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Lee JY, Castelli V, Bonsack B, García-Sánchez J, Kingsbury C, Nguyen H, Tajiri N, Borlongan CV. Eyeballing stroke: Blood flow alterations in the eye and visual impairments following transient middle cerebral artery occlusion in adult rats. Cell Transplant 2021; 29:963689720905805. [PMID: 32098493 PMCID: PMC7444237 DOI: 10.1177/0963689720905805] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Middle cerebral artery occlusion in rodents remains a widely used model
of ischemic stroke. Recently, we reported the occurrence of retinal
ischemia in animals subjected to middle cerebral artery occlusion,
owing in part to the circulatory juxtaposition of the ophthalmic
artery to the middle cerebral artery. In this study, we examined the
eye hemodynamics and visual deficits in middle cerebral artery
occlusion-induced stroke rats. The brain and eye were evaluated by
laser Doppler at baseline (prior to middle cerebral artery occlusion),
during and after middle cerebral artery occlusion. Retinal
function-relevant behavioral and histological outcomes were performed
at 3 and 14 days post-middle cerebral artery occlusion. Laser Doppler
revealed a typical reduction of at least 80% in the ipsilateral
frontoparietal cortical area of the brain during middle cerebral
artery occlusion compared to baseline, which returned to near-baseline
levels during reperfusion. Retinal perfusion defects closely
paralleled the timing of cerebral blood flow alterations in the acute
stages of middle cerebral artery occlusion in adult rats,
characterized by a significant blood flow defect in the ipsilateral
eye with at least 90% reduction during middle cerebral artery
occlusion compared to baseline, which was restored to near-baseline
levels during reperfusion. Moreover, retinal ganglion cell density and
optic nerve depth were significantly decreased in the ipsilateral eye.
In addition, the stroke rats displayed eye closure. Behavioral
performance in a light stimulus-mediated avoidance test was
significantly impaired in middle cerebral artery occlusion rats
compared to control animals. In view of visual deficits in stroke
patients, closely monitoring of brain and retinal perfusion via laser
Doppler measurements and examination of visual impairments may
facilitate the diagnosis and the treatment of stroke, including
retinal ischemia.
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Affiliation(s)
- Jea-Young Lee
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Vanessa Castelli
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Brooke Bonsack
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Julián García-Sánchez
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Chase Kingsbury
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Hung Nguyen
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Naoki Tajiri
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Cesar V Borlongan
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
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Blair NP, Leahy S, Nathanael Matei, Shahidi M. Control of retinal blood flow levels by selected combinations of cervical arterial ligations in rat. Exp Eye Res 2020; 197:108088. [PMID: 32502531 DOI: 10.1016/j.exer.2020.108088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
Abstract
The effect of various combinations of cervical arterial ligations (Combinations) on retinal blood flow (RBF) levels is not known in rats. We hypothesized: 1) No artery exists between the Circle of Willis and the eye, 2) Selective Combinations enable varying RBF levels between normal and zero, 3) In certain Combinations, the capillary bed of the head participates in supplying the eye. Twenty-six Combinations were studied in one eye of 20 Long-Evans rats under general anesthesia. RBF was quantitatively evaluated with our published imaging methods based on direct measurements of venous diameter and blood velocity from the displacement of fluorescent microspheres over time. For each Combination, one or more RBF values (runs) were measured. Data were obtained from 59 runs (2.9 ± 2.7 runs/rat). Levels of RBF ranged from normal to zero. An artery between the Circle of Willis and the eye was excluded. With some Combinations, flow traversed the capillary bed. Combinations were consolidated into five Groups based on the blood flow paths remaining after the ligations. A mixed linear model accounting for multiple measurements in the same eye demonstrated an effect of Group on RBF (P < 0.0005). By major source of ocular blood supply, the trend of RBF levels was: ipsilateral carotid artery > contralateral carotid artery > ipsilateral distal internal carotid artery retrograde from Circle of Willis. The findings advanced knowledge of the sources of blood supply to the rat eye and demonstrated a method of selective cervical arterial ligations for varying RBF levels with potential to impact future retinal ischemia research.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, United States.
| | - Sophie Leahy
- Department of Ophthalmology, University of Southern California, United States.
| | - Nathanael Matei
- Department of Ophthalmology, University of Southern California, United States.
