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Ischemic stroke is one of the leading causes of death and long-term disability worldwide; however, effective clinical approaches are still limited. The transcriptional factor Nrf2 is a master regulator in cellular and organismal defense against endogenous and exogenous stressors by coordinating basal and stress-inducible activation of multiple cytoprotective genes. The Nrf2 network not only tightly controls redox homeostasis but also regulates multiple intermediary metabolic processes. Therefore, targeting Nrf2 has emerged as an attractive therapeutic strategy for the prevention and treatment of CNS diseases including stroke. Here, the current understanding of the Nrf2 regulatory network is critically examined to present evidence for the contribution of Nrf2 pathway in rodent ischemic stroke models. This review outlines the literature for Nrf2 studies in preclinical stroke and focuses on the evidence for the role of Nrf2 in primary and secondary brain injuries. The dynamic change and functional importance of Nrf2 signaling, as well as Nrf2 targeted intervention, are revealed in permanent, transient, and global cerebral ischemia models. In addition, key considerations, pitfalls, and future potentials for Nrf2 studies in preclinical stroke investigation are discussed.

Background: Although N 6 -methyladenosine (m 6 A) plays a very important role in different biological processes, its function in the brain has not been fully explored. Thus, we investigated the roles of the RNA demethylases Alkbh5/Fto in cerebral ischemia-reperfusion injury. Methods: We used a rat model and primary neuronal cell culture to study the role of m 6 A and Alkbh5/Fto in the cerebral cortex ischemic penumbra after cerebral ischemia-reperfusion injury. We used Alkbh5-shRNA and Lv-Fto ( in vitro ) to regulate the expression of Alkbh5/Fto to study their regulation of m 6 A in the cerebral cortex and to study brain function after ischemia-reperfusion injury. Results: We found that RNA m 6 A levels increased consecutive to the increase of Alkbh5 expression in both the cerebral cortex of rats after middle cerebral artery occlusion, and in primary neurons after oxygen deprivation/reoxygenation. In contrast, Fto expression decreased after these perturbations. Our results suggest that knocking down Alkbh5 can aggravate neuronal damage. This is due to the demethylation of Alkbh5 and Fto, which selectively demethylate the Bcl2 transcript, preventing Bcl2 transcript degradation and enhancing Bcl2 protein expression. Conclusion: Collectively, our results demonstrate that the demethylases Alkbh5/Fto co-regulate m 6 A demethylation, which plays a crucial role in cerebral ischemia-reperfusion injury. The results provide novel insights into potential therapeutic mechanisms for stroke.

BackgroundIschemic stroke is the second leading cause of death worldwide, characterized by high mortality and a narrow therapeutic window for thrombolysis. Gut microbiota dysbiosis and gliosis following ischemic stroke are key drivers of post‐stroke neurological impairment. Sodium oligomannate (GV‐971) is a low‐molecular‐weight acidic oligosaccharide that targets the gut–brain axis. It alleviates gliosis and improves cognitive dysfunction by remodeling gut microbiota in Alzheimer’s disease. However, it is still unknown whether GV‐971 has pharmacological activity against ischemic stroke.Methods Here, we explore the efficacy of GV‐971 on infarct volume, gliosis, blood‐brain barrier integrity, gut microbiota composition, and post‐stroke cognitive impairment (PSCI) using a middle cerebral artery occlusion/reperfusion (MCAO/R) model in male Sprague‐Dawley rats.ResultsAdminister medication before surgery for 4 consecutive days and once after surgery, after stroke 24‐hour triphenyltetrazolium chloride (TTC) staining revealed that 0.3 mg/kg GV‐971 significantly reduced infarct volume in ischemic brain tissue from 37.81±2.391% to 13.30±4.801% and neurological impairment score of GV‐971 treatment significantly decreased from 11.50±0.54 to 7.29±1.47. After stroke 24‐hour immunofluorescence analysis of glial activation confirmed that GV‐971 significantly reduced central inflammatory responses. Western blot combined with Evans blue staining collectively demonstrated that after stroke 24‐hour, GV‐971 exerts a significant protective effect on the blood‐brain barrier. In the gut, GV‐971 reversed microbial dysbiosis, as revealed by shotgun metagenomics, enhanced intestinal barrier integrity, and suppressed colonic inflammation. Antibiotic depletion abolished GV‐971's neuroprotective effect, while fecal microbiota transplantation from GV‐971‐treated donors restored protection, supporting a microbiota‐dependent contribution. Furthermore, GV‐971‐treated rats subjected to MCAO/R exhibited significant improvements in motor and cognitive function. For example, on day 35, Y‐maze test results indicated that GV‐971 administered either before MCAO/R (pre‐treatment) or during the perioperative period (co‐treatment) increased spontaneous alternation rate from 60.95±4.91% to 85.60±6.32% and 85.64±5.027%. On day 32, novel object recognition assay results indicated that GV‐971 treatment increased new‐object exploration from 0.2039±0.03752 to 0.3991±0.1122 (pre‐treatment) and 0.5066±0.06982 (co‐treatment). On day 42, Barnes maze test results indicated that GV‐971 treatment reduced the time required to locate the target hole from 76.45±17.41s to 31.03±20.75 s and 33.37±19.30 s for pre‐ and co‐treatment, respectively.ConclusionTaken together, GV‐971 demonstrated neuroprotective potential in experimental ischemic stroke.

