Overexpression of olfactory receptor 78 ameliorates brain injury in cerebral ischaemia-reperfusion rats by activating Prkaca-mediated cAMP/PKA-MAPK pathway.

Ischemic stroke is one of the main causes of disability and death. However, recanalization of occluded cerebral arteries is effective only within a very narrow time window. Therefore, it is particularly important to find neuroprotective biological targets for cerebral artery recanalization. Here, gene expression profiles of datasets GSE160500 and GSE97537 were downloaded from the GEO database, which were related to ischemic stroke in rats. Olfactory receptor 78 (Olfr78) was screened, and which highly associated with Calcium signalling pathway and MAPK pathway. Interacting protein of Olfr78, Prkaca, was predicted by STRING, and their interaction was validated by Co-IP analysis. Then, a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) and a neuronal cell model stimulated by oxygen-glucose deprivation/reoxygenation (OGD/R) were constructed, and the results showed that expression of Olfr78 and Prkaca was downregulated in MCAO rats and OGD/R-stimulated neurons. Overexpression of Olfr78 or Prkaca inhibited the secretion of inflammatory factors, Ca2+ overload, and OGD/R-induced neuronal apoptosis. Moreover, Overexpression of Prkaca increased protein levels of cAMP, PKA and phosphorylated p38 in OGD/R-stimulated neurons, while SB203580, a p38 inhibitor, treatment inhibited activation of the cAMP/PKA-MAPK pathway and counteracted the effect of Olfr78 overexpression on improvement of neuronal functions. Meanwhile, overexpression of Olfr78 or Prkaca markedly inhibited neuronal apoptosis and improved brain injury in MCAO/R rats. In conclusion, overexpression of Olfr78 inhibited Ca2+ overload and reduced neuronal apoptosis in MCAO/R rats by promoting Prkaca-mediated activation of the cAMP/PKA-MAPK pathway, thereby improving brain injury in cerebral ischaemia-reperfusion.

Microglia in radiation-induced brain injury: Cellular and molecular mechanisms and therapeutic potential.

BACKGROUND: Radiation-induced brain injury is a neurological condition resulting from radiotherapy for malignant tumors, with its underlying pathogenesis still not fully understood. Current hypotheses suggest that immune cells, particularly the excessive activation of microglia in the central nervous system and the migration of peripheral immune cells into the brain, play a critical role in initiating and progressing the injury. This review aimed to summarize the latest advances in the cellular and molecular mechanisms and the therapeutic potential of microglia in radiation-induced brain injury. METHODS: This article critically examines recent developments in understanding the role of microglia activation in radiation-induced brain injury. It elucidates associated mechanisms and explores novel research pathways and therapeutic options for managing this condition. RESULTS: Post-irradiation, activated microglia release numerous inflammatory factors, exacerbating neuroinflammation and facilitating the onset and progression of radiation-induced damage. Therefore, controlling microglial activation and suppressing the secretion of related inflammatory factors is crucial for preventing radiation-induced brain injury. While microglial activation is a primary factor in neuroinflammation, the precise mechanisms by which radiation prompts this activation remain elusive. Multiple signaling pathways likely contribute to microglial activation and the progression of radiation-induced brain injury. CONCLUSIONS: The intricate microenvironment and molecular mechanisms associated with radiation-induced brain injury underscore the crucial roles of immune cells in its onset and progression. By investigating the interplay among microglia, neurons, astrocytes, and peripheral immune cells, potential strategies emerge to mitigate microglial activation, reduce the release of inflammatory agents, and impede the entry of peripheral immune cells into the brain.

Electrical impedance tomography provides information of brain injury during total aortic arch replacement through its correlation with relative difference of neurological biomarkers.

