Hypoxic-ischemic Brain Damage Research Articles

Sodium butyrate mediates histone crotonylation and alleviated neonatal rats hypoxic-ischemic brain injury through gut-brain axis.

Neonatal hypoxic-ischemic encephalopathy (HIE) refers to nervous system damage caused by perinatal hypoxia, which is the major cause of long-term neuro-developmental disorders in surviving infants. However, the mechanisms still require further investigation. In this study, we found that the butanoate metabolism pathway exhibited significantly decreased and short chain fatty acid (SCFAs)-producing bacteria, especially butyrate-producing bacteria, were significantly decreased in fecal of neonatal hypoxic-ischemic brain damage (HIBD) rats. Surprisingly, Sodium butyrate (SB) treatment could ameliorate pathological damage both in the cerebral cortex and hippocampus and facilitate recovery of SCFAs-producing bacteria related to metabolic pathways in neonatal HIBD rats. Moreover, we found that in samples from SB treatment neonatal HIBD rats cortex with high levels of butyrate acid along with aberrant key crotonyl-CoA-producing enzymes ACADS levels were observed compared HIBD rats. We also demonstrated that a decrease in histone 3-lysine 9-crotonylation (H3K9cr) downregulated expression of the HIE-related neurotrophic genes Bdnf, Gdnf, Cdnf, and Manf in HIBD rats. Furthermore, SB restored H3K9cr binding to HIE-related neurotrophic genes. Collectively, our results indicate that SB contributes to ameliorate pathology of HIBD by altering gut microbiota and brain SCFAs levels subsequently affecting histone crotonylation-mediated neurotrophic-related genes expression. This may be a novel microbiological approach for preventing and treating HIE.

Research advances in the role of endogenous neurogenesis on neonatal hypoxic-ischemic brain damage.

Hypoxic-ischemic brain damage (HIBD) is the main cause of perinatal mortality and neurologic complications in neonates, but it remains difficult to cure due to scarce treatments and complex molecular mechanisms remaining incompletely explained. Recent, mounting evidence shows that endogenous neurogenesis can improve neonatal neurological dysfunction post-HIBD. However, the capacity for spontaneous endogenous neurogenesis is limited and insufficient for replacing neurons lost to brain damage. Therefore, it is of great clinical value and social significance to seek therapeutic techniques that promote endogenous neurogenesis, to reduce neonatal neurological dysfunction from HIBD. This review summarizes the known neuroprotective effects of, and treatments targeting, endogenous neurogenesis following neonatal HIBD, to provide available targets and directions and a theoretical basis for the treatment of neonatal neurological dysfunction from HIBD.

Neuroprotection of Bone Marrow-Derived Mesenchymal Stem Cell-Derived Extracellular Vesicle-Enclosed miR-410 Correlates with HDAC4 Knockdown in Hypoxic-Ischemic Brain Damage.

Evidence exists reporting that miR-410 may rescue neurological deficits, neuronal injury, and neuronal apoptosis after experimental hypoxic ischemia. This study aimed to explore the mechanism by which miR-410 transferred by bone marrow-derived mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) may alleviate hypoxic-ischemic brain damage (HIBD) in newborn mice. BMSCs were isolated from total bone marrow cells of femur and tibia of newborn mice, and primary neurons were extracted from the cerebral cortex of newborn mice within 24h of birth. EVs were extracted from BMSCs transfected with the mimic or inhibitor of miR-410. Primary neurons were subjected to hypoxia and treated with overexpression (oe)-HDAC4, small interfering RNA (siRNA)-β-catenin, or Wnt pathway inhibitor and/or EV (miR-410 mimic) or EV (miR-410 inhibitor). A neonatal mouse HIBD model was established and treated with EVs. When BMSC-EVs were endocytosed by primary neurons, miR-410 was upregulated, neuronal viability was elevated, and apoptosis was inhibited. miR-410 in BMSC-EVs targeted HDAC4, thus increasing neuronal viability and reducing apoptosis. Conversely, overexpression of HDAC4 activated the Wnt pathway and enhanced the nuclear translocation of β-catenin. Treatment with miR-410-containing BMSC-EVs improved learning and memory abilities of HIBD mice while attenuating apoptosis by inactivating the Wnt pathway via targeting HDAC4. Taken together, the findings suggest that miR-410 delivered by BMSC-EVs alleviates HIBD by inhibiting HDAC4-dependent Wnt pathway activation.