Weitong Song,1 Lu Bai,1 Yuya Yang,1 Yongchao Wang,2 Pingxiang Xu,1,3 Yuming Zhao,1 Xuelin Zhou,1,3 Xiaorong Li,1,3 Ming Xue1,3 1Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China; 2CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, People’s Republic of China; 3Beijing Laboratory for Biomedical Detection Technology and Instrument, Beijing, People’s Republic of ChinaCorrespondence: Ming Xue, Department of Pharmacology, School of Basic Medical Sciences, Capital Medical University, Youanmen, Beijing, 100069, People’s Republic of China, Tel +8610-83950416, Fax +8610-83911520, Email xuem@ccmu.edu.cnPurpose: We designed a novel isoliquiritigenin (ISL) loaded micelle prepared with DSPE-PEG2000 as the drug carrier modified with the brain-targeting polypeptide angiopep-2 to improve the poor water solubility and low bioavailability of ISL for the treatment of acute ischemic stroke.Methods: Thin film evaporation was used to synthesize the ISL micelles (ISL-M) modified with angiopep-2 as the brain targeted ligands. The morphology of the micelles was observed by the TEM. The particle size and zeta potential were measured via the nanometer particle size analyzer. The drug loading, encapsulation and in vitro release rates of micelles were detected by the HPLC. The UPLC-ESI-MS/MS methods were used to measure the ISL concentrations of ISL in plasma and main tissues after intravenous administration, and compared the pharmacokinetics and tissue distributions between ISL and ISL-M. In the MCAO mice model, the protective effects of ISL and ISL-M were confirmed via the behavioral and molecular biology experiments.Results: The results showed that the drug loading of ISL-M was 7.63 ± 2.62%, the encapsulation efficiency was 68.17 ± 6.23%, the particle size was 40.87 ± 4.82 nm, and the zeta potential was − 34.23 ± 3.35 mV. The in vitro release experiments showed that ISL-M had good sustained-release effect and pH sensitivity. Compared with ISL monomers, the ISL-M could significantly prolong the in vivo circulation time of ISL and enhance the accumulation in the brain tissues. The ISL-M could ameliorate the brain injury induced by the MCAO mice via inhibition of cellular autophagy and neuronal apoptosis. There were no the cellular structural damages and other adverse effects for ISL-M on the main tissues and organs.Conclusion: The ISL-M could serve as a promising and ideal drug candidate for the clinical application of ISL in the treatment of acute ischemic stroke.Keywords: isoliquiritigenin, micelle, brain distribution, pharmacokinetics, ischemic stroke, MCAO

