Animal Models Of Cerebral Ischemia Research Articles

Edaravone Dexborneol provides neuroprotective effect by inhibiting neurotoxic activation of astrocytes through inhibiting NF-κB signaling in cortical ischemia

Edaravone Dexborneol (EDB), comprised of edaravone and (+)- bornel, has been demonstrated to have synergistic effects of antioxidant and anti-inflammatory, which makes it to be applied for stroke as a protectant. However, the underlying mechanism of neuroprotection of EDB has not been fully elucidated. Increasing evidence has shown that neurotoxic A1 astrocytes were closely related to neuronal death after cerebral ischemia. However, whether EDB could provide neuroprotection by modulating the activation of astrocytes has not yet been elucidated. The present study aimed to explore whether EDB afforded neuroprotection by modulating A1 polarization of astrocytes and the down-stream signaling after cerebral ischemia. We first validated the neuroprotective effects of EDB in mice suffering focal cerebral ischemia via evaluating behavioral test, infarct volumes and neuronal survival. As for the down-stream signaling, our data further showed that EDB alleviated neuronal death by suppressing activation of neurotoxic A1 astrocytes via inhibition of NF-κB signaling pathway in vitro. Additionally, administration of EDB reduced the number of A1 reactive astrocytes in mice of focal cerebral ischemia. The above findings demonstrated that EDB provided neuroprotective effect by inhibiting neurotoxic activation of A1 astrocytes in animal model of cerebral ischemia, which indicated that EDB-mediated phenotypic regulation of astrocytes is a potential research direction to promote neurological recovery in central nervous system (CNS) diseases.

Kukoamine A Activates Akt/GSK-3β Pathway to Repress Oxidative Stress and Inflammation to Alleviate Myocardial Ischemia-reperfusion Injury

Background: Myocardial ischemia-reperfusion injury (MI/RI) is a serious complication after revascularization of myocardial infarction, which causes myocardium damage. Kukoamine A (KuA) can repress oxidative stress and neuronal apoptosis in cerebral ischemia animal models. Objective: In the present study, our objective was to explore the role of KuA in MI/RI and the underlying mechanism of KuA in oxidative stress and inflammation of MI/RI. Methods: H9c2 cells’ cytotoxicity was detected using the lactate dehydrogenase (LDH) assay kit. ROS level was measured by immunofluorescence. Male C57BL/6 mice were used to establish MI/RI mice by ligating the left anterior descending coronary artery (LAD). Results: KuA treatment decreased the apoptosis and the cytotoxicity, increased the viability, and reduced the activities of myocardial infarction markers (CKMB, MYO, and cTnI) in hypoxia/ reoxygenation (H/R)-induced H9c2 cells. KuA reduced the levels of ROS, MDA, and inflammatory factors (IL-6, IL-1β, and TNF-α), and facilitated MMP and SOD levels in H/R-induced H9c2 cells. Besides, KuA activated Akt/GSK-3β axis, which was repressed by PI3K inhibitor LY294002. Moreover, KuA improved survival times, decreased the infarct size of mice, and recovered cardiac function in MI/RI mice. Finally, KuA alleviated MI/RI through Akt/GSK-3β pathway in vivo. Conclusion: Thus, KuA exerts a protective function in MI/RI through the Akt/GSK-3β axis to repress oxidative stress and inflammation.

Pseudoginsenoside-F11 reduces cognitive impairment and white matter injury in vascular dementia by alleviating autophagy-lysosomal pathway deficiency