Postoperative neurological dysfunction (PND) is one of the most common complications after a total aortic arch replacement (TAAR). Electrical impedance tomography (EIT) monitoring of cerebral hypoxia injury during TAAR is a promising technique for preventing the occurrence of PND. This study aimed to explore the feasibility of electrical impedance tomography (EIT) for warning of potential brain injury during total aortic arch replacement (TAAR) through building the correlation between EIT extracted parameters and variation of neurological biomarkers in serum. Patients with Stanford type A aortic dissection and requiring TAAR who were admitted between December 2021 to March 2022 were included. A 16-electrode EIT system was adopted to monitor each patient's cerebral impedance intraoperatively. Five parameters of EIT signals regarding to the hypothermic circulatory arrest (HCA) period were extracted. Meanwhile, concentration of four neurological biomarkers in serum were measured regarding to time before and right after surgery, 12 h, 24 h and 48 h after surgery. The correlation between EIT parameters and variation of serum biomarkers were analyzed. A total of 57 TAAR patients were recruited. The correlation between EIT parameters and variation of biomarkers were stronger for patients with postoperative neurological dysfunction (PND(+)) than those without postoperative neurological dysfunction (PND(-)) in general. Particularly, variation of S100B after surgery had significantly moderate correlation with two parameters regarding to the difference of impedance between left and right brain which were MRAIabs and TRAIabs (0.500 and 0.485 with p < 0.05, respectively). In addition, significantly strong correlations were seen between variation of S100B at 24 h and the difference of average resistivity value before and after HCA phase (ΔARVHCA), the slope of electrical impedance during HCA (kHCA) and MRAIabs (0.758, 0.758 and 0.743 with p < 0.05, respectively) for patients with abnormal S100B level before surgery. Strong correlations were seen between variation of TAU after surgery and ΔARVHCA, kHCA and the time integral of electrical impedance for half flow of perfusion (TARVHP) (0.770, 0.794 and 0.818 with p < 0.01, respectively) for patients with abnormal TAU level before surgery. Another two significantly moderate correlations were found between TRAIabs and variation of GFAP at 12 h and 24 h (0.521 and 0.521 with p < 0.05, respectively) for patients with a normal GFAP serum level before surgery. The correlations between EIT parameters and serum level of neurological biomarkers were significant in patients with PND, especially for MRAIabs and TRAIabs, indicating that EIT may become a powerful assistant for providing a real-time warning of brain injury during TAAR from physiological perspective and useful guidance for intensive care units.

NLRP3 promotes radiation-induced brain injury by regulating microglial pyroptosis.

PURPOSE: Radiation-induced brain injury, one of the side effects of cranial radiotherapy in tumour patients, usually results in durable and serious cognitive disorders. Microglia are important innate immune-effector cells in the central nervous system. However, the interaction between microglia and neurons in radiation-induced brain injury remains uncharacterised. METHODS AND MATERIALS: We established a microglia-neuron indirect co-culture model to assess the interaction between them. Microglia exposed to radiation were examined for pyroptosis using lactate dehydrogenase (LDH) release, Annexin V/PI staining, SYTOX staining and western blot. The role of nucleotide-binding oligomerisation domain-like receptor family pyrin domain containing 3 (NLRP3) was investigated in microglia exposed to radiation and in mouse radiation brain injury model through siRNA or inhibitor. Mini-mental state examination and cytokines in blood were performed in 23 patients who had experienced cranial irradiation. RESULTS: Microglia exerted neurotoxic features after radiation in the co-culture model. NLRP3 was up-regulated in microglia exposed to radiation, and then caspase-1 was activated. Thus, the gasdermin D protein was cleaved, and it triggered pyroptosis in microglia, which released inflammatory cytokines. Meanwhile, treatment with siRNA NLRP3 in vitro and NLRP3 inhibitor in vivo attenuated the damaged neuron cell and cognitive impairment, respectively. What is more, we found that the patients after radiation with higher IL-6 were observed to have a decreased MMSE score. CONCLUSIONS: These findings indicate that radiation-induced pyroptosis in microglia may promote radiation-induced brain injury via the secretion of neurotoxic cytokines. NLRP3 was evaluated as an important mediator in radiation-induced pyroptosis and a promising therapeutic target for radiation-induced brain injury.

Clinical effect of external ventricular drainage under intracranial pressure monitoring in the treatment of aneurysmal subarachnoid hemorrhage patients and investigation of the mechanism of miR-146a-5p/STC1 axis in inhibiting early brain injury in aneurys.