Dexmedetomidine alleviates olfactory cognitive dysfunction by promoting neurogenesis in the subventricular zone of hypoxic-ischemic neonatal rats

Background: Hypoxic-ischemic brain damage (HIBD) is the main cause of neurological dysfunction in neonates. Olfactory cognitive function is important for feeding, the ability to detect hazardous situations and social relationships. However, only a few studies have investigated olfactory cognitive dysfunction in neonates with HIBD; furthermore, the specific mechanisms involved are yet to be elucidated. It has been reported that neurogenesis in the subventricular zone (SVZ) is linked to olfactory cognitive function. Recently, dexmedetomidine (DEX) has been shown to provide neuroprotection in neonates following HIBD. In the present study, we investigated whether DEX could improve olfactory cognitive dysfunction in neonatal rats following HIBD and attempted to determine the underlying mechanisms. Methods: We induced HIBD in rats using the Rice–Vannucci model, and DEX (25 μg/kg, i.p.) was administered immediately after the induction of HIBD. Next, we used triphenyl tetrazolium chloride (TTC) staining and the Zea-longa score to assess the success of modelling. The levels of BDNF, TNF-α, IL-1β and IL-6 were determined by western blotting. Immunofluorescence staining was used to detect microglial activation and microglial M1/M2 polarization as well as to evaluate the extent of neurogenesis in the SVZ. To evaluate the olfactory cognitive function, the rats in each group were raised until post-natal days 28–35; then, we performed the buried food test and the olfactory memory test. Results: Analysis showed that HIBD induced significant brain infarction, neurological deficits, and olfactory cognitive dysfunction. Furthermore, we found that DEX treatment significantly improved olfactory cognitive dysfunction in rat pups with HIBD. DEX treatment also increased the number of newly formed neuroblasts (BrdU/DCX) and neurons (BrdU/NeuN) in the SVZ by increasing the expression of BDNF in rat pups with HIBD. Furthermore, analysis showed that the neurogenic effects of DEX were possibly related to the inhibition of inflammation and the promotion of M1 to M2 conversion in the microglia. Conclusion: Based on the present findings, DEX treatment could improve olfactory cognitive dysfunction in neonatal rats with HIBD by promoting neurogenesis in the SVZ and enhancing the expression of BDNF in the microglia. It was possible associated that DEX inhibited neuroinflammation and promoted M1 to M2 conversion in the microglia.

Up-regulating microRNA-214-3p relieves hypoxic-ischemic brain damage through inhibiting TXNIP expression.

A list of microRNAs (miRs) has been referred to involve in the development of hypoxic-ischemic brain damage (HIBD). Based on that, we probed the concrete role of miR-214-3p regulating thioredoxin-interacting protein (TXNIP) in the illness. A neonatal HIBD mouse model was established using the Rice-Vannucci method, followed by measurements of miR-214-3p and TXNIP levels in brain tissues. After modeling, mice were given brain injection of the compounds that could alter miR-214-3p and TXNIP expression. Afterward, neurological function, neuronal inflammation, neuronal apoptosis, neuron morphology, and the number of Nissl body were assessed in HIBD mice. The binding of miR-214-3p to TXNIP was analyzed. Lower miR-214-3p and higher TXNIP were analyzed in brain tissues of mice with HIBD. Up-regulating miR-214-3p or depleting TXNIP improved neurological function, reduced neuronal inflammation and neuronal apoptosis, attenuated morphological damage of neurons, and increased the number of Nissl bodies in mice with HIBD. TXNIP was targeted by miR-214-3p and overexpressing TXNIP reversed the therapeutic effect of miR-214-3p on HIBD mice. It is noted that promotion of miR-214-3p relieves HIBD in mice through inhibiting TXNIP expression.

Remifentanil alleviates hypoxic-ischemic brain damage-induced cognitive impairment via BACH1

Hypoxia-ischemia (HI) is among the most frequent causes of death and disability in neonates. We aimed here to examine the neuroprotective effects of Remifentanil (RE) and the underlying mechanisms in a rat model of hypoxic-ischemic brain damage (HIBD). We found that RE improved the learning memory ability, reduced neuronal cell damage and apoptosis, reduced inflammation induced by suppressing the expression of BTB domain and CNC homolog 1 (BACH1) in rats with HIBD. BACH1 attenuated the alleviating effect of RE on cognitive impairment in HIBD rats. Moreover, RE inhibited TRAF3 expression by downregulating BACH1, and TRAF3 attenuated the therapeutic effect of RE on cognitive impairment by activating the NF-κB signaling. In conclusion, our findings demonstrated that RE inhibits the expression of BACH1, which in turn inhibits the NF-κB signaling pathway by suppressing TRAF3. RE may be a promising therapeutic agent to attenuate HIBD-induced cognitive impairment.

