Brain Ischemia-reperfusion Injury Research Articles

Effect of ethanol extract of nigella sativa L seeds and propofol on BDNF protein level as neuroplasticity and neuroprotection of traumatic brain injury in rats

Background Traumatic brain injury (TBI) is a change in brain function or evidence of brain pathology caused by external mechanical forces. Brain Derived Neurotrophic Factor (BDNF) is a neurotropin that functions as a neuron protective. Nigella sativa L is reported to have an antioxidant effect, administration of Nigella Sativa L to rats treated with ischemia-reperfusion brain injury. Propofol is an anesthetic agent frequently used intravenously in the management of TBI. The effect of propofol on brain tissue after TBI may be neuroprotective. We aimed to compare the potential of Nigella sativa L and propofol as neuroplasticity and neuroprotection in rats with TBI. Methods This was a laboratory experimental animal model with the post-test only control group design, namely measuring the effect of treatment by comparing the five groups of rats consisting of 30 rats. BDNF levels in rat brain tissue were collected at day 7 of treatment and measured by ELISA. Results The average BDNF protein levels per group, namely G1 (221,243 pg/mL), G2 (172,139 pg/mL), G3 (255,483 pg/mL), G4 (227,089 pg/mL), and G5 (272,603 pg/mL) respectively. Based on the ANOVA statistic, p-value = 0.032 (there was a significant difference between groups), with the Levene Test (0.077) or having variance between the same groups, sequentially the difference in average BDNF protein levels of the five groups is G5>G3>G4>G1>G2, meaning that the combination of Nigella sativa and propofol has more potential to increase BDNF protein levels than Nigella sativa, and Nigella sativa has more potential than propofol. Conclusion We concluded that both nigella sativa and propofol have the potential to increase BDNF protein levels. Nigella Sativa L had a better effect than propofol in repairing damaged neuron cells (neuroplasticity) and increasing BDNF protein levels (neuroprotection) for 7 days of administration in rat traumatic brain injury.

ML218 modulates calcium binding protein, oxidative stress, and inflammation during ischemia-reperfusion brain injury in mice

Cerebral ischemia disrupts calcium homeostasis in the brain causing excitotoxicity, oxidative stress, inflammation, and neuronal cell apoptosis. During ischemic conditions, T-type calcium channel channels contribute to increase in intracellular calcium ions in both neurons and glial cells therefore, the current study hypothesizes the antagonism of these channels using ML218, a novel specific T-Type inhibitor in experimental model of cerebral ischemia-reperfusion (CI/R) brain injury. CI/R injury was induced in Swiss Albino mice by occlusion of common carotid arteries followed by reperfusion. Animals were assessed for learning and memory (MWM), motor coordination (Rota rod), neurological function (neurological deficit score), cerebral infarction, edema, and histopathological alterations. Biochemical assessments were made for calcium binding proteins (Calmodulin- CaM, calcium/calmodulin-dependent protein kinase II-CaMKII, S100B), oxidative stress (4-hydroxy 2-nonenal-4-HNE, glutathione-GSH, inflammation (nuclear factor kappa-light-chain-enhancer of activated B-p65-NF-kB, tumor necrosis factor-TNF-α, interleukin-IL-10) inducible nitric oxide synthase (iNOS) levels, and acetylcholinesterase activity (AChE) in brain supernatants. Furthermore, serum levels of NF-kB, iNOS, and S100B were also assessed. CI/R animals showed impairment in learning, memory, motor coordination, and neurological function along with increase in cerebral infarction, edema, and histopathological alterations. Furthermore, increase in brain calcium binding proteins, oxidative stress, inflammation, and AChE activity along with serum NF-kB, iNOS, and S100B levels were recorded in CI/R animals. Administration of ML218 (5 mg/kg and 10 mg/kg; i.p.) was observed to recuperate CI/R induced impairments in behavioral, biochemical, and histopathological analysis. Hence, it may be concluded that ML218 mediates neuroprotection during CI/R via decreasing brain and serum calcium binding proteins, inflammation, iNOS, and oxidative stress markers.

Use of Analgesics and Sedatives in Nontraumatic Patients after Sudden Cardiac Arrest during the Peri-Resuscitation Period in the Emergency Department.