Aneurismal subarachnoid hemorrhage (aSAH) is a common disease in the neural system, with high death rate. Our study aimed to explore the clinical effect of external ventricular drainage under intracranial pressure monitoring in the treatment of patients with aSAH and investigate the role along with mechanism of miR-146a-5p in aSAH. Ninety-six aSAH patients were allocated into control group (CG) and study group (SG). The CG was released by lumbar puncture. The SG underwent external ventricular drainage based on intracranial pressure monitoring. The prognosis, daily living ability, neurological function, S100ß and NSE (neuron-specific enolase) levels and incidence of complications were monitored. Besides, a rat model of SAH was built to assess the neurobehavioral function, blood-brain barrier permeability, brain water content, neuronal apoptosis as well as inflammation. SAH cell model stimulated by oxyhemoglobin, and cell apoptosis as well as inflammation were measured. Luciferase reporter assay was implemented to explore the interaction between miR-146a-5p and STC1. Results showed higher GOS and BI scores but lower NIHSS scores, S100ß and NSE levels and complication rates in SG compared with CG. Additionally, miR-146a-5p presented down-regulation in brain tissues of SAH rat model, and overexpressed miR-146a-5p reduced brain injury along with neuroinflammation in SAH rat model. Oxyhemoglobin-induced nerve cell apoptosis along with inflammation after SAH, and overexpressed miR-146a-5p repressed oxyhemoglobin-induced nerve cell apoptosis along with inflammation. STC1 is the target mRNA of miR-146a-5p, and overexpressed miR-146a-5p represses oxyhemoglobin-induced nerve cell apoptosis along with inflammation via regulating STC1 expression. In conclusion, external ventricular drainage under intracranial pressure monitoring could promote prognosis, promote daily living ability, improve neurological function, reduce S100ß protein and NSE levels, and reduce the incidence of complications in patients with aSAH. Meanwhile, miR-146a-5p inhibited early brain injury and neuroinflammation in aSAH via regulating STC1 expression.

What Is Brain Damage and Does Electroconvulsive Therapy Cause It?

ABSTRACT: Surveys show public misperceptions and confusion about brain damage and electroconvulsive therapy (ECT). Fictional movies have misrepresented ECT to suggest brain damage and to ridicule mental illness and psychiatric patients. "Brain damage" has become a colloquial expression without consistent meaning. In contrast, brain injury is the medical term for destruction of brain cells, such as from kinetic impact (concussion), hypoxia, or infection. Studies of both high-resolution magnetic resonance imaging (MRI) and enzyme assays find that causes of brain injury are accompanied by observable structural changes on MRI and elevated blood and cerebrospinal fluid levels of brain enzymes that leak from injured brain cells. Concussion is also followed by intracerebral bleeding, progressive brain atrophy, diffuse axonal injury, cranial nerve injury, and 2-4 fold increased risk for dementia. In contrast, there is no evidence that ECT produces any of these. Studies of ECT patients find no brain edema, structural change persisting 6 months, or elevated levels of leaked brain enzymes. Statistical comparisons between brain injury and ECT effects indicate no similarity ( P < 0.00000001). Moreover, the kinetic, thermal, and electrical effects of ECT are far below levels that could possibly cause harm. This robust evidence shows that there is no basis to claim that ECT causes brain injury.

Rutaecarpine Alleviates Early Brain Injury-Induced Inflammatory Response Following Subarachnoid Hemorrhage via SIRT6/NF-[Formula: see text]B Pathway.

Subarachnoid hemorrhage (SAH), a specific subtype of cerebrovascular accident, is characterized by the extravasation of blood into the interstice between the brain and its enveloping delicate tissues. This pathophysiological phenomenon can precipitate an early brain injury (EBI), which is characterized by inflammation and neuronal death. Rutaecarpine (Rut), a flavonoid compound discovered in various plants, has been shown to have protective effects against SAH-induced cerebral insult in rodent models. In our study, we used a rodent SAH model to evaluate the effect of Rut on EBI and investigated the effect of Rut on the inflammatory response and its regulation of SIRT6 expression in vitro. We found that Rut exerts a protective effect on EBI in SAH rats, which is partly due to its ability to inhibit the inflammatory response. Notably, Rut up-regulated Sirtuin 6 (SIRT6) expression, leading to an increase in H3K9 deacetylation and inhibition of nuclear factor-kappa B (NF-[Formula: see text]B) transcriptional activation, thereby mediating the inflammatory response. In addition, further data showed that SIRT6 was proven to mediate the regulation of Rut on the microglial inflammatory response. These findings highlight the importance of SIRT6 in the regulation of inflammation and suggest a potential mechanism for the protective effect of Rut on EBI. In summary, Rut may have the potential to prevent and treat SAH-induced brain injury by interacting with SIRT6. Our findings may provide a new therapeutic strategy for the treatment of SAH-induced EBI.

