Cerebral Hypoxia-ischemia Research Articles

FGF21 Alleviates Hypoxic-Ischemic White Matter Injury in Neonatal Mice by Mediating Inflammation and Oxidative Stress Through PPAR-γ Signaling Pathway.

White matter injury (WMI), the most common type of brain damage in infants born preterm, is characterized by failure in oligodendrocyte progenitor cell maturation and myelination, thereby contributing to long-term neurological impairments. Regrettably, effective therapies for promoting remyelination and improving function are currently lacking for this growing population affected by WMI. Recombinant human fibroblast growth factor (rhFGF) 21 modulated microglial activation and then ameliorated brain damage and improved neurological deficits in several central nervous system diseases. However, the effects of rhFGF21 treatment on WMI in preterm infants remain uncertain. In this study, we established an in vivo mouse model of cerebral hypoxia-ischemia (HI)-induced brain WMI and an in vitro model using oxygen-glucose deprivation (OGD)-treated HMC3 cells to investigate the neuroprotective effects of rhFGF21 against WMI and elucidated the potential mechanism. Our findings demonstrated that administration of rhFGF21 significantly ameliorated the retardation of oligodendrocyte differentiation, promoted myelination, and mitigated axonal deficits, synaptic loss, and GFAP scarring, thereby improving lifelong cognitive and neurobehavioral dysfunction associated with WMI. Moreover, rhFGF21 modulated microglial polarization, promoted a shift from the M1 to the M2 microglial phenotype, and suppressed microglial activation, thus ameliorating inflammatory response and oxidative stress. Additionally, rhFGF21 treatment significantly inhibited the HMGB1/NF-κB pathway linked to inflammation, and activated the NRF2 pathway associated with oxidative stress through the upregulation of PPAR-γ. Importantly, the beneficial effects of rhFGF21 on HI-induced WMI and microglial activation were dramatically inhibited by PPAR-γ antagonist and its siRNA. Our findings provide compelling evidence that rhFGF21 treatment mitigated the inflammatory response and oxidative stress through the modulation of microglial polarization via the PPAR-γ-mediated HMGB1/NF-κB pathway and the NRF2 pathway, respectively, contributes to neuroprotection and the amelioration of WMI in neonatal mice. Thus, rhFGF21 represents a promising therapeutic agent for the treatment of neonatal WMI.

Neonatal hypoxia-ischemia alters the events governing the hippocampal critical period of postnatal synaptic plasticity leading to deficits in working memory in mice.

The postnatal critical period of synaptic plasticity (CPsp) is characterized by profound neural network refinement, which is shaped by synaptic activity and sculpted by maturation of the GABAergic network. Even after therapeutic hypothermia (TH), neonatal hypoxia-ischemia (HI) impairs two triggers for the initiation of the CPsp in the hippocampus: i) PSA-NCAM developmental decline and ii) parvalbumin (PV) + interneuron (IN) maturation. Thus, we investigated whether neonatal HI despite TH disturbs other events governing the onset, consolidation and closure of the postnatal CPsp in the hippocampus. We induced cerebral HI in P10 C57BL6 mice with right carotid ligation and 45 m of hypoxia (FiO2 = 0.08), followed by normothermia (36 °C, NT) or TH (31 °C) for 4 h with anesthesia-exposed shams as controls. ELISA, immunoblotting and immunohistochemistry were performed at 24 h (P11), 5 days (P15), 8 days (P18) and 30 days (P40) after HI injury. We specifically assessed: i) BDNF levels and TrkB activation, controlling the CPsp, ii) Otx2 and NPTX2 immunoreactivity (IR), engaging CPsp onset and iii) NogoR1, Lynx1 IR, PNN formation and myelination (MBP) mediating CPsp closure. Pups aged to P40 also received a battery of tests assessing working memory. Here, we documented deficits in hippocampal BDNF levels and TrkB activation at P18 in response to neonatal HI even with TH. Neonatal HI impaired in the CA1 the developmental increase in PV, Otx2, and NPTX2 between P11 and P18, the colocalization of Otx2 and PV at P18 and P40, the accumulation of NPTX2 in PV+ dendrites at P18 and P40, and the expression of NogoR and Lynx1 at P40. Furthermore, neonatal HI decreased BDNF and impaired PNN development and myelination (MBP) at P40. Most of these abnormalities were insensitive to TH and correlated with memory deficits. Neonatal HI appears to disrupt many of the molecular and structural events initiating and consolidating the postnatal hippocampal CPsp, perhaps due to the early and delayed deficits in TrkB activation leading to memory deficits.