Background: While cardiopulmonary resuscitation (CPR) may be life-saving for patients in cardiac arrest, it simultaneously puts them at risk for skeletal and soft tissue injuries. The prevalence of cardiovascular and thoracic wall injuries related to CPR varies significantly in the literature, from 21% to more than 78%. After restoration of circulation, ischemia-reperfusion brain injury ensues. Sedation is one of the interventions that can reduce its effects on brain cells. The purpose of this study was to analyse the use of analgesics and sedatives in nontraumatic patients after sudden cardiac arrest in the peri-resuscitation period in the emergency department. Methods: This was a retrospective cohort study. An analysis was performed on the electronic health records of 131 patients who underwent CPR, with ages ranging from 24 to 96 years. The study protocol was in accordance with the Declaration of Helsinki. Results: Chest wall injuries were assessed based on the results of X-ray imaging (n = 39; 31%) and computed tomography (n = 87; 69%). Of the 126 cases, 17.5% had rib fractures and 6.3% had rib and sternal fractures. Almost 78% of the patients (n = 102) received sedatives and/or analgesics during the peri-resuscitation period. Monotherapy was used in 85 cases. Among these drugs the most frequently mentioned were midazolam (45.2%), fentanyl (26.8%), and propofol (20.8%). Conclusions: As only two-thirds of the patients received sedation and half received analgesics, there is still room for a broader incorporation of analgesia and sedation into peri-resuscitation care protocols.

Modulating the RPS27A/PSMD12/NF-κB pathway to control immune response in mouse brain ischemia-reperfusion injury

BackgroundInvestigating immune cell infiltration in the brain post-ischemia-reperfusion (I/R) injury is crucial for understanding and managing the resultant inflammatory responses. This study aims to unravel the role of the RPS27A-mediated PSMD12/NF-κB axis in controlling immune cell infiltration in the context of cerebral I/R injury.MethodsTo identify genes associated with cerebral I/R injury, high-throughput sequencing was employed. The potential downstream genes were further analyzed using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Protein-Protein Interaction (PPI) analyses. For experimental models, primary microglia and neurons were extracted from the cortical tissues of mouse brains. An in vitro cerebral I/R injury model was established in microglia using the oxygen-glucose deprivation/reoxygenation (OGD/R) technique. In vivo models involved inducing cerebral I/R injury in mice through the middle cerebral artery occlusion (MCAO) method. These models were used to assess neurological function, immune cell infiltration, and inflammatory factor release.ResultsThe study identified RPS27A as a key player in cerebral I/R injury, with PSMD12 likely acting as its downstream regulator. Silencing RPS27A in OGD/R-induced microglia decreased the release of inflammatory factors and reduced neuron apoptosis. Additionally, RPS27A silencing in cerebral cortex tissues mediated the PSMD12/NF-κB axis, resulting in decreased inflammatory factor release, reduced neutrophil infiltration, and improved cerebral injury outcomes in I/R-injured mice.ConclusionRPS27A regulates the expression of the PSMD12/NF-κB signaling axis, leading to the induction of inflammatory factors in microglial cells, promoting immune cell infiltration in brain tissue, and exacerbating brain damage in I/R mice. This study introduces novel insights and theoretical foundations for the treatment of nerve damage caused by I/R, suggesting that targeting the RPS27A and downstream PSMD12/NF-κB signaling axis for drug development could represent a new direction in I/R therapy.

The effects and mechanisms of AM1241 in alleviating cerebral ischemia-reperfusion injury

ObjectiveResearch has shown that cerebral ischemia-reperfusion injury (CIRI) involves a series of physiological and pathological mechanisms, including inflammation, oxidative stress, and cell apoptosis. The cannabinoid receptor 2 agonist AM1241 has been found to have anti-inflammatory and anti-oxidative stress effects. However, it is unclear whether AM1241 has a protective effect against brain ischemia-reperfusion injury, and its underlying mechanisms are not yet known. MethodsIn this study, we investigated the anti-inflammatory, anti-oxidative stress, and anti-apoptotic effects of AM1241 and its mechanisms in BV2 cells stimulated with H2O2 and in a C57BL/6 mouse model of CIRI in vitro and in vivo, respectively. ResultsIn vitro, AM1241 significantly inhibited the release of pro-inflammatory cytokines TNF-α and IL-6, reactive oxygen species (ROS), and the increase in Toll-like receptor 4/myeloid differentiation protein 2 (MD2/TLR4) complex induced by H2O2. Under H2O2 stimulation, MD2 overexpression resulted in increased levels of MD2/TLR4 complex, TNF-α, IL-6, NOX2, BAX, and Cleaved-Caspase3 (C-Caspase3), as well as the activation of the MAPK pathway and NF-κB, which were reversed by AM1241. In addition, molecular docking experiments showed that AM1241 directly interacted with MD2. Surface Plasmon Resonance (SPR) experiments further confirmed the binding of AM1241 to MD2. In vivo, AM1241 significantly attenuated neurofunctional impairment, brain edema, increased infarct volume, oxidative stress levels, and neuronal apoptosis in CIRI mice overexpressing MD2. ConclusionOur study demonstrates for the first time that AM1241 alleviates mouse CIRI by inhibiting the MD2/TLR4 complex, exerting anti-inflammatory, anti-oxidative stress and anti-apoptotic effects.

