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.

The effect of calpain inhibitor-I on copper oxide nanoparticle-induced damage and cerebral ischemia-reperfusion in a rat model.

This study aimed to investigate the effects of the calpain inhibitor N-Acetyl-Leu-Leu-norleucinal (ALLN) on neuroapoptotic cell damage caused by Copper Oxide Nanoparticles (CuO-NP) and exacerbation of damage through brain ischemia/reperfusion (I/R) in a rat model. Male Wistar Albino rats (n=80) were divided into eight groups: Control, I/R, CuO-NP, CuO-NP+I/R, I/R+ALLN, CuO-NP+ALLN, CuO-NP+I/R+ALLN, and DMSO. Biochemical markers (MBP, S100B, NEFL, NSE, BCL-2, Cyt-C, Calpain, TNF-α, Caspase-3, MDA, and CAT) were measured in serum and brain tissue samples. Histological examinations (H&E staining), DNA fragmentation analysis (TUNEL) were performed, along with Caspase-3 assessment. The ALLN-treated groups exhibited significant improvements in biochemical markers and a remarkable reduction in apoptosis compared to the damaged groups (CuO-NP and I/R). H&E and Caspase-3 staining revealed damage-related morphological changes and reduced apoptosis in the ALLN-treated group. However, no differences were observed among the groups with TUNEL staining. The findings suggest that ALLN, as a calpain inhibitor, has potential implications for anti-apoptotic treatment, specifically in mitigating neuroapoptotic cell damage caused by CuO-NP and I/R.

Neuroprotective effects of a hemoglobin-based oxygen carrier (stroma-free hemoglobin nanoparticle) on ischemia reperfusion injury.

The application of hemoglobin (Hb)-based oxygen carriers (HBOCs) to the treatment of cerebral ischemia has been investigated. A cluster of 1 Hb and 3 human serum albumins (Hb-HSA3) was found to exert neuroprotective effects on ischemia/reperfusion injury. Stroma-free hemoglobin nanoparticles (SFHbNP), a subsequently developed HBOC consisting of a spherical polymerized stroma-free Hb core with a HSA shell, contains the natural antioxidant enzyme catalase and, thus, is expected to exert additive effects. We herein investigated whether SFHbNP exerted enhanced neuroprotective effects in a rat transient middle cerebral artery occlusion (tMCAO) model. Rats were subjected to 2-hour tMCAO and divided into the following 3 groups with the intravenous administration of the respective reagents: (1) phosphate-buffered saline (PBS), as a vehicle (2) Hb-HSA3, and (3) SFHbNP. After 24-hour reperfusion, infarct and edema volumes decreased in the order of the PBS, Hb-HSA3, and SFHbNP groups, with a significant difference (p < 0.05) between the PBS and SFHbNP groups. Similar reductions were observed in oxidative stress, leukocyte recruitment, and blood-brain barrier disruption in the order of the PBS, Hb-HSA3, and SFHbNP groups. In the early phase of reperfusion within 6 h, microvascular HBOC perfusion and cerebral blood flow were maintained at high levels during the reperfusion period in the Hb-HSA3 and SFHbNP groups. However, a difference was observed in tissue oxygen partial pressure levels, which significantly decreased after 6-hour reperfusion in the Hb-HSA3 group, but remained high in the SFHbNP group. A superior oxygen transport ability appears to be related to the enhanced neuroprotective effects of SFHbNP.

Dl-3-n-butylphthalide promotes angiogenesis in ischemic stroke mice through upregulating autocrine and paracrine sonic hedgehog.