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, United States.
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Matei N, Leahy S, Auvazian S, Thomas B, Blair NP, Shahidi M. Relation of Retinal Oxygen Measures to Electrophysiology and Survival Indicators after Permanent, Incomplete Ischemia in Rats. Transl Stroke Res 2020; 11:1273-1286. [PMID: 32207038 DOI: 10.1007/s12975-020-00799-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 12/28/2022]
Abstract
Studies in experimental ischemia models by permanent bilateral common carotid artery occlusion (BCCAO) have reported reduced retinal electrophysiological function, coupled with inner retinal degeneration and gliosis. In the current study, we tested the hypothesis that long-term (up to 14 days) BCCAO impairs oxygen delivery (DO2), which affects oxygen metabolism (MO2) and extraction fraction (OEF), electrophysiological function, morphology, and biochemical pathways. Twenty-one rats underwent BCCAO (N = 12) or sham surgery (N = 9) and were evaluated in separate groups after 3, 7, or 14 days. Electroretinography (ERG), optical coherence tomography, blood flow and vascular oxygen tension imaging, and morphological and biochemical evaluations were performed in both eyes. Reduced ERG b-wave amplitudes and delayed implicit times were reported at 3, 7, and 14 days following BCCAO. Total retinal blood flow, MO2, and DO2 were reduced in all BCCAO groups. OEF was increased in both 3- and 7-day groups, while no significant difference was observed in OEF at 14 days compared to the sham group. At 14 days following BCCAO, total and inner retinal layer thickness was reduced, while the outer nuclear layer thickness and gliosis were increased. There was an increase in nuclei containing fragmented DNA at 3 days following BCCAO. The compensatory elevation in OEF following BCCAO did not meet the tissue demand, resulting in the subsequent reduction of MO2. The associations between retinal MO2, DO2, and retinal function were shown to be significant in the sequelae of persistent ischemia. In sum, measurements of DO2, MO2, and OEF may become useful for characterizing salvageable tissue in vision-threatening pathologies.
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Affiliation(s)
- Nathanael Matei
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
| | - Sophie Leahy
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
| | - Selin Auvazian
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
| | - Biju Thomas
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
| | - Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA.
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Kingsbury C, Heyck M, Bonsack B, Lee JY, Borlongan CV. Stroke gets in your eyes: stroke-induced retinal ischemia and the potential of stem cell therapy. Neural Regen Res 2019; 15:1014-1018. [PMID: 31823871 PMCID: PMC7034271 DOI: 10.4103/1673-5374.270293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Stroke persists as a global health and economic crisis, yet only two interventions to reduce stroke-induced brain injury exist. In the clinic, many patients who experience an ischemic stroke often further suffer from retinal ischemia, which can inhibit their ability to make a functional recovery and may diminish their overall quality of life. Despite this, no treatments for retinal ischemia have been developed. In both cases, ischemia-induced mitochondrial dysfunction initiates a cell loss cascade and inhibits endogenous brain repair. Stem cells have the ability to transfer healthy and functional mitochondria not only ischemic neurons, but also to similarly endangered retinal cells, replacing their defective mitochondria and thereby reducing cell death. In this review, we encapsulate and assess the relationship between cerebral and retinal ischemia, recent preclinical advancements made using in vitro and in vivo retinal ischemia models, the role of mitochondrial dysfunction in retinal ischemia pathology, and the therapeutic potential of stem cell-mediated mitochondrial transfer. Furthermore, we discuss the pitfalls in classic rodent functional assessments and the potential advantages of laser Doppler as a metric of stroke progression. The studies evaluated in this review highlight stem cell-derived mitochondrial transfer as a novel therapeutic approach to both retinal ischemia and stroke. Furthermore, we posit the immense correlation between cerebral and retinal ischemia as an underserved area of study, warranting exploration with the aim of these treating injuries together.