BackgroundVascular dementia (VaD) resulting from chronic cerebral hypoperfusion (CCH) induces cognitive impairment and white matter injury (WMI). We previously found that CCH induces dysfunction of the autophagy-lysosomal pathway (ALP) in white matter (WM) of rats. Enhancing oligodendrocyte autophagy to counteract ALP deficiency is beneficial for cognitive recovery. Pseudogenoside-F11 (PF11), a saponin extracted from Panax quinquefolium l., provides neuroprotective benefits in many animal models of cerebral ischemia and dementia. PurposeTo investigate how PF11 affects cognitive deterioration in rats with VaD induced by two vessel occlusion (2VO), and to determine if PF11 regulates ALP dysfunction in WM. MethodsCCH-related VaD was induced in rats using the 2VO method. PF11 (6, 12, 24 mg/kg, intragastric administration) was given continuously for 4 weeks postoperatively. Behavioral tests related to cognitive function were performed on the 28th day following 2VO. Transmission electron microscopy, immunofluorescence, western blotting and Luxol fast blue staining were used to assess the WMI and the mechanism of action of PF11 in 2VO-induced VaD. ResultsPF11 (12 mg/kg) ameliorated 2VO-induced cognitive impairment. PF11 also alleviated WMI on the 28th day following 2VO, as characterized by reduction of neuronal axonal demyelination and axonal loss. Furthermore, PF11 prevented mature oligodendrocytes death by attenuating ALP deficiency in WM on the 14th day following 2VO, as manifested by enhancement of mechanistic target of rapamycin-mediated autophagy and lysosomal function, thereby reducing the aberrant accumulation of autophagy substrates and increasing the level of autophagosomes in WM. In addition, PF11 also prevented microglia and astrocytes from activating in WM on the 28th day following 2VO. ConclusionPF11 significantly ameliorates cognitive impairment and WMI, and the mechanism is at least partly related to lessening ALP dysfunction in WM by enhancing autophagy and reducing lysosomal defects in oligodendrocytes.

Vagus nerve electrical stimulation in the recovery of upper limb motor functional impairment after ischemic stroke.

Ischemic stroke (IS) is characterized by high mortality, disability rates, and a high risk of recurrence. Motor dysfunction, such as limb hemiparesis, dysphagia, auditory disorders, and speech disorders, usually persists after stroke, which imposes a heavy burden on society and the health care system. Traditional rehabilitation therapies may be ineffective in promoting functional recovery after stroke, and alternative strategies are urgently needed. The Food and Drug Administration (FDA) has approved invasive vagus nerve stimulation (iVNS) for the improvement of refractory epilepsy, treatment-resistant depression, obesity, and moderate to severe upper limb motor impairment following chronic ischemic stroke. Additionally, the FDA has approved transcutaneous vagus nerve stimulation (tVNS) for the improvement of cluster headaches and acute migraines. Recent studies have demonstrated that vagus nerve stimulation (VNS) has neuroprotective effects in both transient and permanent cerebral ischemia animal models, significantly improving upper limb motor impairments, auditory deficits, and swallowing difficulties. Firstly, this article reviews two potential neuronal death pathways following IS, including autophagy and inflammatory responses. Then delves into the current status of preclinical and clinical research on the functional recovery following IS with VNS, as well as the potential mechanisms mediating its neuroprotective effects. Finally, the optimal parameters and timing of VNS application are summarized, and the future challenges and directions of VNS in the treatment of IS are discussed. The application of VNS in stroke rehabilitation research has reached a critical stage, and determining how to safely and effectively translate this technology into clinical practice is of utmost importance. Further preclinical and clinical studies are needed to elucidate the therapeutic mechanisms of VNS.

Efficacy of bumetanide in animal models of ischemic stroke: a systematic review and meta-analysis.

This meta-analysis aimed to describe the efficacy of bumetanide in improving infarct volume, brain edema, and behavioral outcomes in animal models of cerebral ischemia. Embase, PubMed and Web of Science databases were searched from their inception to February 2024 (INPLASY:202430023). Data on the animal species, stroke model, drug dose, time of treatment, method of administration, study quality, and outcomes were extracted and pooled in a meta-analysis. The combined standardized mean difference (SMD) or mean difference (MD) estimates and 95% confidence intervals (CIs) were calculated using random- or fixed-effects models. Thirteen eligible studies involving >200 animals fulfilled the inclusion criteria and were included in this meta-analysis. Meta-analyses demonstrated that bumetanide treatment significantly reduced cerebral infarct volume (SMD: -0.42; 95% CI: -0.75, -0.09; p < 0.01; n = 186 animals) and consistently relieved brain edema (SMD: -1.39; 95% CI: -2.06, -0.72; p < 0.01; n = 64 animals). Subgroup analyses demonstrated that bumetanide treatment reduced infarct volume in transient but not permanent cerebral ischemia models. When administered after the stroke, it was more effective than treatment initiation before the stroke. Eight studies assessed the effect of bumetanide on behavioral function and the results showed that bumetanide treatment significantly improved neurobehavioral deficits (SMD: -2.35; 95% CI: -2.72, -1.97; p < 0.01; n = 250 animals). We conclude that bumetanide appears to be effective in reducing infarct volume and brain edema and improving behavioral recovery in animal models of cerebral ischemia. This mechanism needs to be confirmed through further investigation.