HSPD1 gene polymorphism is associated with an increased risk of ischemic stroke in smokers

Background: Ischemic stroke (IS) is a leading cause of death and disability worldwide. Since the influence of vascular stressors prompts cross-reactivity with microbial and human HSPD1 (HSP60), which results in the degradation of vascular endothelium and intimal infiltration by mononuclear cells, HSP60 is viewed as a key player in the autoimmune theory of atherosclerosis. The aim of the study: The present pilot study investigated whether the tag SNP rs11682567 HSPD1 is associated with the risk of IS. Materials and methods: DNA samples from 1176 unrelated Russian subjects (708 IS patients and 468 healthy controls) were genotyped for tagging SNP rs11682567 in the HSPD1 gene using the MassArray-4 system. A log-additive regression model was used to interpret the associations between genotypes and IS risk. Results: We discovered that smoking, a major environmental endothelial stressor, dramatically modifies the link between rs11682567 and IS, with a relationship only being seen in smokers (risk allele G; OR = 2.11, 95% CI = 1.17-3.82; P = 0.0075). The functional annotation of this SNP revealed that risk allele G of rs11682567 impacts the expression and alternative splicing of genes that regulate brain ischemia-reperfusion injury, reactive oxygen species production, toll-like receptor 4 internalization, and pro-inflammatory properties. Moreover, allele G rs11682567 creates binding sites for transcription factors jointly involved in biological processes encompass neurogenesis, monocyte differentiation, fatty acid metabolism, cell signalling, and apoptosis. Conclusion: Thus, rs11682567 SNP in the HSPD1 gene represents a novel genetic marker of ischemic stroke, whose significance for the pathogenesis of IS is mediated by smoking.

Investigating the Pharmacological Mechanisms of Total Flavonoids from Eucommia ulmoides Oliver Leaves for Ischemic Stroke Protection.

The aim of this study was to explore how the total flavonoids from Eucommia ulmoides leaves (EULs) regulate ischemia-induced nerve damage, as well as the protective effects mediated by oxidative stress. The cell survival rate was significantly improved compared to the ischemic group (p < 0.05) after treatment with the total flavonoids of EULs. The levels of reactive oxygen species (ROS), lactate dehydrogenase (LDH), and malondialdehyde (MDA) decreased, while catalase (CAT) and glutathione (GSH) increased, indicating that the total flavonoids of EULs can significantly alleviate neurological damage caused by ischemic stroke by inhibiting oxidative stress (p < 0.01). The mRNA expression level of VEGF increased (p < 0.01), which was consistent with the protein expression results. Meanwhile, the protein expression of ERK and CCND1 increased (p < 0.01), suggesting that the total flavonoids of EULs could protect PC12 cells from ischemic injury via VEGF-related pathways. MCAO rat models indicated that the total flavonoids of EULs could reduce brain ischemia-reperfusion injury. In conclusion, this study demonstrates the potential mechanisms of the total flavonoids of EULs in treating ischemic stroke and their potential therapeutic effects in reducing ischemic injury, which provides useful information for ischemic stroke drug discovery.

Advancements in understanding the role of ferroptosis in hypoxia-associated brain injury: a narrative review.