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Affiliation(s)
- Chase Kingsbury
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Matt Heyck
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Brooke Bonsack
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Jea-Young Lee
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Cesar V Borlongan
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
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Karamian P, Burford J, Farzad S, Blair NP, Shahidi M. Alterations in Retinal Oxygen Delivery, Metabolism, and Extraction Fraction During Bilateral Common Carotid Artery Occlusion in Rats. Invest Ophthalmol Vis Sci 2019; 60:3247-3253. [PMID: 31343655 PMCID: PMC6660186 DOI: 10.1167/iovs.19-27227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Purpose The purpose of the current study was to investigate alterations in retinal oxygen delivery, metabolism, and extraction fraction and elucidate their relationships in an experimental model of retinal ischemia. Methods We subjected 14 rats to permanent bilateral common carotid artery occlusion using clamp or suture ligation, or they underwent sham procedure. Within 30 minutes of the procedure, phosphorescence lifetime imaging was performed to measure retinal vascular oxygen tension and derive arterial and venous oxygen contents, and arteriovenous oxygen content difference. Fluorescent microsphere and red-free retinal imaging were performed to measure total retinal blood flow. Retinal oxygen delivery rate (DO2), oxygen metabolism rate (MO2), and oxygen extraction fraction (OEF) were calculated. Results DO2 and MO2 were lower in ligation and clamp groups compared to the sham group, and also lower in the ligation group compared to the clamp group (P ≤ 0.05). OEF was higher in the ligation group compared to clamp and sham groups (P ≤ 0.03). The relationships of MO2 and OEF with DO2 were mathematically modeled by exponential functions. With moderate DO2 reductions, OEF increased while MO2 minimally decreased. Under severe DO2 reductions, OEF reached a maximum value and subsequently MO2 decreased with DO2. Conclusions The findings improve knowledge of mechanisms that can maintain MO2 and may clarify the pathophysiology of retinal ischemic injury.
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Affiliation(s)
- Preny Karamian
- Department of Ophthalmology, University of Southern California, Los Angeles, California, United States
| | - James Burford
- Department of Ophthalmology, University of Southern California, Los Angeles, California, United States
| | - Shayan Farzad
- Department of Ophthalmology, University of Southern California, Los Angeles, California, United States
| | - Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, Los Angeles, California, United States
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Kato H, Kanai Y, Watabe T, Ikeda H, Horitsugi G, Hatazawa J. Quantitative measurement of regional cerebral blood flow and oxygen metabolism in a rat model of cerebral hypoperfusion. Brain Res 2019; 1719:208-216. [PMID: 31132338 DOI: 10.1016/j.brainres.2019.05.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 05/07/2019] [Accepted: 05/23/2019] [Indexed: 10/26/2022]
Abstract
This study was aimed at evaluating the regional changes in the cerebral metabolic rate of oxygen (CMRO2) in relation to the cerebral blood flow (CBF) in the bilateral common carotid artery occlusion (BCAO) rat model. Ligation of the bilateral common carotid arteries (or a sham operation in control animals) was performed in 10-week-old male Wistar rats. O-15 PET images were acquired in the subacute phase (1 week after the surgery) and chronic phase (6 weeks after the surgery) with the animals under anesthesia, using a small-animal PET system and the O-15 gas steady-state inhalation method with arterial blood sampling developed in our previous study. Histopathological staining by Klüver-Barrera method and immunocytochemistry staining by glial fibrillary acidic protein were performed. Cognitive function was tested by using the apparatus of Y-maze. Significantly lower CBF and higher oxygen extraction fraction were observed in broad areas of the cerebrum in the subacute phase in the BCAO rats, with recovery in the chronic phase. A stable decrease of the CMRO2 in the subacute phase of arterial occlusion and later was observed in the BCAO rat model, mainly in the anterior cerebral artery territory. Atrophy and rarefaction of corpus callosum were found in the BCAO in the chronic phase. Activity of astrocytes in the BCAO was prominent in the both phases. Working memory was impaired in the BCAO in the chronic phase. Regional changes in cerebral perfusion and oxygen metabolism in the subacute and chronic phases of arterial occlusion were clarified in a rat model of BCAO by quantitative O-15 PET based on the steady-state method.
