Animal Models Of Ischemic Stroke Research Articles

Edaravone dexborneol provides neuroprotective benefits by suppressing NLRP3 inflammasome-induced microglial pyroptosis in experimental ischemic stroke

Edaravone dexborneol (EDB) is a traditional prescription that consists of two components, edaravone and (+)-borneol, which have synergistic antioxidant and anti-inflammatory activities in animal models of ischemic stroke. Pyroptosis is a form of cell death that has only recently been discovered. In this study, we investigated the therapeutic effects and potential mechanisms of EDB in acute ischemic stroke. We used an in vivo mouse transient middle cerebral artery occlusion (tMCAO) model along with an in vitro BV2 cell oxygen-glucose deprivation (OGD) model to perform specific experiments. The executive protein of pyroptosis, gasdermin D (GSDMD), was increased after tMCAO. The administration of EDB dramatically reduced sensorimotor deficits and infarct sizes in mice with tMCAO. In addition, EDB inhibited the production of the NLRP3-inflammasome and the activation of the NF-κB signaling pathway. This effect inhibited both the in vitro and in vivo expression of inflammatory factors, including IL-1β and IL-18. Collectively, our data indicate that EDB exerted positive effects after ischemic stroke. EDB inhibited the activation of NLRP3 inflammasome-induced microglial pyroptosis in experimental ischemic stroke. The findings of this research indicate that the NF-κB/NLRP3/GSDMD signaling pathway may serve as a therapeutic target for EDB to promote functional recovery after stroke.

Re-directing nanomedicines to the spleen: A potential technology for peripheral immunomodulation.

Modulation of peripheral immune cells in the spleen plays a key role in many life-threatening conditions such as stroke. Immune cell changes can lead to the excessive release of pro-inflammatory cytokines into the circulation and preferential loss of innate immune cells which can further exacerbate tissue damage and predispose patients to infectious complications. Reversing these processes represents an attractive treatment strategy and has shown to have beneficial effects in animal models of ischemic stroke, sepsis, traumatic brain injury (TBI) as well as myocardial infraction (MI). However, systemic interventions are often challenging to deliver due to the non-selective broad range of action of many treatments. More selective targeted treatment approaches are therefore desirable. The spleen is considered a natural filtration site for many nanomaterials due to the spontaneous tendency of this organ to filter blood-borne molecules. This selective targeting of nanomaterials to the spleen therefore offers considerable potential in the management of many conditions affected by peripheral inflammation. In this review, we will explore the key nanomaterials-related parameters that mediate splenic targeting and how these could influence the actual localization and function of nanomaterials once in the spleen. We aim to emphasize the potential of utilising nanomaterials as selective tools for peripheral immunomodulation to accelerate clinical translation.

Delivery of self-replicating messenger RNA into the brain for the treatment of ischemic stroke.

Ischemic stroke is caused by the occlusion of cerebral arteries. In the ischemic stroke, ischemia-reperfusion injury increases the damage in the brain after reperfusion. In the previous study, heme oxygenase-1 (HO1) mRNA was delivered into the ischemic brain, showing that HO1-mRNA had higher therapeutic effect and less side-effect than HO1-plasmid (pHO1). However, mRNA is degraded faster than plasmid DNA reducing the duration of gene expression. In this study, self-replicating mRNA (Rep-mRNA) was developed using a replicon system from Venezuelan Equine Encephalitis virus to compensate this disadvantage of mRNA delivery. Deoxycholic acid-conjugated polyethylenimine (DA-PEI) was used as a carrier of the mRNAs. The Rep-mRNA/DA-PEI complex had a size of around 90nm and a zeta-potential of 33mV. In the in vitro transfection assays, gene expression by the HO1-Rep-mRNA/DA-PEI complex persisted at least 14days, while that by the HO1-mRNA/DA-PEI complex approached basal level at 3days after transfection. Therapeutic effects of the HO1-Rep-mRNA/DA-PEI complexes were evaluated in the ischemic stroke animal model. The complexes were injected into the brain stereotaxically. HO1 expression by the HO1-Rep-mRNA/DA-PEI complex persisted at least 7days after injection, but the pHO1/DA-PEI or HO1-mRNA/DA-PEI complex showed basal level of HO1-expression at 7days after injection. Due to higher and longer expression of HO1, the apoptosis level and infarct size were decreased by the HO1-Rep-mRNA/DA-PEI complexes, compared with the pHO1/DA-PEI and HO1-mRNA/DA-PEI complex. These results suggest that HO1-Rep-mRNA/DA-PEI complex may have a potential as a long-lasting therapeutic system for the treatment of ischemic stroke.