A Rat Model of Middle Cerebral Artery Occlusion/Reperfusion without Damaging the Anatomical Structure of Cerebral Vessels.

Ischemic stroke stands as the primary cause of long-term disability and mortality among adults worldwide. Animal models of ischemic stroke have significantly contributed to our understanding of its pathological mechanisms and the development of potential treatments. Presently, there are two common methods involving filament (endovascular suture) techniques to induce animal models of cerebral ischemia. However, these methods have inherent limitations, such as reduced blood perfusion to the brain, damage to the external carotid artery system, impaired food and/or water intake, and sensory dysfunction of the face. This article introduces a new method for inducing a rat ischemic stroke model without compromising the cerebral vascular anatomy. In this study, the common carotid artery (CCA) of Sprague-Dawley rats was exposed, and an incision was made. A filament was then inserted through the incision into the internal carotid artery to occlude the middle cerebral artery. After 1.5 h of induced ischemia, the occluding filament was fully removed from both the internal carotid artery and the CCA. The incision in the CCA was subsequently sutured using 11-0 microsurgical sutures under a microscope (magnification 4x). Through the utilization of microsurgical techniques to repair the CCA, this study successfully developed a unique method to induce an ischemic stroke model in rats while preserving the anatomical integrity of cerebral blood vessels.

MSCs-derived exosomes containing miR-486-5p attenuate cerebral ischemia and reperfusion (I/R) injury

ObjectivesThis study aims to investigate the impact of mesenchymal stem cell (MSC)-derived exosomes (Exo) on cerebral ischemia and reperfusion (I/R) injury, along with the underlying mechanism. MethodsAn animal model of cerebral ischemia was induced using middle cerebral artery occlusion (MCAO), and a cell model utilizing Neuro‐2a cells was established through oxygen-glucose deprivation/reoxygenation (OGD/R). Exosomes isolated from mouse MSCs were administered to mice or used to stimulate Neuro‐2a cells. Exosomes from MSCs transfected with miR-NC, miR-486-5p mimics, miR-486-5p inhibitor, or phosphatase and tensin homolog (PTEN) short hairpin RNAs (sh-PTEN) were employed to stimulate Neuro‐2a cells. The regulatory axis of miR-486-5p and PTEN was confirmed through rescue experiments. ResultsExo-miR-486-5p mimics alleviated cerebral I/R injury, improving neurological deficits and reducing the infarct ratio. Furthermore, Exo-miR-486-5p mimics attenuated OGD/R-induced defects in cell viability and inhibited apoptosis in Neuro‐2a cells. These mimics also reduced levels of lactate dehydrogenase (LDH) and malondialdehyde (MDA) while enhancing superoxide dismutase (SOD) activity, both in brain tissue homogenates of mice and cell supernatants. Mechanistically, PTEN was identified as a target of miR-486-5p, and the downregulation of PTEN notably elevated Exo-miR-486-inhibitor-induced reductions in cell viability while mitigating cell apoptosis. ConclusionThe results of this study demonstrate the potential of exosomes derived from MSCs to protect against cerebral I/R injury via the miR-486-5p and PTEN axis.

Linarin ameliorates ischemia-reperfusion injury by the inhibition of endoplasmic reticulum stress targeting AKR1B1

Due to various factors, there is still a lack of effective neuroprotective agents for ischemic stroke in clinical practice. Neuroinflammation and neuronal apoptosis mediated by endoplasmic reticulum stress are some of the important pathological mechanisms in ischemic stroke. Linarin has been reported to have anti-inflammation, antioxidant, and anti-apoptotic effects in myocardial ischemia, osteoarthritis, and kidney disease. Whether it exerts neuroprotective functions in ischemic stroke has not been investigated. The results showed that linarin could reduce the infarct volume in cerebral ischemia animal models, improve the neurological function scores and suppress the expression of inflammatory factors mediating the NF-κB. Meanwhile, it could protect the neurons from OGD/R-induced-apoptosis, which was related to the PERK-eIF2α pathway. Our results suggested linarin could inhibit neuronal inflammation and apoptosis induced by endoplasmic reticulum stress. Furthermore, the neuroprotective effect of linarin may be related to the inhibition of AKR1B1. Our study offers new insight into protecting against ischemia-reperfusion injury by linarin treatment in stroke.