Dl-3-n-butylphthalide (NBP) is a small-molecule drug used in the treatment of ischemic stroke in China, which is proven to ameliorate the symptoms of ischemic stroke and improve the prognosis of patients. Previous studies have shown that NBP accelerates recovery after stroke by promoting angiogenesis. In this study, we investigated the mechanisms underlying the angiogenesis-promoting effects of NBP in ischemic stroke models in vitro and in vivo. OGD/R model was established in human umbilical vein endothelial cells (HUVECs) and human brain microvascular endothelial cells (HBMECs), while the tMCAO model was established in mice. The cells were pretreated with NBP (10, 50, 100 µM); the mice were administered NBP (4, 8 mg/kg, i.v.) twice after tMCAO. We showed that NBP treatment significantly stimulated angiogenesis by inducing massive production of angiogenic growth factors VEGFA and CD31 in both in vitro and in vivo models of ischemic stroke. NBP also increased the tubule formation rate and migration capability of HUVECs in vitro. By conducting the weighted gene co-expression network analysis, we found that these effects were achieved by upregulating the expression of a hedgehog signaling pathway. We demonstrated that NBP treatment not only changed the levels of regulators of the hedgehog signaling pathway but also activated the transcription factor Gli1. The pro-angiogenesis effect of NBP was abolished when the hedgehog signaling pathway was inhibited by GDC-0449 in HUVECs, by Sonic Hedgehog(Shh) knockdown in HUVECs, or by intracerebroventricular injection of AAV-shRNA(shh)-CMV in tMCAO mice. Furthermore, we found that HUVECs produced a pro-angiogenic response not only to autocrine Shh, but also to paracrine Shh secreted by astrocytes. Together, we demonstrate that NBP promotes angiogenesis via upregulating the hedgehog signaling pathway. Our results provide an experimental basis for the clinical use of NBP.

Effects of putrescine on oxidative stress, spermidine/spermine-N(1)-acetyltransferase, inflammation and energy levels in liver and serum in rats with brain ischemia-reperfusion.

We aimed to examine the effects of brain ischemia-reperfusion (IR) especially on serum parameters or liver enzymes, free radicals, cytokines, oxidatively damaged DNA, spermidine/spermine N-1-acetyltransferase (SSAT). The effects of addition of putrescine on IR will be evaluated in terms of inflammation and oxidant-antioxidant balance in liver.The study was conducted on 46 male Albino Wistar rats weighing 200-250 g. The rats were grouped into: 1-Sham group (n = 6). 2-IR group (n = 8): The carotid arteries were ligated for 30-min and reperfusion was achieved for 30-min under general anesthesia. 3-Ischemia + putrescine + reperfusion group (IPR) (n = 8): Unlike the IR group, a single dose of 250 µmol kg-1 putrescine was given by gavage at the beginning of reperfusion. In putrescine treatment groups in addition to the procedures performed in the IR group a total of 4 doses of 250 µmol kg-1 putrescine were given at 12-h intervals, with the first dose immediately after 30-min reperfusion (4-IR+putrescine group (IR+P1) (n = 8)); 3 h after the 30-min reperfusion (5-IR+putrescine group (IR+P2) (n = 8)); 6 h after the 30-min reperfusion (6-IR+putrescine group (IR+P3) (n = 8)). ALT, AST, ATP, NO, SSAT, 8-OHdG levels were analyzed in the serum, and liver samples. NF-κB and IL-6 levels were analyzed in the liver samples.Brain IR causes inflammatory, oxidative and DNA damage in the liver, and putrescine supplementation through gavage reduces liver damage by showing anti-inflammatory and antioxidant effects.

Using dual polarities of transcranial direct current stimulation in global cerebral ischemia and its following reperfusion period attenuates neuronal injury.

Multiple neuronal injury pathways are activated during cerebral ischemia and reperfusion (I/R). This study was designed to decrease potential neuronal injuries by using both transcranial direct current stimulation (tDCS) polarities in cerebral ischemia and its following reperfusion period. Ninety rats were randomly divided into six groups. In the sham group, rats were intact. In the I/R group, global cerebral I/R was only induced. In the I/R + c-tDCS and I/R + a-tDCS groups, cathodal and anodal currents were applied, respectively. In the I/R + c/a-tDCS, cathodal current was used in the cerebral ischemia and anodal in the reperfusion. In the I/R + a/c-tDCS group, cathodal and anodal currents were applied in the I/R, respectively. Hippocampal tissue was used to determine the levels of IL-1ß, TNF-α, NOS, SOD, MDA, and NMDAR. Hot plate and open field tests evaluated sensory and locomotor performances. The cerebral edema was also measured. Histological assessment was assessed by H/E and Nissl staining of the hippocampal CA1 region. All tDCS modes significantly decreased IL-1ß and TNF-α levels, especially in the c/a-tDCS. All tDCS caused a significant decrease in MDA and NOS levels while increasing SOD activity compared to the I/R group, especially in the c/a-tDCS mode. In the c-tDCS and a/c-tDCS groups, the NMDAR level was significantly decreased. The c/a-tDCS group improved sensory and locomotor performances more than other groups receiving tDCS. Furthermore, the least neuronal death was observed in the c/a-tDCS mode. Using two different polarities of tDCS could induce more neuroprotective versus pathophysiological pathways in cerebral I/R, especially in c/a-tDCS mode. HIGHLIGHTS: Multiple pathways of neuronal injury are activated in cerebral ischemia and reperfusion (I/R). Using tDCS could modulate neuroinflammation and oxidative stress pathways in global cerebral I/R. Using c/a-tDCS mode during cerebral I/R causes more neuroprotective effects against neuronal injuries of cerebral I/R.