Incidence and clinical analysis of asymptomatic intracranial hemorrhage in neonates with cerebral hypoxic-ischaemic risk based on multisequence MR images

The incidence and clinical distribution of intracranial haemorrhage (ICH) in neonates at risk of cerebral hypoxia–ischaemia have not been reported in specific studies. Based on conventional magnetic resonance imaging (MRI) versus susceptibility weighted imaging (SWI), this study aimed to analyse the occurrence of asymptomatic ICH in newborns with or without risk of cerebral hypoxia–ischaemia and to accumulate objective data for clinical evaluations of high-risk neonates and corresponding response strategies. 317 newborns were included. MRI revealed that the overall incidence of ICH was 59.31%. The most common subtype was intracranial extracerebral haemorrhage (ICECH) which included subarachnoid haemorrhage (SAH) and subdural haemorrhage (SDH). ICECH accounted for 92.02% of ICH. The positive detection rate of ICECH by SWI was significantly higher than that by T1WI. The incidence of total ICH, ICECH and SAH was greater among children who were delivered vaginally than among those who underwent caesarean delivery. Asymptomatic neonatal ICH may be a common complication of the neonatal birth process, and SWI may improve the detection rate. Transvaginal delivery and a weight greater than 2500 g were associated with a high incidence of ICECH in neonates. The impact of neonatal cerebral hypoxia–ischaemia risk factors on the occurrence of asymptomatic ICH may be negligible.

Evaluation of Neonatal Cerebral Circulation Under Hypoxic Ischemic Risk Factors Based on Quantitative Analysis of Cerebral Veins with Magnetic Resonance Susceptibility Weighted Imaging.

To observe the regulation of cerebral circulation in vivo based on image segmentation algorithms for deep learning in medical imaging to automatically detect and quantify the neonatal deep medullary veins (DMVs) on susceptibility weighted imaging (SWI) images. To evaluate early cerebral circulation self-rescue for neonates undergoing risk of cerebral hypoxia-ischaemia in vivo. SWI images and clinical data of 317 neonates with or without risk of cerebral hypoxia-ischaemia were analyzed. Quantitative parameters showing the number, width, and curvature of DMVs were obtained using an image segmentation algorithm. The number of DMVs was greater in males than in females (p < 0.01), and in term than in preterm infants (p = 0.001). The width of DMVs was greater in term than in preterm infants (p < 0.01), in low-risk than in high-risk group (p < 0.01), and in neonates without intracranial extracerebral haemorrhage (ICECH) than with ICECH (p < 0.05). The curvature of DMVs was greater in term than in preterm infants (P < 0.05). The width of both bilateral thalamic veins and anterior caudate nucleus veins were positively correlated with the number of DMVs; the width of bilateral thalamic veins was positively correlated with the width of DMVs. The DMVs quantification based on image segmentation algorithm may provide more detailed and stable quantitative information in neonate. SWI vein quantification may be an observable indicator for in vivo assessment of cerebral circulation self-regulation in neonatal hypoxic-ischemic brain injury.

Neuronal autosis is Na+/K+-ATPase alpha 3-dependent and involved in hypoxic-ischemic neuronal death

Macroautophagy (hereafter called autophagy) is an essential physiological process of degradation of organelles and long-lived proteins. The discovery of autosis, a Na+/K+-ATPase (ATP1)-dependent type of autophagic cell death with specific morphological and biochemical features, has strongly contributed to the acceptance of a pro-death role of autophagy. However, the occurrence and relevance of autosis in neurons has never been clearly investigated, whereas we previously provided evidence that autophagy mechanisms could be involved in neuronal death in different in vitro and in vivo rodent models of hypoxia-ischemia (HI) and that morphological features of autosis were observed in dying neurons following rat perinatal cerebral HI. In the present study, we demonstrated that neuronal autosis could occur in primary cortical neurons using two different stimulations enhancing autophagy flux and neuronal death: a neurotoxic concentration of Tat-BECN1 (an autophagy-inducing peptide) and a hypoxic/excitotoxic stimulus (mimicking neuronal death induced by cerebral HI). Both stimulations induce autophagic neuronal death (dependent on canonical autophagic genes and independent on apoptotic, necroptotic or ferroptotic pathways) with all morphological and biochemical (ATP1a-dependent) features of autosis. However, we demonstrated that autosis is not dependent on the ubiquitous subunit ATP1a1 in neurons, as in dividing cell types, but on the neuronal specific ATP1a3 subunit. We also provided evidence that, in different in vitro and in vivo models where autosis is induced, ATP1a3-BECN1 interaction is increased and prevented by cardiac glycosides treatment. Interestingly, an increase in ATP1a3-BECN1 interaction is also detected in dying neurons in the autoptic brains of human newborns with severe hypoxic-ischemic encephalopathy (HIE). Altogether, these results suggest that ATP1a3-BECN1-dependent autosis could play an important role in neuronal death in HI conditions, paving the way for the development of new neuroprotective strategies in hypoxic-ischemic conditions including in severe case of human HIE.