TMT-based quantitative proteomics analysis of neuroprotective effects of Forsythoside A on the MPTP-induced Parkinson's disease mouse model

Parkinson's disease (PD) is a prevalent neurodegenerative disorder characteristized by the presence of dyskinesia and the progressive loss of dopaminergic neurons. Although certain drugs can mitigate the symptoms of PD, they are unable to delay the disease progression, and their prolonged use may result in complications. Therefore, there exists an urgent necessity to identify potential agents that can effectively delay PD progression with fewer side effects. Recent research has unveiled that several traditional Chinese medicines (TCM) exhibit neuroprotective properties in various models pertinent to PD. Forsythoside A (FSA), the primary bioactive compound derived from TCM Lianqiao, has undergone extensive research in animal models of Alzheimer's disease and cerebral ischemia. However, the investigation into the impact of FSA on PD is limited in existing research. In this study, we aimed to evaluate the neuroprotective effects of FSA on MPTP-induced PD mouse model. FSA demonstrated significant improvements in the behavioral and neuropathological changes triggered by MPTP in mice. Furthermore, it exerted a suppressive effect on the activations of astrocyte and microglia. Meanwhile, Tandem mass tag (TMT)-based quantitative proteomics of striatal tissue and bioinformatics analysis were performed to elucidate the underlying mechanisms of FSA on PD mouse model. Proteomics demonstrated a total of 68 differentially expressed proteins (DEPs) were identified between HFSA and MPTP groups including 26 upregulated and 42 downregulated. Systematic bioinformatics analysis of the 68 DEPs illustrated that they were predominantly related to estrogen signaling pathway and calcium signaling pathway. The related DEPs (PLCβ4, Grm2, HPAC and Cox4i1) expression levels were verified by Western blot. FSA effectively restored the altered expression of the four DEPs induced by MPTP. Summarily, FSA exerted remarkable neuroprotective effects in MPTP-induced mice. Further, our research may provide proteomics insights that contribute to the further exploration of FSA as a potential treatment for PD.

Protein misfolding: an additional player in the stroke-heart syndrome

Abstract Background Patients suffering from acute ischemic stroke experience an increased risk of major adverse cardiovascular events, introducing the term of stroke-heart syndrome (SHS). Beside common risk factors, the so-called brain-heart axis represents a relevant yet not fully understood biological matrix driving this multi-organ condition. Together with inflammatory and neurohormonal signals, protein misfolding appears as an additional component of this matrix. In fact, previous studies employing animal models of cerebral ischemia identified wrongly arranged toxic proteins (oligomers). In light of the spreading capabilities of such proteins, we questioned whether protein misfolding plays a role in the SHS. Purpose The purpose of this study is to investigate the occurrence of protein misfolding in the post-stroke cardiac dysfunction by assessing presence, origin, localization and routes of oligomers in the heart following an acute ischemic stroke. Its biological and physiological relevance are evaluated by in vivo and in vitro assessments of the myocardium. Methods Acute cerebral ischemic injury was induced in the mouse by left transient middle cerebral artery occlusion for 45 minutes followed by 48 hours of reperfusion in 3-4 month-old C57BL/6J wild type males. Sham operated littermate mice were used as controls. Forty-eight hours after acute cerebral ischemia, cardiac function was evaluated by electrocardiography and compared to pre-operative assessment. Organs were harvested after the abovementioned assessment for the localization and semi-quantification of oligomers in heart and lymph nodes. Furthermore, biological responses related to protein homeostasis in the myocardium were assessed on mRNA and protein levels. Results Our preliminary results show that acute ischemic stroke is associated with an increased presence of oligomers in the heart. In addition, higher levels of oligomers were detected in axillary lymph nodes isolated from stroke mice, suggesting a possible route of oligomers spreading (Fig 1A). Correlating with oligomers occurrence, molecular analyses showed significant upregulation of the inositol-requiring enzyme 1 (IRE1), and catalase at mRNA level (Fig 1B). On the other hand, the expression of the 78-kDa glucose-regulated protein (GRP78), and catalase significantly decreased at protein level, indicating impaired myocardial protein quality control and oxidative stress after acute ischemic stroke (Fig 1C). Stroke-induced cardiac dysfunction was presented by decreased heart weight to tibia length ratio as well as slower and irregular heart rhythm suggesting signs of arrhythmia (Fig 2). Conclusions Acute ischemic stroke is associated with an increased oligomers occurrence in the myocardium and ultimately correlates with altered cardiac resistance against proteotoxicity. Further experiments will be conducted in order to elucidate the role of oligomers as active players or bystanders in the stroke-heart syndrome.