MircoRNA-29a in Astrocyte-derived Extracellular Vesicles Suppresses Brain Ischemia Reperfusion Injury via TP53INP1 and the NF-κB/NLRP3 Axis.

Brain ischemia reperfusion injury (BIRI) is defined as a series of brain injury accompanied by inflammation and oxidative stress. Astrocyte-derived extracellular vesicles (EVs) are importantly participated in BIRI with involvement of microRNAs (miRs). Our study aimed to discuss the functions of miR-29a from astrocyte-derived EVs in BIRI treatment. Thus, astrocyte-derived EVs were extracted. Oxygen and glucose deprivation (OGD) cell models and BIR rat models were established. Then, cell and rat activities and pyroptosis-related protein levels in these two kinds of models were detected. Functional assays were performed to verify inflammation and oxidative stress. miR-29a expression in OGD cells and BIR rats was measured, and target relation between miR-29a and tumor protein 53-induced nuclear protein 1 (TP53INP1) was certified. Rat neural function was tested. Astrocyte-derived EVs improved miR-29a expression in N9 microglia and rat brains. Astrocyte-derived EVs inhibited OGD-induced injury and inflammation in vitro, reduced brain infarction, and improved BIR rat neural functions in vivo. miR-29a in EVs protected OGD-treated cells and targeted TP53INP1, whose overexpression suppressed the protective function of EVs on OGD-treated cells. miR-29a alleviated OGD and BIRI via downregulating TP53INP1 and the NF-κB/NLRP3 pathway. Briefly, our study demonstrated that miR-29a in astrocyte-derived EVs inhibits BIRI by downregulating TP53INP1 and the NF-κB/NLRP3 axis.

Interruption of Endolysosomal Trafficking After Focal Brain Ischemia.

A typical neuron consists of a soma, a single axon with numerous nerve terminals, and multiple dendritic trunks with numerous branches. Each of the 100 billion neurons in the brain has on average 7,000 synaptic connections to other neurons. The neuronal endolysosomal compartments for the degradation of axonal and dendritic waste are located in the soma region. That means that all autophagosomal and endosomal cargos from 7,000 synaptic connections must be transported to the soma region for degradation. For that reason, neuronal endolysosomal degradation is an extraordinarily demanding and dynamic event, and thus is highly susceptible to many pathological conditions. Dysfunction in the endolysosomal trafficking pathways occurs in virtually all neurodegenerative diseases. Most lysosomal storage disorders (LSDs) with defects in the endolysosomal system preferentially affect the central nervous system (CNS). Recently, significant progress has been made in understanding the role that the endolysosomal trafficking pathways play after brain ischemia. Brain ischemia damages the membrane fusion machinery co-operated by N-ethylmaleimide sensitive factor (NSF), soluble NSF attachment protein (SNAP), and soluble NSF attachment protein receptors (SNAREs), thus interrupting the membrane-to-membrane fusion between the late endosome and terminal lysosome. This interruption obstructs all incoming traffic. Consequently, both the size and number of endolysosomal structures, autophagosomes, early endosomes, and intra-neuronal protein aggregates are increased extensively in post-ischemic neurons. This cascade of events eventually damages the endolysosomal structures to release hydrolases leading to ischemic brain injury. Gene knockout and selective inhibition of key endolysosomal cathepsins protects the brain from ischemic injury. This review aims to provide an update of the current knowledge, future research directions, and the clinical implications regarding the critical role of the neuronal endolysosomal trafficking pathways in ischemic brain injury.

