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Aims: This study aimed to explore the effects of long noncoding RNA (lncRNA) H19 knockdown on angiogenesis and blood–brain barrier (BBB) integrity following cerebral ischemia/reperfusion (I/R) and elucidate their underlying regulatory mechanisms. Methods: A middle cerebral artery occlusion/reperfusion model was used to induce cerebral I/R injury. The cerebral infarct volume and neurological impairment were assessed using 2,3,5‐triphenyl‐tetrazolium chloride staining and neurobehavioral tests, respectively. Relevant proteins were evaluated using western blotting and immunofluorescence staining. Additionally, a bioinformatics website was used to predict the potential target genes of lncRNA H19. Finally, a rescue experiment was conducted to confirm the potential mechanism. Results: Silencing of H19 significantly decreased the cerebral infarct volume, enhanced the recovery of neurological function, mitigated BBB damage, and stimulated endothelial cell proliferation following ischemic stroke. Insulin‐like growth factor 2 mRNA‐binding protein 2 (IMP2) is predicted to be a potential target gene for lncRNA H19. H19 knockdown increased IMP2 protein expression and IMP2 inhibition reversed the protective effects of H19 inhibition. Conclusion: Downregulation of H19 enhances angiogenesis and mitigates BBB damage by regulating IMP2, thereby alleviating cerebral I/R injury. [ABSTRACT FROM AUTHOR]

Objectives: FTO is known to be involved in cerebral ischemia/reperfusion (I/R) injury. However, its related specific mechanisms during this condition warrant further investigations. This study aimed at exploring the impacts of FTO and the FYN/DRP1 axis on mitochondrial fission, oxidative stress (OS), and ferroptosis in cerebral I/R injury and the underlying mechanisms. Methods: The cerebral I/R models were established in mice via the temporary middle cerebral artery occlusion/reperfusion (tMCAO/R) and hypoxia/reoxygenation models were induced in mouse hippocampal neurons via oxygen–glucose deprivation/reoxygenation (OGD/R). After the gain‐ and loss‐of‐function assays, related gene expression was detected, along with the examination of mitochondrial fission, OS‐ and ferroptosis‐related marker levels, neuronal degeneration and cerebral infarction, and cell viability and apoptosis. The binding of FTO to FYN, m6A modification levels of FYN, and the interaction between FYN and Drp1 were evaluated. Results: FTO was downregulated and FYN was upregulated in tMCAO/R mouse models and OGD/R cell models. FTO overexpression inhibited mitochondrial fission, OS, and ferroptosis to suppress cerebral I/R injury in mice, which was reversed by further overexpressing FYN. FTO overexpression also suppressed mitochondrial fission and ferroptosis to increase cell survival and inhibit cell apoptosis in OGD/R cell models, which was aggravated by additionally inhibiting DRP1. FTO overexpression inhibited FYN expression via the m6A modification to inactive Drp1 signaling, thus reducing mitochondrial fission and ferroptosis and enhancing cell viability in cells. Conclusions: FTO overexpression suppressed FYN expression through m6A modification, thereby subduing Drp1 activity and relieving cerebral I/R injury. [ABSTRACT FROM AUTHOR]

The brain is quite sensitive to changes in energy supply because of its high energetic demand. Even small changes in energy metabolism may be the basis of impaired brain function, leading to the occurrence and development of cerebral ischemia/reperfusion (I/R) injury. Abundant evidence supports that metabolic defects of brain energy during the post‐reperfusion period, especially low glucose oxidative metabolism and elevated glycolysis levels, which play a crucial role in cerebral I/R pathophysiology. Whereas research on brain energy metabolism dysfunction under the background of cerebral I/R mainly focuses on neurons, the research on the complexity of microglia energy metabolism in cerebral I/R is just emerging. As resident immune cells of the central nervous system, microglia activate rapidly and then transform into an M1 or M2 phenotype to correspond to changes in brain homeostasis during cerebral I/R injury. M1 microglia release proinflammatory factors to promote neuroinflammation, while M2 microglia play a neuroprotective role by secreting anti‐inflammatory factors. The abnormal brain microenvironment promotes the metabolic reprogramming of microglia, which further affects the polarization state of microglia and disrupts the dynamic equilibrium of M1/M2, resulting in the aggravation of cerebral I/R injury. Increasing evidence suggests that metabolic reprogramming is a key driver of microglial inflammation. For example, M1 microglia preferentially produce energy through glycolysis, while M2 microglia provide energy primarily through oxidative phosphorylation. In this review, we highlight the emerging significance of regulating microglial energy metabolism in cerebral I/R injury. [ABSTRACT FROM AUTHOR]

