Middle Cerebral Artery Occlusion Surgery Research Articles

Abolishing UCHL1's hydrolase activity exacerbates ischemia-induced axonal injury and functional deficits in mice.

Ubiquitin C-terminal hydrolase L1 (UCHL1) is a neuronal protein important in maintaining axonal integrity and motor function and may be important in the pathogenesis of many neurological disorders. UCHL1 may ameliorate acute injury and improve recovery after cerebral ischemia. In the current study, the hypothesis that UCHL1's hydrolase activity underlies its effect in maintaining axonal integrity and function is tested after ischemic injury. Hydrolase activity was inhibited by treatment with a UCHL1 hydrolase inhibitor or by employing knockin mice bearing a mutation in the hydrolase active site (C90A). Ischemic injury was induced by oxygen-glucose deprivation (OGD) in brain slice preparations and by transient middle cerebral artery occlusion (tMCAO) surgery in mice. Hydrolase activity inhibition increased restoration time and decreased the amplitude of evoked axonal responses in the corpus callosum after OGD. Mutation of the hydrolase active site exacerbated white matter injury as detected by SMI32 immunohistochemistry, and motor deficits as detected by beam balance and cylinder testing after tMCAO. These results demonstrate that UCHL1 hydrolase activity ameliorates white matter injury and functional deficits after acute ischemic injury and support the hypothesis that UCHL1 activity plays a significant role in preserving white matter integrity and recovery of function after cerebral ischemia.

Exploring the “gene–metabolite” network of ischemic stroke with blood stasis and toxin syndrome by integrated transcriptomics and metabolomics strategy

A research model combining a disease and syndrome can provide new ideas for the treatment of ischemic stroke. In the field of traditional Chinese medicine, blood stasis and toxin (BST) syndrome is considered an important syndrome seen in patients with ischemic stroke (IS). However, the biological basis of IS-BST syndrome is currently not well understood. Therefore, this study aimed to explore the biological mechanism of IS-BST syndrome. This study is divided into two parts: (1) establishment of an animal model of ischemic stroke disease and an animal model of BST syndrome in ischemic stroke; (2) use of omics methods to identify differentially expressed genes and metabolites in the models. We used middle cerebral artery occlusion (MCAO) surgery to establish the disease model, and utilized carrageenan combined with active dry yeast and MCAO surgery to construct the IS-BST syndrome model. Next, we used transcriptomics and metabolomics methods to explore the differential genes and metabolites in the disease model and IS-BST syndrome model. It is found that the IS-BST syndrome model exhibited more prominent characteristics of IS disease and syndrome features. Both the disease model and the IS-BST syndrome model share some common biological processes, such as thrombus formation, inflammatory response, purine metabolism, sphingolipid metabolism, and so on. Results of the “gene–metabolite” network revealed that the IS-BST syndrome model exhibited more pronounced features of complement-coagulation cascade reactions and amino acid metabolism disorders. Additionally, the “F2 (thrombin)–NMDAR/glutamate” pathway was coupled with the formation process of the blood stasis and toxin syndrome. This study reveals the intricate mechanism of IS-BST syndrome, offering a successful model for investigating the combination of disease and syndrome.

Inactivation of cGAS signaling pathway mediated by TDP-43 deficiency protects microglia from hypoxia/reoxygenation induced injury

BackgroundMicroglia are damaged during cerebral ischemia–reperfusion (I/R). This study was performed to investigate the regulatory effect of tAR DNA-binding protein-43 (TDP-43) on microglia after cerebral I/R in vitro and in vivo. MethodThe hypoxia/reoxygenation (H/R) treated microglia and rats with middle cerebral artery occlusion surgery were constructed respectively. The TDP-43 expression in brain tissues and microglia of each group was evaluated by qPCR and western blotting methods. Cell viability and cell apoptosis were combined to evaluate the degree of cell injury. As for animal experiments, neurological score and infarct volume were obtained to evaluate neurological injury. ResultsThe levels of TDP-43 in the brain tissues of I/R group were higher than that in sham group. Both TDP-43 and Iba1, a typical microglia marker, were expressed in the brain tissues. TDP-43 was also elevated in microglia with H/R treatment. Inhibition of TDP-43 significantly down-regulated neurological deficit scores of rats after I/R surgery, and weakened the H/R treatment induced injury by promoting cell viability, inhibiting cell apoptosis, down-regulating IL-6 and iNOS levels, and up-regulating Arg-1 and IL-10 levels. Inactivation of cGAS pathway mediated by TDP-43 knockdown protects microglia from H/R treatment induced injury. ConclusionThe highly expressed TDP-43 level is associated with cerebral I/R, and inhibition of TDP-43 protects microglia from H/R induced injury through cGAS pathway in vitro and in vivo.