Neuroprotective Effects of Human-Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cell Extracellular Vesicles in Ischemic Stroke Models.

Stroke represents the second leading cause of death and the primary cause of long-term disability in humans. The transplantation of mesenchymal stem cells (MSC) reportedly improves functional outcomes in animal models of cerebral ischemia. Here, we evaluate the neuroprotective potential of extracellular vesicles secreted from human-induced pluripotent stem cell-derived mesenchymal stem cells (hiPS-MSC-EV) using preclinical cell-based and animal-based models of ischemic strokes. hiPS-MSC-EV were isolated using an ultrafiltration method. HT22 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury for 2 h, followed by treatment with hiPS-MSC-EV (100 μg/mL). Male C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO) followed by an intravenous injection of hiPS-MSC-EV (100 μg) at three distinct time points. Our experimental approach revealed hiPS-MSC-EV promoted HT22 cell proliferation, reduced apoptosis, and altered cellular morphology following OGD/R. In addition, hiPS-MSC-EV reduced the volume of infarcts, improved spontaneous movement abilities, and enhanced angiogenesis by expressing the VEGF and CXCR4 proteins in the infarcted hemisphere of the MCAO-treated mouse model. Our findings provide evidence of the potential neuroprotective effects of hiPS-MSC-derived extracellular vesicles (hiPS-MSC-EVs) in both in vitro and in vivo mouse models of ischemic stroke. These results suggest that hiPS-MSC-EVs may play a role in neurorestoration and offer insights into potential cell-free strategies for addressing cerebral ischemia.

Electroacupuncture protective effects after cerebral ischemia are mediated through miR-219a inhibition

BackgroundElectroacupuncture (EA) is a complementary and alternative therapy which has shown protective effects on vascular cognitive impairment (VCI). However, the underlying mechanisms are not entirely understood.MethodsRat models of VCI were established with cerebral ischemia using occlusion of the middle cerebral artery or bilateral common carotid artery. The brain structure and function imaging were measured through animal MRI. miRNA expression was detected by chip and qPCR. Synaptic functional plasticity was detected using electrophysiological techniques.ResultsThis study demonstrated the enhancement of Regional Homogeneity (ReHo) activity of blood oxygen level-dependent (BOLD) signal in the entorhinal cortical (EC) and hippocampus (HIP) in response to EA treatment. miR-219a was selected and confirmed to be elevated in HIP and EC in VCI but decreased after EA. N-methyl-D-aspartic acid receptor1 (NMDAR1) was identified as the target gene of miR-219a. miR-219a regulated NMDAR-mediated autaptic currents, spontaneous excitatory postsynaptic currents (sEPSC), and long-term potentiation (LTP) of the EC-HIP CA1 circuit influencing synaptic plasticity. EA was able to inhibit miR-219a, enhancing synaptic plasticity of the EC-HIP CA1 circuit and increasing expression of NMDAR1 while promoting the phosphorylation of downstream calcium/calmodulin-dependent protein kinase II (CaMKII), improving overall learning and memory in VCI rat models.ConclusionInhibition of miR-219a ameliorates VCI by regulating NMDAR-mediated synaptic plasticity in animal models of cerebral ischemia.

Impact of NKG2D Signaling on Natural Killer and T-Cell Function in Cerebral Ischemia.