Constraint-Induced Movement Therapy Promotes Myelin Remodeling and Motor Function by Mediating Sox2/Fyn Signals in Rats With Hemiplegic Cerebral Palsy.

Hypoxic-ischemic brain injury in infants often leads to hemiplegic motor dysfunction. The mechanism of their motor dysfunction has been attributed to deficiencies of the transcription factor sex-determining region (SRY) box 2 (Sox2) or the non-receptor-type tyrosine kinase Fyn (involved in neuronal signal transduction), which causes a defect in myelin formation. Constraint-induced movement therapy (CIMT) following cerebral hypoxia-ischemia may stimulate myelin growth by regulating Sox2/Fyn, Ras homolog protein family A (RhoA), and rho-associated kinase 2 (ROCK2) expression levels. This study investigated how Sox2/Fyn regulates myelin remodeling following CIMT to improve motor function in rats with hemiplegic cerebral palsy (HCP). To investigate the mechanism of Sox2 involvement in myelin growth and neural function in rats with HCP, Lentivirus (Lenti)-Sox2 adeno-associated virus and negative control-Lenti-Sox2 (LS) adeno-associated virus were injected into the lateral ventricle. The rats were divided into a control group and an HCP group with different interventions (CIMT, LS, or negative control-LS [NS] treatment), yielding the HCP, HCP plus CIMT (HCP + CIMT), HCP + LS, HCP + LS + CIMT, HCP + NS, and HCP + NS + CIMT groups. Front-limb suspension and RotaRod tests, Golgi-Cox staining, transmission electron microscopy, immunofluorescence staining, western blotting, and quantitative polymerase chain reaction experiments were used to analyze the motor function, dendrite/axon area, myelin ultrastructure, and levels of expression of oligodendrocytes and Sox2/Fyn/RhoA/ROCK2 in the motor cortex. The rats in the HCP + LS + CIMT group had better values for motor function, dendrite/axon area, myelin ultrastructure, oligodendrocytes, and Sox2/Fyn/RhoA/ROCK2 expression in the motor cortex than rats in the HCP and HCP + NS groups. The improvement of motor function and myelin remodeling, the expression of oligodendrocytes, and the expression of Sox2/Fyn/RhoA/ROCK2 in the HCP + LS group were similar to those in the HCP + CIMT group. CIMT might overcome RhoA/ROCK2 signaling by upregulating the transcription of Sox2 to Fyn in the brain to induce the maturation and differentiation of oligodendrocytes, thereby promoting myelin remodeling and improving motor function in rats with HCP. The pathway mediated by Sox2/Fyn could be a promising therapeutic target for HCP.

FTO-Mediated m6A Modification of FTH1 Inhibits Ferroptosis of Neurons in Neonatal Cerebral Hypoxic Ischemia.

FTO alpha-ketoglutarate dependent dioxygenase (FTO) is aberrantly expressed in brain disorders. However, the roles of FTO in neonatal hypoxic-ischemic brain injury (HIE) are still unclear. This study aims to investigate the potential of FTO in neonatal HIE. Oxygen-glucose deprivation (OGD) was used to establish HIE in vitro. mRNA levels were detected by real-time reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). Protein expression was detected by Western blot. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), ferrous iron (Fe2+) and glutathione (GSH) was detected by specific kit. m6A sites were analyzed using SRAMP and further verify by methylated RNA immunoprecipitation (MeRIP) assay. Cell proliferation was determined by Cell Counting Kit-8 (CCK-8) assay. Cell death was determined by propidium iodide (PI) staining. FTO was downregulated in patients with neonatal HIE and OGD-treated neurons. Moreover, FTO mRNA expression was decreased in ferroptosis inducer, especially ferric ammonium citrate (FAC). However, overexpression of FTO inhibited the ferroptosis of neurons. Moreover, FTO-mediated N6-methyladenosine (m6A) modification of ferritin heavy chain 1 (FTH1) suppressed its mRNA expression and stability, inhibiting its protein expression. However, overexpression of FTH1 abrogated the effects of FTO and promoted the ferroptosis of neurons. In summary, FTO functions as a protective role in neonatal HIE via inhibiting FTH1 signaling. Thence, targeting may be a promising strategy for FTO neonatal HIE.