TAK1 inhibition mitigates intracerebral hemorrhage-induced brain injury through reduction of oxidative stress and neuronal pyroptosis via the NRF2 signaling pathway.

Introduction: Intracerebral hemorrhage (ICH) often triggers oxidative stress through reactive oxygen species (ROS). Transforming growth factor-ß-activated kinase 1 (TAK1) plays a pivotal role in regulating oxidative stress and inflammation across various diseases. 5Z-7-Oxozeaenol (OZ), a specific inhibitor of TAK1, has exhibited therapeutic effects in various conditions. However, the impact of OZ following ICH and its underlying molecular mechanisms remain elusive. This study aimed to explore the possible role of OZ in ICH and its underlying mechanisms by inhibiting oxidative stress-mediated pyroptosis. Methods: Adult male Sprague-Dawley rats were subjected to an ICH model, followed by treatment with OZ. Neurobehavioral function, blood-brain barrier integrity, neuronal pyroptosis, and oxidative stress markers were assessed using various techniques including behavioral tests, immunofluorescence staining, western blotting, transmission electron microscopy, and biochemical assays. Results: Our study revealed that OZ administration significantly inhibited phosphorylated TAK1 expression post-ICH. Furthermore, TAK1 blockade by OZ attenuated blood-brain barrier (BBB) disruption, neuroinflammation, and oxidative damage while enhancing neurobehavioral function. Mechanistically, OZ administration markedly reduced ROS production and oxidative stress by facilitating nuclear factor-erythroid 2-related factor 2 (NRF2) nuclear translocation. This was accompanied by a subsequent suppression of the NOD-like receptor protein 3 (NLRP3) activation-mediated inflammatory cascade and neuronal pyroptosis. Discussion: Our findings highlight that OZ alleviates brain injury and oxidative stress-mediated pyroptosis via the NRF2 pathway. Inhibition of TAK1 emerges as a promising approach for managing ICH.

ALKBH5 targets ACSL4 mRNA stability to modulate ferroptosis in hyperbilirubinemia-induced brain damage.

Bilirubin-induced brain damage is a serious clinical consequence of hyperbilirubinemia, yet the underlying molecular mechanisms remain largely unknown. Ferroptosis, an iron-dependent cell death, is characterized by iron overload and lipid peroxidation. Here, we report a novel regulatory mechanism of demethylase AlkB homolog 5 (ALKBH5) in acyl-coenzyme A synthetase long-chain family member 4 (ACSL4)-mediated ferroptosis in hyperbilirubinemia. Hyperdifferential PC12 cells and newborn Sprague-Dawley rats were used to establish in vitro and in vivo hyperbilirubinemia models, respectively. Proteomics, coupled with bioinformatics analysis, first suggested the important role of ferroptosis in hyperbilirubinemia-induced brain damage. In vitro experiments showed that ferroptosis is activated in hyperbilirubinemia, and ferroptosis inhibitors (desferrioxamine and ferrostatin-1) treatment effectively alleviates hyperbilirubinemia-induced oxidative damage. Notably, we observed that the ferroptosis in hyperbilirubinemia was regulated by m6A modification through the downregulation of ALKBH5 expression. MeRIP-seq and RIP-seq showed that ALKBH5 may trigger hyperbilirubinemia ferroptosis by stabilizing ACSL4 mRNA via m6A modification. Further, hyperbilirubinemia-induced oxidative damage was alleviated through ACSL4 genetic knockdown or rosiglitazone-mediated chemical repression but was exacerbated by ACSL4 overexpression. Mechanistically, ALKBH5 promotes ACSL4 mRNA stability and ferroptosis by combining the 669 and 2015 m6A modified sites within 3' UTR of ACSL4 mRNA. Our findings unveil a novel molecular mechanism of ferroptosis and suggest that m6A-dependent ferroptosis could be an underlying clinical target for the therapy of hyperbilirubinemia.

