Acute Cerebral Ischemic Injury Research Articles

Ethanol extract of Verbena officinalis alleviates MCAO-induced ischaemic stroke by inhibiting IL17A pathway-regulated neuroinflammation

BackgroundThe prevention and treatment of ischaemic stroke is a worldwide challenge, and effective clinical treatment strategies are lacking. Studies have demonstrated the efficacy of Verbena officinalis in managing cerebrovascular disorders. However, the neuroprotective bioactive components and mechanisms remain unclear. PurposeTo investigate the pharmacological combinatorial components and mechanism underlying the anti-ischemic stroke effect of the ethanol extract of Verbena officinalis (VO Ex). Study design and methodsThe components of VO Ex were identified by HPLC. A middle cerebral artery occlusion (MCAO) induced brain injury model was used to assess the therapeutic effect of VO Ex. The activity of the chemical components of VO Ex was evaluated using a primary astrocyte injury model induced by oxygen-glucose deprivation/reperfusion (OGD/R). RNA sequencing was used to reveal the potential targets of VO Ex against cerebral ischemia–reperfusion injury (CIRI), and the results were verified by qRT-PCR and western blotting. The key components and target binding ability were predicted by molecular docking. Finally, the mechanism of combinatorial components was verified by experiments. ResultsThe HPLC results indicated that the main ingredients of VO Ex were hastatoside, verbenalin, acteoside, luteolin, apigenin and hispidulin. In vivo experiments showed that VO Ex improved MCAO-induced acute cerebral ischemic injury. Transcriptomic data and biological experiments suggested that VO Ex exerted therapeutic effects through IL17A signalling pathways. The in vitro experiments indicated that verbenalin, acteoside, luteolin, apigenin and hispidulin exhibited neuroprotective activities. The novel formula of VALAH, derived from the aforementioned active ingredients, exhibited superior efficacy compared to each individual component. Molecular docking and mechanistic studies have confirmed that VALAH functions in the treatment of ischaemic stroke by suppressing the activation of the IL17A signalling pathway. ConclusionThis work is the first to reveal that VO Ex effectively inhibits the IL17A signaling pathway and mitigates neuroinflammation following ischemic stroke. Moreover, we identified the novel formula VALAH as the bioactive combinatorial components for VO Ex. Further research suggests that the activity of VALAH is associated with IL17A-mediated regulation of neuroinflammation. This finding provides new insights into the efficacious components and mechanisms of traditional Chinese medicine.

Pro‑angiogenic activity of salvianolate and its potential therapeutic effect against acute cerebral ischemia.

Salvianolate (Sal) is a medicinal composition that is widely used in China for the treatment of coronary heart disease and angina pectoris. The aim of the present study was to investigate the potential macrophage-mediated pro-angiogenic effects of Sal in vitro. In addition, another aim was to explore the effects of Sal in a rat model of transient middle cerebral artery occlusion (tMCAO) along with the potential mechanism by which it promotes angiogenesis. In this study, human umbilical vein endothelial cells (HUVECs) and Raw264.7 macrophages in vitro, and a rat tMCAO model in vivo were used to detect the pro-angiogenic effect and mechanism of Sal. The results of in vitro experiments showed that the viability, migration and tube formation of HUVECs were promoted by the supernatant of Sal-treated Raw264.7 macrophages (s-Sal) but not by Sal alone. s-Sal also increased the levels of phosphorylated (p-)VEGFR-2, p-AKT and p-p38 MAPK in HUVECs while Sal alone did not. In vivo, treatment with Sal significantly reduced the cerebral infarction volume and neurological deficit scores in the rat tMCAO model. Similar to the mechanism observed in the in vitro experiments, Sal treatment upregulated the protein expression of VEGF and VEGFR-2, in addition to the phosphorylation of VEGFR-2, AKT and p38, in the brain tissues of the tMCAO model rats. In summary, the results of the present study suggest that the mechanism of Sal-mediated angiogenesis is associated with stimulation of the VEGF/VEGFR-2 signaling pathway by macrophages. This suggests the potential of Sal as a therapeutic option for the treatment of acute cerebral ischemic injury, which may act via the promotion of angiogenesis.