Electroacupuncture Ameliorates Cerebral Ischemia-reperfusion Injury by Inhibiting Pyroptosis through the Sirtuin-1 Pathway

Abstract Objective: NOD-like receptor protein 3 (NLRP3)-mediated pyroptosis is pivotal in the pathological development of cerebral ischemia/reperfusion injury (CIRI). Although previous research has shown that electroacupuncture (EA) can alleviate CIRI through sirtuin-1 (SIRT1), the mechanism has not been well elucidated. Our study aimed to clarify whether the neuroprotective functions of EA are related to the reduction in NLRP3-mediated pyroptosis through the SIRT1 pathway. Materials and Methods: Rats received daily pretreatment with EA for 5 consecutive days before undergoing middle cerebral artery occlusion surgery. The Longa score was used to assess neurologic function. Infarct volume and morphological alterations were analyzed using 2,3,5-triphenyltetrazolium chloride and hematoxylin and eosin staining. In addition, neuronal pyroptosis was identified by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling/caspase-1 and neuronal nuclear antigen/caspase-1 immunofluorescence double staining. Levels of expression of pyroptosis markers were assessed by Western blotting and enzyme-linked immunosorbent assay. Results: EA improved deficits in neurologic function and minimized cerebral infarct volume. Mechanistically, a number of neuronal pyroptotic cells and protein levels of NLRP3, apoptosis-associated speck-like protein containing a CARD, and gasdermin D in the cerebral cortex were markedly reduced by EA treatment, and conversely, SIRT1 levels were increased. Notably, the specific SIRT1 inhibitor, EX527, reversed the effects of EA. Conclusions: EA potentially exerts a neuroprotective effect against CIRI through the SIRT1 pathway in NLRP3-mediated pyroptosis.

Impact of social isolation on corticosterone release and recovery after stroke in aged rats: A behavioral and biochemical analysis

Social isolation (SI) after stroke reduces recovery. The aim of this study was to evaluate the effects of SI on corticosterone release and recovery after stroke in aged rats. A total of 64 male Wistar rats (aged 24 months) were used in the present study. All rats were housed in pairs for two weeks. After two weeks, rats were randomly assigned to one of four groups: (1) rats underwent sham surgery and kept socially isolated (control/social isolated (CO/SI) group); (2) rats underwent sham surgery and kept pair housed (control/pair housed (CO/PH) group); (3) rats underwent middle cerebral artery occlusion (MCAO) surgery and kept socially isolated (stroke/isolated (ST/SI) group); (4) rats underwent MCAO surgery and kept pair housed (stroke/pair housed (ST/PH)) group. Behaviors were assessed using the adhesive removal test, rotarod test and social interaction test at 1st, 7th, 14th and 21st days after stroke. Serum biochemical analysis was also performed on the behavioral testing days. Results showed THAT serum corticosterone and MDA levels in CO/PH group were significantly lower than CO/SI group. Serum BDNF levels in CO/PH group was significantly higher than CO/SI group. Serum corticosterone and MDA levels in ST/PH group were lower than ST/SI group. In ST/PH group, serum Total antioxidant capacity (TAC) and BDNF levels were significantly higher than ST/SI group. Biochemical analysis of certain regions of the brain (hippocampus, striatum and cerebral cortex) was performed on 21st day after stroke. In the hippocampus of CO/PH group, BDNF and TAC levels were significantly higher than CO/SI group. The hippocampal MDA level of CO/PH group were significantly lower than CO/SI group. BDNF and TAC levels in the hippocampus, striatum and cerebral cortex of ST/PH group were significantly higher and MDA level was significantly lower as compared with ST/SI group. Both ischemic groups showed sensorimotor recovery over a 21-day period, but recovery of ST/PH group was significantly greater than ST/SI group. Total social interaction time in ST/PH group was significantly longer than ST/SI group. Based on the results of this study, social interaction after stroke enhances histologic and sensorimotor recovery through reduction of HPA activity and corticosterone release, leading to increased TAC and BDNF levels.

The Water Extract of Rhubarb Prevents Ischemic Stroke by Regulating Gut Bacteria and Metabolic Pathways.

Rhubarb (RR), Chinese name Dahuang, is commonly used in the treatment of ischemic stroke (IS). However, its potential mechanism is not fully elucidated. This study intended to verify the effect of RR on IS and investigate the possible mechanism of RR in preventing IS. IS in male rats was induced by embolic middle cerebral artery occlusion (MCAO) surgery, and drug administration was applied half an hour before surgery. RR dramatically decreased the neurological deficit scores, the cerebral infarct volume, and the cerebral edema rate, and improved the regional cerebral blood flow (rCBF) and histopathological changes in the brain of MCAO rats. The 16S rRNA analysis showed the harmful microbes such as Fournierella and Bilophila were decreased, and the beneficial microbes such as Enterorhabdus, Defluviitaleaceae, Christensenellaceae, and Lachnospira were significantly increased, after RR pretreatment. 1H-nuclear magnetic resonance (1H-NMR) was used to detect serum metabolomics, and RR treatment significantly changed the levels of metabolites such as isoleucine, valine, N6-acetyllysine, methionine, 3-aminoisobutyric acid, N, N-dimethylglycine, propylene glycol, trimethylamine N-oxide, myo-inositol, choline, betaine, lactate, glucose, and lipid, and the enrichment analysis of differential metabolites showed that RR may participate in the regulation of amino acid metabolism and energy metabolism. RR exerts the role of anti-IS via regulating gut bacteria and metabolic pathways.