Translating Animal Models of Ischemic Stroke to the Human Condition.

Ischemic stroke is a leading cause of death and disability. However, very few neuroprotective agents have shown promise for treatment of ischemic stroke in clinical trials, despite showing efficacy in many successful preclinical studies. This may be attributed, at least in part, to the incongruency between experimental animal stroke models used in preclinical studies and the manifestation of ischemic stroke in humans. Most often the human population selected for clinical trials are more diverse than the experimental model used in a preclinical study. For successful translation, it is critical to develop clinical trial designs that match the experimental animal model used in the preclinical study. This review aims to provide a comprehensive summary of commonly used animal models with clear correlates between rodent models used to study ischemic stroke and the clinical stroke pathologies with which they most closely align. By improving the correlation between preclinical studies and clinical trials, new neuroprotective agents and stroke therapies may be more accurately and efficiently identified.

Optimal therapeutic conditions for the neural stem cell-based management of ischemic stroke: a systematic review and network meta-analysis based on animal studies

BackgroundIn order to promote the clinical translation of preclinical findings, it is imperative to identify the most optimal therapeutic conditions and adopt them for further animal and human studies. This study aimed to fullyexplore the optimal conditions for neural stem cell (NSC)-based ischemic stroke treatment based on animal studies.MethodsThe PubMed, Ovid-Embase, and Web of Science databases were searched in December 2021. The screening of search results, extraction of relevant data, and evaluation of study quality were performed independently by two reviewers.ResultsIn total, 52 studies were included for data analysis. Traditional meta-analysis showed that NSCs significantly reduced the modified neurological severity score (mNSS) and volume of cerebral infarct in animal models of ischemic stroke. Network meta-analysis showed that allogeneic embryonic tissue was the best source of NSCs. Further, intracerebral transplantation was the most optimal route of NSC transplantation, and the acute phase was the most suitable stage for intervention. The optimal number of NSCs for transplantation was 1–5×105 in mouse models and 1×106 or 1.8×106 in rat models.ConclusionsWe systematically explored the therapeutic strategy of NSCs in ischemic stroke, but additional research is required to develop optimal therapeutic strategies based on NSCs. Moreover, it is necessary to further improve and standardize the design, implementation, measuring standards, and reporting of animal-based studies to promote the development of better animal experiments and clinical research.

Biological Mechanism on SIRT1/NLRP3/IL-18 Signaling Pathway of Acupuncture for Treatment of Ischemic Stroke with Center Poststroke Pain.

Objective To evaluate the effect of acupuncture on an animal model of ischemic stroke with central poststroke pain (CPSP) through Sirtuin 1 (SIRT1)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3)/interleukin-18 (IL-18) signaling pathway. Methods Data mining was performed with R package “edgeR,” “limma,” “pathview,” etc., from NCBI Gene Expression Omnibus (GEO) database. Sprague Dawley (SD) rats were divided into 4 groups: sham operation group (Sham group, n = 5), poststroke central pain group (CPSP group, n = 5), poststroke central pain + acupuncture group (AP group, n = 5), central pain after stroke + acupuncture + SIRT1 inhibitor EX527 group (EX527 group, n = 5). Pain behavior testing was performed to determine the mechanical withdrawal threshold (MWT). Quantitative real-time PCR (qRT-PCR) was performed to verify the data mining results from the GEO database. Results The KEGG key pathway map was created using the R package “pathview” package, demonstrating that the expression levels of NLRP3's downstream inflammatory factors IL-18 were downregulated in both of siSIRT1 group compared to the control group and the NLRP3 reconstituted group compared to NLRP3 KO group. QRT-PCR results on animal models of CPSP ischemic stroke showed that the expression levels of SIRT1 were downregulated, the activation of the NLRP3 inflammasome was upregulated, and the expression levels of IL-18 were upregulated in the brain tissues of the surrounding area of the injury. As the pain threshold of CPSP rats was increased, the expression level of S1RT1 was upregulated, and the activation of NLRP3 inflammasome was downregulated. The expression level of IL-18 was downregulated after acupuncture treatment. Conclusion Acupuncture may inhibit CPSP in an animal model of ischemic stroke by upregulating SIRT1 expression levels, inhibition of the activation of the inflammasome, and downregulating IL-18 expression levels.