Multi-pathway neuroprotective effects of a novel salidroside derivative SHPL-49 against acute cerebral ischemic injury

SHPL-49 ((2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(4-(4-methoxyphenyl) butoxy) tetrahydro-2H-pyran-3,4,5-triol) is a novel glycoside derivative obtained from structural modification of salidroside, which is isolated from the medicinal plant Rhodiola rosea L. SHPL-49 was administered to rats with permanent middle cerebral artery occlusion (pMCAO) for 5 days, and it was found that SHPL-49 could alleviate the cerebral infarct volume and reduce the neurological deficit score. Moreover, the effective time window of SHPL-49 in the pMCAO model was from 0.5 to 8 h after embolization. In addition, the result of immunohistochemistry showed that SHPL-49 could increase the number of neurons in the brain tissue and reduce the occurrence of apoptosis. Morris water maze and Rota-rod experiments showed that SHPL-49 could improve neurological deficits, repair neurocognitive and motor dysfunction, and enhance learning and memory ability in the pMCAO model after 14 days of SHPL-49 treatment. Further in vitro experiments showed that SHPL-49 significantly reduced the calcium overload of PC-12 cells and the production of reactive oxygen species (ROS) induced by oxygen and glucose deprivation (OGD), and increased the levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), decreased the production of malondialdehyde (MDA). Furthermore, SHPL-49 could reduce cell apoptosis by increasing protein expression ratio of anti-apoptotic factor Bcl-2 to pro-apoptotic factor Bax in vitro. SHPL-49 also regulated the expression of Bcl-2 and Bax in ischemic brain tissue, and even inhibited the caspase cascade of pro-apoptotic proteins Cleaved-caspase 9 and Cleaved-caspase 3. Taken together, SHPL-49 exhibited neuroprotective effects against cerebral ischemic injury through multiple pathways, such as alleviating calcium overload, reducing oxidative stress damage, and inhibiting apoptosis.

Salvianolic acids for injection alleviates cerebral ischemia-induced neurodegeneration by inhibiting endoplasmic reticulum stress and neuroinflammation

BackgroundCerebral ischemia is one of the leading causes of neurological deficit, dementia, and disability globally. Salvianolic acids for injection (SAFI), a multi-component drug derived from Salvia miltiorrhiza L., has been clinically used in China to treat ischemic stroke. PurposeThis study was designed to investigate the mechanisms of SAFI in alleviating cerebral ischemia-induced neurodegeneration, especially its regulatory effects on excessive ER stress. Basic proceduresThe rat acute cerebral ischemic injury model was established by a 1.5 h occlusion of the middle cerebral artery followed by 24 h of reperfusion. The neurological deficits, neurobehavior, cerebral infarct volume and edema of rats were examined. Hematoxylin and eosin staining, transmission electron microscopy analysis and TUNEL staining were performed to study the brain injury and cell apoptosis. Western blot and immunofluorescence assay were carried out to study the effects and mechanism of SAFI on ischemic injury. Main findingsResults showed that SAFI significantly inhibited the acute neurodegeneration, reduced brain infarct volumes and decreased brain water content of rats. SAFI also downregulated the relative protein levels of Bax/Bcl-2, Bim, Caspase-12, and reduced the number of TUNEL-positive cells in brain tissue, indicating the anti-apoptotic effects of SAFI. Both of immunofluorescence assay and western blot results showed that SAFI downregulated the expression of endoplasmic reticulum (ER) stress maker GRP78. SAFI dramatically inhibited the ER stress-related PERK/eIF2α/ATF4/CHOP and IRE1α/TRAF2/ASK1/JNK signaling pathways. SAFI also alleviated NF-κB triggered inflammatory response, and inhibited the production of IL-6 and IL-β. ConclusionsOur studies indicated that inhibition of excessive ER stress contributes to the protective effects of SAFI against cerebral ischemia-induced neurodegeneration and neuroinflammation.