Cerebral ischemia/reperfusion (I/R) injury remains a grievous health threat, and herein effective therapy is urgently needed. This study explored the protection of neuroglobin (Ngb) in rats with cerebral I/R injury. The focal cerebral I/R rat models were established by middle cerebral artery occlusion (MCAO) and neuronal injury models were established by oxygen–glucose deprivation/reoxygenation (OGD/R) treatment. The brain injury of rats was assessed. Levels of Ngb, Bcl‐2, Bax, endoplasmic reticulum stress (ERS)‐related markers, and Syt1 were measured by immunofluorescence staining and Western blotting. The cytotoxicity in neurons was assessed by lactate dehydrogenase (LDH) release assay. Levels of intracellular Ca2+ and mitochondrial function‐related indicators were determined. The binding between Ngb and Syt1 was detected by co‐immunoprecipitation. Ngb was upregulated in cerebral I/R rats and its overexpression alleviated brain injury. In OGD/R‐induced neurons, Ngb overexpression decreased LDH level and neuronal apoptosis, decreased Ca2+ content, and mitigated mitochondrial dysfunction and ERS‐related apoptosis. However, Ngb silencing imposed the opposite effects. Importantly, Ngb could bind to Syt1. Syt1 knockdown partially counteracted the alleviation of Ngb on OGD/R‐induced injury in neurons and cerebral I/R injury in rats. Briefly, Ngb extenuated cerebral I/R injury by repressing mitochondrial dysfunction and endoplasmic reticulum stress‐mediated neuronal apoptosis through Syt1. [ABSTRACT FROM AUTHOR]

Stroke is a serious life‐threatening medical condition and is one of the principal reasons for death and disabilities worldwide. The aim of the present study was to determine the neuroprotective effects of hydroxychloroquine (HCQ) and the timing of its administration in cerebral ischemia/reperfusion (I/R) in rats. A global I/R model was used, and HCQ was administered in either pre‐ or post‐treatment doses of 25 and 50 mg/kg. Effects of HCQ on infarct size, histological changes, oxidative stress, and learning and memory were evaluated. Phospho‐AMPK and SQSTM1/p62 protein levels were also measured to elucidate the possible mechanisms involved. HCQ in both pre‐ (at doses of 25 and 50 mg/kg) or post‐treatment (at a dose of 50 mg/kg) protocols reduces brain infarct size and histopathological changes and improves learning and memory after cerebral I/R. Pre‐treatment with HCQ reduced AMPK activity with no significant effect on SQSTM1/p62 increment. Post‐treatment with HCQ increased AMPK activity and SQSTM1/p62 protein levels. Our results show the neuroprotective effects of HCQ on cerebral I/R through the reduction in infarct size, histopathological changes, and improvement in memory and learning functions. Moreover, AMPK and autophagy may play a role in this protective effect. [ABSTRACT FROM AUTHOR]