Increased apoptosis, tumor necrosis factor-α, and DNA damage attenuated by 3',4'-dihydroxyflavonol in rats with brain Ischemia-reperfusion.

OBJECTIVES: This research was aimed to find out the effects of 3',4'-dihydroxyflavonol (DiOHF) on apoptosis, DNA damage, and tumor necrosis factor-α (TNF-α) levels in the frontal cortex of rats with induced experimental brain ischemi reperfusion. MATERIALS AND METHODS: A total of 38 Wistar albino male rats were used. Groups were created as 1-Sham; 2-Ischemia-reperfusion (I/R); 3-I/R + DiOHF (10 mg/kg); 4-Ischemia + DiOHF + reperfusion; 5-DiOHF + I/R. I/R was performed by carotid artery ligation for 30 min in anesthesized animals. Following experimental applications, blood samples were taken from anesthetized rats to obtain erythrocyte and plasma. Later, the rats were killed by cervical dislocation, and frontal cortex samples were taken and stored at - 80oC for the analysis. RESULTS: In the ischemic frontal cortex tissue sections degenerate neuron numbers, Terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL) positive cell ratio and caspase-3 positive cell ratio increased. Malondialdehyde, TNF-α, and 8-OHdG levels were increased in both plasma and tissue in ischemia group, whereas tissue and erythrocyte glutathione levels were significantly suppressed. However, these values were significantly reversed by DiOHF treatment. CONCLUSION: The results of the study showed that I/R significantly increased apoptosis, TNF-α, and DNA damage in rats with brain I/R. However, 10 mg/kg intraperitoneal DiOHF treatment improved deterioted parameters.

Abatement of neurobehavioral and neurochemical dysfunctions in cerebral ischemia/reperfusion injury by Tetrapleura tetraptera fruit extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Tetrapleura tetraptera Taub. (family Fabaceae), is generally found in the lowland forest of tropical Africa. Its leaves and fruits are traditionally used in West Africa for the management of brain disorders. AIM OF THE STUDY: This study evaluated the effect of Tetrapleura tetraptera methanol fruit extract (TT) on bilateral common carotid artery occlusion-induced cerebral ischemia/reperfusion (I/R) injury in male Wistar rats. MATERIALS AND METHODS: Rats pretreated with TT for 7 days before a 30 min bilateral common carotid artery occlusion and reperfusion for 24 h were assessed for neurobehavioural deficits. Cortical, striatal and hippocampal oxidative stress, pro-inflammatory events, electrolyte imbalance and neurochemical dysfunctions, as well as hippocampal histopathological alterations, were also evaluated. HPLC-DAD analysis was performed to identify likely compounds contributing to the bioactivity of the extract. RESULTS: TT reduced I/R-induced behavioral deficits and ameliorated I/R-induced oxidative stress by restoring reduced glutathione level, increasing catalase and superoxide dismutase activities, and also reducing both lipid peroxidation and xanthine oxidase activity in the brain. TT attenuated I/R-increased myeloperoxidase and lactate dehydrogenase activities as well as disturbances in Na+ and K+ levels. Alterations elicited by I/R in the activities of Na+/K+ ATPase, complex I, glutamine synthetase, acetylcholinesterase, and dopamine metabolism were abated by TT pretreatment. TT prevented I/R-induced histological changes in the hippocampus. HPLC-DAD analysis revealed the presence of aridanin, a marker compound for Tetrapleura tetraptera, and other phytochemicals. CONCLUSIONS: These findings indicate that Tetrapleura tetraptera fruit has a protective potential against stroke through modulation of redox and electrolyte imbalances, and attenuation of neurotransmitter dysregulation and other neurochemical dysfunctions. Tetrapleura tetraptera fruit could be a promising source for the discovery of bioactives for stroke therapy.

Neuroprotective effects of combination therapy of regional cold perfusion and hemoglobin-based oxygen carrier administration on rat transient cerebral ischemia.