Mental disorder as an example of sequelae of cerebral hypoxia-ischemia in case of acute blood loss in forensic medicine

Mental disorder as an example of sequelae of cerebral hypoxia-ischemia in case of acute blood loss in forensic medicine

Therapeutic hypothermia modulates the neurogenic response of the newborn piglet subventricular zone after hypoxia-ischemia

BackgroundNeuroprotection combined with neuroregeneration may be critical for optimizing functional recovery in neonatal encephalopathy. To investigate the neurogenic response to hypoxia-ischemia (HI) followed by normothermia (38.5 °C) or three different hypothermic temperatures (35, 33.5, or 30 °C) in the subventricular zone (SVZ) of the neonatal piglet.MethodsFollowing transient cerebral HI and resuscitation, 28 newborn piglets were randomized to: normothermia or whole-body cooling to 35 °C, 33.5 °C, or 30 °C during 2–26 h (all n = 7). At 48 h, piglets were euthanized and SVZ obtained to evaluate its cellularity, pattern of cell death, radial glia length, doublecortin (DCX, neuroblasts) expression, and Ki67 (cell proliferation) and Ki67/Sox2 (neural stem/progenitor dividing) cell counts.ResultsNormothermic piglets showed lower total (Ki67+) and neural stem/progenitor dividing (Ki67+Sox2+) cell counts when compared to hypothermic groups. Cooling to 33.5 °C obtained the highest values of SVZ cellularity, radial glia length processes, neuroblast chains area and DCX immunohistochemistry. Cooling to 30 °C, however, revealed decreased cellularity in the lateral SVZ and shorter radial glia processes when compared with 33.5 °C.ConclusionsIn a neonatal piglet model, hypothermia to 33.5 °C modulates the neurogenic response of the SVZ after HI, highlighting the potential beneficial effect of hypothermia to 33.5 °C on endogenous neurogenesis and the detrimental effect of overcooling beyond this threshold.ImpactNeuroprotection combined with neuroregeneration may be critical for optimizing functional recovery in neonatal encephalopathy.Hypothermia may modulate neurogenesis in the subventricular zone (SVZ) of the neonatal hypoxic-ischemic piglet.Cooling to 33.5 °C obtained the highest values of SVZ cellularity, radial glia length processes, neuroblast chains area and doublecortin immunohistochemistry; cooling to 30 °C, however, revealed decreased cellularity and shorter radial glia processes.In a neonatal piglet model, therapeutic hypothermia (33.5 °C) modulates the neurogenic response of the SVZ after hypoxia-ischemia, highlighting also the detrimental effect of overcooling beyond this threshold.

Sub-dose anesthetics combined with chloride regulators protect the brain against chronic ischemia-hypoxia injury.

Cerebral ischemia-hypoxia leads to excitotoxicity-mediated neuronal damage and cognitive dysfunction, especially in the elderly. Excessive intracellular [Cl- ]i accumulation weakens γ-aminobutyric acid (GABA) compensatory effects. Sub-anesthetic dose of propofol protected the brain against ischemia-hypoxia, which was abolished by blocking Cl- efflux transporter K+ /Cl- cotransporter 2 (KCC2). We aimed to determine whether low-dose anesthetic combined with [Cl- ]i regulators could restore the compensatory GABAergic system and improve cognitive function. Chronic cerebral hypoxia (CCH) model was established by bilateral carotid artery ligation in aged rats. Sub-dose of anesthetics (propofol and sevoflurane) with or without KCC2 agonist N-ethylmaleimide (NEM) or Na+ /K+ /Cl- cotransporter 1 (NKCC1) antagonist bumetanide (BTN) was administered systemically 30 days post-surgery. Primary rat hippocampal neuronal cultures were subjected to hypoxic injury with or without drug treatment. Memory function, hippocampal neuronal survival, GABAergic system functioning, and brain-derived neurotrophic factor (BDNF) expressions were evaluated. Sub-anesthetic dose of combined propofol (1.2 μg mL-1 ) and sevoflurane [0.7 MAC (minimum alveolar concentration)] did not aggravate the hypoxic brain injury in rats or cell damage in neuronal cultures. Adding either BTN or NEM protected against hypoxic injury, associated with improved cognitive function in vivo, less intracellular accumulation of [Cl- ]i , reduced cell death, restored GABAergic compensation, and increased BDNF expression both in vivo and in vitro. Sub-anesthetic dose of propofol and sevoflurane is a recommended anesthesia regimen in at-risk patients. Restoration of [Cl- ]i homeostasis and GABAergic could further reduce the brain damage caused by ischemia-hypoxia.