Aims: Remote ischemic pre‐conditioning (RIPC) protects against ischemia/reperfusion (I/R) injury. However, the mechanisms underlying this protection remain unclear. In the present study, we investigated the role of Janus‐activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway and cell cycle arrest, and their relationship with neuronal apoptosis following RIPC. Methods: A rat cerebral I/R injury model was induced by middle cerebral artery occlusion (MCAO), and AG490 was used to investigate the mechanisms of RIPC. p‐JAK2‐, p‐STAT3‐, cyclin D1‐, and cyclin‐dependent kinase 6 (CDK6) expression was assessed by Western blotting and immunofluorescence staining. Results: RIPC reduced the infarct volume, improved neurological function, and increased neuronal survival. Furthermore, p‐JAK2 and p‐STAT3 were detected during the initial phase of reperfusion; the expression levels were significantly increased at 3 and 24 h after reperfusion and were suppressed by RIPC. Additionally, the MCAO‐induced upregulation of the cell cycle regulators cyclin D1 and CDK6 was ameliorated by RIPC. Meanwhile, cyclin D1 and CDK6 were colocalized with p‐STAT3 in the ischemic brain. Conclusion: RIPC ameliorates the induction of the JAK2/STAT3 pathway and cell cycle regulators cyclin D1 and CDK6 by MCAO, and this net inhibition of cell cycle re‐entry by RIPC is associated with downregulation of STAT3 phosphorylation. [ABSTRACT FROM AUTHOR]

To investigate the function of miR‐454 in ischemic stroke, this study was carried out. Cerebral ischemia/reperfusion (I/R) injury animal model and a SHSY5Y cell culture model of oxygen‐glucose deprivation/reoxygenation (OGD/R) were constructed. The effects of miR‐454 were detected by evaluating the levels of biochemical markers, gene expression, and pathophysiological markers. The results showed that NOX4 level was elevated, while miR‐454 expression was reduced in I/R brain samples and in OGD/R‐treated cells. The miR‐454 agomir declined NOX4 level and reactive oxygen species (ROS) production in rats suffering from I/R. Furthermore, microRNA‐145 (miR‐454) overexpression inhibited NOX4 level and ROS production in cells treated by OGD/R and decreased luciferase activity in cells transfected with NOX4‐wild type (WT) reporter plasmid. Meanwhile, our results proved that the protected effects of miR‐454 on SH‐SY5Y cells treated by OGD/R were reversed by pcDNA‐NOX4 transfection. MiR‐454 protected animals from brain injury induced by cerebral I/R via directly regulating its target gene NOX4, illustrating a curatively potential target for treating ischemic stroke. [ABSTRACT FROM AUTHOR]

Cerebral ischemia/reperfusion (I/R) injuries are common and often cause severe complications. Ozone has been applied for protecting I/R injury in animal models of several organs including cerebra, but the detailed mechanism remains unclear. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase measurement were used to determine the influence of ozone on cell activity and damage of SH‐SY5Y cells. Some redox items such as catalase (CAT), malondialdehyde (MDA), glutathione peroxidase (GSH‐Px), and superoxide dismutase (SOD) were measured by enzyme‐linked immunosorbent assay. The mitochondrial membrane potential (ΔΨm) was determined by JC‐1 assay. Cytochrome‐c (cyt‐c) level in the cytoplasm and mitochondrion was measured by western blotting. Apoptosis was determined by flow cytometry, and some apoptosis‐related molecules were detected by quantitative real‐time polymerase chain reaction and western blotting. Ozone alleviated oxidative damage by increasing GSH‐Px, SOD, CAT, and decreasing MDA. Ozone decreased mitochondrial damage caused by I/R injury and inhibited the release of cyt‐c from mitochondrion to cytoplasm in SH‐SY5Y cells. The cell apoptosis caused by I/R was inhibited by ozone, and ozone could decrease apoptosis by increasing the ratio of Bcl‐2/Bax and inhibiting caspase signaling pathway in SH‐SY5Y cells. Ozone has the ability of maintaining redox homeostasis, decreasing mitochondrion damage, and inhibiting neurocytes apoptosis induced by I/R. Therefore, ozone may be a promising protective strategy against cerebral I/R injury. [ABSTRACT FROM AUTHOR]