Posterior reversible encephalopathy syndrome coexists with acute cerebral infarction: challenges of blood pressure management.

Hypertension is the most common cause of posterior reversible encephalopathy syndrome (PRES) and acute cerebral infarction. Due to the lack of randomized controlled clinical trials (RCTs), early antihypertensive methods are diverse, even contradictory. So far, there is no consensus on the method of blood pressure (BP) management when the 2 diseases coexist. Generally, antihypertensive therapy should be initiated quickly in the acute phase of PRES, as most patients have elevated BP. However, various factors must be considered before the administration of early antihypertensive therapy in acute cerebral infarction. The coexistence of PRES and acute cerebral infarction is uncommon clinically, and more complicated subsequent BP management. This article reports a case of PRES coexisting with acute lacunar cerebral infarction, which was caused by hypertension. We have analyzed and summarized the antihypertensive principles in PRES and different phases of acute cerebral ischemic injury. We assert that when PRES and acute cerebral infarction coexist, the antihypertensive treatment should be individualized, and careful consideration should be given to the various influencing factors.

Hydrogen Sulfide Overproduction Is Involved in Acute Ischemic Cerebral Injury Under Hyperhomocysteinemia.

ObjectivesThis study aimed to identify the involvement of hydrogen sulfide overproduction in acute brain injury under ischemia/reperfusion and hyperhomocysteinemia.MethodsIn vitro and in vivo experiments were conducted to determine: the effect of sodium hydrosulfide treatment on the human neuroblastoma cell line (SH-SY5Y) under conditions of oxygen and glucose deprivation; the changes of hydrogen sulfide levels, inflammatory factors, energetic metabolism, and mitochondrial function in the brain tissue of rats under either ischemia/reperfusion alone or a combination of ischemia/reperfusion and hyperhomocysteinemia; and the potential mechanism underlying the relationship between homocysteine and these changes through the addition of the related inhibitors. Furthermore, experimental technologies, including western blot, enzyme-linked immunosorbent assay, immunofluorescence, reverse transcription polymerase chain reaction, and flow cytometry, were used.ResultsOur study found that high concentration of sodium hydrosulfide treatment aggravated the decrease in mitochondrial membrane potential, the increase in both mitochondrial permeability transition pore and translocation of cytochrome C, as well as the accumulation of reactive oxygen species in oxygen and glucose deprived SH-SY5Y cells. As a result, neurological deficit appeared in rats with ischemia/reperfusion or ischemia/reperfusion and hyperhomocysteinemia, and a higher water content and larger infarction size of cerebral tissue appeared in rats combined ischemia/reperfusion and hyperhomocysteinemia. Furthermore, alterations in hydrogen sulfide production, inflammatory factors, and mitochondria morphology and function were more evident under the combined ischemia/reperfusion and hyperhomocysteinemia. These changes were, however, alleviated by the addition of inhibitors for CBS, CSE, Hcy, H2S, and NF-κB, although at different levels. Finally, we observed a negative relationship between the blockage of: (a) the nuclear factor kappa-B pathway and the levels of cystathionine β-synthase and hydrogen sulfide; and (b) the hydrogen sulfide pathway and the levels of inflammatory factors.ConclusionHydrogen sulfide overproduction and reactive inflammatory response are involved in ischemic cerebral injury under hyperhomocysteinemia. Future studies in this direction are warranted to provide a scientific base for targeted medicine development.