Galectin-3 modulates microglial activation and neuroinflammation in early brain injury after subarachnoid hemorrhage.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (SAH) is a devastating acute cerebrovascular event with high mortality and permanent disability rates. Higher galectin-3 levels on days 1-3 have been shown to predict the development of delayed cerebral infarction or adverse outcomes after SAH. Recent single-cell analysis of microglial transcriptomic diversity in SAH revealed that galectin could influence the development and course of neuroinflammation after SAH. METHODS: This study aimed to investigate the role and mechanism of galectin-3 in SAH and to determine whether galectin-3 inhibition prevents early brain injury by reducing microglia polarization using a mouse model of SAH and oxyhemoglobin-treated activation of mouse BV2 cells in vitro. RESULTS: We found that the expression of galectin-3 began to increase 12 h after SAH and continued to increase up to 72 h. Importantly, TD139-inhibited galectin-3 expression reduced the release of inflammatory factors in microglial cells. In the experimental SAH model, TD139 treatment alleviated neuroinflammatory damage after SAH and improved defects in neurological functions. Furthermore, we demonstrated that galectin-3 inhibition affected the activation and M1 polarization of microglial cells after SAH. TD139 treatment inhibited the expression of TLR4, p-NF-κB p65, and NF-κB p65 in microglia activated by oxyhemoglobin as well as eliminated the increased expression and phosphorylation of JAK2 and STAT3. CONCLUSION: These findings suggest that regulating microglia polarization by galectin-3 after SAH to improve neuroinflammation may be a potential therapeutic target.

Intracerebral hemorrhage-induced brain injury in mice: The role of peroxiredoxin 2-Toll-like receptor 4 inflammatory axis.

BACKGROUND: Peroxiredoxin 2 (Prx2), an intracellular protein that regulates redox reactions, released from red blood cells is involved in inflammatory brain injury after intracerebral hemorrhage (ICH). Toll-like receptor 4 (TLR4) may be crucial in this process. This study investigated the role of the Prx2-TLR4 inflammatory axis in brain injury following experimental ICH in mice. METHODS: First, C57BL/6 mice received an intracaudate injection of autologous arterial blood or saline and their brains were harvested on day 1 to measure Prx2 levels. Second, mice received an intracaudate injection of either recombinant mouse Prx2 or saline. Third, the mice were co-injected with autologous arterial blood and conoidin A, a Prx2 inhibitor, or vehicle. Fourth, the mice received a Prx2 injection and were treated with TAK-242, a TLR4 antagonist, or saline (intraperitoneally). Behavioral tests, magnetic resonance imaging, western blot, immunohistochemistry/immunofluorescence staining, and RNA sequencing (RNA-seq) were performed. RESULTS: Brain Prx2 levels were elevated after autologous arterial blood injection. Intracaudate injection of Prx2 caused brain swelling, microglial activation, neutrophil infiltration, neuronal death, and neurological deficits. Co-injection of conoidin A attenuated autologous arterial blood-induced brain injury. TLR4 was expressed on the surface of microglia/macrophages and neutrophils and participated in Prx2-induced inflammation. TAK-242 treatment attenuated Prx2-induced inflammation and neurological deficits. CONCLUSIONS: Prx2 can cause brain injury following ICH through the TLR4 pathway, revealing the Prx2-TLR4 inflammatory axis as a potential therapeutic target.

Weight-Drop Method for Inducing Closed Head Diffuse Traumatic Brain Injury.

Traumatic brain injury (TBI) is one of the foremost causes of disability and death globally. Prerequisites for successful therapy of disabilities associated with TBI involved improved knowledge of the neurobiology of TBI, measurement of quantitative changes in recovery dynamics brought about by therapy, and the translation of quantitative methodologies and techniques that were successful in tracking recovery in preclinical models to human TBI. Frequently used animal models of TBI in research and development include controlled cortical impact, fluid percussion injury, blast injury, penetrating blast brain injury, and weight-drop impact acceleration models. Preclinical models of TBI benefit from controlled injury settings and the best prospects for biometric quantification of injury and therapy-induced gradual recovery from disabilities. Impact acceleration closed head TBI paradigm causes diffuse TBI (DTBI) without substantial focal brain lesions in rats. DTBI is linked to a significant rate of death, morbidity, and long-term disability. DTBI is difficult to diagnose at the time of hospitalization with imaging techniques making it challenging to take prompt therapeutic action. The weight-drop method without craniotomy is an impact acceleration closed head DTBI model that is used to induce mild/moderate diffuse brain injuries in rodents. Additionally, we have characterized neuropathological and neurobehavioral outcomes of the weight-drop model without craniotomy for inducing closed head DTBI of graded severity with a range of mass of weights (50-450 gm). This chapter also discusses techniques and protocols for measuring numerous functional disabilities and pathological changes in the brain brought on by DTBI.

