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Toung TJK, Mehr N, Mirski M, Koehler RC. Embolic occlusion of internal carotid artery in conscious rats: Immediate effects of cerebral ischemia. Physiol Rep 2023; 11:e15613. [PMID: 36802121 PMCID: PMC9938005 DOI: 10.14814/phy2.15613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/20/2023] Open
Abstract
In most preclinical models of focal ischemic stroke, vascular occlusion is performed under general anesthesia. However, anesthetic agents exert confounding effects on mean arterial blood pressure (MABP), cerebrovascular tone, oxygen demand, and neurotransmitter receptor transduction. Moreover, the majority of studies do not use a blood clot, which more fully models embolic stroke. Here, we developed a blood clot injection model to produce large cerebral artery ischemia in unanesthetized rats. Under isoflurane anesthesia, an indwelling catheter was implanted in the internal carotid artery via a common carotid arteriotomy and preloaded with a 0.38-mm-diameter clot of 1.5, 3, or 6 cm length. After discontinuing anesthesia, the rat was returned to a home cage where it regained normal mobility, grooming, eating activity, and a stable recovery of MABP. One hour later, the clot was injected over a 10-s period and the rats were observed for 24 h. Clot injection produced a brief period of irritability, then 15-20 min of complete inactivity, followed by lethargic activity at 20-40 min, ipsilateral deviation of the head and neck at 1-2 h, and limb weakness and circling at 2-4 h. Neurologic deficits, elevated MABP, infarct volume, and increased hemisphere water content varied directly with clot size. Mortality after 6-cm clot injection (53%) was greater than that after 1.5-cm (10%) or 3-cm (20%) injection. Combined non-survivor groups had the greatest MABP, infarct volume, and water content. Among all groups, the pressor response correlated with infarct volume. The coefficient of variation of infarct volume with the 3-cm clot was less than that in published studies with the filament or standard clot models, and therefore may provide stronger statistical power for stroke translational studies. The more severe outcomes from the 6-cm clot model may be useful for the study of malignant stroke.
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Affiliation(s)
- Thomas J. K. Toung
- Department of Anesthesiology and Critical Care MedicineJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Noah Mehr
- Department of Anesthesiology and Critical Care MedicineJohns Hopkins UniversityBaltimoreMarylandUSA
- Present address:
Department of PathologyUniversity of Chicago, School of MedicineChicagoIllinoisUSA
| | - Marek Mirski
- Department of Anesthesiology and Critical Care MedicineJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Raymond C. Koehler
- Department of Anesthesiology and Critical Care MedicineJohns Hopkins UniversityBaltimoreMarylandUSA
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Wang R, Wang H, Liu Y, Chen D, Wang Y, Rocha M, Jadhav AP, Smith A, Ye Q, Gao Y, Zhang W. Optimized mouse model of embolic MCAO: From cerebral blood flow to neurological outcomes. J Cereb Blood Flow Metab 2022; 42:495-509. [PMID: 32312170 PMCID: PMC8985433 DOI: 10.1177/0271678x20917625] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The embolic middle cerebral artery occlusion (eMCAO) model mimics ischemic stroke due to large vessel occlusion in humans and is amenable to thrombolytic therapy with rtPA. However, two major obstacles, the difficulty of the eMCAO surgery and unpredictable occurrence of clot autolysis, had impeded its application in mice. In this study, we modified catheters to produce suitable fibrin-rich embolus and optimized the eMCAO model using cerebral blood flow (CBF) monitored by both laser Doppler flowmetry (LDF) and 2D laser speckle contrast imaging (LSCI) to confirm occlusion of MCA. The results showed that longer embolus resulted in higher mortality. There was a compensatory increase in MCA territory perfusion after eMCAO associated with decreased infarct volume; however, this was only partly dependent on recanalization as clot autolysis was only observed in ∼30% of mice. Cortical CBF monitoring with LSCI showed that the size of peri-core area at 3 h displayed the best correlation with infarct volume that is attributed to compensatory collateral blood flow. The peri-core area best predicted functional outcome after eMCAO. In summary, we developed a reliable eMCAO mouse model that better mimics embolic ischemic stroke in humans, which will increase the potential for successful translation of stroke neuroprotective therapies.