Low-density lipoprotein receptor (LDLR) regulates NLRP3-mediated neuronal pyroptosis following cerebral ischemia/reperfusion injury

BackgroundInflammatory response has been recognized as a pivotal pathophysiological process during cerebral ischemic stroke. NLRP3 inflammasome, involved in the regulation of inflammatory cascade, can simultaneously lead to GSDMD-executed pyroptosis in cerebral ischemia. Low-density lipoprotein receptor (LDLR), responsible for cholesterol uptake, was noted to exert potential anti-inflammatory bioactivities. Nevertheless, the role of LDLR in neuroinflammation mobilized by cerebral ischemia/reperfusion (I/R) has not been investigated.MethodsIschemic stroke mice model was accomplished by middle cerebral artery occlusion. Oxygen-glucose deprivation was employed after primary cortical neuron was extracted and cultured. A pharmacological inhibitor of NLRP3 (CY-09) was administered to suppress NLPR3 activation. Histological and biochemical analysis were performed to assess the neuronal death both in vitro and in vivo. In addition, neurological deficits and behavioral deterioration were evaluated in mice.ResultsThe expression of LDLR was downregulated following cerebral I/R injury. Genetic knockout of Ldlr enhanced caspase-1-dependent cleavage of GSDMD and resulted in severe neuronal pyroptosis. LDLR deficiency contributed to excessive NLRP3-mediated maturation and release of IL-1β and IL-18 under in vitro and in vivo ischemic conditions. These influences ultimately led to aggravated neurological deficits and long-term cognitive dysfunction. Blockade of NLRP3 substantially retarded neuronal pyroptosis in Ldlr−/− mice and cultured Ldlr−/− neuron after experimental stroke.ConclusionsThese results demonstrated that LDLR modulates NLRP3-mediated neuronal pyroptosis and neuroinflammation following ischemic stroke. Our findings characterize a novel role for LDLR as a potential therapeutic target in neuroinflammatory responses to acute cerebral ischemic injury.

The Development of Stem Cell-Based Treatment for Acute Ischemic Cerebral Injury.

Acute ischemic brain injury is a serious disease that severely endangers the life safety of patients. Such disease is hard to predict and highly lethal with very limited effective treatments currently. Although currently, there exist treatments like drug therapy, hyperbaric oxygen therapy, rehabilitation therapy and other treatments in clinical practice, these are not significantly effective for patients when the situation is severe. Thus scientists must explore more effective treatments. Stem cells are undifferentiated cells with a strong potential of self-renewal and differentiate into various types of tissues and organs. Their emergence has brought new hopes for overcoming difficult diseases, further improving medical technology and promoting the development of modern medicine. Some combining therapies and genetically modified stem cell therapy have also been proven to produce obvious neuroprotective function for acute ischemic brain injury. This review is an introduction to the current research findings and discusses the definition, origin and classification of stem cells, as well as the future prospects of the stem cell-based treatment for acute ischemic cerebral injury.

MicroRNA-19a mediates neuroprotection through the PTEN/AKT pathway in SK-N-SH cells after oxygen-glucose deprivation/reoxygenation injury.

Ischemic stroke is one of the most common public health problems worldwide. The aim of the present study was to investigate the role of miR-19a and its possible target genes in SK-N-SH cells subjected to oxygen-glucose deprivation/re-oxygenation (OGD/R) injury. SK-N-SH cells are a suitable model for host transfection. SK-N-SH cells were transfected with miR-19a mimic or inhibitor and PTEN-small interfering (si) RNA in order to alter the expression of miR-19a, PTEN and AKT. The expression changes in acute cerebral ischemic injury (ACII) were verified using RT-qPCR and Western blotting. Expression changes and the association between miR-19a and PTEN following OGD/R were also assessed using a double luciferase analysis. In addition, cell viability and apoptosis were measured using an MTT and flow cytometry. miR-19a was downregulated; however, PTEN was markedly increased following OGD/R injury. miR-19a mimics increased cell viability, decreased cell apoptosis of SK-N-SH cells following OGD/R, which effects was similar to PTEN siRNA; however, miR-19a inhibitor had the opposite roles with miR-19a mimics. The present study provides novel information about the cell apoptosis and invasion mechanisms associated with the miR-19a/PTEN/AKT pathway and may present a potential therapeutic approach for OGD/R injury.

PKCγ and PKCε are Differentially Activated and Modulate Neurotoxic Signaling Pathways During Oxygen Glucose Deprivation in Rat Cortical Slices.