Ferroptosis, a form of programmed cell death driven by lipid peroxidation and dependent on iron ions, unfolds through a sophisticated interplay of multiple biological processes. These include perturbations in iron metabolism, lipid peroxidation, aberrant amino acid metabolism, disruptions in hypoxia-inducible factor-prolyl hydroxylase (HIF-PHD) axis, and endoplasmic reticulum (ER) stress. Recent studies indicate that ferroptosis may serve as a promising therapeutic target for hypoxia-associated brain injury such as hypoxic-ischemic brain damage (HIBD) and cerebral ischemia-reperfusion injury (CIRI). HIBD is a neonatal disease that can be fatal, causing death or mental retardation in newborns. HIBD is a kind of diffuse brain injury, which is characterized by apoptosis of nerve cells and abnormal function and structure of neurons after cerebral hypoxia and ischemia. At present, there are no fundamental prevention and treatment measures for HIBD. The brain is the most sensitive organ of the human body to hypoxia. Cerebral ischemia will lead to the damage of local brain tissue and its function, and CIRI will lead to a series of serious consequences. We hope to clarify the mechanism of ferroptosis in hypoxia-associated brain injury, inhibit the relevant targets of ferroptosis in hypoxia-associated brain injury to guide clinical treatment, and provide guidance for the subsequent treatment of disease-related drugs. Our research incorporated data on "ferroptosis", "neonatal hypoxic ischemia", "hypoxic ischemic brain injury", "hypoxic ischemic encephalopathy", "brain ischemia-reperfusion injury", and "therapeutics", which were sourced from Web of Science, PubMed, and comprehensive reviews and articles written in English. This review delineates the underlying mechanisms of ferroptosis and the significance of these pathways in hypoxia-associated brain injury, offering an overview of therapeutic strategies for mitigating ferroptosis. Ferroptosis involves dysregulation of iron metabolism, lipid peroxidation, amino acid metabolism, dysregulation of HIF-PHD axis and endoplasmic reticulum stress (ERS). By reviewing the literature, we identified the involvement of the above processes in HIBD and CIRI, and summarized a series of therapeutic measures for HIBD and CIRI by inhibiting ferroptosis. We hope this study would provide guidance for the clinical treatment of HIBD and CIRI in the future.

Improvement of neuronal and cognitive functions following treatment with 3′,4′ dihydroxyflavonol in experimental focal cerebral ischemia-reperfusion injury in rats

IntroductionIschemia/reperfusion is a pathological condition by the restoration of perfusion and oxygenation following a period of restricted blood flow to an organ. To address existing uncertainty in the literature regarding the effects of 3′, 4′-dihydroxy flavonol (DiOHF) on cerebral ischemia/reperfusion injury, our study aims to investigate the impact of DiOHF on neurological parameters, apoptosis (Caspase-3), aquaporin 4 (AQP4), and interleukin-10 (IL-10) levels in an experimental rat model of brain ischemia-reperfusion injury. Materials/methodsA total of 28 Wistar-albino male rats were used in this study. Experimental groups were formed as 1-Control, 2-Sham, 3-Ischemia-reperfusion, 4-Ischemia-reperfusion + DiOHF (10 mg/kg). The animals were anaesthetized, and the carotid arteries were ligated (ischemia) for 30 min, followed by reperfusion for 30 min. Following reperfusion, DiOHF was administered intraperitoneally to the animals at a dose of 10 mg/kg for 1 week. During the one-week period neurological scores and new object recognition tests were performed. Then, caspase 3 and AQP4 levels were determined by PCR method and IL-10 by ELISA method in hippocampus tissue samples taken from animals sacrificed under anaesthesia. ResultsBrain ischemia reperfusion significantly increased both caspase 3 and AQP4 values in the hippocampus tissue, while decreasing IL-10 levels. However, 1-week DiOHF supplementation significantly suppressed increased caspase 3 and AQP4 levels and increased IL-10 values. While I/R also increased neurological score values, it suppressed the ability to recognize new objects, and the administered treatment effectively ameliorated the adverse effects observed, resulting in a positive outcome. ConclusionsThe results of the study show that brain ischemia caused by bilateral carotid occlusion in rats and subsequent reperfusion causes tissue damage, but 1-week DiOHF application has a healing effect on both hippocampus tissue and neurological parameters.

Oxidized mitochondrial DNA activates the cGAS-STING pathway in the neuronal intrinsic immune system after brain ischemia-reperfusion injury

In the context of stroke and revascularization therapy, brain ischemia-reperfusion injury is a significant challenge that leads to oxidative stress and inflammation. Central to the cell's intrinsic immunity is the cGAS-STING pathway, which is typically activated by unusual DNA structures. The involvement of oxidized mitochondrial DNA (ox-mtDNA)—an oxidative stress byproduct—in this type of neurological damage has not been fully explored. This study is among the first to examine the effect of ox-mtDNA on the innate immunity of neurons following ischemia-reperfusion injury. Using a rat model of transient middle cerebral artery occlusion and a cellular model of oxygen-glucose deprivation/reoxygenation, we have discovered that ox-mtDNA activates the cGAS-STING pathway in neurons. Importantly, pharmacologically limiting the release of ox-mtDNA into the cytoplasm reduces inflammation and improves neurological functions. Our findings suggest that targeting ox-mtDNA release may be a valuable strategy to attenuate brain ischemia-reperfusion injury following revascularization therapy for acute ischemic stroke.