Retinoic acid attenuates ischemic injury-induced activation of glial cells and inflammatory factors in a rat stroke model.

Stroke is a leading cause of death and long-term disability which can cause oxidative damage and inflammation of the neuronal cells. Retinoic acid is an active metabolite of vitamin A that has various beneficial effects including antioxidant and anti-inflammatory effects. In this study, we investigated whether retinoic acid modulates oxidative stress and inflammatory factors in a stroke animal model. A middle cerebral artery occlusion (MCAO) was performed on adult male rats to induce focal cerebral ischemia. Retinoic acid (5 mg/kg) or vehicle was injected into the peritoneal cavity for four days before MCAO surgery. The neurobehavioral tests were carried out 24 h after MCAO and cerebral cortex tissues were collected. The cortical damage was assessed by hematoxylin-eosin staining and reactive oxygen species assay. In addition, Western blot and immunohistochemical staining were performed to investigate the activation of glial cells and inflammatory cytokines in MCAO animals. Ionized calcium-binding adapter molecule-1 (Iba-1) and glial fibrillary acidic protein (GFAP) were used as markers of microglial and astrocyte activation, respectively. Tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were used as representative pro-inflammatory cytokines. Results showed that MCAO damage caused neurobehavioral defects and histopathological changes in the ischemic region and increased oxidative stress. Retinoic acid treatment reduced these changes caused by MCAO damage. We detected increases in Iba-1 and GFAP in MCAO animals treated with vehicle. However, retinoic acid alleviated increases in Iba-1 and GFAP caused by MCAO damage. Moreover, MCAO increased levels of nuclear factor-κB and pro-inflammatory cytokines, including TNF-α and IL-1β. Retinoic acid alleviated the expression of these inflammatory proteins. These findings elucidate that retinoic acid regulates microglia and astrocyte activation and modulates pro-inflammatory cytokines. Therefore, this study suggests that retinoic acid exhibits strong antioxidant and anti-inflammatory properties by reducing oxidative stress, inhibiting neuroglia cell activation, and preventing the increase of pro-inflammatory cytokines in a cerebral ischemia.

Dihydroergotamine protects against ischemic stroke by modulating microglial/macrophage polarization and inhibiting inflammation in mice

ABSTRACT Objectives The search for drugs that can protect the brain tissue and reduce nerve damage in acute ischemic stroke has emerged as a research hotspot. We investigated the potential protective effects and mechanisms of action of dihydroergotamine against ischemic stroke. Methods C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO), and dihydroergotamine at a dose of 10 mg/kg/day was intraperitoneally injected for 14 days. Adhesive removal and beam walking tests were conducted 1, 3, 5, 7, 10, and 14 days after MCAO surgery. Thereafter, the mechanism by which dihydroergotamine regulates microglia/macrophage polarization and inflammation and imparts ischemic stroke protection was studied using enzyme-linked immunosorbent assay, immunofluorescence staining, and western blotting. Results From the perspective of a drug repurposing strategy, dihydroergotamine was found to inhibit oxygen-glucose deprivation damage to neurons, significantly improve cell survival rate, and likely exert a protective effect on ischemic brain injury. Dihydroergotamine significantly improved neural function scores and survival rates and reduced brain injury severity in mice. Furthermore, dihydroergotamine manifests its protective effect on ischemic brain injury by reducing the expression of TNF-α and IL-1β in mouse ischemic brain tissue, inhibiting the polarization of microglia/macrophage toward the M1 phenotype and promoting polarization toward the M2 phenotype. Conclusion This study is the first to demonstrate the protective effect of dihydroergotamine, a first-line treatment for migraine, against ischemic nerve injury in vitro and in vivo.

Epigallocatechin gallate improves neuronal damage in animal model of ischemic stroke and glutamate-exposed neurons via modulation of hippocalcin expression.