Abstract: Background and Purpose: Curcumin, a natural antioxidant isolated from Curcuma longa, has been reported to exert neuroprotective effect in animal models of ischemic stroke. However, the underlying mechanism is still not fully understood. The purpose of this study was to investigate the effect of curcumin treatment on neuronal apoptosis in the periinfarct cortex after cerebral ischemia/reperfusion (I/R) injury and in mouse N2a cells after oxygen‐glucose deprivation/reoxygenation (OGD/R) injury and its underlying mechanism. Methods: The cerebral I/R injury was established by 1‐hr middle cerebral artery occlusion (MCAO) and reperfusion in mice. Infarct volume was determined by TTC staining, and neurological score was evaluated by mNSS. Cell morphology in the ischemic boundary zone were detected by HE staining. The number and apoptotic rate of neurons in ischemic boundary zone were assayed by immunohistochemistry and TUNEL, respectively. Mouse neuroblastoma N2a cells were subjected to OGD/R. Cell viability was assessed with CCK‐8. The mitochondrial membrane potential was measured using JC‐1 staining. The expression of Bax, Bcl‐2, and caspase‐3 was detected using Western blotting. Besides, cellular distribution of Bax was determined by immunofluorescence assays. Results: Curcumin treatment reduced infarct volume, improved neurological function, alleviated the morphological damage of neurons, and increased neuronal survival rate after I/R injury in vivo. Moreover, curcumin treatment improved cell viability, reduced cell apoptosis, increased Bcl‐2 protein levels while decreased Bax and caspase‐3 expressions in mouse N2a cells after OGD/R injury. Besides, curcumin treatment inhibited Bax activation and maintained mitochondrial membrane integrity. Conclusion: Curcumin promotes neuron survival in vivo and in vitro to exert neuroprotective effects against ischemia injury. Moreover, our results for the first time demonstrated curcumin inhibited ischemia‐induced mitochondrial apoptosis via restricting Bax activation, which may be one of the possible mechanisms underlying the neuroprotective effects of curcumin. [ABSTRACT FROM AUTHOR]

SUMMARY Aims: The aims of this study were to find out whether kallikrein could induce angiogenesis and affect the cerebral blood flow (rCBF) in the early period after cerebral ischemia/reperfusion (CI/R). Methods: The adenovirus carried human tissue kallikrein (HTK) gene was administrated into the periinfarction region after CI/R. At 12, 24, and 72 h after treatments, neurological deficits were evaluated; expression of HTK and vascular endothelial growth factor (VEGF) were detected by immunohistochemistry staining; the infarction volume was measured; and rCBF was examined by 14C-iodoantipyrine microtracing technique. Results: The expression of VEGF was enhanced significantly in pAdCMV-HTK group than controls over all time points ( P < 0.05). Furthermore, the rCBF in pAdCMV-HTK group increased markedly than controls at 24 and 72 h after treatment ( P < 0.05), and the improved neurological deficit was accompanied by reduced infarction volume in pAdCMV-HTK group 24 and 72 h posttreatment. Conclusion: In the early period after CI/R, kallikrein could induce the angiogenesis and improve rCBF in periinfarction region, and further reduce the infarction volume and improve the neurological deficits. [ABSTRACT FROM AUTHOR]

Abstract: In our present investigation the neuroprotective effect of alcoholic extract of Hawthorn (Crataegus oxycantha) was evaluated against middle cerebral artery occlusion induced ischemia/reperfusion injury in rats. Male Sprague–Dawley rats were pretreated with 100mg/kg body weight of the extract by oral gavage for 15 days. The middle cerebral artery was then occluded for 75min followed by 24h of reperfusion. The pretreated rats showed significantly improved neurological behavior with reduced brain infarct when compared to vehicle control rats. The glutathione level in brain was found to be significantly (p <0.05) low in vehicle control rats after 24h of reperfusion when compared to sham operated animals. However, in Hawthorn extract pretreated rats the levels were found to be close to that of sham. Malondialdehyde levels in brain of sham and pretreated group were found to be significantly lower than the non-treated vehicle group (p <0.05). The nitric oxide levels in brain were measured and found to be significantly (p <0.05) higher in vehicle than in sham or extract treated rats. Conclusion: Our results suggest that Hawthorn extract which is a well known prophylactic for cardiac conditions may very well protect the brain against ischemia–reperfusion. The reduced brain damage and improved neurological behavior after 24h of reperfusion in Hawthorn extract pretreated group may be attributed to its antioxidant property which restores glutathione levels, circumvents the increase in lipid peroxidation and nitric oxide levels thereby reducing peroxynitrite formation and free radical induced brain damage. [Copyright &y& Elsevier]