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Affiliation(s)
- Hiroki Kato
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan.
| | - Yasukazu Kanai
- Kansai BNCT Medical Center, Osaka Medical College, Osaka, Japan
| | - Tadashi Watabe
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hayato Ikeda
- Cyclotron and Radioisotope Center Division of Radiation Protection and Safety Control, Tohoku University, Sendai, Japan
| | - Genki Horitsugi
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
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Baker WB, Sun Z, Hiraki T, Putt ME, Durduran T, Reivich M, Yodh AG, Greenberg JH. Neurovascular coupling varies with level of global cerebral ischemia in a rat model. J Cereb Blood Flow Metab 2013; 33:97-105. [PMID: 23032485 PMCID: PMC3597370 DOI: 10.1038/jcbfm.2012.137] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this study, cerebral blood flow, oxygenation, metabolic, and electrical functional responses to forepaw stimulation were monitored in rats at different levels of global cerebral ischemia from mild to severe. Laser speckle contrast imaging and optical imaging of intrinsic signals were used to measure changes in blood flow and oxygenation, respectively, along with a compartmental model to calculate changes in oxygen metabolism from these measured changes. To characterize the electrical response to functional stimulation, we measured somatosensory evoked potentials (SEPs). Global graded ischemia was induced through unilateral carotid artery occlusion, bilateral carotid artery occlusion, bilateral carotid and right subclavian artery (SCA) occlusion, or carotid and SCA occlusion with negative lower body pressure. We found that the amplitude of the functional metabolic response remained tightly coupled to the amplitude of the SEP at all levels of ischemia observed. However, as the level of ischemia became more severe, the flow response was more strongly attenuated than the electrical response, suggesting that global ischemia was associated with an uncoupling between the functional flow and electrical responses.
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Affiliation(s)
- Wesley B Baker
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Aytac E, Seymen HO, Uzun H, Dikmen G, Altug T. Effects of iloprost on visual evoked potentials and brain tissue oxidative stress after bilateral common carotid artery occlusion. Prostaglandins Leukot Essent Fatty Acids 2006; 74:373-8. [PMID: 16687243 DOI: 10.1016/j.plefa.2006.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Accepted: 03/19/2006] [Indexed: 11/18/2022]
Abstract
Effects of iloprost on visual evoked potentials and oxidant/antioxidant status were evaluated after bilateral carotid artery occlusion. There were three experimental groups; Sham (S) group (n=10), bilateral common carotid artery occluded (BCCAO) group (n=10) and after bilateral common carotid artery occlusion, iloprost-treated (BCCAOI) group (n=10). Iloprost was administered (0.5ng/kg/day) for 10 days by intraperitoneal injection. N(2) and P(2) latencies (millisecond) and N(2)-P(2) (microV) amplitudes were recorded 10 days after operation for evaluating VEPs. The rats were sacrificed by decapitation immediately after recording of VEPs. Malondialdehyte (MDA), glutathione (GSH), Cu-Zn superoxide dysmutase (SOD) were studied spectrophotometricly. After BCCAO, MDA levels were increased, GSH and Cu-Zn SOD levels were decreased significantly, and abnormal VEPs parameters were observed. Iloprost treatment after BCCAO decreased MDA and increased GSH levels significantly. Low Cu-Zn SOD levels and impaired VEPs remained after iloprost treatment. Iloprost treatment may protect the brain tissue from oxidative damage during cerebral hypoperfusion.