Epigallocatechin gallate (EGCG) is a polyphenolic component of green tea that has anti-oxidative and anti-inflammatory effects in neurons. Ischemic stroke is a major neurological disease that causes irreversible brain disorders. It increases the intracellular calcium concentration and induces apoptosis. The regulation of intracellular calcium concentration is important to maintain the function of the nervous system. Hippocalcin is a neuronal calcium sensor protein that controls intracellular calcium concentration. We investigated whether EGCG treatment regulates the expression of hippocalcin in stroke animal model and glutamate-induced neuronal damage. We performed middle cerebral artery occlusion (MCAO) to induce cerebral ischemia. EGCG (50 mg/kg) or phosphate buffered saline was injected into the abdominal cavity just before MCAO surgery. The neurobehavioral tests were performed 24 h after MCAO surgery and cerebral cortex tissue was collected. MCAO damage induced severe neurobehavioral disorders, increased infarct volume, and decreased the expression of hippocalcin in the cerebral cortex. However, EGCG treatment improved these deficits and alleviated the decrease in hippocalcin expression in cerebral cortex. In addition, EGCG dose-dependently alleviated neuronal cell death and intracellular calcium overload in glutamate-exposed neurons. Glutamate exposure reduced hippocalcin expression, decreased Bcl-2 expression, and increased Bax expression. However, EGCG treatment mitigated these changes caused by glutamate toxicity. EGCG also attenuated the increase in caspase-3 and cleaved caspase-3 expressions caused by glutamate exposure. The effect of EGCG was more pronounced in non-transfected cells than in hippocalcin siRNA-transfected cells. These findings demonstrate that EGCG protects neurons against glutamate toxicity through the regulation of Bcl-2 family proteins and caspase-3. It is known that hippocalcin exerts anti-apoptotic effect through the modulation of apoptotic pathway. Thus, we can suggest evidence that EGCG has a neuroprotective effect by regulating hippocalcin expression in ischemic brain damage and glutamate-exposed cells.

Enriched environment treatment promotes neural functional recovery together with microglia polarization and remyelination after cerebral ischemia in rats

BackgroundMicroglia activation and oligodendrocyte maturation are critical for remyelination after cerebral ischemia. Studies have shown that enriched environment (EE) can effectively alleviate stroke-induced neurological deficits. However, little is known about the mechanism associated with glial cells underlying the neuroprotection of EE. Therefore, this study focuses on investigating the effect of EE on activated microglia polarization as well as oligodendrogenesis in the progress of remyelination following cerebral ischemia. MethodsThe ischemia/reperfusion (I/R) injury model was established by middle cerebral artery occlusion (MCAO) in rats. Animals executed 4 weeks of environmental intervention after performing MCAO or sham surgery and were divided into sham, MCAO, and MCAO+EE groups. Cognitive function, myelin damage, microglia activation and polarization, inflammation, oligodendrogenesis, remyelination, and protein expression of the PI3K/AKT/GSK3β signaling pathway were determined. ResultsThe staining of NeuN indicated that the infarct size of MCAO rats was decreased under EE. EE intervention improved animal performance in the Morris water maze test and novel object recognition test, promoting the recovery of cognitive function after I/R injury. EE treatment alleviated myelin damage in MCAO rats, as evidenced by the lower fluorescence intensity ratio of SMI-32/MBP in MCAO+EE group. EE increased the fluorescence intensity ratio of NG2+/Ki67+/Olig2+, MBP, and MOG, enhancing the proliferation and differentiation of OPCs and oligodendrogenesis after MCAO. In terms of remyelination, more myelinated axons and lower G/ratio were detected in MCAO+EE rats compared with MCAO group. Moreover, EE treatment decreased the number of Iba1+/CD86+ M1 microglia, increased the number of Iba1+/CD206+ M2 microglia, and suppressed the inflammation response after I/R injury, which could be attributed to the augmented expression of PI3K/AKT/GSK3β axis. ConclusionEE improved long‑term recovery of cognitive function after cerebral I/R injury, at least in part by promoting M2 microglia transformation through activation of the PI3K/AKT/GSK3β signaling pathway, inhibiting inflammation to provide a favorable microenvironment for oligodendrocyte maturation and remyelination. The effect of the EE on myelin and inflammation could account for the neuroprotection provided by EE.

Electronic Cigarette Vape Exposure Exacerbates Post-Ischemic Outcomes in Female but Not in Male Rats.