Dexmedetomidine suppresses hippocampal astrocyte pyroptosis in cerebral hypoxic-ischemic neonatal rats by upregulating microRNA-148a-3p to inactivate the STAT/JMJD3 axis.

Dexmedetomidine (DEX), a selective α2-adrenoceptor agonist, is an anesthetic and sedative agent and has been reported to confer neuroprotective effects after cerebral hypoxic ischemia (CHI). This study was undertaken to elucidate the mechanisms by which microRNA (miR)-148a-3p is involved in the neuroprotective effect of DEX on hypoxic-ischemic brain damage in neonatal rats. Neonatal rats were exposed to CHI conditions, a miR-148a-3p inhibitor, and DEX. Hippocampal astrocytes were isolated to construct an oxygen-glucose deprivation (OGD) model. qRT-PCR and western blot were utilized to inspect miR-148a-3p, STAT1, STAT3, JMJD3, cleaved-Caspase-1, ASC, NLRP3, GSDMD, and GSDMD-N expression in rats and astrocytes. TUNEL staining was employed to measure astrocyte apoptosis rate, immunofluorescence to inspect cleaved-Caspase-1 and ASC levels, and ELISA to determine IL-1β and IL-18 expression. The target genes of miR-148a-3p were predicted using online software and verified by a dual-luciferase reporter gene assay. A prominent increase in astrocyte apoptosis rate and the expression of pyroptosis- and inflammation-related factors were found in rats with CHI and OGD-treated astrocytes. DEX suppressed astrocyte apoptosis rate and decreased expression of pyroptosis- and inflammation-related factors. Knockdown of miR-148a-3p facilitated astrocyte pyroptosis, indicating that DEX exerted its protective effect by upregulating miR-148a-3p. miR-148a-3p negatively mediated STAT to inactivate JMJD3. Overexpression of STAT1 and STAT3 facilitated pyroptosis in astrocytes, which was negated by the overexpression of miR-148a-3p. DEX inhibited hippocampal astrocyte pyroptosis by upregulating miR-148a-3p to inactivate the STAT/JMJD3 axis, thereby alleviating cerebral damage in neonatal rats with CHI.

Yap1-Usp14 Axis Inhibits Neuronal Mitophagy During Neonatal Hypoxia-Ischemia Encephalopathy by Regulation of Beclin-1 Ubiquitination in Mouse.

Neonatal hypoxic-ischemic encephalopathy (HIE) that results from perinatal cerebral hypoxia-ischemia has become one of the leading causes of acute mortality and chronic disability in infants and children. Despite that neuronal mitophagy and subsequent clearance of damaged neurons exert protective effect, the pathogenesis of HIE and effective treatment strategies for intervention of HIE remain poorly understood. Here, we report that ubiquitin-specific protease 14 (Usp14, a deubiquitinating enzyme) is closely associated with HIE progression by its negative regulation in neuronal mitophagy in mouse. The expression of Usp14 is elevated in both an oxygen-glucose deprivation (OGD) mouse neuronal cell line culture model in vitro and a HIE mouse model in vivo. Mechanistically, OGD treatment activates Hippo signaling that enhances Yap1 phosphorylation levels at Ser-127 but inhibits Yap1 protein level, which potentiates Usp14 transcription and leads to the downregulated ubiquitination at Lys-63 of Beclin-1, a key molecule in autophagy, resulting in the suppressed neuronal mitophagy, subsequent failure in the clearance of damaged neurons, and finally possible dysregulation in brain functions. Thus, our results provide with Usp14 as a novel target and treatment strategy for intervention of HIE, which may help diagnose and treat HIE in clinic.

Functional neuropathology of neonatal hypoxia-ischemia by single-mouse longitudinal electroencephalography.