Background Typically defined as a thromboinflammatory disease, ischemic stroke features early and delayed inflammatory responses, which determine the extent of ischemia-related brain damage. T and natural killer cells have been implicated in neuronal cytotoxicity and inflammation, but the precise mechanisms of immune cell-mediated stroke progression remain poorly understood. The activating immunoreceptor NKG2D is expressed on both natural killer and T cells and may be critically involved. Methods and Results An anti-NKG2D blocking antibody alleviated stroke outcome in terms of infarct volume and functional deficits, coinciding with reduced immune cell infiltration into the brain and improved survival in the animal model of cerebral ischemia. Using transgenic knockout models devoid of certain immune cell types and immunodeficient mice supplemented with different immune cell subsets, we dissected the functional contribution of NKG2D signaling by different NKG2D-expressing cells in stroke pathophysiology. The observed effect of NKG2D signaling in stroke progression was shown to be predominantly mediated by natural killer and CD8+ T cells. Transfer of T cells with monovariant T-cell receptors into immunodeficient mice with and without pharmacological blockade of NKG2D revealed activation of CD8+ T cells irrespective of antigen specificity. Detection of the NKG2D receptor and its ligands in brain samples of patients with stroke strengthens the relevance of preclinical observations in human disease. Conclusions Our findings provide a mechanistic insight into NKG2D-dependent natural killer- and T-cell-mediated effects in stroke pathophysiology.

Tat-RAN attenuates brain ischemic injury in hippocampal HT-22 cells and ischemia animal model

Oxidative stress plays a key role in the pathogenesis of neuronal injury, including ischemia. Ras-related nuclear protein (RAN), a member of the Ras superfamily, involves in a variety of biological roles, such as cell division, proliferation, and signal transduction. Although RAN reveals antioxidant effect, its precise neuroprotective mechanisms are still unclear. Therefore, we investigated the effects of RAN on HT-22 cell which were exposed to H2O2-induced oxidative stress and ischemia animal model by using the cell permeable Tat-RAN fusion protein. We showed that Tat-RAN transduced into HT-22 cells, and markedly inhibited cell death, DNA fragmentation, and reactive oxygen species (ROS) generation under oxidative stress. This fusion protein also controlled cellular signaling pathways, including mitogen-activated protein kinases (MAPKs), NF-κB, and apoptosis (Caspase-3, p53, Bax and Bcl-2). In the cerebral forebrain ischemia animal model, Tat-RAN significantly inhibited both neuronal cell death, and astrocyte and microglia activation. These results indicate that RAN significantly protects against hippocampal neuronal cell death, suggesting Tat-RAN will help to develop the therapies for neuronal brain diseases including ischemic injury.

Effect of VEGF on neurological impairment and prognosis of acute cerebral infarction patients: A retrospective case-control study.

Due to the complex pathological mechanism of acute cerebral infarction, the role of vascular endothelial growth factor (VEGF) on the disease is not clear. Therefore, a retrospective case-control study was performed to explore the effect of VEGF on neurological impairment and prognosis of acute cerebral infarction patients. A total of 100 patients with acute cerebral infarction admitted to our hospital from April 2021 to April 2022 were selected. Blood samples from all patients would be routinely collected to detect the expression of serum VEGF. Pearson chi-square, Spearman correlation and univariate Logistic regression were used to analyze the clinical data to explore the relationship between VEGF expression and basic information, stroke degree, quality of life, and prognosis of patients. To determine whether VEGF can provide relevant basis for the early prevention and prognostic treatment of acute cerebral infarction. And multivariate logistic regression was used to calculate the odds ratio between each variable and VEGF expression. Pearson chi-square test and Spearman correlation coefficient showed that sex, degree of stroke, limb convulsions, loss of consciousness, hemiplegia, aphasia, mental functioning score, overall quality of life score, and short-term prognosis were significantly correlated with VEGF expression in 100 patients. Univariate logistic regression was used to describe the ORs and 95% confidence interval of subjects at the univariate level, and the degree of stroke (OR = 83.333, P < 0.001), tic of limbs (OR = 26.316, P < 0.001), loss of consciousness (OR = 23.256, P < 0.001), hemiplegia (OR = 62.500, P < 0.001), aphasia (OR = 76.923, P < 0.001), mental functioning score (OR = 7.937, P < 0.001), overall quality of life score (OR = 5.464, P < 0.001), short-term prognosis (OR = 37.037, P < 0.001) was significantly correlated with the high expression of VEGF. The level of serum VEGF was positively correlated with neurological impairment degree and prognosis in patients with acute cerebral infarction, the more severe the degree of stroke and the worse the prognosis.