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Affiliation(s)
- Erman Aytac
- Istanbul University, Cerrahpasa Medical Faculty, Department of Physiology, Cerrahpasa, Istanbul, Turkey
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Davidson CM, Pappas BA, Stevens WD, Fortin T, Bennett SA. Chronic cerebral hypoperfusion: loss of pupillary reflex, visual impairment and retinal neurodegeneration. Brain Res 2000; 859:96-103. [PMID: 10720618 DOI: 10.1016/s0006-8993(00)01937-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adult rats underwent permanent bilateral occlusion of the common carotid arteries (2VO) to determine the effect of chronic cerebral ischemia on vision and retina. They were monitored post-surgically for the presence of the pupillary reflex to light. Some rats were tested for 6 months post-surgically on a radial arm maze task and then tested in another water-escape task which explicitly tested visual function. Another group of rats were tested post-surgically for 3 months on a task which simultaneously assessed visual and tactile discrimination ability. The thicknesses of the retinal sub-layers were then measured for some rats. Fourteen of the 25 rats that underwent 2VO lost the pupillary reflex. This seemed to occur within 5 days. Rats that lost the pupillary reflex but not rats whose reflex was intact, were impaired on all visually guided mazes. Tactile discrimination ability was unaffected. Only rats that lost the pupillary reflex showed reduced thickness of the retinal outer nuclear and plexiform layers, reduced cell density in the retinal ganglion cell layer and astrocytosis and degeneration of the optic tract. We conclude that 2VO can eliminate the pupillary reflex. Photoreceptors and retinal ganglion cells degenerate, but it is unclear if these are the cause(s) or result(s) of the loss of the pupillary reflex. These effects are accompanied by impairment of visually guided behavior. The possibility that visual system damage may also occur in acute ischemia merits further investigation.
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Affiliation(s)
- C M Davidson
- Department of Pathology, Queen's University, Kingston ON, Canada
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Heim C, Zhang J, Lan J, Sieklucka M, Kurz T, Riederer P, Gerlach M, Sontag KH. Cerebral oligaemia episode triggers free radical formation and late cognitive deficiencies. Eur J Neurosci 2000; 12:715-25. [PMID: 10712651 DOI: 10.1046/j.1460-9568.2000.00916.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sixty minutes of cerebral oligaemic hypoxia, induced by bilateral clamping of the carotid arteries (BCCA) in pentobarbital-anaesthetized normotensive rats, induces a late progressive cognitive decline when compared with sham-operated controls. Analysis at BCCA of hippocampal metabolism using microdialysis showed increased release of glutamate, aspartate and gamma-aminobutyric acid, followed by a progressive rise in the formation of hydroxyl free radicals measured as 2,3-dihydroxybenzoic acid (2,3-DHBA), their reaction product with salicylate, though only in the re-perfusion phase. In the striatum increased dopamine release occurred during BCCA, whereas glutamate and aspartate showed an increase only during the late re-perfusion phase. gamma-Aminobutyric acid (GABA) concentration increased during BCCA and early re-perfusion. An increase in 2,3-DHBA was seen during BCCA, and persisted over 2 h of re-perfusion. Six and 13 months after surgery, though not as early as 3 months, BCCA-treated rats perform worse than sham-operated controls in a water-maze, where decreased swimming speed reveals striatal dysfunction, while hippocampal dysfunction manifested as diminished spatial bias. These results show that cerebral oligaemia, similarly to cerebral ischaemia, leads to increased extracellular dopamine, aspartate and glutamate, and the production of hydroxyl radicals in structures associated with learning and memory processes. Unlike cerebral ischaemia, in cerebral oligaemia the appearance of spatial memory deficits is delayed.
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Affiliation(s)
- C Heim
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
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Heim C, Arzberger T, Sontag T, Xiao A, Herbinger KH, Weindl A, Sontag KH. Progressive degeneration of dopamine system functions after transient cerebral oligemia in rats. Brain Res 1999; 851:235-46. [PMID: 10642849 DOI: 10.1016/s0006-8993(99)02193-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A reduction in cerebral blood flow to oligemic levels was achieved in pentobarbital-anesthetized adult rats by clamping both carotid arteries (BCCA) for 60 min. To assess the extent to which the animals' dopaminergic system was affected over an increasing time span, their spontaneous locomotor activity in an unfamiliar environment and in response to the subcutaneous administration of apomorphine was tested at various times after either BCCA or sham operation. Eight to 14 days after the operation, it was possible to observe a diminished locomotor activity in response to apomorphine injection in BCCA as compared with sham-operated animals, while oral stereotypical behavior such as licking was increased. At 3 months, there was only a subtle decrease in apomorphine-induced locomotor activity, and stereotypical behavior was similar in both groups. At 7 months, the BCCA rats covered shorter distances than sham-operated controls during the habituation phase; after apomorphine injection, more stereotypic movements, such as, e.g., sniffing, were observed, and less running. Twelve months after surgery, no further differences could be observed between the two groups during the habituation phase, but the injection of apomorphine led to increased stereotypic sniffing movements, rearing and locomotor activity in BCCA animals to a greater extent than in the controls. At 12 months, sensorimotor disturbances elicited by the rota rod test, which were only transiently observed at 11 weeks and 7 months, did not appear any different from the normal age-related motor decline of the sham-operated controls. The animals' motor co-ordination in the chimney test was not significantly disturbed during the time between 7 and 12 months after surgery. At 15 months, nocturnal locomotor activities in BCCA rats were significantly decreased. In situ hybridization (ISH) histochemistry revealed decreased D1 receptor mRNA (D1RmRNA) in striatal neurons 19 months after surgery, while D2 receptor mRNA (D2RmRNA) and the neuronal number remained the same. The present results show that just as is already known for the immature rat brain, the adult rat brain, too, reacts to a transient decrease in its blood supply by appearance of long-lasting alterations in function, and that even a single oligemic episode is capable of inducing progressive dopaminergic dysfunctions and ultimately the partial loss of striatal D1RmRNA.