The effects of hypothermia on glutamate and γ-aminobutyric acid metabolism during ischemia in monkeys: a repeated-measures ANOVA study

During an ischemic stroke, the brain releases various factors, including glutamate and γ-aminobutyric acid. Glutamate can cause neurotoxic effects through certain receptors and exacerbate neurological damage, while γ-aminobutyric acid as an inhibitory neurotransmitter can antagonize the excitotoxic effects of glutamate and enhance the tolerance of neurons to ischemia. Therefore, in this study, the content of amino acid neurotransmitters in brain tissue before ischemia, after 10 min of ischemia, hypothermic perfusion, and rewarming were analyzed by high-performance liquid chromatography-UV in an animal model of ischemic stroke generated by blocking the bilateral common carotid arteries of rhesus monkeys. The changes in amino acid neurotransmitters in the rhesus monkey brain during post-ischemia hypothermic perfusion and rewarming were investigated by statistical methods of repeated measures ANOVA, showing that the concentration change of glutamate had not only a temporal factor but also was influenced by temperature, and there was an interaction effect between the two. Time but not temperature affected the change in γ-aminobutyric acid concentration, and there was an interaction effect between the two. Accordingly, hypoperfusion exerts a protective effect during ischemia by inhibiting the release of excitatory amino acid neurotransmitters, while the antagonistic effect of GABA on Glu is not significant.

Neuroprotective Effect of Polyherbal Recipe Containing Ginger, Chinese Date, and Wood Ear Mushroom against Ischemic Stroke with Metabolic Syndrome Condition via Epigenetic Modification of Inflammation and Oxidative Stress.

Currently, the prevalence of stroke with metabolic syndrome (MetS) is increasing and the current therapeutic efficiency is still limited. Therefore, the applications of herbal recipes have gained much attention. The polyherbal recipe containing ginger, Chinese date, and wood ear mushroom is reputed for atherosclerosis and stroke prevention. It has been long-term consumed without scientific support. Therefore, this study was carried out to determine the neuroprotective effect and its mechanisms in animal model of ischemic stroke with MetS. Male Wistar rats weighing 180-220 g were exposed to a 16-week high-fat high-carbohydrate feeding. The rats with the MetS characteristic were exposed to a temporary occlusion of the right middle cerebral artery (MCAO) for 90 minutes. They were orally fed with the polyherbal recipe (GCJ) at the doses of 100, 200, and 300 mg/kg BW for 21 days and assessed the neurological deficit, ion volume, cortical neuron density in the cerebral cortex, oxidative stress status, inflammation, and expressions of histone deacetylase 3 (HDAC3) and DNA methyltransferase 1 (DNMT1). The results showed that GCJ significantly improved all mentioned parameters. Therefore, GCJ is the potential neuroprotectant against ischemic stroke with MetS. The underlying mechanisms may involve the reduction of oxidative stress, inflammation, and the modification of epigenetic mechanism via the reduction of HDAC3 and DNMT1. However, further clinical investigation is essential to confirm this positive modulation effect.

Citicoline Treatment in Acute Ischemic Stroke: A Randomized, Single-Blind TMS Study.

BackgroundRecent research on animal models of ischemic stroke supports the idea that pharmacological treatment potentially enhancing intrinsic brain plasticity could modulate acute brain damage, with improved functional recovery. One of these new drugs is citicoline, which could provide neurovascular protection and repair effects.ObjectivesThe objective of this randomized, single-blind experimental study was to evaluate whether the treatment with Rischiaril® Forte was able to restore intracortical excitability measures, evaluated through transcranial magnetic stimulation (TMS) protocols, in patients with acute ischemic stroke.MethodsPatients with acute ischemic stroke were recruited and assigned to an eight-week therapy of standard treatment (control group - CG) or CDP-choline (Rischiaril® Forte, containing 1,000 mg of citicoline sodium salt) added to conventional treatment (treatment group - TG). Each subject underwent a clinical evaluation and neurophysiological assessment using TMS, pretretament and posttreatment.ResultsA total of thirty participants (mean [SD] age, 68.1 [9.6] years; 11 women [37%]) completed the study. We did not observe significant changes in clinical scores after CDP-choline treatment (all p > 0.05), but we observed a significant improvement in short-interval intracortical inhibition (SAI) (p = 0.003) in the TG group compared to the CG group.ConclusionsThe eight-week treatment with citicoline after acute ischemic stroke may restore intracortical excitability measures, which partially depends on cholinergic transmission. This study extends current knowledge of the application of citicoline in acute ischemic stroke.