Cerebral ischemia is known to trigger a series of intracellular events such as changes in metabolism, membrane function and intracellular transduction, which eventually leads to cell death. Many of these processes are mediated by intracellular signaling cascades that involve protein kinase activation. Among all the kinases activated, the serine/threonine kinase family, protein kinase C (PKC), particularly, has been implicated in mediating cellular response to cerebral ischemic and reperfusion injury. In this study, using oxygen-glucose deprivation (OGD) in acute cortical slices as an in vitro model of cerebral ischemia, I show that PKC family of isozymes, specifically PKCγ and PKCε are differentially activated during OGD. Detecting the expression and activation levels of these isozymes in response to different durations of OGD insult revealed an early activation of PKCε and delayed activation of PKCγ, signifying their roles in response to different durations and stages of ischemic stress. Specific inhibition of PKCγ and PKCε significantly attenuated OGD induced cytotoxicity, rise in intracellular calcium, membrane depolarization and reactive oxygen species formation, thereby enhancing neuronal viability. This study clearly suggests that PKC family of isozymes; specifically PKCγ and PKCε are involved in OGD induced intracellular responses which lead to neuronal death. Thus isozyme specific modulation of PKC activity may serve as a promising therapeutic route for the treatment of acute cerebral ischemic injury.

Inhibition of histone deacetylase 3 by MiR-494 alleviates neuronal loss and improves neurological recovery in experimental stroke

HDAC3 is an essential negative regulator of neuronal plasticity and memory formation. Although a chemical inhibitor has been invented, little is known about its endogenous modulators. We explored whether miR-494 affects HDAC3-mediated neuronal injury following acute ischemic stroke. A substantial increase in plasma miR-494 was detected in AIS patients and was positively associated with the mRS at one year after symptom onset. The miR-494 levels were transiently increased in the infarcted brain tissue of mice. In contrast, miR-494 levels were reduced in neurons but increased in the medium after OGD. Intracerebroventricular injection of miR-494 agomir reduced neuronal apoptosis and infarct volume at the acute stage of MCAO, promoted axonal plasticity and long-term outcomes at the recovery stage, suppressed neuronal ataxin-3 and HDAC3 expression and increased acetyl-H3K9 levels in the ipsilateral hemisphere. In vitro studies confirmed that miR-494 posttranslationally inhibited HDAC3 in neurons and prevented OGD-induced neuronal axonal injury. The HDAC3 inhibitor increased acetyl-H3K9 levels and reversed miR-494 antagomir-aggravated acute cerebral ischemic injury, as well as brain atrophy and long-term functional recovery. These results suggest that miR-494 may serve as a predictive biomarker of functional outcomes in AIS patients and a potential therapeutic target for the treatment of ischemic stroke.

Effect of melilotus on brain inflammatory factors of rats with acute cerebral ischemic injury

Effect of melilotus on brain inflammatory factors of rats with acute cerebral ischemic injury

Impact of G-CSF on expressions of Egr-1 and VEGF in acute ischemic cerebral injury.

The aim of the present study was to investigate the protective effect of granulocyte colony-stimulating factor (G-CSF) on acute ischemic cerebral injury, and its mechanism through the impact of G-CSF on early growth response-1 (Egr-1) and vascular endothelial growth factor (VEGF) expressions. Male Sprague-Dawley (SD) rats were divided them into three groups, i.e., the sham, model and G-CSF groups to measure the effect of G-CSF on the volume of cerebral infarction and level of lactate dehydrogenase (LDH) in rats. Hematoxylin and eosin (H&E) staining method was performed for histopathological examination. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the mRNA and protein expressions of Egr-1 and VEGF in different groups. Furthermore, Statistical Product and Service Solutions (SPSS) 17.0 software was applied to detect the differences in the expression of Egr-1 and VEGF between the two groups. Compared with the sham group, we found that the volume of cerebral infarction and LDH content in the model group were significantly elevated. By contrast, in the model group, those indicators in the G-CSF group were obviously decreased. H&E staining results also showed that G-CSF could decrease the necrotic area in cerebral infarction and the incidence of inflammation, and sustain the integrity of the molecular structure. Immunofluorescence staining results revealed that the protein expressions of Egr-1 and VEGF in the model group were all significantly decreased, while those in the G-CSF group were remarkably elevated. RT-PCR and western blot analysis revealed that the mRNA and protein expressions of Egr-1 and VEGF in the model group were decreased obviously, but those in the G-CSF group were elevated significantly, and the differences between the two groups showed statistical significance (P<0.05). G-CSF manifests a significant protective effect on the acute ischemic cerebral injury, which may be realized through its effect on the expressions of Egr-1 and VEGF.