Regional cold perfusion and hemoglobin-based oxygen carrier administration both exert neuroprotective effects against cerebral ischemia reperfusion injury. We herein investigated whether the combination of these two therapies leads to stronger neuroprotective effects. Combination therapy was performed with the regional perfusion of cold HemoAct, a core-shell structured hemoglobin-albumin cluster, in a rat transient middle cerebral artery occlusion model. The effects of combination therapy, the intra-arterial administration of 10 °C HemoAct (10H) initiated at the onset of reperfusion, were compared with those of monotherapies, the intra-arterial administration of 10 °C saline (10S) and 37 °C HemoAct (37H), and an untreated control under the condition of 2-hour ischemia/24-hour reperfusion. The durability of therapeutic effects and the therapeutic time window of combination therapy were assessed based on comparisons with the 10H and control groups. Significantly better neurological findings and smaller infarct volumes were observed in the three treated (10S, 37H, and 10H) groups than in the control group. Among the 3 treated groups, only the 10H group showed significant improvements over the control group in the other items examined, including cerebral blood flow reduction, brain edema, and protein extravasation. The significant therapeutic effects of combination therapy on neurological disabilities and infarct volumes were confirmed at least until 7 days after reperfusion. Furthermore, combination therapy ameliorated neurological disabilities and hemorrhagic transformation in rats subjected to 4- and 5-hour ischemia/24-hour reperfusion. Since therapeutic effects may be expected until at least 5 h of complete ischemia and reperfusion, this combination therapy is a promising neuroprotective strategy against severe ischemic stroke.

FTY720 Protects Against Ischemia-Reperfusion Injury by Preventing the Redistribution of Tight Junction Proteins and Decreases Inflammation in the Subacute Phase in an Experimental Stroke Model.

Injury due to brain ischemia followed by reperfusion (I/R) may be an important therapeutic target in the era of thrombectomy. FTY720, a widely known sphingosine-1-phosphate receptor agonist, exerts various neuroprotective effects. The aim of this study was to examine the protective effect of FTY720 with respect to I/R injury, especially focusing on blood-brain barrier (BBB) protection and anti-inflammatory effects. Male rats were subjected to transient ischemia and administered vehicle or 0.5 or 1.5 mg/kg of FTY720 immediately before reperfusion. Positron emission tomography (PET) with [18F]DPA-714 was performed 2 and 9 days after the insult to serially monitor neuroinflammation. Bovine and rat brain microvascular endothelial cells (MVECs) were also subjected to oxygen-glucose deprivation (OGD) and reperfusion, and administered FTY720, phosphorylated-FTY720 (FTY720-P), or their inhibitor. FTY720 dose-dependently reduced cell death, the infarct size, cell death including apoptosis, and inflammation. It also ameliorated BBB disruption and neurological deficits compared to in the vehicle group. PET indicated that FTY720 significantly inhibited the worsening of inflammation in later stages. FTY720-P significantly prevented the intracellular redistribution of tight junction proteins but did not increase their mRNA expression. These results suggest that FTY720 can ameliorate I/R injury by protecting the BBB and regulating neuroinflammation.

PEG-amino acid-przewaquinone a conjugations: Synthesis, physicochemical properties and protective effect in a rat model of brain ischemia-reperfusion.

A total of 21 PEG-przewaquinone A conjugations with high drug loading ability, good water solubility and in vivo slow-release quality were obtained by conjugating przewaquinone A with PEG through amino acids and tripeptides spacers respectively. Notably, compound 3a can obviously reduce the brain ischemia-reperfusion damage dose-dependently in a rat model, which indicated the efficacy of our PEG prodrug strategy.

Ginsenoside Rb1 protects brain through Cav-1 for mice with cerebral ischemia-reperfusion injury / 中国临床药理学与治疗学

