sulfate; Male; Neuroprotective Agents; Plant Extracts; Random Allocation; Tacrolimus; Treatment Outcome

Statins exert beneficial effects in brain diseases including stroke. Here, we investigated whether oral prophylactic atorvastatin provides long-term neuroprotection and functional recovery in permanent middle cerebral artery occlusion (pMCAO), and whether cerebral hemodynamics are affected. Male Long-Evans rats were treated with 10 mg/kg oral atorvastatin for 14 days and subjected to pMCAO. Cerebral hemodynamics were measured by bolus tracking MRI and laser Doppler flowmetry (LDF). Infarct volume was quantified at 1 week by T2-MRI and at 3 weeks by histology. Rats were also subjected to neuroscoring and cylinder test. The number of animals per group was 10. The infarct volumes were 100.8 +/- 8.2 and 47.3 +/- 5.5 mm(3) in vehicle, and 68.7 +/- 11.0 and 28.6 +/- 3.82 mm(3) in atorvastatin group at 7 and 21 days post-ischemia, respectively (mean +/- SEM). Atorvastatin significantly reduced infarct volume both at 7 and 21 days (P = 0.04 and 0.03, respectively, 1-way ANOVA). Interestingly, no improvement in cerebral hemodynamic parameters was observed in atorvastatin treated animals. The vehicle group recovered normal neuroscore at day 13, whereas atorvastatin group recovered already at day 10 after pMCAO. All treatment groups preferred to use the unaffected forelimb for rearing in Cylinder test, whereas the defected forelimb use was minimal in all groups. These results suggest that oral atorvastatin protects cerebral tissue against the subsequent pMCAO without influencing cerebral hemodynamic parameters, and it may well be that persons with ongoing atorvastatin treatment benefit in the incidence of stroke.

Topics: Animals; Atorvastatin; Behavior, Animal; Blood Circulation; Brain Infarction; Brain Ischemia; Dizocilpine Maleate; Heptanoic Acids; Infarction, Middle Cerebral Artery; Magnetic Resonance Imaging; Male; Motor Activity; Neuroprotective Agents; Psychomotor Performance; Pyrroles; Rats; Rats, Long-Evans; Recovery of Function; Staining and Labeling; Time; Time Factors

Computer-assisted procedures are used to measure infarct areas in animal stroke models, but this approach usually follows the less objective manual tracing of the boundaries of the infarct. Building on previously reported methodology using scanned images of triphenyltetrazolium chloride (TTC)-stained rat brains in the intraluminal thread model, we developed an objective method to assess ischemic damage in both the mouse and rat brains. The unique addition to our approach is the use of sham-treated animals, which thereby permits the removal of normal brain white matter from the ipsilateral injured brain. All brain sections per animal were scanned simultaneously using a Microtek Scanmaker 4 flatbed scanner. Color segmentation on full color images of 2 mm coronal brain sections was performed. Using Image Pro Plus (4.0) and color segmentation, ischemic and normal white matter areas were measured in the green channel and the entire brain area in the red channel. The percent of unstained tissue was calculated for sham-treated animals and for those with cerebral ischemia. By subtracting the average unstained area of the sham-treated group from the average unstained area from the ischemic group, the ischemic area was calculated. This methodology was validated using mouse and rat permanent and transient, focal ischemia models and MK-801 in the permanent ischemia models. MK-801, dosed at 3 mg/kg i.p. prior to the injury, reduced the injury by 75% in the mouse and 44% in the rat permanent occlusion models. The benefits of this methodology include: objectivity of the analysis of the ischemic injury, use of readily available software so that costs can be contained and removal of normal subcortical white matter from the calculation. This method should allow more consistent evaluation of changes in the infarct size, therefore, resulting in reduced variability and higher productivity.

Topics: Animals; Brain Infarction; Brain Ischemia; Carotid Arteries; Coloring Agents; Diagnostic Imaging; Disease Models, Animal; Dizocilpine Maleate; Image Processing, Computer-Assisted; Ischemic Attack, Transient; Laser-Doppler Flowmetry; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Stroke