Abstract WP213: The Effect Of Nicotine Withdrawal On Stroke Outcome In Female Rats

Significance: Smoking-derived nicotine (N) is known to synergistically magnify the risk and severity of cerebral ischemia in females. Most importantly, smoking is the one preventable risk factor and giving up smoking reduces the risk for cerebral ischemia. However, how long the harmful effects of N on the brain persist after women stop smoking is unknown. In a laboratory study using an animal model of cerebral ischemia, we demonstrated that N alters brain energy metabolism and thus exacerbates ischemic brain damage. Therefore, the current study aims to investigate how long after N withdrawal (NW) N toxicity on brain energy metabolism persists and its impact on stroke outcomes in female rats. Methods: Female Sprague-Dawley rats (n=8/group) were randomly exposed to either saline or N (4.5 mg/kg) for 16-21 days after which point, they were withdrawn from N exposure and able to recover for 0, 15, or 30 days. These rats were then randomly assigned to either have their cortical tissue collected for global metabolomic (Metabolon Inc) and Western blot analysis or undergo a sham surgery or transient middle-cerebral artery occlusion (tMCAO; 90 min). Post-stroke cognition was tested with contextual fear conditioning at month following tMCAO, subsequently the brains were collected for infarct quantification. Results: Analysis of the metabolomics data revealed an increase in carbohydrate metabolites in the 30-day NW group when compared to the N-exposed group, suggesting persistence of N toxicity in the brain. Furthermore, fear conditioning data revealed a significantly lower freezing time in all NW groups when compared to the saline group implying that spatial memory deficits persist even after 30 days of NW. Lastly, the observed infarct volume was 26%(p&lt;0.05), 25%(p&lt;0.05), and 16%(p&lt;0.05) higher in the 0, 15, and 30 day NW groups respectively, when compared to the saline group. Conclusion: Even after 30 days of NW, N-induced global metabolomic changes in the brain persist and may be responsible for increased ischemic brain damage as well as cognitive deficits in female rats.

Photothrombotic Middle Cerebral Artery Occlusion in Mice: A Novel Model of Ischemic Stroke.

Stroke is one of the main causes of death and disability worldwide. Over the past decades, several animal models of focal cerebral ischemia have been developed allowing to investigate pathophysiological mechanisms underlying stroke progression. Despite intense preclinical research efforts, the need for noninvasive mouse models of vascular occlusion targeting the middle cerebral artery yet avoiding mechanical intervention is still pressing. Here, by applying the photothrombotic stroke model to the distal branch of the middle cerebral artery, we developed a novel strategy to induce a targeted occlusion of a large blood vessel in mice. This approach induces unilateral damage encompassing most of the dorsal cortex from the motor up to the visual regions 1 week after stroke. Pronounced limb dystonia one day after the damage is partially recovered after one week. Furthermore, we observe the insurgence of blood vessel leakage and edema formation in the peri-infarct area. Finally, this model elicits a notable inflammatory response revealed as a strong increase in astrocyte density and morphologic complexity in the perilesional region of the cortex compared with both other regions of the ipsilesional and contralesional hemispheres, and in sham-operated mice. To conclude, the stroke model we developed induces in mice the light-mediated occlusion of one of the main targets of human ischemic stroke, the middle cerebral artery, free from the limitations of commonly used preclinical models.

Rehabilitation in Animal Models of Stroke.

The purpose of this review was to evaluate the efficacy of rehabilitation strategies in animal models of stroke and their correlation with human stroke studies. General description of a stroke, functional recovery, and rehabilitation modalities were included from published studies in the field of animal models of cerebral ischemia and ischemia-reperfusion. In stroke survivors, rehabilitation plays a significant role to improve motor function, cognition, and other subtle behaviors. Targeted pharmacological agents, including neuroprotective drugs, are helpful in animal models of stroke. However, no drug has yet been found that meets the criteria that would make it the Food and Drug Administration-approved treatment for human stroke. Instead, the rehabilitation of stroke in humans is limited to physical and occupational therapy, speech therapy, environmental enrichment, and social activities, as well as spiritual and family support. Studies on stroke injury and the significance of stroke animals' rehabilitation, including physical and pharmacological, approaches are highlighted.