Polyphenols for the Treatment of Ischemic Stroke: New Applications and Insights.

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Currently, the main therapeutic strategy involves the use of intravenous thrombolysis to restore cerebral blood flow to prevent the transition of the penumbra to the infarct core. However, due to various limitations and complications, including the narrow time window in which this approach is effective, less than 10% of patients benefit from such therapy. Thus, there is an urgent need for alternative therapeutic strategies, with neuroprotection against the ischemic cascade response after IS being one of the most promising options. In the past few decades, polyphenolic compounds have shown great potential in animal models of IS because of their high biocompatibility and ability to target multiple ischemic cascade signaling pathways, although low bioavailability is an issue that limits the applications of several polyphenols. Here, we review the pathophysiological changes following cerebral ischemia and summarize the research progress regarding the applications of polyphenolic compounds in the treatment of IS over the past 5 years. Furthermore, we discuss several potential strategies for improving the bioavailability of polyphenolic compounds as well as some essential issues that remain to be addressed for the translation of the related therapies to the clinic.

Proteomics on the role of muscone in the “consciousness-restoring resuscitation” effect of musk on ischemic stroke

Ethnopharmacological relevanceMusk is a representative drug of aroma-relieving traditional Chinese medicine, and it is a commonly used traditional Chinese medicine for the treatment of ischemic stroke. Muscone is the core medicinal component of musk. Aim of the studyWe sought to identify the target of muscone in the treatment of ischemic stroke using network pharmacology, an animal model of ischemic stroke, and differential proteomics. Materials and methodsThe drug targets of muscone in the treatment of ischemic stroke were predicted and analyzed using information derived from sources such as the Traditional Chinese Medicine Systems Pharmacology database and Swiss Target Prediction tool. The animal model of focal cerebral ischemia was established by suture-based occlusion of the middle cerebral artery of rats. The rats were divided into six groups: sham-operated control, model, musk, muscone1, muscone2, and muscone3. Neurological deficit scores were calculated after intragastric administration of musk or muscone. The microcirculation blood flow of the pia mater was detected using a laser speckle blood flow meter. The cerebral infarction rate was detected by 2,3,5-triphenyltetrazolium chloride staining. The necrosis rate of the cerebral cortex and the hippocampal neurons was detected by hematoxylin and eosin staining. Blood-brain barrier damage was detected by the Evans blue method. Quantitative proteomics analysis in the sham-operated control, model, and muscone groups was performed using tandem-mass-tags. Considering fold changes exceeding 1.2 as differential protein expression, the quantitative values were compared among groups by analysis of variance. Furthermore, a protein-protein interaction network was constructed, and differentially expressed proteins were analyzed by gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. ResultsNetwork pharmacology identified 339 targets for the intersection of 17 components of musk and cerebral ischemia-reperfusion injury. The GO and KEGG enrichment items mainly identified regulation of neuronal synaptic structure and transfer function, synaptic neurotransmitters, and receptor activity. Zoopery showed that the model group had a higher behavioral score, cerebral infarction rate, cortical and hippocampal neuron death rate, Evans blue exudation in the brain, and bilateral pia mater microcirculation blood flow differences than the sham-operated control group (P <0.01). Compared with the model group, the behavioral score, infarction rate, hippocampal neuronal mortality, and Evans blue content decreased significantly in the musk, muscone2, and muscone3 groups (P <0.05). Proteomic analysis showed that 160 genes were differentially expressed among the sham-operated control, model, and muscone groups. GO items with high enrichment included neuronal synapses, postsynaptic signal transduction, etc. KEGG items with high enrichment included cholinergic synapses, calcium signaling pathway, dopaminergic synapses, etc. Protein interaction analysis revealed that the top three protein pairs were Ndufa10/Ndufa6, Kcna2/Kcnab2, and Gsk3b/Traf6. ConclusionsMuscone can reduce neuronal necrosis, protect the blood-brain barrier, and improve the neurological damage caused by cerebral ischemia via molecular mechanisms mainly involving the regulation of neuronal synaptic connections. Muscone is an important active component responsible for the “consciousness-restoring resuscitation” effect of musk on ischemic stroke.