Nicotine-containing electronic cigarette (EC) vaping has become popular worldwide, and our understanding of the effects of vaping on stroke outcomes is elusive. Using a rat model of transient middle cerebral artery occlusion, the current exploratory study aims to evaluate the sex-dependent effects of EC exposure on brain energy metabolism and stroke outcomes. Adult Sprague-Dawley rats of both sexes were randomly assigned to air/EC vapor (5% nicotine Juul pods) exposure for 16 nights, followed by randomization into 3 cohorts. The first cohort underwent exposure to air/EC preceding randomization to transient middle cerebral artery occlusion (90 minutes) or sham surgery, followed by survival for 21 days. During the survival period, rats underwent sensorimotor and Morris water maze testing. Subsequently, brains were collected for histopathology. A second cohort was exposed to air/EC after which brains were collected for unbiased metabolomics analysis. The third cohort of animals was exposed to air/EC and received transient middle cerebral artery occlusion/sham surgery, and brain tissue was collected 24 hours later for biochemical analysis. In females, EC significantly increased (P<0.05) infarct volumes by 94% as compared with air-exposed rats, 165±50 mm3 in EC-exposed rats, and 85±29 mm3 in air-exposed rats, respectively, while in males such a difference was not apparent. Morris water maze data showed significant deficits in spatial learning and working memory in the EC sham or transient middle cerebral artery occlusion groups compared with the respective air groups in rats of both sexes (P<0.05). Thirty-two metabolites of carbohydrate, glycolysis, tricarboxylic acid cycle, and lipid metabolism were significantly altered (P≤0.05) due to EC, 23 of which were specific for females. Steady-state protein levels of hexokinase significantly decreased (P<0.05) in EC-exposed females; however, these changes were not seen in males. Even brief EC exposure over 2 weeks impacts brain energy metabolism, exacerbates infarction, and worsens poststroke cognitive deficits in working memory more in female than male rats.

Sinigrin improves cerebral ischaemia-reperfusion injury by inhibiting the TLR4 pathway-mediated oxidative stress.

Cerebral ischaemia-reperfusion (CIR) injury occurs in stroke patients after the restoration of cerebral perfusion. Sinigrin, a phytochemical found in cruciferous vegetables, exhibits strong antioxidant activity. This study investigated the role of sinigrin in oxidative stress using a CIR injury model. The effects of sinigrin were studied in middle cerebral artery occlusion (MCAO) rats and oxygen-glucose deprivation/reoxygenation (OGD/R)-injured SH-SY5Y cells. Sinigrin treatment improved brain injury and neurological deficits induced by MCAO surgery in rats. Sinigrin inhibited apoptosis in brain tissues and SH-SY5Y cells following OGD/R induction. Additionally, sinigrin elevated the levels of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) while reducing malondialdehyde (MDA) levels. Furthermore, sinigrin inhibited the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signalling pathway. The anti-apoptotic and antioxidant activities of sinigrin in OGD/R-injured SH-SY5Y cells were reversed by TLR4 overexpression. In conclusion, sinigrin inhibits oxidative stress in CIR injury by suppressing the TLR4/MyD88 signalling pathway.

Abstract TP298: Cellular Senescence and Microglial Dysfunction are Linked to Progressive Cognitive Deficits in the Chronic Phase of Ischemic Stroke

Improvements in acute stroke treatment, including endovascular thrombectomy and critical care management, have increased survival rates after stroke. However, many survivors have significant neurological deficits, as stroke remains one of the leading causes of long-term disability. Despite this, the chronic progression and long-term sequelae of ischemic stroke pathology remains woefully understudied. This study examined long-term progressive deficits in young adult male C57Bl/6 mice at 3 and 6 months after a 60-minute transient middle cerebral artery occlusion (MCAO) or sham surgery to identify secondary injury processes, and neuropathology of chronic stroke human brains. Depressive-like behavior persisted for 6 months post-stroke (PS) (p= &lt;0.0001). Cognitive function progressively worsened from 3 to 6 months as seen by a continual reduction in the discrimination index in the novel object recognition task (p=.0063). Deficits in memory retention in mice 6-months PS were observed using the fear-conditioning test (p=.0084). Brain atrophy was evident by MicroCT imaging. Histopathological assessment revealed increased microglial activation in the hippocampus and frontal cortex in both mouse and human brains chronically after stroke. Interestingly, we also observed microglia activation proximal to apoptotic neurons in the brains of stroke mice, as shown by TUNEL assay. TUNEL co-labeling with a neuronal marker showed the same neuronal apoptosis in human samples from patients with chronic stroke, in both the hippocampus and thalamus. Disease-associated microglial (DAM) phenotypes were marked by both increased proliferative status and senescent-like phenotypes, including elevated production of cytokines and other proinflammatory molecules. Our findings demonstrate that experimental stroke accelerates inflammaging in the brain, which induces premature senescence within the chronic infarct microenvironment. Cellular senescence and chronic neurodegenerative signatures likely contribute to progressive cognitive impairment following stroke. The chronic and evolving neurological consequences of stroke may offer viable targets for delayed treatment strategies to reduce risk of vascular dementia and neurodegenerative disease.