Diterpene ginkgolides protect against cerebral ischemia/reperfusion damage in rats by activating Nrf2 and CREB through PI3K/Akt signaling.

Diterpene ginkgolides meglumine injection (DGMI) is a therapeutic extract of Ginkgo biloba L, which has been used for the treatment of cerebral ischemic stroke in China. Ginkgolides A, B and C are the main components of DGMI. This study was designed to investigate the neuroprotective effects of DGMI components against ischemic stroke in vivo and in vitro. Acute cerebral ischemic injury was induced in rats by occlusion of the middle cerebral artery (MCA) for 1.5 h followed by 24 h reperfusion. The rats were treated with DGMI (1, 3 and 10 mg/kg, iv) at the onset of reperfusion and 12 h after reperfusion. Administration of DGMI significantly decreased rat neurological deficit scores, reduced brain infarct volume, and induced protein kinase B (Akt) phosphorylation, which prompted the nuclear translocation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and phosphorylation of the survival regulatory protein cyclic AMP-responsive element binding protein (CREB). Nrf2 activation led to expression of the downstream protein heme oxygenase-1 (HO-1). In addition, PC12 cells were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) in vitro, treatment with DGMI (1, 10 and 20 μg/mL) or ginkgolides A, B or C (10 μmol/L for each) significantly reduced PC12 cell death and increased phosphorylation of Akt, nuclear translocation of Nrf2 and activation of CREB. Activation of Nrf2 and CREB could be reversed by co-treatment with a phosphoinositide-3-kinase (PI3K) inhibitor LY294002. These observations suggest that ginkgolides act as novel extrinsic regulators activating both Akt/Nrf2 and Akt/CREB signaling pathways, protecting against cerebral ischemia/reperfusion (I/R) damage in vivo and in vitro.

Pien-Tze-Huang protects cerebral ischemic injury by inhibiting neuronal apoptosis in acute ischemic stroke rats

Ethnopharmacological relevancePien-Tze-Huang (PZH) is a famous formula of traditional Chinese medicine used to treating stroke. However, the protective effect of PZH and its mechanisms in acute ischemic stroke remain to be explored. Aim of the studyTo investigate the protective effect of PZH on neuronal apoptosis in acute cerebral ischemic injury rats and explore its underlying mechanisms. Materials and methodsThe effects of PZH were studied in acute ischemic stroke rats induced by transient middle cerebral artery occlusion, and the mitochondria-mediated apoptotic proteins including cytochrome C (Cyt C), Bax, Bcl-xl, P53, caspase-3, and caspase-9 as well as AKT and glycogen synthase kinase-3 beta (GSK-3β) were assessed. ResultsFour days of PZH treatment (180 mg/kg) could significantly reduce cerebral infarct volume, improve neurological deficit, attenuate inflammatory response, and inhibit neuronal apoptosis in acute ischemic stroke rats. Moreover, PZH treatment significantly decreased cytosolic Cyt C, Bax, P53, cleaved caspase-3, and cleaved caspase-9 levels, but elevated mitochondrial Cyt C and Bcl-xl levels. PZH treatment also increased phosphorylation of AKT and GSK-3β. ConclusionPZH potently protects the brain from cerebral ischemia/reperfusion injury in vivo, and inhibiting mitochondria-mediated neuronal apoptosis as well as attenuating inflammatory responses may be involved in this effect. This study provides experimental basis of PZH in treating acute cerebral ischemic stroke, which would provide some novel insights for its prevention and treatment of ischemic stroke.