MicroRNA-7 attenuates secondary brain injury following experimental intracerebral hemorrhage via inhibition of NLRP3.

BACKGROUND AND PURPOSE: The pathophysiological mechanisms underlying brain injury resulting from intracerebral hemorrhage (ICH) remain incompletely elucidated, and efficacious therapeutic interventions to enhance the prognosis of ICH patients are currently lacking. Previous research indicates that MicroRNA-7 (miR-7) can suppress the expression of Nod-like receptor protein 3 (NLRP3), thereby modulating neuroinflammation in Parkinson's disease pathogenesis. However, the potential regulatory effects miR-7 on NLRP3 inflammasome after ICH are yet to be established. This study aims to ascertain whether miR-7 mitigates secondary brain injury following experimental ICH by inhibiting NLRP3 and to investigate the underlying mechanisms. METHODS: An ICH model was established by stereotaxically injecting 100 µL of autologous blood into the right basal ganglia of Sprague-Dawley (SD) rats. Subsequently, these rats were allocated into three groups: sham, ICH + Vehicle, and ICH + miR-7, each comprising 18 animals. Twelve hours post-modeling, rats received intraventricular injections of 10 µL physiological saline, 10 µL phosphate, and 10 µL phosphate-buffered saline solution containing 0.5 nmol of miR-7 mimics, respectively. Neurological function was assessed on day three post-modeling, followed by euthanasia for brain tissue collection. Brain water content was determined using the dry-wet weight method. The expression of inflammatory cytokines in cerebral tissues surrounding the hematoma was analyzed through immunohistochemistry and Western blot assays. These cytokines were re-evaluated using Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Moreover, bioinformatics tools were employed to predict miR-7's binding to NLRP3. A wild-type luciferase reporter gene vector and a corresponding mutant vector were constructed, followed by transfection of miR-7 mimics into HEK293T cells to assess luciferase activity. RESULTS: Our study demonstrates that the administration of miR-7 mimics markedly reduced neurological function scores and attenuated brain edema in rats following ICH. A significant upregulation of NLRP3 expression in microglia/macrophage adjacent to the hematoma was observed, substantially reduced after the treatment with miR-7 mimics. Furthermore, this intervention ameliorated neurodegenerative changes and effectively decreased the protein and mRNA levels of pro-inflammatory cytokines, namely TNF-α, IL-1ß, IL-6, and Caspase1, in the cerebral tissues proximate to the hematomas. In addition, miR-7 mimics distinctly inhibited the luciferase activity associated with the wild-type reporter gene, an effect not mirrored in its mutant variant. CONCLUSIONS: The miR-7 suppressed NLRP3 expression in microglia/macrophage to reduce the production of inflammatory cytokines, leading to conducting certain neuroprotection post-ICH in rats.

Cannabidiol reduces intraventricular hemorrhage brain damage, preserving myelination and preventing blood brain barrier dysfunction in immature rats.

Intraventricular hemorrhage (IVH) is an important cause of long-term disability in extremely preterm infants, with no current treatment. This study assessed the potential neuroprotective effects of cannabidiol (CBD) in an IVH model using immature rats. IVH was induced in 1-day-old (P1) Wistar rats by left periventricular injection of Clostridial collagenase. Some rats received CBD prenatally (10 â€‹mg/kg i.p. to the dam) and then 5 â€‹mg/kg i.p. 6, 30 and 54 â€‹h after IVH (IVH+CBD, n â€‹= â€‹30). Other IVH rats received vehicle (IVH+VEH, n â€‹= â€‹34) and vehicle-treated non-IVH rats served as controls (SHM, n â€‹= â€‹29). Rats were humanely killed at P6, P14 or P45. Brain damage (motor and memory performance, area of damage, Lactate/N-acetylaspartate ratio), white matter injury (ipsilateral hemisphere and corpus callosum volume, oligodendroglial cell density and myelin basic protein signal), blood-brain barrier (BBB) integrity (Mfsd2a, occludin and MMP9 expression, gadolinium leakage), inflammation (TLR4, NFκB and TNFα expression, infiltration of pro-inflammatory cells), excitotoxicity (Glutamate/N-acetylspartate ratio) and oxidative stress (protein nitrosylation) were then evaluated. CBD prevented the long-lasting motor and cognitive consequences of IVH, reduced brain damage in the short- and long-term, protected oligodendroglial cells preserving adequate myelination and maintained BBB integrity. The protective effects of CBD were associated with the modulation of inflammation, excitotoxicity and oxidative stress. In conclusion, in immature rats, CBD reduced IVH-induced brain damage and its short- and long-term consequences, showing robust and pleiotropic neuroprotective effects. CBD is a potential candidate to ameliorate IVH-induced immature brain damage.