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Affiliation(s)
- Rongrong Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Hailian Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yaan Liu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Di Chen
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yangfan Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Marcelo Rocha
- Pittsburgh Institute of Brain Disorders & Recovery and UPMC Stroke Institute, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ashutosh P Jadhav
- Pittsburgh Institute of Brain Disorders & Recovery and UPMC Stroke Institute, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Amanda Smith
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Qing Ye
- Pittsburgh Institute of Brain Disorders & Recovery and UPMC Stroke Institute, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Yanqin Gao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Wenting Zhang
- Pittsburgh Institute of Brain Disorders & Recovery and UPMC Stroke Institute, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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A Novel Thromboplastin-Based Rat Model of Ischemic Stroke. Brain Sci 2021; 11:brainsci11111475. [PMID: 34827474 PMCID: PMC8615413 DOI: 10.3390/brainsci11111475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 11/17/2022] Open
Abstract
The thromboembolic ischemia model is one of the most applicable for studying ischemic stroke in humans. The aim of this study was to develop a novel thromboembolic stroke model, allowing, by affordable tools, to reproduce cerebral infarction in rats. In the experimental group, the left common carotid artery, external carotid artery, and pterygopalatine branch of maxillary artery were ligated. A blood clot that was previously formed (during a 20 min period, in a catheter and syringe, by mixing with a thromboplastin solution and CaCl2) was injected into the left internal carotid artery. After 10 min, the catheter was removed, and the incision was sutured. The neurological status of the animals was evaluated using a 20-point scale. Histological examination of brain tissue was performed 6, 24, 72 h, and 6 days post-stroke. All groups showed motor and behavioral disturbances 24 h after surgery, which persisted throughout the study period. A histological examination revealed necrotic foci of varying severity in the cortex and subcortical regions of the ipsilateral hemisphere, for all experimental groups. A decrease in the density of hippocampal pyramidal neurons was revealed. Compared with existing models, the proposed ischemic stroke model significantly reduces surgical time, does not require an expensive operating microscope, and consistently reproduces brain infarction in the area of the middle cerebral artery supply.
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Hyperbaric Oxygen Improves Cerebral Ischemia/Reperfusion Injury in Rats Probably via Inhibition of Autophagy Triggered by the Downregulation of Hypoxia-Inducing Factor-1 Alpha. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6615685. [PMID: 33816617 PMCID: PMC7987430 DOI: 10.1155/2021/6615685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/05/2021] [Accepted: 03/03/2021] [Indexed: 01/01/2023]
Abstract
Ischemic stroke, accompanied with high mortality and morbidity, may produce heavy economic burden to societies and families. Therefore, it is of great significance to explore effective therapies. Hyperbaric oxygen (HBO) is a noninvasive, nondrug treatment method that has been proved able to save ischemic penumbra by improving hypoxia, microcirculation, and metabolism and applied in various ischemic diseases. Herewith, we fully evaluated the effect of HBO on ischemic stroke and investigated its potential mechanism in the rat ischemia/reperfusion(I/R) model. Sixty Sprague-Dawley male rats were randomly divided into three groups—sham group, MCAO group, and MCAO+HBO group. In the latter two groups, the middle cerebral artery occlusion was performed (MCAO) for 2 hours, and then the occlusion was removed in order to establish the ischemic/reperfusion model. Subsequently, HBO was performed immediately after I/R (2 hours per day for 3 days). 72 hours after MCAO, the brain was dissected for our experiment. Finally, the data from three groups were analyzed by one-way analysis of variance (ANOVA) and followed by a Bonferroni test. In this article, we reported that HBO effectively reduced the infarction and edema and improved neurological functions to a certain extent. As shown by western blot analysis, HBO significantly reduced autophagy by regulating autophagy-related proteins (mTOR, p-mTOR, Atg13, LC3B II and LC3B II) in the hippocampus 72 hours after I/R, which was accompanied by inhibiting the expression of hypoxia inducible factor-1α (HIF-1α) in hippocampus. The results suggest that HBO may improve cerebral I/R injury, possibly via inhibiting HIF-1α, the upstream molecule of autophagy, and therefore, subsequently inhibiting autophagy in the rat model of ischemic stroke.
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