Target ischemic stroke model creation method using photoacoustic microscopy with simultaneous vessel monitoring and dynamic photothrombosis induction

The ischemic stroke animal model evaluates the efficacy of reperfusion and neuroprotective strategies for ischemic injuries. Various conventional methods have been reported to induce the ischemic models; however, controlling specific neurological deficits, mortality rates, and the extent of the infarction is difficult as the size of the affected region is not precisely controlled. In this paper, we report a single laser-based localized target ischemic stroke model development method by simultaneous vessel monitoring and photothrombosis induction using photoacoustic microscopy (PAM), which has minimized the infarct size at precise location with high reproducibility. The proposed method has significantly reduced the infarcted region by illuminating the precise localization. The reproducibility and validity of suggested method have been demonstrated through repeated experiments and histological analyses. These results demonstrate that our method can provide the ischemic stroke model closest to the clinical pathology for brain ischemia research from inducement, occurrence mechanisms to the recovery process.

Pharmacokinetic and Pharmacodynamic Properties of Indole-3-carbinol in Experimental Focal Ischemic Injury.

Indole-3-carbinol (I3C) is reported to have neuroprotective properties in an animal model of ischemic stroke. However, the pharmacokinetics of I3C in stroke animals are unknown. Furthermore, the most effective method of I3C delivery for the treatment of stroke has yet to be determined.Therefore, the objective of this study was to evaluatepharmacokinetics and pharmacodynamicsof I3C to discover the most effective delivery route for protecting the brain from ischemic injury. With oral and intravenous administration, the pharmacokinetics and pharmacodynamics of I3C in sham and middle cerebral artery occluded (MCAO) rats were investigated. I3C administration in sham and MCAO rats did not alter the pharmacokinetic parameters such as maximum plasma concentration (Cmax), time to reach Cmax, half-life, area under the curve, mean residential time, volume of distribution, clearance, bioavailability, and tissue distribution. A higher amount of diindolylmethane (DIM) was observed with oral administration of I3C compared to intravenous administration in the plasma (5 fold), brain (4 fold), and cerebrospinal fluid (CSF) (2-3 fold). Orally delivered I3C significantly reduced neurological deficits, brain infarction (20%), blood-brain barrier leakage (15 μg/g), and brain water content (75%) in MCAO rats compared to intravenous administration of I3C. I3C pharmacokinetic parameters were similar in sham and MCAO rats, but I3C and DIM penetration in the brain and CSF was significantly higher in MCAO rats than in sham animals, and I3C oral intake significantly reduced MCAO-induced neurological impairments. Consequently, compared to intravenous treatment, I3C oral delivery is more effective in treating ischemic stroke.

Pharmacological Validation of ASIC1a as a Druggable Target for Neuroprotection in Cerebral Ischemia Using an Intravenously Available Small Molecule Inhibitor.

Acidosis is a hallmark of ischemic stroke and a promising neuroprotective target for preventing neuronal injury. Previously, genetic manipulations showed that blockade of acid-sensing ion channel 1a (ASIC1a)-mediated acidotoxicity could dramatically alleviate the volume of brain infarct and restore neurological function after cerebral ischemia. However, few pharmacological candidates have been identified to exhibit efficacy on ischemic stroke through inhibition of ASIC1a. In this work, we examined the ability of a toxin-inspired compound 5b (C5b), previously found to effectively inhibit ASIC1a in vitro, to exert protective effects in animal models of ischemic stroke in vivo. We found that C5b exerts significant neuroprotective effects not only in acid-induced neuronal death in vitro but also ischemic brain injury in vivo, suggesting that ASIC1a is a druggable target for therapeutic development. More importantly, C5b is able to cross the blood brain barrier and significantly reduce brain infarct volume when administered intravenously in the ischemic animal model, highlighting its systemic availability for therapies against neurodegeneration due to acidotoxicity. Together, our data demonstrate that C5b is a promising lead compound for neuroprotection through inhibiting ASIC1a, which warrants further translational studies.

Multimodal imaging of hemorrhagic transformation biomarkers in an ischemic stroke model.