Neonatal cerebral hypoxia-ischemia (HI) results in symptomatic seizures and long-term neurodevelopmental disability. The Rice-Vannucci model of rodent neonatal HI has been used extensively to examine and translate the functional consequences of acute and chronic HI-induced encephalopathy. Yet, longitudinal electrophysiological characterization of this brain injury model has been limited by the size of the neonatal mouse's head and postnatal maternal dependency. We overcome this challenge by employing a novel method of longitudinal single-mouse electroencephalography (EEG) using chronically implanted subcranial electrodes in the term-equivalent mouse pup. We characterize the neurophysiological disturbances occurring during awake and sleep states in the acute and chronic phases following newborn brain injury. C57BL/6 mice underwent long-term bilateral subcranial EEG and electromyographic electrode placement at postnatal day 9 followed by unilateral carotid cauterization and exposure to 40 minutes of hypoxia the following day. EEG recordings were obtained prior, during, and intermittently after the HI procedure from postnatal day 10 to weaning age. Quantitative EEG and fast Fourier transform analysis were used to evaluate seizures, cortical cerebral dysfunction, and disturbances in vigilance states. We observed neonatal HI-provoked electrographic focal and bilateral seizures during or immediately following global hypoxia and most commonly contralateral to the ischemic injury. Spontaneous chronic seizures were not seen. Injured mice developed long-term asymmetric EEG background attenuation in all frequencies and most prominently during non-rapid eye movement (NREM) sleep. HI mice also showed transient impairments in vigilance state duration and transitions during the first 2 days following injury. The functional burden of mouse neonatal HI recorded by EEG resembles closely that of the injured human newborn. The use of single-mouse longitudinal EEG in this immature model can advance our understanding of the developmental and pathophysiological mechanisms of neonatal cerebral injury and help translate novel therapeutic strategies against this devastating condition.

The effects of different herbal compound and extracts from different extraction methods on hypoxia tolerance in mice

Objective: To investigate the effects of different prescription compositions of traditional Chinese medicine and its different extraction methods of compound formula extracts on hypoxia tolerance in mice, in order to preferably select their prescription compositions and preparation extraction methods. Methods: Male BALB/c mice were randomly divided into 6 groups: blank control group, compound danshen group, compound Rhodiola Rosea alcohol-water extract group (Rhodiola rosea, Astragali Radix, Polygonati Rhizoma, Lycii Fructus), compound Rhodiola Rosea water extract group, compound Astragalus alcohol-water extract group (Astragali Radix, Polygonati Rhizoma, Lycii Fructus) and compound Astragalus water extract group, 30 mice in each group. Each group was administered continuously by gavage for 10 d. The blank group was gavaged with sterilized injection water. The mice in the other groups were treated with 0.15 g/kg of compound danshen, 3 g/kg of compound Rhodiola Rosea alcohol-water extract or water extract, and 1.7 g/kg of compound Astragalus alcohol-water extract or water extract, respectively. Each group was subjected to normobaric hypoxia tolerance test, sodium nitrite toxicity survival test and acute cerebral ischemia-hypoxia test 1 h after the last gavage, and the mice brain tissues were used to determine the activity of antioxidant enzymes and metabolites related to oxidative stress. Results: Compared with the blank control group, in normobaric hypoxia tolerance test, the survival time of mice in the compound danshen group and the compound Astragalus alcohol-water extract group and water extraction group was prolonged significantly (P＜0.01), and the number of open-mouth gasping after cerebral ischemia and hypoxia was increased significantly (P＜0.05). There was no statistical difference in survival time after sodium nitrite injection in each group. Compared with the blank control group, the activities of T-AOC, SOD, GSH and CAT were increased significantly (P＜0.05, P＜0.01) and the content of MDA was decreased significantly (P＜0.01) in the compound Astragalus water extract group. Compared with the compound danshen group, the activities of SOD, CAT and GSH were increased significantly (P＜0.01, P＜0.05) and the content of MDA was decreased significantly (P＜0.05). Conclusion: Compound Astragalus water extraction has the best effect of hypoxia tolerance, compound Rhodiola Rosea can eliminate Rhodiola rosea and consists of Astragali Radix, Polygonati Rhizoma, Lycii Fructus and its extraction method is water extraction.

Lactate receptor HCAR1 regulates neurogenesis and microglia activation after neonatal hypoxia-ischemia.

Neonatal cerebral hypoxia-ischemia (HI) is the leading cause of death and disability in newborns with the only current treatment being hypothermia. An increased understanding of the pathways that facilitate tissue repair after HI may aid the development of better treatments. Here, we study the role of lactate receptor HCAR1 in tissue repair after neonatal HI in mice. We show that HCAR1 knockout mice have reduced tissue regeneration compared with wildtype mice. Furthermore, proliferation of neural progenitor cells and glial cells, as well as microglial activation was impaired. Transcriptome analysis showed a strong transcriptional response to HI in the subventricular zone of wildtype mice involving about 7300 genes. In contrast, the HCAR1 knockout mice showed a modest response, involving about 750 genes. Notably, fundamental processes in tissue repair such as cell cycle and innate immunity were dysregulated in HCAR1 knockout. Our data suggest that HCAR1 is a key transcriptional regulator of pathways that promote tissue regeneration after HI.