Mesenchymal Stem Cell-derived Extracellular Vesicle-enclosed microRNA-93 Prevents Hypoxic-ischemic Brain Damage in Rats

Hypoxic-ischemic brain damage (HIBD) usually induces chronic neurological disorder and even acute death, but effective neuroprotective strategy is still limited. Herein, we performed this study to clarify the mechanism of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) containing microRNA-93 (miR-93) in influencing this damage via regulation of the histone deacetylase 4 (HDAC4)/B-cell lymphoma-2 (Bcl-2) axis. Initially, differentially expressed Bcl-2 was identified in middle cerebral artery occlusion (MCAO), and the upstream regulatory miR-93 and its potential target HDAC4 were also predicted through bioinformatics analysis. HIBD was modeled in vitro by exposing hippocampal neurons to oxygen-glucose deprivation (OGD) and in vivo by MCAO in rats. EVs were isolated from the bone marrow MSCs of well-grown rats. Our experimental data validated that HDAC4 was highly expressed while miR-93 and Bcl-2 were poorly expressed in MCAO rats. Furthermore, HDAC4 overexpression, through inhibiting Bcl-2 via deacetylation, promoted the infarct volume and pathological changes in hippocampal tissues and neuron apoptosis, and impaired neurobehavioral ability of MCAO rats. Of note, miR-93 was found to target HDAC4. Importantly, MSC-derived EVs overexpressing miR-93 suppressed HDAC4 expression and subsequently impeded the apoptosis of OGD-exposed hippocampal neurons in vitro, and also ameliorated HIBD in vivo. Taken together, miR-93 delivered by MSC-derived EVs can ameliorate HIBD by suppressing hippocampal neuron apoptosis through targeting the HDAC4/Bcl-2 axis, a finding which may be of great significance in the treatment of HIBD.

The protective effect of MiR-27a on the neonatal hypoxic-ischemic encephalopathy by targeting FOXO1 in rats.

BackgroundNeonatal hypoxic-ischemic encephalopathy (HIE), a kind of hypoxic-ischemic brain damage caused by perinatal asphyxia, is the most crucial cause of neonatal death and long-term neurological dysfunction in children. We aimed to investigate the protective effects of micro (mi)R-27a on HIE in neonatal rats.MethodsA rat model of neonatal HIE was constructed by modification of the Rice-Vannucci model. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to test the expressions of miR-27a, FOXO1 messenger RNA (mRNA), interleukin-1β (IL-1β) mRNA, and tumor necrosis factor-α (TNF-α) mRNA, and western blot was applied to test the expression of FOXO1. In order to overexpress miR-27a, an intracerebroventricular injection (i.c.v) of miR-27a mimic was administered. We adopted 2,3,5-triphenytetrazolium chloride (TTC) staining and brain water content measurement to test the effects of miR-27a on the infarcted volume and edema in brain after HIE. Flow cytometry (FCM) analysis was applied to test the effects of miR-27a on the infiltrated peripheral immune cells in the rat brains after HIE.ResultsWe successfully established a rat model of neonatal HIE. It was revealed that the expressions of miR-27a decreased gradually after HIE, however, the expressions of FOXO1 mRNA increased. After injection of the miR-27a mimic, the expression of miR-27a in the rat HIE model brains was significantly upregulated, however, the expression of FOXO1 was robustly downregulated. Both TTC staining and brain water content showed that the infarcted volume and brain edema was markedly increased after HIE. Interestingly, the overexpression of miR-27a reduced the infarcted volume and edema induced by HIE. Additionally, RT-qPCR and FCM analysis showed that HIE lead to increases of IL-1β, TNF-α, and infiltrated immune cells. Overexpression of miR-27a could reduce the expressions of IL-1β mRNA and TNF-α mRNA, and the cell numbers of infiltrated peripheral macrophages and neutrophils in the brain.ConclusionsMiR-27a plays protective roles by reducing infarct volume and brain edema, and inhibiting inflammatory factors and infiltrated peripheral immune cells by targeting FOXO1 in neonatal HIE rats.