Increase in repulsive guidance molecule-a (RGMa) in lacunar and cortical stroke patients is related to the severity of the insult

Repulsive guidance molecule-a (RGMa) inhibits angiogenesis and increases inflammation. Animal models of cerebral ischemia have shown that an increased expression of RGMa leads to larger infarction and its inhibition attenuates effects of ischemia. We report on the relationship of RGMa to stroke types and severity. This is a prospective study in patients admitted to the stroke service in Qatar. We collected the clinical determinants, including NIHSS at admission, imaging and outcome at discharge and 90-days. RGMa levels were determined by measuring mRNA levels extracted from peripheral blood mononuclear cells (PBMCs) within 24 h of onset and at 5 days. There were 90 patients (lacunar: 64, cortical: 26) and 35 age-matched controls. RGMa mRNA levels were significantly higher in the stroke patients: day 1: 1.007 ± 0.13 versus 2.152 ± 0.19 [p < 0.001] and day-5: 3.939 ± 0.36 [p < 0.0001]) and significantly higher in patients with severe stroke (NIHSS ≥ 8) compared to milder symptoms (NIHSS < 8) at day 1 (NIHSS ≥ 8: 2.563 ± 0.36; NIHSS < 8: 1.947 ± 0.2) and day 5 (NIHSS ≥ 8: 5.25 ± 0.62; NIHSS < 8: 3.259 ± 0.419). Cortical stroke patients had marginally higher RGMa mRNA levels compared to lacunar stroke at day 1 (cortical stroke: 2.621 ± 0.46 vs lacunar stroke: 1.961 ± 0.19) and day 5 (cortical stroke: 4.295 ± 0.76 vs lacunar stroke: 3.774 ± 0.39). In conclusion, there is an increase in the level of RGMa mRNA in patients with acute stroke and seen in patients with lacunar and cortical stroke. The increase in RGMa mRNA levels is related to the severity of the stroke and increases over the initial 5 days. Further studies are required to determine the effects of the increase in RGMa on stroke recovery.

Effect of Cilostazol in Animal Models of Cerebral Ischemia and Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis.

Cilostazol, a phosphodiesterase III inhibitor, appears to be a promising agent for preventing cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage. Here, the authors perform a systematic review and meta-analysis to quantitatively assess the effects of cilostazol on brain structural and functional outcomes in animal models of cerebral ischemia and subarachnoid hemorrhage-induced cerebral vasospasm. By using the PRISMA guidelines, a search of the PubMed, Scopus, and Web of Science was conducted to identify relevant studies. Study quality of each included study for both systematic reviews were scored by using an adapted 15-item checklist from the Collaborative Approach to Meta-Analysis of Animal Data from Experimental Studies. We calculated a standardized mean difference as effect size for each comparison. For each outcome, comparisons were combined by using random-effects modeling to account for heterogeneity, with a restricted maximum likelihood estimate of between-study variance. A total of 22 (median [Q1, Q3] quality score of 7 [5, 8]) and 6 (median [Q1, Q3] quality score of 6 [6, 6]) studies were identified for cerebral ischemia and subarachnoid hemorrhage-induced cerebral vasospasm, respectively. Cilostazol significantly reduced the infarct volume in cerebral ischemia models with a pooled standardized mean difference estimate of - 0.88 (95% confidence interval [CI] [- 1.07 to - 0.70], p < 0.0001). Cilostazol significantly reduced neurofunctional deficits in cerebral ischemia models with a pooled standardized mean difference estimate of - 0.66 (95% CI [- 1.06 to - 0.28], p < 0.0001). Cilostazol significantly improved the basilar artery diameter in subarachnoid hemorrhage-induced cerebral vasospasm with a pooled standardized mean difference estimate of 2.30 (95% CI [0.94 to 3.67], p = 0.001). Cilostazol also significantly improved the basilar artery cross-section area with a pooled standardized mean estimate of 1.88 (95% CI [0.33 to 3.43], p < 0.05). Overall, there was between-study heterogeneity and asymmetry in the funnel plot observed in all comparisons. Published animal data support the overall efficacy of cilostazol in reducing infarct volume and neurofunctional deficits in cerebral ischemia models and cerebral vasospasm in subarachnoid hemorrhage models.