Abstract 105: Sex Difference in Brain Energy Metabolism After Electronic Cigarette Vape Exposure May Contribute to Worsened Stroke Injury in Rats

Introduction: Electronic cigarettes (EC) are battery-powered nicotine delivery devices that have gained popularity as alternatives to tobacco cigarettes for young smokers and smokers trying to cease. Because of its relative novelty, our understanding about the effects of EC vaping on stroke outcome is limited. Here we aim to investigate the effects of EC on energy metabolism in the brain and on stroke outcome in animals of both sexes. Methods: Female and male Sprague-Dawley rats (2-3 months old; n=8) were randomly assigned to either air or EC vapor (5% nicotine Juul pods) exposure for 16 nights using the EcigAero-TM Aerosol Exposure Apparatus. After the exposure period, the rats were divided into two cohorts. The brains were collected from the first cohort of rats for unbiased metabolomic (Metabolon Inc.) or Western blot analysis. The second cohort underwent transient middle cerebral artery occlusion (tMCAO; 90 min) or sham surgery and was survived for 21 days. During the post-tMCAO/sham survival, cognition was assessed using the Morris water maze followed by brain collection for histopathological analysis. Results: Metabolomic analysis showed substantial changes in glycolytic metabolites in EC-exposed female rats in relation to air controls, implying altered brain energetics. In EC-exposed female animals, a significant increase (p&lt;0.05) in glucose, glucose 6-phosphate, fructose-6-phosphate, and fructose 1-6 diphosphate was noted compared to air controls. However, such changes were not seen in EC-exposed male rats. Quantification of infarct volume demonstrated that, compared to air rats, EC-exposed rats displayed a significantly increased infarct volume in female rats while showing a trend of increase in male rats. In female rats, infarct volumes were 86 ± 19 mm 3 and 151 ± 25 mm 3 for air and EC groups, respectively, a significant difference (p&lt;0.05). In the male rat air group, tMCAO resulted in an infarct volume of 80 ± 37 mm 3 , while EC yielded 130 ± 38 mm 3 . Behavioral testing showed worsened post-stroke cognitive outcome in EC groups compared to air groups in rats of both sexes. Conclusion: EC vape exposure, even for as short as two weeks, impacts glucose metabolism and worsens post-stroke cognitive deficits in female more than male rats.

Abstract WP316: Single-Cell RNA Sequencing Reveals a Massive Alteration in the Molecular Landscape of Microglia After Ischemic Stroke

Introduction: Ischemic stroke, a prevalent and often devastating disease, remains poorly treated. Neuroinflammation is a key element of stroke pathophysiology and represents a promising therapeutic target. Among the central components driving neuroinflammation, microglia - the primary resident immune cells within the brain parenchyma - are key players in mediating the immune response in the stroke brain. However, how microglia respond to stroke is incompletely understood. In this study, we took advantage of a mouse genetic tool (ie, Tmem119-CreERT2), sorted microglia, and performed single-cell RNA sequencing (scRNA-seq) analysis using a mouse model of permanent stroke. Moreover, as stroke exhibits sexual dimorphism, we included both male and female mice. Methods: Young male and female Ai6/TMEM119-CreERT2;Ai6 (Tmem119-Ai6) mice with microglia labeled with ZsGreen underwent permanent middle cerebral artery occlusion (pMCAO) or sham surgery. On day 3 after stroke, ZsGreen+ cells (microglia) in the brain were isolated by FACS, and used for scRNA-seq analysis. Results: First, we confirmed that in Tmem119-Ai6 mice, expression of fluorescent ZsGreen was almost exclusively in microglia in the brain, with minimal presence in blood cells. Our unbiased scRNA-seq analysis of ZsGreen+ cells revealed 13 distinct microglial clusters after stroke. Importantly, 4 major stroke-related microglial clusters were identified. One cluster shared a gene signature with the reported disease-associated microglia (DAM) subset. The other 3 clusters were characterized by an interferon (IFN) response signature, a highly proliferative state, and a macrophage-like profile, respectively. RNA in situ hybridization analysis showed that cells from these clusters mainly resided within the stroke boundaries. Notably, our scRNA-seq data suggest no major sexual dimorphism in the microglial response to permanent stroke. Conclusions: This is the first scRNA-seq study with a focus on microglia in the context of sex and stroke. We propose that 4 microglial subsets may be deemed as common stroke-associated microglia. Future work will be designed to elucidate the functional significance of these subsets and their potential implications for stroke therapy.