Hyperforin protects against acute cerebral ischemic injury through inhibition of interleukin-17A-mediated microglial activation

Hyperforin, a pharmacologically active component of the medicinal plant Hypericum perforatum (St. John's wort), has been shown to be neuroprotective against acute ischemic stroke. However, the underlying mechanisms are still unclear and need to be fully elucidated. C57BL/6 wildtype (WT) mice or interleukin (IL)-17A knock-out mice were subjected to middle cerebral artery occlusion (60min) followed by reperfusion for 72h. Hyperforin (0.5μg) was injected slowly into the right ventricle of WT mice 1, 24 and 48h after middle cerebral artery occlusion (MCAO) onset. Here, we found that hyperforin treatment decreased the mRNA and protein expression of IL-17A at 72h after MCAO onset. Hyperforin reduced infarct volumes and increased neurologic scores accompanied by a decrease in microglial activation and a shift from M1 to M2 phenotypes in the peri-infarct striatum. Furthermore, we revealed that IL-17A was essential to the microglial activation in the acute phase of ischemic stroke. IL-17A knock-out (il-17a−/−) or anti-IL-17 A monoclonal antibody treatment markedly decreased the microglial activation and induced a shift from M1 to M2 phenotypes of activated microglia. In addition, treatment with recombinant mouse IL-17A abolished the protective effects of hyperforin on acute ischemic brain injury, attenuated the inhibitory effects of hyperforin on the microglial activation, and inhibited the enhanced shift from M1 to M2 phenotypes mediated by hyperforin. In conclusion, our results clearly showed that hyperforin could protect against acute cerebral ischemic injury through inhibition of interleukin-17A-mediated microglial activation and polarization of microglia to M2 phenotype.

Oleoylethanolamide attenuates apoptosis by inhibiting the TLR4/NF-κB and ERK1/2 signaling pathways in mice with acute ischemic stroke.

This study was carried out to investigate the exact mechanisms behind the neuroprotective effects of oleoylethanolamide (OEA) after acute cerebral ischemic injury. Transient focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 90min followed by reperfusion. OEA (40mg/kg, ip) was administered with a single injection upon reperfusion. The number of apoptotic cells was detected by TUNEL staining. The expression of Bax, Bcl-2, and TLR4, as well as the activities of NF-κB, Akt, and ERK1/2 were analyzed by western blot. Our data showed that OEA treatment alleviated cell apoptosis in a mouse model of ischemic stroke, accompanied by suppression of Bax, as well as upregulation of antiapoptotic protein Bcl-2 level. The changes of Bax and Bcl-2 could not be observed in PPARα knockout mice models with OEA administration. Importantly, OEA inhibited MCAO-induced TLR4 expression, NF-κB activation, IκBα degradation, and ERK1/2 phosphorylation. Our findings demonstrated that the neuroprotective effects of OEA on cerebral ischemia may be attributed to its antiapoptotic property achieved, at least in part, through the PPARα signaling and inhibition of both TLR4/NF-κB and ERK1/2 signaling pathways. These results provide new evidence indicating the neuroprotective effect of OEA on ischemic stroke.

MicroRNA-146a down-regulation correlates with neuroprotection and targets pro-apoptotic genes in cerebral ischemic injury in vitro