Effect of ethanol extract of nigella sativa L seeds and propofol on BDNF protein level as neuroplasticity and neuroprotection of traumatic brain injury in rats

Background Traumatic brain injury (TBI) is a change in brain function or evidence of brain pathology caused by external mechanical forces. Brain Derived Neurotrophic Factor (BDNF) is a neurotropin that functions as a neuron protective. Nigella sativa L is reported to have an antioxidant effect, administration of Nigella Sativa L to rats treated with ischemia-reperfusion brain injury. Propofol is an anesthetic agent frequently used intravenously in the management of TBI. The effect of propofol on brain tissue after TBI may be neuroprotective. We aimed to compare the potential of Nigella sativa L and propofol as neuroplasticity and neuroprotection in rats with TBI. Methods This was a laboratory experimental animal model with the post-test only control group design, namely measuring the effect of treatment by comparing the five groups of rats consisting of 30 rats. BDNF levels in rat brain tissue were collected at day 7 of treatment and measured by ELISA. Results The average BDNF protein levels per group, namely G1 (221,243 pg/mL), G2 (172,139 pg/mL), G3 (255,483 pg/mL), G4 (227,089 pg/mL), and G5 (272,603 pg/mL) respectively. Based on the ANOVA statistic, p-value = 0.032 (there was a significant difference between groups), with the Levene Test (0.077) or having variance between the same groups, sequentially the difference in average BDNF protein levels of the five groups is G5&gt;G3&gt;G4&gt;G1&gt;G2, meaning that the combination of Nigella sativa and propofol has more potential to increase BDNF protein levels than Nigella sativa, and Nigella sativa has more potential than propofol. Conclusion We concluded that both nigella sativa and propofol have the potential to increase BDNF protein levels. Nigella Sativa L had a better effect than propofol in repairing damaged neuron cells (neuroplasticity) and increasing BDNF protein levels (neuroprotection) for 7 days of administration in rat traumatic brain injury.

Formononetin alleviates cerebral ischemia-reperfusion injury in rats by targeting the PARP-1/PARG/Iduna signaling pathway

Formononetin has been demonstrated to protect against cerebral ischemia–reperfusion injury, however its mechanism has to be further researched. This study examined the effect of formononetin on cerebral ischemia–reperfusion injury in rats using the PARP-1/PARG/Iduna signaling pathway. In male SD rats, a model of cerebral ischemia–reperfusion injury was developed. Animals were randomly assigned to one of eight groups: Sham operation, Sham operation + formononetin, MCAO, MCAO + formononetin, PARP inhibitor (PJ34) + MCAO, formononetin + PJ34 + MCAO, PARG inhibitor (Ethacridine lactate) + MCAO, and ethacridine lactate + formononetin. The neurological deficit test, TTC staining, HE staining, Nissl staining, TUNEL staining, and western blotting were utilized to assess formononetin's protective effects in MCAO rats. The data show that formononetin can effectively alleviate neurological dysfunction and pathological changes in brain tissue in rats with cerebral ischemia–reperfusion injury, reduce the area of cerebral infarction and neuronal apoptosis, decrease the protein levels of PARP-1, PARG, Caspase-3, P53, and AIF in brain tissue, and increase the protein levels of Iduna and p-AKT. As a result, we concluded that formononetin improves brain ischemia–reperfusion injury in rats by modulating the PARP-1/PARG/Iduna signaling pathway.

Effect of Cyclosporin H on ischemic injury and neutrophil infiltration in cerebral infarct model of rats via PET imaging.