Bioinformatics-based analysis reveals IDR-1018-mediated ceRNA regulation network for protective effect on hypoxia-ischemic brain injury in neonatal mice

Activation of an innate immune response serves as a key, contributing factor in perinatal brain injury. The current study sought to evaluate the clinical significance of innate defense regulatory peptide 1018 (IDR-1018)-derived peptide mediating ceRNA regulation network as a biomarker in neonatal mice with hypoxic-ischemic brain damage (HIBD). Firstly, bioinformatics analyses were performed to screen the HIBD-related candidate genes, miRNAs, and lncRNAs. The StarBase, miRDB, and LncBase databases were retrieved to obtain the lncRNA-miRNA-mRNA network, which revealed the ceRNA regulatory network mediated by IDR-1018. Subsequently, RT-qPCR was adopted to determine the expression patterns of MIAT, miR-7a-5p, and Plp2 in neonatal mice with HIBD after treatment with IDR-1018. Moreover, the relationship among mRNA, miRNA, and lncRNA in primary hippocampal neurons was verified by means of dual-luciferase reporter assay and RIP assay. Initial findings demonstrated that Plp2, mmu-miR-7a-5p, and three lncRNAs (MIAT, XIST, and 1700020I14RIK) were related to HIBD. Moreover, IDR-1018 could relieve HIBD in neonatal mice. Plp2 and MIAT were down-regulated, while mmu-miR-7a-5p was up-regulated in the striatum, hippocampus, and cortical tissues of the neonatal mice with HIBD, whereas treatment with the IDR-1018 could revere these trends. Additionally, MIAT acted as a ceRNA of miR-7a-5p to elevate Plp2 expression. In conclusion, our findings highlighted that IDR-1018 relieved HIBD in neonatal mice via the MIAT/miR-7a-5p/Plp2 axis.

Polymorphism of innate immunity receptor genes in newborns with hypoxic-ischemic brain damage

Polymorphism of innate immunity receptor genes in newborns with hypoxic-ischemic brain damage

Spectrum of magnetic resonance imaging (MRI) patterns in hospitalised hypoxic ischemic encephalopathy babies in a tertiary care hospital of Odisha

Background: Hypoxic ischemic encephalopathy (HIE) refers to the CNS dysfunction associated with Perinatal Asphyxia (PA) which is an important causes of permanent damage to CNS tissue. MRI imaging methods attributes to better understanding of pathological events and disease progression that may provide decision regarding intervention. MRI has a higher sensitivity and is extremely valuable in assessing the extent of hypoxic-ischemic brain damage during the early postnatal period and later infancy. It is also more specific which clearly differentiates fluid filled cavities, oedema, gliosis and hemorrhage. On this background this study was undertaken to evaluate the MRI changes of all grades of HIE patients. They were also followed up at different time intervals for upto 1 year to correlate the MRI changes and neurodevelopmental outcome. Objectives: To find out different MRI findings in hypoxic ischemic encephalopathy babies. Assesment of severity of HIE from MR imaging and correlate these findings with clinical & neurodevelopmental outcome. Methods: All hemodynamically stable HIE babies irrespective of their severity were subjected to MRI between day 7 and day 21 of life and their findings were interpreted.

Octadecaneuropeptide Alleviates Motor and Cognitive Impairments in Neonatal Rats Following Hypoxic-Ischemic Brain Damage.

Hypoxic-ischemic brain damage (HIBD) is among the leading causes of neonatal brain injury. ODN, a peptide derived from diazepam-binding inhibitor (DBI), has potent antioxidant and anti-apoptotic properties. It remains unclear, however, whether ODN is an effective treatment for HIBD. Here, we reported that treatment with ODN (10ng/day, i.c.v.) alleviated the deficits in myodynamia and motor coordination and cognitive functions in HIBD. Meanwhile, ODN prevented the neuronal loss in the cortex and hippocampus in HIBD rats. In addition, ODN decreased ROS by generating less oxidants and more antioxidants, as reflected by a dramatic increase in total antioxidant capacity, glutathione reductase, and catalase and a marked decrease in H2O2 and total nitric oxide synthase. Collectively, these data show ODN alleviates neuron injury and motor and memory deficits by attenuating ROS production and could be used as a novel molecular for treating HIBD.