Human–rat integrated microRNAs profiling identified a new neonatal cerebral hypoxic–ischemic pathway melatonin‐sensitive

Neonatal encephalopathy (NE) is a pathological condition affecting long‐term neurodevelopmental outcomes. Hypothermia is the only therapeutic option, but does not always improve outcomes; hence, researchers continue to hunt for pharmaceutical compounds. Melatonin treatment has benefitted neonates with hypoxic–ischemic (HI) brain injury. However, unlike animal models that enable the study of the brain and the pathophysiologic cascade, only blood is available from human subjects. Therefore, due to the unavailability of neonatal brain tissue, assumptions about the pathophysiology in pathways and cascades are made in human subjects with NE. We analyzed animal and human specimens to improve our understanding of the pathophysiology in human neonates. A neonate with NE who underwent hypothermia and enrolled in a melatonin pharmacokinetic study was compared to HI rats treated/untreated with melatonin. MicroRNA (miRNA) analyses provided profiles of the neonate's plasma, rat plasma, and rat brain cortexes. We compared these profiles through a bioinformatics tool, identifying Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways common to HI brain injury and melatonin treatment. After evaluating the resulting pathways and the literature, to validate the method, the key proteins expressed in HI brain injury were investigated using cerebral cortexes. The upregulated miRNAs in human neonate and rat plasma helped identify two KEGG pathways, glioma and long‐term potentiation, common to HI injury and melatonin treatment. A unified neonatal cerebral melatonin‐sensitive HI pathway was designed and validated by assessing the expression of protein kinase Cα (PKCα), phospho (p)‐Akt, and p‐ERK proteins in rat brain cortexes. PKCα increased in HI‐injured rats and further increased with melatonin. p‐Akt and p‐ERK returned phosphorylated to their basal level with melatonin treatment after HI injury. The bioinformatics analyses validated by key protein expression identified pathways common to HI brain injury and melatonin treatment. This approach helped complete pathways in neonates with NE by integrating information from animal models of HI brain injury.

Stroke propensity in the Th3+/ mouse model of β-thalassemia intermedia

β-thalassemia is associated with multiple hematological and cerebrovascular symptoms linked to a hypercoagulable state that has not been fully replicated in animal models for the development of stroke treatments. Herein we compared the physiological properties and responses to transient cerebral hypoxia-ischemia (tHI) between six-month-old wildtype and heterozygous Th3/+ mice, a model of non-transfusion-dependent β-thalassemia intermedia (β-TI). We found that Th3/+ mice developed microcytic anemia, splenomegaly, higher platelet counts, and increased platelet-erythrocyte plus erythrocyte-leukocyte aggregates. Furthermore, Th3/+ mice showed diminished cerebrovascular reactivity (CVR) and cortical oxygen saturation under repetitive hypercapnic challenges. When subjected to a sub-threshold tHI insult, platelets and leukocytes in Th3/+ mice adhered to the cerebrovascular wall or formed aggregates, while their counterparts flew through smoothly in wildtype mice. Subsequently, Th3/+ mice showed increased fibrin deposition around cerebral blood vessels and larger infarction than wildtype mice, especially in female Th3/+ mice. Collectively these results showed that Th3/+ mice mimic key clinical features and a propensity to thromboembolism in β-TI patients. The hypercoagulable state in Th3/+ mice is likely caused by multiple hematological and CVR anomalies that are similar, but are not identical to those in the mouse model of sickle cell anemia. As such, we suggest that Th3/+ mice are a useful model to study the pathological mechanisms and prophylactic stroke treatments in thalassemia patients.

CNS Antigen-Specific Neuroinflammation Attenuates Ischemic Stroke With Involvement of Polarized Myeloid Cells.