AIM: To investigate the protective effect of ginsenoside Rb1 on brain through Cav-1 in mice with cerebral ischemia-reperfusion injury. METHODS: One hundred and twenty C57/B6 mice were randomly divided into sham operation group, model group, model + ginsenoside Rb1 group, ginsenoside Rb1+ Cav-1 siRNA group, ginsenoside Rb1+siNC group, 24 in each group. The model of cerebral ischemia-reperfusion injury in mice was established by middle cerebral artery occlusion (MCAO). The ginsenoside Rb1 group received intraperitoneally injection of ginsenoside Rb1 (40 mg/kg); the sham operation group and model group were intraperitoneally injected with an equal amount of physiological saline immediately after modeling. For the ginsenoside Rb1+ cav-1 siRNA group and the ginsenoside Rb1+siNC group, cav-1 siRNA and siNC were injected into the lateral ventricle 24 h before molding, respectively, and the other operations were the same as the ginsenoside Rb1 group. The neurobehavioral scores of the mice in each group were measured at 24 h after reperfusion, and the water content of brain tissue, cerebral infarction volume, Cav-1 mRNA and Cav-1, Bcl-2 and Bax protein expressions in the cerebral cortex penumbra were measured in each group. RESULTS:Compared with the sham operation group, the neurobehavioral scores, cerebral infarction volume and brain tissue water content in the model group were significantly increased (P<0.05), and the expressions of Cav-1 mRNA and Cav-1 protein, and the Bcl-2 /Bax ratio were significantly decreased (P<0.05). Compared with the model group, the neurobehavioral scores, cerebral infarction volume and brain tissue water content in the ginsenoside Rb1 group were significantly decreased, and the expressions of Cav-1 mRNA and Cav-1 protein, and the Bcl-2 /Bax ratio were significantly increased (P<0.05). Compared with the ginsenoside Rb1 group, the neurobehavioral scores, cerebral infarction volume and brain tissue water content in the ginsenoside Rb1 + cav-1 siRNA group were significantly increased, and the expressions of Cav-1 mRNA and Cav-1 protein, and the Bcl-2 /Bax ratio were significantly decreased (P<0.05). CONCLUSION: Ginsenoside Rb1 can protects brain for mice with cerebral ischemia-reperfusion injury. After Cav-1 siRNA decreased the expression of Cav-1 protein in the brain tissue of mice, it significantly reverses the cerebral protective effect of ginsenoside Rb1, indicating that Cav-1 protein mediated the cerebral protective effect of ginsenoside Rb1 on cerebral ischemia reperfusion injury mice.

Combined Ischemic Preconditioning and Resveratrol Improved Bloodbrain Barrier Breakdown via Hippo/YAP/TAZ Signaling Pathway.

BACKGROUND: Transient Ischemia/Reperfusion (I/R) is the main reason for brain injury and results in disruption of the Blood-Brain Barrier (BBB). It had been reported that BBB injury is one of the main risk factors for early death in patients with cerebral ischemia. Numerous investigations focus on the study of BBB injury which have been carried out. OBJECTIVE: The objective of this study was to investigate the treatment function of the activation of the Hippo/Yes-Associated Protein (YAP) signaling pathway by combined Ischemic Preconditioning (IPC) and resveratrol (RES) before brain Ischemia/Reperfusion (BI/R) improves Blood-Brain Barrier (BBB) disruption in rats. METHODS: Sprague-Dawley (SD) rats were pretreated with 20 mg/kg RES and IPC and then subjected to 2 h of ischemia and 22 h of reperfusion. The cerebral tissues were collected; the cerebral infarct volume was determined; the Evans Blue (EB) level, the brain Water Content (BWC), and apoptosis were assessed; and the expressions of YAP and TAZ were investigated in cerebral tissues. RESULTS: Both IPC and RES preconditioning reduced the cerebral infarct size, improved BBB permeability, lessened apoptosis, and upregulated expressions of YAP and transcriptional co-activator with PDZ-binding motif (TAZ) compared to the Ischemia/Reperfusion (I/R) group, while combined IPC and RES significantly enhanced this action. CONCLUSION: combined ischemic preconditioning and resveratrol improved blood-brain barrier breakdown via Hippo/YAP/TAZ signaling pathway.