The dry root of Scutellaria baicalensis, has traditionally been applied in the treatment of cerebral ischemia in Chinese clinics. Baicalin (BA) is considered the key ingredient in it for the brain protection effects. The bioavailability of BA is very low because of its poor lipid and water solubility, which limits the therapeutic effects and clinical application. The aim of the present study was to develop a novel BA-loaded liposome (BA-LP) formulation to improve the drug lipophilicity and further to enhance the drug-concentration in the brain tissues. This study is also designed to investigate the pharmacokinetics of BA in the pathological conditions of stroke and evaluate the pharmacokinetic differences of BA caused by stroke after intravenous administration with BA and BA-LP. In this study, the novel BA-LP prepared in early stage were characterized by morphology, size, zeta potential, encapsulation rate and the in vitro release. The pharmacokinetics and biodistribution of BA and BA-LP were investigated by intravenous administration in rats with middle cerebral artery occlusion (MCAO) model and normal group respectively. BA-LP had a mean particle size of 160–190 nm, zeta potential of −5.7 mV, and encapsulation efficiency of 42 ± 1%. The BA-LP showed a sustained-release behavior, the in vitro drug-release kinetic model of BA-LP fit well with the biphasic dynamic model equation: Q = 1 − (60.12e0.56t − 59.08e0.0014t). Pharmacokinetic behavior in MCAO rats is not consistent with that of normal rats. The middle cerebral artery occlusion rats got higher Cmax and AUC0–t, which were about 1.5–2 times to normal rats both in BA and liposome groups. In addition, it got especially higher distribution in brain, while BA were not detected in brain tissues on normal rats. The Cmax and AUC0–t values were significantly greater with liposome than BA on both normal and MCAO rats. The tissue distribution behavior was significantly altered in the case of liposome administrated in comparison with BA, which the concentrations in the heart, liver, spleen, lungs and brain were all increased after administrated liposome, but decreased in kidneys. The TI values showed that the target of liposome was improved especially to heart, spleen and brain, and the brain’s target was higher in striatum and cerebellum. In conclusion, BA-LP might be a potential drug delivery system to improve the therapeutic efficacy of BA. In addition, these results also suggest that the pathological damages of ischemia-reperfusion have a significant impact on the pharmacokinetic traits of BA.

Stroke is one of the leading causes of death and long-term disability worldwide. However, effective therapeutic approaches are still limited. The disruption of blood supply triggers complicated temporal and spatial events involving hemodynamic, biochemical, and neurophysiologic changes, eventually leading to pathological disturbance and diverse clinical symptoms. Ginseng ( ), a popular herb distributed in East Asia, has been extensively used as medicinal and nutritional supplements for a variety of disorders worldwide. In recent years, ginseng has displayed attractive beneficial effects in distinct neurological disorders including stroke, involving multiple protective mechanisms. In this article, we reviewed the literature on ginseng studies in the experimental stroke field, particularly focusing on the evidence on the preventive or therapeutic efficacy and mechanisms of ginseng and ginsenosides in various stroke models of mice and rats. We also summarized the efficacy and underlying mechanisms of ginseng and ginsenosides on short- and long-term stroke outcomes.

During cerebral ischemia, oxygen and glucose levels decrease, producing many consequences such as the generation of reactive oxygen species, tissue injury, and the general metabolism collapse. Resveratrol triggers signaling dependent on the protein kinase activated by adenosine monophosphate (AMPK), the sensor of cellular energy metabolism that regulates autophagy, eliminates damaged mitochondria, and increases energy sources. In the present study, we investigated the participation of AMPK activation in the protective effect of resveratrol on cerebral ischemia and excitotoxicity. We found that resveratrol increased the levels of phosphorylated AMPK in the cerebral cortex of rats subjected to middle cerebral artery occlusion (MCAO) and in primary cultured neurons exposed to glutamate-induced excitotoxicity. Resveratrol (1.8 mg/Kg; i. v.; administered at the beginning of reperfusion) decreased the infarct area and increased survival of rats subjected to MCAO. In neuronal cultures, resveratrol treatment (40 μM, after excitotoxicity) reduced the production of superoxide anion, prevented the overload of intracellular Ca +2 associated to mitochondrial failure, reduced the release of the lactate dehydrogenase enzyme, and reduced death. It also promoted mitophagy (increased Beclin 1 level, favored the recruitment of LC3-II, reduced LAMP1, and reduced mitochondrial matrix protein HSP60 levels). In both models, inhibition of AMPK activation with Compound C obstructed the effect of resveratrol, showing that its protective effect depends, partially, on the activation of the AMPK/autophagy pathway.