Brain ischemia-reperfusion injury is a complex process, and neuroinflammation is an important secondary contributing pathological event. Neutrophils play major roles in ischemic neuroinflammation. Once activated, neutrophils express formyl peptide receptors (FPRs), which are special receptors of a class of chemoattractants and may be potential targets to regulate the activity of neutrophils and control cerebral ischemic injury. This study was aimed to explore the ameliorating effect of Cyclosporin H (CsH), a potent FPR antagonist, on brain ischemic injury by inhibiting the activation and migration of neutrophils, and improving cerebral blood flow. We employed a middle cerebral artery occlusion (MCAO) Model on rats and performed behavioral, morphological, and microPET imaging assays to investigate the potential restoring efficacy of CsH on cerebral ischemic damages. Peptide N-cinnamoyl-F-(D)L-F-(D)L-F (cFLFLF), an antagonist to the neutrophil FPR with a high binding affinity, was used for imaging neutrophil distribution. We found that CsH had similar effect with edaravone on improving the neurobehavioral deficient symptoms after cerebral ischemia-reperfusion, and treatment with CsH also alleviated ischemic cerebral infarction. Compared with the MCAO Model group, [18F]FDG uptake ratios of the CsH and edaravone treatment groups were significantly higher. The CsH-treated groups also showed significant increases in [18F]FDG uptake at 144h when compared with that of 24h. This result indicates that like edaravone, treatment with both doses of CsH promoted the recovery of blood supply after cerebral ischemic event. Moreover, MCAO-induced cerebral ischemia significantly increased the radiouptake of [68Ga]Ga-cFLFLF at 72h after ischemia-reperfusion operation. Compared with MCAO Model group, radiouptake values of [68Ga]-cFLFLF in both doses of CsH and edaravone groups were all decreased significantly. These results showed that both doses of CsH resulted in a similar therapeutic effect with edaravone on inhibiting neutrophil infiltration in cerebral infarction. Potent FPR antagonist CsH is promisingly beneficial in attenuating neuroinflammation and improving neurobehavioral function against cerebral infarction. Therefore, FPR may become a novel target for regulating neuroinflammation and improving prognosis for ischemic cerebrovascular disorders.

Analysis of hippocampus in rats with acute brain ischemia-reperfusion injury treated with leuprolide acetate, an agonist of GnRH.

The hippocampus is highly vulnerable to damage in the brain ischemia-reperfusion injury model. Leuprolide acetate has been shown to promote neurological recovery after injury in various regions of the central nervous system. The objective of this study was to assess the histology of the hippocampus and the expression of neuronal recovery markers, specifically the 200 kDa neurofilaments and the myelin basic protein, in rats with brain ischemia-reperfusion injury treated with leuprolide acetate. The rats were divided into three groups: Sham, ischemia-reperfusion with saline solution, and ischemia-reperfusion treated with leuprolide acetate. Coronal brain slices were obtained and stained with hematoxylin-eosin. The histological analysis involved quantifying the number of neurons in the hippocampal regions CA1, CA3 and DG. The myelin basic protein and neurofilaments were quantified using western blot. The number of neurons in CA1 and DG was significantly higher in the leuprolide acetate group compared to the untreated group. Additionally, the expression of neurofilament and myelin basic protein markers was significantly increased in rats treated with leuprolide acetate compared to the untreated rats. Leuprolide acetate promotes the recovery of hippocampal neurons in an acute brain ischemia-reperfusion injury model. These findings suggest that leuprolide acetate could be a potential therapeutic intervention for reversing damage in hippocampal ischemic lesions.

Obesity as a Limiting Factor for Remote Ischemic Postconditioning-Mediated Neuroprotection after Stroke.

Remote ischemic postconditioning (RIPostC) may protect the brain from ischemia/reperfusion (I/R) injury. The association between RIPostC and obesity has not yet been extensively studied. Twelve-week-old male Zucker diabetic fatty (ZDF; n=68) and Zucker diabetic lean (ZDL; n=51) rats were subjected to focal cerebral ischemia for 90 minutes, followed by 24 hours of reperfusion. RIPostC was performed with 5-minute I/R cycles using a tourniquet on the right hind limb. The results showed a negative association between obesity and neurological impairment in ischemic animals. We observed a 70% greater infarct size in ZDF rats compared with their lean counterparts, as evaluated by 2,3,5-triphenyltetrazolium chloride staining. To measure the total fragmented DNA in peripheral lymphocytes, comet assay was performed. Obese rats exhibited higher levels of DNA damage (by approximately 135%) in peripheral blood lymphocytes even before the induction of stroke. RIPostC did not attenuate oxidative stress in the blood in obese rats subjected to ischemia. Focal cerebral ischemia increased core and penumbra tissue glutamate release in the brain and decreased it in the blood of ischemic ZDL rats, and these changes improved following RIPostC treatment. However, changes in blood and tissue glutamate content were not detected in ischemic ZDF rats or after RIPostC intervention. Our findings suggest that obese animals respond more severely to ischemia-reperfusion brain injury. However, obese animals did not achieve neuroprotective benefits of RIPostC treatment.

Near-Infrared Afterglow ONOO--Triggered Nanoparticles for Real-Time Monitoring and Treatment of Early Ischemic Stroke.