Abstract WP301: STAT3 Inhibition Reduces Infarct and Neuroinflammation in Experimental Stroke

Signal Transducer and Activator of Transcription 3 (STAT3) activation is increased in the brain following cerebral ischemia. STAT3, a transcription factor, is a positive regulator of cell survival and is implicated in cytoprotection following ischemia in multiple cell types, including neurons and endothelial cells. We hypothesized that pharmacological inhibition of STAT3 activation in mice during the reperfusion phase after middle cerebral artery occlusion (MCAO) will lead to increased infarct size. We subjected mice to 1-hour MCAO, following which they received STAT3 inhibitor Stattic (20 mg/kg), or vehicle, for 24 hours delivered subcutaneously via osmotic pump. Twenty-four hours later, infarct was measured by TTC and inflammatory cells were measured by flow cytometry. For experiments involving splenectomy, spleens were surgically removed 14 days prior to MCAO surgery. Surprisingly, we found that STAT3 inhibition reduces infarct after MCAO, with infarct in the hemisphere reducing from 49.90 ± 2.44 % in vehicle to 32.86 ± 1.55 % in Stattic-treated mice. Since STAT3 is involved in inflammatory processes, as well as cytoprotection, this led us to hypothesize that the reduction in infarct we observe may be due to decreased inflammation. We carried out FACS analysis and observed that Stattic inhibits MCAO-induced infiltration of B-, T- and dendritic cells into the brain. Neutrophil and monocyte infiltration into the brain were unaffected by Stattic. Since MCAO is known to induce splenic atrophy, with spleen size being inversely proportional to infarct volume, we measured spleen weights. Interestingly Stattic-treated mice had larger spleens (66.31 ± 5.40 g) compared to vehicle-treated mice (46.43 ± 4.60 g), indicating a dampened peripheral immune response upon inhibition of STAT3. Furthermore, Stattic was no longer effective in reducing infarct size in splenectomized mice. We conclude that pharmacological inhibition of STAT3 reduces infarct following MCAO, with the mechanism of protection involving differential regulation of the peripheral immune response.

TRIM59 suppresses the brain ischaemia/reperfusion injury and pyroptosis of microglial through mediating the ubiquitination of NLRP3

Cerebral ischaemia/reperfusion (I/R) injury induces irreversible brain injury and causes functional impairment. Ubiquitination plays a crucial role in protein degradation, but its role in cerebral I/R injury remains unclear. Differentially expressed genes in stroke were identified by analysing the microarray dataset GSE119121. Cerebral I/R was simulated in vitro by treating human microglial HMC3 cells with oxygen–glucose deprivation/reperfusion (OGD/R). Cell viability was tested by Cell Counting Kit 8 (CCK-8) assays, and pyroptosis was examined by flow cytometry. Lactate dehydrogenase (LDH) and inflammatory cytokine secretion were measured by LDH cytotoxicity assays and enzyme-linked immunosorbent assay (ELISA), respectively. The cerebral I/R animal model was established by middle cerebral artery occlusion (MCAO) surgery in rats. Bioinformatic analysis indicated that tripartite motif-containing protein 59 (TRIM59) is downregulated in stroke, which was verified in cerebral I/R models. The upregulation of TRIM59 promoted viability and inhibited pyroptosis in OGD/R-treated microglia and alleviated cerebral I/R injury in vivo. TRIM59 attenuated NOD-like receptor family pyrin domain containing 3 (NLRP3) protein expression through ubiquitination, thus degrading NLRP3 and alleviating OGD/R-induced injury. TRIM59 relieves cerebral I/R injury in vivo and in vivo. Mechanistically, TRIM59 directly interacts with NLRP3 and inhibits NLRP3 through ubiquitination. Targeting the TRIM59/NLRP3 signalling axis may be an effective therapeutic strategy for cerebral I/R.

Retinoic acid alleviates the reduction of Akt and Bad phosphorylation and regulates Bcl-2 family protein interactions in animal models of ischemic stroke.

Ischemic stroke causes a lack of oxygen and glucose supply to brain, eventually leads to severe neurological disorders. Retinoic acid is a major metabolic product of vitamin A and has various biological effects. The PI3K-Akt signaling pathway is an important survival pathway in brain. Phosphorylated Akt is important in regulating survival and apoptosis. We examined whether retinoic acid has neuroprotective effects in stroke model by regulating Akt and its downstream protein, Bad. Moreover, we investigated the relationship between retinoic acid and Bcl-2 family protein interactions. Animals were intraperitoneally administered vehicle or retinoic acid (5 mg/kg) for four days before surgery and ischemic stroke was induced by middle cerebral artery occlusion (MCAO) surgery. Neurobehavioral tests were performed 24 h after MCAO and cerebral cortical tissues were collected. Cresyl violet staining and TUNEL histochemistry were performed, Western blot and immunoprecipitation analysis were performed to elucidate the expression of various proteins. Retinoic acid reduced neurological deficits and histopathological changes, decreased the number of TUNEL-positive cells, and alleviated reduction of phospho-PDK1, phospho-Akt, and phospho-Bad expression caused by MCAO damage. Immunoprecipitation analysis showed that MCAO damage reduced the interaction between phospho-Bad and 14-3-3, which was attenuated by retinoic acid. Furthermore, retinoic acid mitigated the increase in Bcl-2/Bad and Bcl-xL/Bad binding levels and the reduction in Bcl-2/Bax and Bcl-xL/Bax binding levels caused by MCAO damage. Retinoic acid alleviated MCAO-induced increase of caspase-3 and cleaved caspase-3 expression. We demonstrate that retinoic acid prevented apoptosis against cerebral ischemia through phosphorylation of Akt and Bad, maintenance of phospho-Bad and 14-3-3 binding, and regulation of Bcl-2 family protein interactions. .