It has been reported that neutrophil extracellular traps (NETs) play important roles in non-infectious diseases. In ischemic stroke, neutrophils infiltrate damaged brain tissue soon after injury and aggravate inflammation. Using a rat permanent MCAO model, we showed citrullinated histone H3 + (CitH3, a marker of NETosis) induction in neutrophils in leptomeninges and in peripheral blood soon after MCAO. Entry of CitH3 + cells occurred through leptomeninges after 6 h of MCAO and these cells were observed in cerebral cortex from 12 h and subsequently in striatum. It is interesting to note that CitH3 + induction began in circulating neutrophils before they migrated to brain parenchyma and they were detected as intact or lysed form. High mobility group box 1 (HMGB1), a danger associated molecular pattern (DAMP) molecule, was accumulated massively in serum after permanent MCAO and plays a critical role in CitH3 inductions in neutrophils in brain parenchyma and in peripheral blood. Both the all-thiol and disulfide types of HMGB1 induced CitH3 via their specific receptors, CXCR4 and TLR4, respectively. Importantly, HMGB1 not only induced NETosis but was included as a part of the extruded NETs, and contribute to NETosis-mediated neuronal death. Therefore, it would appear a vicious cycle exists between neuronal cell death and NETosis and HMGB1 mediates detrimental effects exerted by this cycle. When NETosis was suppressed by a PAD inhibitor in MCAO animals, delayed immune cell infiltrations were markedly suppressed and damages in blood vessels were significantly mitigated. The study shows NETosis with the involvement of HMGB1 as a mediator in a vicious cycle aggravates inflammation and subsequent damage in the ischemic brain.

Aim: In China, warfarin is usually prescribed with Chuanxiong Rhizoma for treating thromboembolism diseases. However, the reason for their combination is still being determined. The present study explored the pharmacokinetics interactions of warfarin, Chuanxiong Rhizoma, and gut microbiota in the rat model of middle cerebral artery occlusion (MCAO). Methods: A total of 48 rats were randomly divided into six groups: MCAO rats orally administered warfarin (W group), pseudo germ-free MCAO rats orally administered warfarin (W-f group), MCAO rats co-administered Chuanxiong Rhizoma and warfarin (C + W group), pseudo germ-free MCAO rats co-administered Chuanxiong Rhizoma and warfarin (C + W-f group), MCAO rats co-administered warfarin and senkyunolide I (S + W group); pseudo germ-free MCAO rats co-administered warfarin and senkyunolide I (S + W-f group). After treatment, all animals’ blood and stool samples were collected at different time points. The stool samples were used for 16S rRNA sequencing analysis. Ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method was established to quantify warfarin, internal standards, and the main bioactive components of Chuanxiong in blood samples. The main pharmacokinetics parameters of warfarin were calculated by DAS 2.1.1 software. Results: The relative abundance of Allobaculum and Dubosiella in the pseudo germ-free groups (W-f, C + W-f, S + W-f) was lower than that in the other three groups (W, C + W, S + W). The relative abundance of Lactobacillus in the W-f group was higher than that of the W group, while the relative abundance of Akkermansia decreased. The relative abundance of Ruminococcaceae _UCG-014 and Ruminococcaceae _NK4A214_group in the S + W-f group was lower than in the S + W group. Compared to the W group, the AUC 0-t and C max of warfarin in the W-f group increased significantly to 51.26% and 34.58%, respectively. The AUC 0-t and C max in the C + W group promoted 71.20% and 65.75% more than the W group. Compared to the W group, the AUC 0-t and C max increased to 64.98% and 64.39% in the S + W group. Conclusion: Chuanxiong Rhizoma and senkyunolide I (the most abundant metabolites of Chuanxiong Rhizoma aqueous extract) might affect the pharmacokinetics features of warfarin in MCAO rats through, at least partly, gut microbiota.

Ischemia/reperfusion (I/R) caused by ischemic stroke treatments leads to brain injury and its pathological mechanism is related to autophagy. The underlying mechanism of kaempferol on cerebral I/R injury needs to be explored. To establish I/R injury, we used a middle cerebral artery occlusion-reperfusion (MCAO) model in rats. MCAO rats were treated with the same amount of saline (I/R group); Treatment group rats were treated orally with kaempferol (50, 100, 200 mg/kg) for 7 days before surgery. After reperfusion for 24 h, the scores of neurological deficits and infarct volume in each group were evaluated. LC3, Beclin-1 p62, AMPK and mTOR protein expression levels were examined by TTC staining, immunofluorescence staining, qRT-PCR and western blotting assay. H&E and TTC staining showed that compared with model group, the infarction size of rats in kaempferol group was markedly reduced. Meanwhile, the results showed that kaempferol had a dose-dependent nerve function repairability. Nissl and TUNEL staining showed that kaempferol could reduce neuronal apoptosis and ameliorate neuronal impairment after I/R. Western blotting and qRT-PCR results showed that kaempferol could protect the brain from ischemia reperfusion by activating autophagy. In addition, add AMPK inhibitor, western blotting and immumohistochemical staining showed that kaempferol mediated AMPK/mTOR signal pathway in MCAO rats. Kaempferol could mediate the AMPK signal pathway to regulate autophagy and inhibit apoptosis to protect brain against I/R injury.