Early detection and drug intervention with the appropriate timing and dosage are the main clinical challenges for ischemic stroke (IS) treatment. The conventional therapeutic agents relay fluorescent signals, which require real-time external light excitation, thereby leading to inevitable autofluorescence and poor tissue penetration. Herein, we report endogenous peroxynitrite (ONOO-)-activated BDP-4/Cur-CL NPs that release NIR afterglow signals (λmax 697 nm) for real-time monitoring of the progression of ischemia reperfusion (I/R) brain injury while releasing curcumin for the safe treatment of IS. The BDP-4/Cur-CL NPs exhibited bright NIR afterglow luminescence (maximum 732-fold increase), superb sensitivity (LOD = 82.67 nM), high energy-transfer efficiency (94.6%), deep tissue penetration (20 mm), outstanding antiapoptosis, and anti-inflammatory effects. The activated NIR afterglow signal obtained in mice with middle cerebral artery occlusion (MCAO) showed three functions: (i) the BDP-4/Cur-CL NPs are rapidly activated by endogenous ONOO-, instantly illuminating the lesion area, distinguishing I/R damage from normal areas, which can be successfully used for endogenous ONOO- detection in the early stage of IS; (ii) real-time reporting of in situ generation and dynamic fluctuations of endogenous ONOO- levels in the lesion area, which is of great value in monitoring the evolutionary mechanisms of IS; and (iii) dynamic monitoring of the release of curcumin drug for safe treatment. Indeed, the released curcumin effectively decreased apoptosis, enhanced survival, alleviated neuroinflammation, reduced brain tissue loss, and improved the cognition of MCAO stroke mice. This work is the first example of afterglow luminescence for early diagnosis, real-time reporting, drug tracing, and treatment for IS.

The Effect of Aging on Nitric Oxide Production during Cerebral Ischemia and Reperfusion in Wistar Rats and Spontaneous Hypertensive Rats: An In Vivo Microdialysis Study.

Nitric oxide (NO) is involved in the pathogenesis of cerebral ischemic injury. Here, we investigated the effects of aging on NO production during cerebral ischemia-reperfusion (IR). Male Wister rats (WRs) were assigned to 12-month-old (older; n = 5) and 3-month-old (younger; n = 7) groups. Similarly, male spontaneous hypertensive rats (SHRs) were allocated to 12-month-old (older; n = 6) and 3-month-old (younger; n = 8) groups. After anesthesia, their NO production was monitored using in vivo microdialysis probes inserted into the left striatum and hippocampus. Forebrain cerebral IR injuries were produced via ligation of the bilateral common carotid arteries, followed by reperfusion. The change in the NO3- of the older rats in the SHR groups in the striatum was less compared to that of the younger rats before ischemia, during ischemia, and after reperfusion (p < 0.05). In the hippocampus, the change in the NO3- of the older rats in the SHR groups was lower compared to that of the younger rats after reperfusion (p < 0.05). There were no significant differences between the two WR groups. Our findings suggested that aging in SHRs affected NO production, especially in the striatum, before and during cerebral ischemia, and after reperfusion. Hypertension and aging may be important factors impacting NO production in brain IR injury.

STIM2 Suppression Blocks Glial Activation to Alleviate Brain Ischemia Reperfusion Injury via Inhibition of Inflammation and Pyroptosis.

Cerebral ischemia/reperfusion injury (CIRI) involves various pathogenic mechanisms, including cytotoxicity, apoptosis, inflammation, and pyroptosis. Stromal interactive molecule 2 (STIM2) is implicated in cerebral ischemia. Consequently, this study investigates the biological functions of STIM2 and its related mechanisms in CIRI progression. Middle cerebral artery occlusion/reperfusion (MCAO/R) mouse models and oxygen-glucose deprivation/reoxygenation (OGD/R) cellular models were established. STIM2 level was upregulated in experimental CIRI models, as shown by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blotting and immunofluorescence staining. Brain infarction and edema were attenuated by STIM2 knockdown, as 2,3,5-triphenyltetrazolium chloride (TTC) staining and brain water content evaluation revealed. STIM2 knockdown relieved neuronal apoptosis, microglia activation, inflammation and pyroptosis in MCAO/R mice, as detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, enzyme-linked immunosorbent assay (ELISA) and western blotting. Results of flow cytometry, ELISA, western blotting and cell counting kit-8 (CCK-8) assays also showed that STIM2 knockdown inhibited inflammation, apoptosis and pyroptosis in OGD/R-treated BV2 cells. Moreover, STIM2 knockdown inhibited apoptosis and pyroptosis in PC12 cells incubated with conditioned medium collected from OGD/R-exposed BV2 cells. Mechanistically, lncRNA Malat1 (metastasis associated lung adenocarcinoma transcript 1) positively regulated STIM2 expression by sponging miR-30d-5p. Their binding relationship was confirmed by luciferase reporter assays. Finally, lncRNA Malat1 elevation or miR-30d-5p knockdown abolished the sh-STIM2-induced inhibition in cell damage. In conclusion, STIM2 knockdown in microglia alleviates CIRI by inhibiting microglial activation, inflammation, apoptosis, and pyroptosis.