Huatanmaitong tablet alleviate cerebral ischemic reperfusion injury with hyperlipidaemia in rats by regulating OATPs/VEGF axis.

Stroke is the top priority pathogenesis of disability and death globally, affecting people worldwide. The presence of high levels of lipids in the blood has been confirmed as a vital factor of ischemic stroke. We aim to examine the effectiveness of Huatanmaitong tablet in hyperlipidemia rats that have experienced an ischemic stroke. We created a rat model of middle cerebral artery occlusion (MCAO) with hyperlipidemia as a basis. Following 8 weeks of high-fat diet, the model rats underwent MCAO surgery. Subsequently, the rats were administered huatanmaitong tablets and lipitor tablets as treatments. Therefore there are five groups, CONTROL, MCAO, hyperlipidemia (HLP), Huatanmaitong tablet (HTMTT) and Lipitor (LIPITOR) groups respective ly. To assess the efficacy of the medication, the serum lipid levels of rats were measured both prior to and following administration. Hematoxylin eosin staining was used to observe the alterations in the brain and liver structures within each group. VEGF and OATPs related factors were detected in brain, liver by using immunohistochemistry, Western blotting, and Quantitative PCR. After the model was established successfully, the infarct volume and behavioral scores of the model group, hyperlipidemia group, Huatan Maitong tablet group and Lipitor group had statistical differences (P<0.05). Blood lipid levels of rats were measured before and after treatment, and it was found that Huatanmaitong tablets effectively reduced these levels. Hematoxylin and eosin staining of the brain and liver showed that huatanmaitong tablets maintained the microstructure stability. Western blotting and real-time PCR revealed that Huatanmaitong tablets improved the expression level of organic anion transport (OATP1B1, OATP2B1) in rat tissues with ischemic stroke, enhancing the transmembrane transport of exogenous substances and maintaining homeostatic balance. Additionally, it down-regulated the expression of VEGF in various organs such as the brain, and liver, demonstrating the ability of Huatanmaitong tablets to remove phlegm, blood stasis, and promote circulation by regulating serum lipid levels, organic anion transport peptide, and VEGF in rats. The behavioral score of ischemic stroke rats can be improved and the neurological impairment symptoms of rats can be alleviated by Huatanmaitong tablet through the regulation of OATPS/VEGF axis.

Recombinant human brain natriuretic peptide attenuates ischemic brain injury in mice by inhibiting oxidative stress and cell apoptosis via activation of PI3K/AKT/Nrf2/HO-1 pathway.

Ischemic stroke followed by cerebral artery occlusion is a main cause of chronic disability worldwide. Recombinant human brain natriuretic peptide (rhBNP) has been reported to alleviate sepsis-induced cognitive dysfunction and brain I/R injury. However, the function and molecular mechanisms of rhBNP in ischemic brain injury have not been clarified. For establishment of an animal model of ischemic brain injury, C57BL/6 mice were treated with middle cerebral artery occlusion (MCAO) surgery for 1h and reperfusion for 24h. After subcutaneous injection of rhBNP into model mice, neurologic deficits were assessed by evaluating behavior of mice according to Longa scoring system, and TTC staining was utilized to determine the brain infarct size of mice. The levels of oxidative stress markers, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA), were detected in hippocampal tissues of mice by corresponding kits. Cell apoptosis in hippocampus tissues was examined by TUNEL staining. Protein levels of antioxidant enzymes (HO-1 and NQO1) in cerebral cortex, apoptotic markers (Bax, Bcl-2, and cleaved caspase), and PI3K/AKT pathway-associated factors in hippocampus were tested by western blot analysis. The results revealed that injection of rhBNP decreased neurologic deficit scores, the percent of brain water content, and infarct volume. Additionally, rhBNP downregulated MDA level, upregulated the levels of SOD, CAT, and GSH in hippocampus of mice, and increased protein levels of HO-1 and NQO1 in the cortex. Cell apoptosis in hippocampus tissues of model mice was inhibited by rhBNP which was shown as the reduced TUNEL-positive cells, the decreased Bax, cleaved caspase-3, and cleaved caspase-9 protein levels, and the enhanced Bcl-2 protein level. In addition, rhBNP treatment activated the PI3K/AKT signaling pathway and upregulated the protein levels of HO-1 and NRF2. Overall, rhBNP activates the PI3K/AKT/HO-1/NRF2 pathway to attenuate ischemic brain injury in mice after MCAO by suppression of cell apoptosis and oxidative stress.