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Affiliation(s)
- C Heim
- Department of Neuropharmacology and Physiology, Max-Planck Institute of Experimental Medicine, Goettingen, Germany
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12
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Ohta H, Nishikawa H, Kimura H, Anayama H, Miyamoto M. Chronic cerebral hypoperfusion by permanent internal carotid ligation produces learning impairment without brain damage in rats. Neuroscience 1997; 79:1039-50. [PMID: 9219966 DOI: 10.1016/s0306-4522(97)00037-7] [Citation(s) in RCA: 159] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To investigate the influence of cerebral hypoperfusion on learning behaviours, we developed a novel rat cerebral hypoperfusion model, in which the bilateral internal carotid arteries were permanently ligated to reduce the cerebral blood flow, and examined its behavioural and histopathological consequences in comparison to those occurring after bilateral common carotid ligation. In the Morris water maze task, rats with common carotid ligation exhibited a learning deficit, whereas rats with internal carotid ligation exhibited normal learning. Both models exhibited significant learning impairments in the eight-arm radial maze task, although the impairment was less severe in internal carotid-ligated rats than in common carotid-ligated rats. The cerebral blood flow of rats with common carotid ligation was reduced significantly both two and 10 days after ligation, and was still below normal three months after ligation. A milder, but significant reduction in the cerebral blood flow was observed in internal carotid-ligated rats. Shrinkage of the optic nerves and a circadian activity rhythm desynchronized to the light/dark cycle were exhibited by the rats with common carotid ligation, whereas these parameters remained unaffected in the rats with internal carotid ligation, suggesting that permanent ligation of common carotid arteries but not internal carotid arteries impairs visual functions. The main pathological changes observed in the brain following common carotid ligation were rarefaction and gliosis of the white matter and neuronal loss in the hippocampal CA1 region. On the other hand, the rats with internal carotid ligation had no significant brain damage. Chronic treatment with idebenone (1.5 and 15 mg/kg/day), a cerebral energy metabolism enhancer, over a three-month period, commencing five days after ligation, ameliorated the impairment of water maze learning in rats with common carotid ligation. The treatment also significantly improved the learning impairment in the radial maze task of internal carotid-ligated rats. Idebenone had no effect on the histopathological changes that followed cerebral hypoperfusion. It is concluded that cerebral hypoperfusion induced by permanent internal carotid ligation impairs the working memory without causing pathological damage to the brain tissues and the visual system, and the learning impairment can be ameliorated by a cerebral energy metabolism enhancer. These findings have the clinical implication that a reduction in blood flow may be an important factor that causes or exacerbates cognitive decline in dementias.
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Affiliation(s)
- H Ohta
- Pharmaceutical Research Division, Takeda Chemical Industries, Ltd., Osaka, Japan
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13
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Relationship between cholinergic dysfunction and discrimination learning disabilities in Wistar rats following chronic cerebral hypoperfusion. Brain Res 1996. [DOI: 10.1016/0006-8993(96)00400-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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