Cathepsin B knockout confers significant brain protection in the mouse model of stroke

BackgroundSignificant advances have been made in our understanding of the endolysosomal cycle. Disruption of this cycle leads to cell death. The objective of this study aims to investigate the role of disrupted endolysosomal cycle in brain ischemia-reperfusion injury. MethodsA total of 57 mice were randomly assigned into four experimental groups: (i) wildtype (wt) sham control; (ii) wt middle cerebral artery occlusion (MCAO); (iii) cathepsin B (CTSB) knockout (KO) sham control; and (iv) CTSB KO MCAO. Mice were subjected either to 0 min (sham) or 40 min of MCAO, followed by reperfusion for 1 or 7 days. Physical and behavioral examinations were conducted in the 7-day reperfusion group for 7 consecutive days after MCAO. Confocal microscopy was used to assess the levels, redistributions, and co-localizations of key endolysosomal cycle-related proteins. Histopathology was examined by light microscopy. ResultsConfocal microscopy revealed a significant accumulation of CTSB in post-ischemic penumbral neurons relative to those in the sham group. In addition, N-ethylmaleimide sensitive factor ATPase (NSF) was irreversibly depleted in these neurons. Furthermore, CTSB-immunostained structures were enlarged and diffusely distributed in both the cytoplasm and extracellular space, indicating the release of CTSB from post-ischemic neurons. Compared to wt mice, CTSB KO mice showed a significant decrease in hippocampal injury area, a significant increase in the number of survival neurons in the striatal core area, and a significant improvement in physical and functional performance in post-MCAO mice. ConclusionBrain ischemia leads to a cascade of events leading to inactivation of NSF, disruption of the endolysosomal cycle, endolysosomal structural buildup and damage, and the release of CTSB, eventually resulting in brain ischemia reperfusion injury. CTSB KO in mice protected the brain from ischemia-reperfusion injury.

Exosomes derived from M2-type microglia ameliorate oxygen-glucose deprivation/reoxygenation-induced HT22 cell injury by regulating miR-124-3p/NCOA4-mediated ferroptosis

BackgroundAlthough it has been reported that miRNA carried by M2 microglial exosomes protects neurons from ischemia–reperfusion brain injury, the mechanism of action remains poorly understood. This study aimed to explore the miRNA signaling pathway by which M2-type microglia-derived exosomes (M2-exosomes) ameliorate oxygen–glucose deprivation/reoxygenation (OGD/R)-induced cytotoxicity in HT22 cells. MethodsBV2 microglia were induced by M2 polarization. Then, M2-exosomes were identified via transmission electron microscopy and special biomarker detection and co-cultured with HT22 cells. Cell proliferation was evaluated using the Cell Counting Kit-8 (CCK-8) assay. Intracellular concentrations of reactive oxygen species (ROS), Fe2+, glutathione (GSH), and malondialdehyde (MDA) were determined using dichlorofluorescein fluorescence and biochemical determination. miR-124-3p levels were determined using qRT-PCR, and protein expressions were examined via western blotting. ResultsOGD/R suppressed the proliferation and induced the accumulation of Fe2+, ROS, and MDA and reduction of GSH in mouse HT22 cells, suggesting ferroptosis of HT22 cells. OGD/R-induced changes in the above mentioned indexes was ameliorated by M2-exosomes but restored by the exosome inhibitor GW4869. M2-exosomes with (mimic-exo) or without miR-124-3p (inhibitor-exo) promoted and suppressed proliferation and ferroptosis-associated indexes of HT22 cells, respectively. Moreover, mimic-exo and inhibitor-exo inhibited and enhanced NCOA4 expression in HT22 cells, respectively. NCOA4 overexpression reversed the protective effects of miR-124-3p mimic-exo in OGD/R-conditioned cells. NCOA4 was targeted and regulated by miR-124-3p. ConclusionsM2-exosome protects HT22 cells against OGD/R-induced ferroptosis injury by transferring miR-124-3p and NCOA4 into HT22 cells, with the latter being a target gene for miR-124-3p.