MicroRNAs (miRNAs) are short, non-coding RNAs that negatively regulate target gene expression, and play an important role in cerebral ischemic injury. MiR-146a has been reported to be highly related to cell invasion, metastasis, immunity, inflammation and apoptosis. Previous studies have indicated that miR-146a can either inhibit or promote apoptosis through different pathophysiological processes. In our previous study, miR-146a in the blood was down-regulated during acute ischemic stroke. However, the connection between miR-146a and acute cerebral ischemic injury and the mechanism underlying the connection remain unclear. Here, we aimed to investigate the role of miR-146a and its possible target genes in human SK-N-SH cells subjected to 16h of oxygen-glucose deprivation and 12h of reperfusion (OGD/R) injury. Cells were transfected with miR-146a mimic or inhibitor to alter the expression of miR-146a. MiR-146a in the SK-N-SH cells was down-regulated after OGD/R injury. Moreover, bioinformatics analysis and dual luciferase assays demonstrated that miR-146a directly recognized the 3′-UTR of the pro-apoptotic genes, Caspase7 and Bcl-2-associated transcription factor 1 (Bclaf1). Furthermore, miR-146a over-expression effectively decreased the mRNA and protein expression of Caspase7 and Bclaf1, and aggravated OGD/R-induced cell apoptosis; in contrast, miR-146a down-regulation was neuroprotective. In conclusion, our study revealed that miR-146a contributes to OGD/R injury in vitro, while negatively regulating the pro-apoptotic genes, Caspase7 and Bclaf1. This special mechanism provides new insight into miRNA regulatory networks. In addition, miR-146a may offer a potential therapeutic approach to cerebral ischemic injury.

Magnetic resonance imaging and diffusion-weighted imaging findings in posterior spinal cord infarction: Case report

Acute spinal cord ischemia (SCI) accounts for 5%e8% of all acute myelopathies [1]. In the SCI, posterior spinal artery (PSA) syndrome is much less common than in anterior spinal artery (ASA) syndrome [2], with PSA accounting for 3% of all acute SCIs and ASA syndrome accounting for 67% [3]. In 1994, Kaneki et al. provided a case report review of 27 cases of PSA syndrome in the literature [2]. Essentially, all 27 cases were diagnosed from neurological findings and the exclusion of other pathological conditions by neuroimaging. Even MRI cannot easily detect acute ischemic lesions in PSA syndrome due to their small size and changes in the signal that occur over the disease course. Diffusion-weighted imaging (DWI) is a well-established diagnostic method for acute cerebral ischemic injury [4] and is a potential tool for the detection of SCI. Among cases of SCI detected by DWI, ASA infarction was more involved than PSA infarction [5e7]. On the other hand, the proportion of PSA infarction among cases of SCI detected by DWI may be high than that among cases diagnosed by clinical sign, although there are only three reports on PSA infarction detected by DWI [5,8,9]. Here, we report clinical and imaging findings in a case of PSA infarction, including time-dependent changes of the apparent diffusion coefficient (ADC) abnormality, and propose that time

Totarol prevents neuronal injury in vitro and ameliorates brain ischemic stroke: Potential roles of Akt activation and HO-1 induction

The natural product totarol, a phenolic diterpenoid and a major constituent isolated from the sap of Podocarpus totara, has been reported to have a potent antimicrobial activity. In this study, we determined whether totarol possessed an additional neuroprotective activity in vitro and in vivo. We found that totarol prevented glutamate- and oxygen and glucose deprivation-induced neuronal death in primary rat cerebellar granule neuronal cells and cerebral cortical neurons. Totarol increased Akt and GSK-3β phosphorylation, Nrf2 and heme oxygenase-1 (HO-1) protein expressions and suppressed oxidative stress by increasing GSH and SOD activities. The PI3K/Akt inhibitor LY294002 prevented totarol neuroprotective effect by suppressing the totarol-induced changes in HO-1 expression and the activities of GSH and SOD. The HO-1 inhibitor ZnPPIX also prevented totarol-increased GSH and SOD activities. In a model of acute cerebral ischemic injury in Sprague–Dawley rats, produced by occlusion of the middle cerebral artery for 2h followed by 22h or 46h of reperfusion, totarol significantly reduced infarct volume and improved the neurological deficit. In this model, totarol increased HO-1 expression and the activities of GSH and SOD. These observations suggest that totarol may be a novel activator of the Akt/HO-1 pathway protecting against ischemic stroke through reduction of oxidative stress.