Hemorrhagic transformation of ischemic stroke has devastating consequences, with high mortality and poor functional outcomes. Animal models of ischemic stroke also demonstrate the potential for hemorrhagic transformation, which complicates biochemical characterization, treatment studies, and hinders poststroke functional outcomes in affected subjects. The incidence of hemorrhagic transformation of ischemic stroke in animal model research is not commonly reported. The postmortem brain of such cases presents a complex milieu of biomarkers due to the presence of healthy cells, regions of varying degrees of ischemia, dead and dying cells, dysregulated metabolites, and blood components (especially reactive Fe species released from lysed erythrocytes). To improve the characterization of hemorrhage biomarkers on an ischemic stroke background, we have employed a combination of histology, X-ray fluorescence imaging (XFI), and Fourier transform infrared (FTIR) spectroscopic imaging to assess 122 photothrombotic (ischemic) stroke brains. Rapid freezing preserves brain biomarkers in situ and minimizes metabolic artifacts due to postmortem ischemia. Analysis revealed that 25% of the photothrombotic models had clear signs of hemorrhagic transformation. The XFI and FTIR metabolites provided a quantitative method to differentiate key metabolic regions in these models. Across all hemorrhage cases, it was possible to consistently differentiate otherwise healthy tissue from other metabolically distinct regions, including the ischemic infarct, the ischemic penumbra, blood vessels, sites of hemorrhage, and a region surrounding the hemorrhage core that contained elevated lipid oxidation. Chemical speciation of deposited Fe demonstrates the presence of heme-Fe and accumulation of ferritin.

Electroacupuncture ameliorates neuroinflammation in animal models.

Neuroinflammation refers to a wide range of immune responses occurring in the brain or spinal cord. It is closely related to a variety of neurodegenerative diseases, for which it potentially represents a new direction for treatment. Electroacupuncture (EA) is one method of acupuncture treatment, which can be used as an adjuvant therapy for many diseases. This review focuses on molecular mechanisms of EA in the reduction of neuroinflammation, summarizes relevant basic research and outlines future directions for investigation. A growing body of basic research has shown that EA can ameliorate neuroinflammation centrally (in animal models of ischemic stroke, Alzheimer's disease, traumatic brain injury, spinal cord injury, Parkinson's disease and vascular dementia) and peripherally (e.g. after a surgical insult or injection of lipopolysaccharide) and that its effects involve different molecular mechanisms, including activation of the α7 nicotinic acetylcholine receptor signaling pathway and P2 type purinergic receptors, inhibition of nuclear factor κB, and mitigation of damage secondary to oxidative stress and NOD-like receptor protein 3 inflammasome activation. EA is capable of regulating multiple cell signal transduction pathways to alleviate neuroinflammation in animal models. Although the findings of animal studies are encouraging, further prospective clinical trials are needed to verify the efficacy of EA for the treatment of neuroinflammation.

Post-stroke Impairment of the Blood-Brain Barrier and Perifocal Vasogenic Edema Is Alleviated by Endovascular Mesenchymal Stem Cell Administration: Modulation of the PKCδ/MMP9/AQP4-Mediated Pathway.

Post-stroke edema and upregulation of aquaporin 4 (AQP4) water transport channels play a significant role in the progression of stroke pathology and deteriorating stroke outcomes. Prior studies from our lab have demonstrated the safety and efficacy of intra-arterial (IA) 1 × 105 mesenchymal stem cells (MSCs) administration post-stroke towards functional restoration and neuroprotection. Protein kinases have been reported to be involved in the signaling cascade of edema, with evidence supporting both its upregulation and downregulation at 24h post-stroke. Among different protein kinase C (PKC) isoforms, the δ isoform is widely reported to play a pivotal role in the progression of ischemic reperfusion injury. Our present study aims to decipher the molecular mechanism of post-stroke IA MSCs mediated alleviation of perifocal vasogenic edema by PKCδ-mediated AQP4 regulation. Ovariectomized female SD rats were infused with 1 × 105 IA MSCs at 6h post middle cerebral artery occlusion (MCAo). Animals were evaluated for behavioral and functional outcomes. Brains were harvested for evaluating infarct size and brain edema. Further, brain tissues were used for biochemical and molecular studies to decipher the possible molecular mechanism related to the regulation of PKCδ-mediated AQP4 expression. 1 × 105 IA MSCs at 6h post-stroke confers neuroprotection as evident by the reduction in infarct size, edema, and improvement of functional outcome. An increase in GSH and catalase and a reduction in nitrite and MDA were observed along with a decrease in AQP4 and PKCδ expressions within the cortical brain regions of IA MSC-infused animals. The study gives preliminary evidence that IA MSCs administration post-stroke modulates PKCδ to regulate AQP4 expression which alleviates vasogenic edema towards neuroprotection. The study is novel and clinically relevant as no previous studies have looked into this aspect following IAdelivery of stem cells in an animal model of ischemic stroke.