Dihydroartemisinin attenuates hypoxic-ischemic brain damage in neonatal rats by inhibiting oxidative stress

Neonatal hypoxic-ischemic encephalopathy (HIE) induced by perinatal asphyxia is a major cause of neurological disability among infants. Dihydroartemisinin (DHA), derived from artemisinin, well known as an anti-malarial medicine, was proved to be able to inhibit oxidative stress and inflammation. However, whether those functions of DHA play roles in hypoxic-ischemic brain damage (HIBD), an animal model of HIE in patient which also been observed to have oxidative stress and inflammation, is unknown. In this study, we demonstrated that the DHA treatment on newborn rats significantly relieved the neuron loss and motor and cognitive impairment caused by HIBD. One of the underlying mechanisms is that DHA enhanced the anti-oxidant capacity of HIBD rats by up-regulating the total antioxidant capacity (T-AOC), gluathione reductase (GR) and catalase (CAT) while down regulating the pro-oxidative substances including hydrogen peroxide (H2O2), total nitric oxide synthase (T-NOS) and inducible nitric oxide synthase (iNOS). Thus, our study illustrated that DHA could alleviate the damage of brains and improve the cognitive and motor function of HIBD rats by inhibiting oxidative stress, provided an opportunity to interrogate potential therapeutics for affected HIE patients.

Neuroprotective Efficacy of Betulinic Acid Hydroxamate, a B55α/PP2A Activator, in Acute Hypoxia-Ischemia-Induced Brain Damage in Newborn Rats.

There is an increasing evidence of the neuroprotective effects of hypoxia inducing factor prolyl-hydroxylase inhibitors (HIF-PHDi) after hypoxic-ischemic (HI) brain damage (HIBD). We studied the neuroprotective effects of betulinic hydroxamate (BAH), a novel B55α/PP2A activator that dephosphorylates and inhibits PHD2 activity, in a rat model of neonatal HIBD. Seven-day-old (P7) Wistar rats were exposed to hypoxia after left carotid artery electrocoagulation and then received vehicle (HI + VEH) or BAH 3mg/kg i.p. 30min post-insult. Brain damage was assessed by magnetic resonance imaging (MRI) and neurobehavioral studies testing motor and cognitive performance at P14 and P37, as well as immunohistochemical studies (TUNEL and myelin basic protein (MBP) signal) at P37. Mechanisms of damage were assessed at P14 determining excitotoxicity (glutamate/N-acetylaspartate ratio by H+-magnetic resonance spectroscopy), oxidative stress (protein nitrosylation by Oxyblot), and inflammation (cytokine and chemokine concentration). BAH reduced brain damage volume and cell death, preventing the development of motor and working memory deficits. BAH showed a robust protective effect on myelination, restoring MBP expression at P37. BAH modulated excitotoxicity, oxidative stress, and inflammation. Most neuroprotective effects were still present despite BAH administration was delayed for 12h, whereas beneficial effects on motor strength at P14 and on cell death and myelination at P37 were preserved even when BAH administration was delayed for 24h. In conclusion, BAH appears as an effective neuroprotective treatment for neonatal HIBD in a manner associated with the modulation of excitotoxicity, oxidative stress, and inflammation, showing a broad therapeutic window.

Telomerase reverse transcriptase (TERT) promotes neurogenesis after hypoxic-ischemic brain damage in neonatal rats

ABSTRACT Objective Neonatal hypoxic-ischemic encephalopathy (HIE) endangers quality of life in children, and curative attempts are rarely effective. Neurogenesis plays an important role in neural repair following brain damage. This study aimed to investigate the role of telomerase reverse transcriptase (TERT) in neurogenesis after neonatal hypoxic-ischemic brain damage (HIBD). Methods Neonatal HIBD models were established in vivo (Sprague-Dawley rats, 7 days old) and in vitro (cultured neural stem cells, NSCs). Lentivirus and adenovirus transfection was used to induce TERT overexpression. Expression of TERT was detected by quantitative real-time PCR and immunofluorescence staining. NSCs apoptosis and proliferation were measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and cell counting assays, respectively. Migration and differentiation of NSCs were assessed by western blotting and immunofluorescence staining. Morris water maze test and modified neurological severity scores were conducted to evaluate the neurological function of rats. Results Overexpression of TERT attenuated apoptosis of NSCs; promoted proliferation, migration, and differentiation of NSCs; and induced myelination in the brains of neonatal rats after HIBD. Moreover, it reduced the impairment of learning, memory, and neurological function after HIBD in neonatal rats. In vitro findings indicated that the expression of Gli1 was increased after OGD, and overexpression of TERT further increased the expression of Gli1 in NSCs after OGD. Discussion TERT promotes neurogenesis and decreases neurological function injury after HIBD in neonatal rats. This neuroprotective pathway may provide a basis for developing therapeutic strategies for neonatal HIE. Furthermore, TERT may represent a target during neural injury and repair in patients with various diseases affecting the nervous system.