Effect of ginsenoside Rgl on cortical ubiquitin-modified protein aggregation after cerebral ischemia-reperfusion in rats / 吉林大学学报(医学版)

Objective: To explore the effect of ginsenoside Rgl on the ubiquitin-modified protein aggregation in the cortex after cerebral ischemia reperfusion (I / R) injury in the rats, and to further clarify the therapeutic mechanism of ginsenoside Rgl in the cerebral I/R injury. Methods: The middle cerebral artery occlusion (MCAO) model was set up with suture method for 1. 5 h of embolization. A total of 72 rats were divided into sham operation group, I/R model group, positive drug control (nimodipine) group, low, middle, and high doses 10, 20, and 40 mg ' k g - 1) of ginsenoside Rgl groups. All 12 rats in each group were given intraperitoneal injection. TTC staining and Longa' s score method were used to detect the infarction areas and the neurological deficit scores of the rats in various groups 24 h after modeling. The death of neurons in the cortex and hippocampus after cerebral ischemia of the rats in various groups were observed with HE staining. Immunohistochemistry and Western blotting method were used to detect the expression of ubiquitin-modified protein aggregation in the cortex of the rats in various groups. Results: Compared with I/R group, the percentages of infarction areas of the rats in nimodipine group and ginsenoside Rgl groups were significantly decreased (P < 0 . 05). and the neurological deficit scores were decreased (P < 0 . 05). The HE staining results showed that compared with sham operation group, the neurons in I/R model group were sparse, showing fragmentation and dissolution; compared with I/R model group, the phenomena of cell nucleus fragmentation, dissolution and powder staining in nimodipine group and different doses of ginsenoside Rgl groups were all improved to different degrees. The immunohistochemical results showed that compared with sham operation group, the positive expression level of ubiquitin-modified protein in I/R model group was increased significantly (P < 0 . 05); compared with I/R model group, the positive expression levels of ubiquitin-modified protein in nimodipine group and different doses of ginsenoside Rgl groups were decreased (P < 0 . 05), especially in high dose of ginsenoside Rgl group (P < 0 . 05). The Western blotting results showed that compared with sham operation group, the level of ubiquitin-modified protein aggregates in I/R model group was significantly increased (P < 0 . 0 5); compared with I/R model group, the levels of ubiquitin-modified protein aggregates in nimodipine group and different doses of ginsenoside Rgl were decreased (P < 0 . 05), especially in high dose of ginsenoside Rgl group. Conclusion: Ginsenoside Rgl can inhibit the formation of ubiquitin-modified protein aggregates induced by I/R injury in the cortex, thereby alleviating the I/R injury in the rats.

Salidroside alleviates ischemic brain injury in mice with ischemic stroke through regulating BDNK mediated PI3K/Akt pathway.

There is evidence suggesting that inhibition of apoptosis plays a critical role in preventing neurons from damage and even death, after brain ischemia/reperfusion, which shows therapeutic potential for clinical treatment of brain injury. In this study, We preformed MCAO model in C57BL/6J wild-type (BDNK+/+) and BDNK knockout (BDNF-/-) mice respectively, and investigated the neuroprotective effect of Salidroside (Sal) and its underlying mechanisms. The results showed that Sal reversed brain infarct size, reduced cerebral edema, decreased the neurological deficit score and diminished TUNEL positive cells significantly. However, BDNK deficiency inhibited the neuroprotective effect of Sal. In addition, Sal increased cell viability, ameliorated neuron cell injury by decreasing LDH activity, and inhibited cell apoptotic rate. Sal suppressed apoptotic signaling via DNA-binding-dependent and -independent mechanisms. Furthermore, the neuroprotective effect of Sal on BDNK was mediated by PI3K/Akt pathway, which was proved by the use of PI3K knockout (PI3K-/-) mice and siRNA-PI3K. In summary, these data strongly suggested that Sal could be used as an effective neuroprotective agent to protect against ischemic stroke after cerebral I/R injury through regulating BDNK-mediated PI3K/Akt apoptotic pathway in DNA-binding-dependent and -independent manners.

[The effect of the biologically active additive epiphamine on antioxidant and NADPH-generating enzymes activity under experimental cerebral ischemia/reperfusion in rats]. / Vozdeistvie BAD épifamin na aktivnost' antioksidantnykh i NADPH-generiruiushchikh fermentov pri éksperimental'noi ishemii/reperfuzii golovnogo mozga u krys.