Comparison of Large Animal Models for Acute Ischemic Stroke: Which Model to Use?

Translation of acute ischemic stroke research to the clinical setting remains limited over the last few decades with only one drug, recombinant tissue-type plasminogen activator, successfully completing the path from experimental study to clinical practice. To improve the selection of experimental treatments before testing in clinical studies, the use of large gyrencephalic animal models of acute ischemic stroke has been recommended. Currently, these models include, among others, dogs, swine, sheep, and nonhuman primates that closely emulate aspects of the human setting of brain ischemia and reperfusion. Species-specific characteristics, such as the cerebrovascular architecture or pathophysiology of thrombotic/ischemic processes, significantly influence the suitability of a model to address specific research questions. In this article, we review key characteristics of the main large animal models used in translational studies of acute ischemic stroke, regarding (1) anatomy and physiology of the cerebral vasculature, including brain morphology, coagulation characteristics, and immune function; (2) ischemic stroke modeling, including vessel occlusion approaches, reproducibility of infarct size, procedural complications, and functional outcome assessment; and (3) implementation aspects, including ethics, logistics, and costs. This review specifically aims to facilitate the selection of the appropriate large animal model for studies on acute ischemic stroke, based on specific research questions and large animal model characteristics.

Evaluating iron deposition in gray matter nuclei of patients with unilateral middle cerebral artery stenosis using quantitative susceptibility mapping

Iron mediated oxidative stress is involved in the process of brain injury after long-term ischemia. While increased iron deposition in the affected brain regions was observed in animal models of ischemic stroke, potential changes in the brain iron content in clinical patients with cerebral ischemia remain unclear. Quantitative susceptibility mapping (QSM), a non-invasive magnetic resonance imaging technique, can be used to evaluate iron content in the gray matter (GM) nuclei reliably. In this study, we aimed to quantitatively evaluate iron content changes in GM nuclei of patients with long-term unilateral middle cerebral artery (MCA) stenosis/occlusion-related cerebral ischemia using QSM.Forty-six unilateral MCA stenosis/occlusion patients and 38 age-, sex- and education-matched healthy controls underwent QSM. Clinical variables of history of hypertension, diabetes, hyperlipidemia, hyperhomocysteinemia, smoking, and drinking in all patients were evaluated. The iron-related susceptibility of GM nucleus subregions, including the bilateral caudate nucleus (CN), putamen (PU), globus pallidus (GP), thalamus, substantia nigra (SN), red nucleus, and dentate nucleus, was assessed. Susceptibility was compared between the bilateral GM nuclei in patients and controls. Receiver operating characteristic curve analysis was used to evaluate the efficacy of QSM susceptibility in distinguishing patients with unilateral MCA stenosis/occlusion from healthy controls. Multiple linear regression analysis was used to evaluate the relationship between ipsilateral susceptibility levels and clinical variables.Except for the CN, the susceptibility in most bilateral GM nucleus subregions was comparable in healthy controls, whereas for patients with unilateral MCA stenosis/occlusion, the ipsilateral PU, GP, and SN exhibited significantly higher susceptibility than the contralateral side (all P < 0.05). Compared with controls, susceptibility of the ipsilateral PU, GP, and SN and of contralateral PU in patients were significantly increased (all P < 0.05). The area under the curve (AUC) was greater for the ipsilateral PU than for the GP and SN (AUC = 0.773, 0.662 and 0.681; all P < 0.05). Multiple linear regression analysis showed that the increased susceptibility of the ipsilateral PU was significantly associated with hypertension, of the ipsilateral GP associated with smoking, and of the ipsilateral SN associated with diabetes (all P < 0.05).Our findings provide support for abnormal iron accumulation in the GM nuclei after chronic MCA stenosis/occlusion and its correlation with some cerebrovascular disease risk factors. Therefore, iron deposition in the GM nuclei, as measured by QSM, may be a potential biomarker for long-term cerebral ischemia.

The Neuroprotective Effect of Isoflurane in Animal Models of Ischemic Stroke and its Mechanism: A Systematic Review and Meta-Analysis

The Neuroprotective Effect of Isoflurane in Animal Models of Ischemic Stroke and its Mechanism: A Systematic Review and Meta-Analysis