Glycyrrhizin Attenuates Hypoxic-Ischemic Brain Damage by Inhibiting Ferroptosis and Neuroinflammation in Neonatal Rats via the HMGB1/GPX4 Pathway.

With unknown etiology and limited treatment options, neonatal hypoxic-ischemic brain damage (HIBD) remains a major cause of mortality in newborns. Ferroptosis, a recently discovered type of cell death triggered by lipid peroxidation, is closely associated with HIBD. High-mobility group box 1 (HMGB1), a molecule associated with inflammation damage, can induce neuronal death in HIBD. However, it remains unknown whether HMGB1 contributes to neuronal ferroptosis in patients with HIBD. Herein, glycyrrhizin (GL), an HMGB1 inhibitor, was used to investigate the relationship between ferroptosis and HMGB1. RAS-selective lethal 3(RSL3), a ferroptosis agonist, was administered to further confirm the changes in the signaling pathway between HMGB1 and ferroptosis. Western blot analysis revealed that GL markedly suppressed the expression of HMGB1 and increased the level of GPX4 in the context of HIBD. We observed changes in neuronal ultrastructure via transmission electron microscopy to further confirm the occurrence of ferroptosis. Real-time PCR indicated that GL inhibited the expression of ferroptosis-related genes and inflammatory factors. Immunofluorescence and immunohistochemistry staining confirmed GL inhibition of neuronal damage and ferroptosis in HIBD associated with GPX4 and ROS. GL not only inhibited ferroptosis induced by RSL3 and oxygen-glucose deprivation in vitro but also inhibited ferroptosis induced by HIBD in vivo. More importantly, GL may improve oxidative stress imbalance and mitochondrial damage, alleviate the downstream production of inflammatory factors, and ultimately reduce ferroptosis and damage to cortical neurons following HIBD via the HMGB1/GPX4 pathway. In conclusion, we showed for the first time that GL could suppress the occurrence of neuronal ferroptosis and reduce neuronal loss in HIBD via the HMGB1/GPX4 pathway. These findings highlight the potential of HMGB1 signaling antagonists to treat neuronal damage by suppressing ferroptosis, provide new and unique insights into GL as a neuroprotective agent, and suggest new prevention and treatment strategies for HIBD.

Atorvastatin inhibits neuronal apoptosis via activating cAMP/PKA/p-CREB/BDNF pathway in hypoxic-ischemic neonatal rats.

Neuronal apoptosis is one of the main pathological processes of hypoxic-ischemic brain damage (HIBD) and is involved in the development of hypoxic-ischemic encephalopathy (HIE) in neonates. Atorvastatin has been found to have neuroprotective effects in some nervous system diseases, but its role in regulating the pathogenesis of neonatal HIBD remains elusive. Thus, this study aimed to explore the effects and related mechanisms of atorvastatin on the regulation of neuronal apoptosis after HIBD in newborn rats. The rat HIBD model and the neuronal oxygen glucose deprivation (OGD) model were established routinely. Atorvastatin, cAMP inhibitor (SQ22536), and BDNF inhibitor (ANA-12) were used to treat HIBD rats and OGD neurons. Cerebral infarction, learning and memory ability, cAMP/PKA/p-CREB/BDNF signaling molecules, and apoptosis-related indicators (TUNEL, cleaved caspase-3, and Bax/Bcl2) were then examined. In vivo, atorvastatin reduced cerebral infarction, improved learning and memory ability, decreased the number of TUNEL-positive neurons, inhibited the expression of cleaved caspase-3 and Bax/Bcl2, and activated the cAMP/PKA/p-CREB/BDNF pathway in the cerebral cortex after HIBD. In vitro, atorvastatin also decreased the apoptosis-related indicators and activated the cAMP/PKA/p-CREB/BDNF pathway in neurons after OGD. Furthermore, inhibition of cAMP or BDNF attenuated the effect of atorvastatin on the reduction of neuronal apoptosis, suggesting that atorvastatin inhibits HIBD-induced neuronal apoptosis and alleviates brain injury in neonatal rats mainly by activating the cAMP/PKA/p-CREB/BDNF pathway. In conclusion, atorvastatin may be developed as a potential drug for the treatment of neonatal HIE.