Background and purpose: Activation of poly(ADP-ribose) polymerase (PARP) is deleterious during cerebral ischemia. We assessed the influence of PARP activation induced by cerebral ischemia on the synthesis of proinflammatory mediators including the cytokines, tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and the adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1).Experimental approach: Ischemia was induced by intravascular occlusion of the left middle cerebral artery for 1 h in male Swiss mice anaesthetized with ketamine and xylazine. The PARP inhibitor PJ34 (1.25–25 mg kg−1) was administered intraperitoneally 15 min before and 4 hours after, the onset of ischemia. Animals were killed 6 h or 24 h after ischemia and cerebral tissue removed for analysis.Key results: Ischemia increased TNF-α protein in cerebral tissue at 6 and 24 h after ischemia. All doses of PJ34 blocked the increase in TNF-α at 6 h and 25 mg kg−1 PJ34 had a sustained effect for up to 24 h. Quantitative real time polymerase chain reaction showed that PJ34 (25 mg kg−1) reduced the increase in TNF-α mRNA by 70% at 6 h. PJ34 also prevented the increase in mRNAs encoding IL-6 (−41%), E-selectin (−81%) and ICAM-1 (−54%). PJ34 (25 mg kg−1) reduced the infarct volume (−26%) and improved neurological deficit, 24 h after ischemia.Conclusions and Implications: PJ34 inhibited the increase in the mRNAs of four inflammatory mediators, caused by cerebral ischemia. The contribution of this effect of PJ34 to neuroprotection remains to be clarified.British Journal of Pharmacology (2006) 149, 23–30. doi:10.1038/sj.bjp.0706837; published online 24 July 2006 [ABSTRACT FROM AUTHOR]

Objective: To investigate whether irisin could protect against blood–brain barrier (BBB) dysfunction following focal cerebral ischemia/reperfusion in rats. Methods and Materials: Seventy‐two adult male Sprague Dawley rats weighing 280–320 g were randomly divided into three groups: sham operation group (S), focal cerebral ischemia/reperfusion group (FC), and irisin group (IR). Focal cerebral ischemia was induced by improved thread occlusion of right middle cerebral artery (MCAO) for 2 hr followed by reperfusion for 24 hr in rats. After 24 hr of reperfusion, the neurological evaluation was performed by the method of Longa's score. The histopathological changes were observed by HE staining. The brain water content was determined by detecting the wet weight and dry weight. The BBB permeability was assessed by fluorescence spectrophotometer and fluorescence microscopy for Evans blue (EB) extravasation. The activity and expression of matrix metalloproteinase‐9 (MMP‐9) in different groups were detected by immunohistochemical staining, Western blot, and gel gelatin zymography. Results: After MCAO, the neurological deficit scores, the infarct volume, the brain water content, and the EB content were higher in the FC group than those in the S group (p < .05). While after irisin treatment, these indicators mentioned above were lower than those in the IR group (p < .05). Moreover, the protein expression of MMP‐9 in the cortex increased significantly after MCAO, while irisin treatment could decrease the protein expression of MMP‐9 in the cortex (p < .05). Conclusion: Our data suggest that irisin can attenuate brain damage both morphologically and functionally and protect BBB from disruption after focal cerebral ischemia/reperfusion, which is highly associated with the inhibition of the expression and activity of MMP‐9 in the brain tissue. [ABSTRACT FROM AUTHOR]