Background and ObjectivesExperimental studies indicate shared molecular pathomechanisms in cerebral hypoxia-ischemia and autoimmune neuroinflammation. This has led to clinical studies investigating the effects of immunomodulatory therapies approved in multiple sclerosis on inflammatory damage in stroke. So far, mutual and combined interactions of autoimmune, CNS antigen-specific inflammatory reactions and cerebral ischemia have not been investigated so far.MethodsActive MOG35-55 experimental autoimmune encephalomyelitis (EAE) was induced in male C57Bl/6J mice. During different phases of EAE, transient middle cerebral artery occlusion (tMCAO, 60 minutes) was induced. Brain tissue was analyzed for infarct size and immune cell infiltration. Multiplex gene expression analysis was performed for 186 genes associated with neuroinflammation and hypoxic-ischemic damage.ResultsMice with severe EAE disease showed a substantial reduction in infarct size after tMCAO. Histopathologic analysis showed less infiltration of CD45+ hematopoietic cells in the infarct core of severely diseased acute EAE mice; this was accompanied by an accumulation of Arginase1-positive/Iba1-positive cells. Gene expression analysis indicated an involvement of myeloid cell-driven anti-inflammatory mechanisms in the attenuation of ischemic injury in severely diseased mice exposed to tMCAO in the acute EAE phase.DiscussionCNS autoantigen-specific autoimmunity has a protective influence on primary tissue damage after experimental stroke, indicating a very early involvement of CNS antigen-specific, myeloid cell-associated anti-inflammatory immune mechanisms that mitigate ischemic injury in the acute EAE phase.

The Novel Pharmacological Approaches to Coumestrol: Focusing on the Psychiatric and Neurological Benefits and the Newly Identified Receptor Interactions

For years, the health benefits of coumestrol (CMT) have been investigated by researchers around the world. Anti-oxidative properties of the phytoestrogen which can be extracted from several plant tissues, have already been reported as well as the cancer chemopreventive capabilities. Recently, psychiatric and neurological effects of this natural compound have become of interest to researchers so that strong evidence would support the idea that CMT can exert significant effects on the central nervous system. Pharmacologically, this phytoestrogen would act as a selective estrogen receptor modulator with several-fold more affinity to β sub-types of the receptors (ERβ); although other mechanisms of action may be involved. The aim of this review was to gather the recent reports regarding the most important pharmacological benefits of CMT focusing on the psychiatric and neurological ones. Furthermore, the mechanisms of action underlying the pharmacological effects were tried to be clarified more. For this purpose, some keywords such as "Coumestrol", "Pharmacological Effects", "Neurological", "Psychiatric" and "Neuropsychiatric" were searched in popular scientific databases such as Google scholar, Scopus and Pubmed. Then the delegated documentations were brought together, categorized and discussed on this basis. Reviewing the gathered information showed that, apart from the effects on reproduction and the related organs which are mainly conducted through estrogen receptors, CMT has reported to improve various disorders all over the body. Particularly, regarding the neurological and psychiatric systems, the advantages in cerebral hypoxia-ischemia, the Alzheimer’s disease, anxiety, depression and cognitive impairments would be the most important ones. Here, other receptors that have shown interactions with CMT (beside estrogen receptors which are the main target), were also reviewed among which insulin receptors, farnesoid X receptors, pregnane X receptors, and constitutive androstane receptors can be mentioned while only the last two seem to be involved in forming the neurological and psychiatric effects.

Neurogenesis Is Reduced at 48 h in the Subventricular Zone Independent of Cell Death in a Piglet Model of Perinatal Hypoxia-Ischemia.

Cellular and tissue damage triggered after hypoxia-ischemia (HI) can be generalized and affect the neurogenic niches present in the central nervous system. As neuroregeneration may be critical for optimizing functional recovery in neonatal encephalopathy, the goal of the present work was to investigate the neurogenic response to HI in the neurogenic niche of the subventricular zone (SVZ) in the neonatal piglet. A total of 13 large white male piglets aged <24 h were randomized into two groups: i) HI group (n = 7), animals submitted to transient cerebral HI and resuscitation; and ii) Control group (n = 6), non-HI animals. At 48 h, piglets were euthanized, and the SVZ and its surrounding regions, such as caudate and periventricular white matter, were analyzed for histology using hematoxylin-eosin staining and immunohistochemistry by evaluating the presence of cleaved caspase 3 and TUNEL positive cells, together with the cell proliferation/neurogenesis markers Ki67 (cell proliferation), GFAP (neural stem cells processes), Sox2 (neural stem/progenitor cells), and doublecortin (DCX, a marker of immature migrating neuroblasts). Hypoxic-ischemic piglets showed a decrease in cellularity in the SVZ independent of cell death, together with decreased length of neural stem cells processes, neuroblast chains area, DCX immunoreactivity, and lower number of Ki67 + and Ki67 + Sox2 + cells. These data suggest a reduction in both cell proliferation and neurogenesis in the SVZ of the neonatal piglet, which could in turn compromise the replacement of the lost neurons and the achievement of global repair.