Statement of Retraction: NF-κB signaling pathway inhibition suppresses hippocampal neuronal apoptosis and cognitive impairment via RCAN1 in neonatal rats with hypoxic-ischemic brain damage

This article refers to:RETRACTED ARTICLE: NF-κB signaling pathway inhibition suppresses hippocampal neuronal apoptosis and cognitive impairment via RCAN1 in neonatal rats with hypoxic-ischemic brain damage

Profiling Temporal Changes of the Pineal Transcriptomes at Single Cell Level Upon Neonatal HIBD.

Neonatal hypoxic-ischemic brain damage (HIBD) often results in various neurological deficits. Among them, a common, yet often neglected, symptom is circadian rhythm disorders. Previous studies revealed that the occurrence of cysts in the pineal gland, an organ known to regulate circadian rhythm, is associated with circadian problems in children with HIBD. However, the underlying mechanisms of pineal dependent dysfunctions post HIBD remain largely elusive. Here, by performing 10x single cell RNA sequencing, we firstly molecularly identified distinct pineal cell types and explored their transcriptome changes at single cell level at 24 and 72 h post neonatal HIBD. Bioinformatic analysis of cell prioritization showed that both subtypes of pinealocytes, the predominant component of the pineal gland, were mostly affected. We then went further to investigate how distinct pineal cell types responded to neonatal HIBD. Within pinealocytes, we revealed a molecularly defined β to α subtype conversion induced by neonatal HIBD. Within astrocytes, we discovered that all three subtypes responded to neonatal HIBD, with differential expression of reactive astrocytes markers. Two subtypes of microglia cells were both activated by HIBD, marked by up-regulation of Ccl3. Notably, microglia cells showed substantial reduction at 72 h post HIBD. Further investigation revealed that pyroptosis preferentially occurred in pineal microglia through NLRP3-Caspase-1-GSDMD signaling pathway. Taken together, our results delineated temporal changes of molecular and cellular events occurring in the pineal gland following neonatal HIBD. By revealing pyroptosis in the pineal gland, our study also provided potential therapeutic targets for preventing extravasation of pineal pathology and thus improving circadian rhythm dysfunction in neonates with HIBD.

Dexmedetomidine Alleviates Hypoxic-Ischemic Brain Damage in Neonatal Rats Through Reducing MicroRNA-134-5p-Mediated NLRX1 Downregulation

BackgroundDexmedetomidine (Dex) is a safe and effective anesthetic adjunct which also has neuroprotective roles. This study aimed to validate the role of Dex in hypoxic-ischemic brain damage (HIBD) in neonatal rats and the functional molecules. MethodsA neonatal rat model of HIBD was established and treated with Dex. The learning and memory abilities of rats were determined by Morris water maze tests. The left-hemisphere encephalatrophy, pathological changes, neuronal apoptosis, and inflammation in rat hippocampal tissues were examined to evaluate the treating effects of Dex on HIBD. Differentially expressed microRNAs (miRNAs) in rats with HIBD were screened using microarray analysis. Potential downstream molecules mediated by miR-134-5p were predicted using bioinformatics analysis. Altered expression of miR-134-5p and NLR family member X1 (NLRX1) was induced in rats after Dex treatment for rescue experiments. ResultsDex treatment significantly enhanced the learning and memory abilities of rats and reduced encephalatrophy in rats. It also alleviated pathological changes, neuronal apoptosis, and the production of pro-inflammatory cytokines in rat hippocampal tissues. miR-134-5p was significantly upregulated in rats with HIBD. Dex treatment reduced the expression of miR-134-5p. NLRX1 was a target gene of miR-134-5p and it reduced the phosphorylation of IκBα and p65, namely the activation of NF-κB signaling. Overexpression of miR-134-5p blocked, whereas overexpression of NLRX1 strengthened the protective effects of Dex on neonatal rats. ConclusionThis study demonstrates that Dex treatment can alleviate HIBD in neonatal rats through restoring NLRX1 expression by suppressing miR-134-5p.