The effect of biologically active additive with immunomodulator properties epiphamine on the activity of antioxidant (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione transferase) and NADPH-generating (glucose-6-phosphate dehydrogenase, NADP-isocitrate dehydrogenase) enzymes has been investigated at experimental cerebral ischemia/reperfusion in rats. The results obtained indicate epiphamine-induced changes of these enzymes activities towards control values. Changes in the content of lactate, a marker of the pathology development, have also been found in experimental animals under ischemia and epiphamine administration caused changes similar to those observed in the case of enzyme activities studied. In most cases, the changes were dose-dependent. Thus, epiphamine can be of considerable interest from the point of view of metabolic changes pharmacological correction at the development of the pathology accompanied by oxidative stress.

Inactivation of NSF ATPase Leads to Cathepsin B Release After Transient Cerebral Ischemia.

Neurons have extraordinary large cell membrane surface area, thus requiring extremely high levels of intracellular membrane-trafficking activities. Consequently, defects in the membrane-trafficking activities preferentially affect neurons. A critical molecule for controlling the membrane-trafficking activities is the N-ethylmaleimide-sensitive factor (NSF) ATPase. This study is to investigate the cascade of events of NSF ATPase inactivation, resulting in a massive buildup of late endosomes (LEs) and fatal release of cathepsin B (CTSB) after transient cerebral ischemia using the 2-vessel occlusion with hypotension (2VO+Hypotension) global brain ischemia model. Rats were subjected to 20 min of transient cerebral ischemia followed by 0.5, 4, 24, and 72 h of reperfusion. Neuronal histopathology and ultrastructure were examined by the light and electron microscopy, respectively. Western blotting and confocal microscopy were utilized for analyzing the levels, redistribution, and co-localization of Golgi apparatus and endosome or lysosome markers. Transient cerebral ischemia leads to delayed neuronal death that occurs at 48-72 h of reperfusion mainly in hippocampal CA1 and neocortical (Cx) layers 3 and 5 pyramidal neurons. During the delayed period, NSF ATPase is irreversibly trapped into inactive protein aggregates selectively in post-ischemic neurons destined to die. NSF inactivation leads to a massive buildup of Golgi fragments, transport vesicles (TVs) and late endosomes (LEs), and release of the 33 kDa LE type of CTSB, which is followed by delayed neuronal death after transient cerebral ischemia. The results support a novel hypothesis that transient cerebral ischemia leads to NSF inactivation, resulting in a cascade of events of fatal release of CTSB and delayed neuronal death after transient cerebral ischemia.

Dysfunction of Membrane Trafficking Leads to Ischemia-Reperfusion Injury After Transient Cerebral Ischemia.

Neurons require an extraordinarily high level of membrane trafficking activities because of enriched axonal terminals and dendritic branches. For that reason, defects in the membrane trafficking pathway are a hallmark of most, and may be all, neurodegenerative disorders. A major cellular membrane trafficking pathway is the Golgi apparatus (Golgi hereafter)-late endosome-lysosome axis for supplying lysosomal enzymes. This pathway is regulated by N-ethylmaleimide-sensitive factor (NSF) ATPase. This review article is to discuss a novel hypothesis that brain ischemia inactivates NSF ATPase, resulting in a cascade of events of disruption of the Golgi-endosome-lysosome pathway, release of cathepsin B (CTSB), and induction of mitochondrial outer membrane permeabilization (MOMP) during the postischemic phase. This hypothesis is supported by recent studies demonstrating that NSF is trapped into inactive protein aggregates in neurons destined to die after brain ischemia. Consequently, Golgi, transport vesicles (TVs), and late endosomes (LEs) are accumulated and damaged, which is followed by CTSB release from these damaged structures. Moderate release of CTSB cleaves Bax-like BH3 protein (Bid) to become active truncated Bid (tBid). Active tBid is then translocated to the mitochondrial outer membrane, resulting in oligomerization of BCL2-associated X protein (Bax) forming the mitochondrial outer membrane pores, and releasing mitochondrial intramembranous proteins. Extensive CTSB release, however, can digest cellular proteins indiscriminately to induce cell death. Based on these new observations, we propose a novel hypothesis, i.e., brain ischemia leads to NSF inactivation, resulting in a massive buildup of damaged Golgi, TVs and LEs, fatal release of CTSB, induction of MOMP, and eventually brain ischemia-reperfusion injury.