Investigating neuropathological changes and underlying neurobiological mechanisms in the early stages of primary blast-induced traumatic brain injury: Insights from a rat model.

The utilization of explosives and chemicals has resulted in a rise in blast-induced traumatic brain injury (bTBI) in recent times. However, there is a dearth of diagnostic biomarkers and therapeutic targets for bTBI due to a limited understanding of biological mechanisms, particularly in the early stages. The objective of this study was to examine the early neuropathological characteristics and underlying biological mechanisms of primary bTBI. A total of 83 Sprague Dawley rats were employed, with their heads subjected to a blast shockwave of peak overpressure ranging from 172 to 421 kPa in the GI, GII, and GIII groups within a closed shock tube, while the body was shielded. Neuromotor dysfunctions, morphological changes, and neuropathological alterations were detected through modified neurologic severity scores, brain water content analysis, MRI scans, histological, TUNEL, and caspase-3 immunohistochemical staining. In addition, label-free quantitative (LFQ)-proteomics was utilized to investigate the biological mechanisms associated with the observed neuropathology. Notably, no evident damage was discernible in the GII and GI groups, whereas mild brain injury was observed in the GIII group. Neuropathological features of bTBI were characterized by morphologic changes, including neuronal injury and apoptosis, cerebral edema, and cerebrovascular injury in the shockwave's path. Subsequently, 3153 proteins were identified and quantified in the GIII group, with subsequent enriched neurological responses consistent with pathological findings. Further analysis revealed that signaling pathways such as relaxin signaling, hippo signaling, gap junction, chemokine signaling, and sphingolipid signaling, as well as hub proteins including Prkacb, Adcy5, and various G-protein subunits (Gnai2, Gnai3, Gnao1, Gnb1, Gnb2, Gnb4, and Gnb5), were closely associated with the observed neuropathology. The expression of hub proteins was confirmed via Western blotting. Accordingly, this study proposes signaling pathways and key proteins that exhibit sensitivity to brain injury and are correlated with the early pathologies of bTBI. Furthermore, it highlights the significance of G-protein subunits in bTBI pathophysiology, thereby establishing a theoretical foundation for early diagnosis and treatment strategies for primary bTBI.

Fetal and neonatal neuroimaging in twin-twin transfusion syndrome.

OBJECTIVES: To describe the types of brain injury and subsequent neurodevelopmental outcome in fetuses and neonates from pregnancies with twin-twin transfusion syndrome (TTTS). Additionally, to determine risk factors for brain injury and to review the use of neuroimaging modalities in these cases. METHODS: This was a retrospective cohort study of consecutive TTTS pregnancies treated with laser surgery in a single fetal therapy center between January 2010 and January 2020. The primary outcome was the incidence of brain injury, classified into predefined groups. Secondary outcomes included adverse outcome (perinatal mortality or neurodevelopmental impairment), risk factors for brain injury and the number of magnetic resonance imaging (MRI) scans. RESULTS: Cranial ultrasound was performed in all 466 TTTS pregnancies and in 685/749 (91%) liveborn neonates. MRI was performed in 3% of pregnancies and 4% of neonates. Brain injury was diagnosed in 16/935 (2%) fetuses and 37/685 (5%) neonates and all predefined injury groups were represented. Four fetal and four neonatal cases of cerebellar hemorrhage were detected. Among those with brain injury, perinatal mortality occurred in 11/16 (69%) fetuses and 8/37 (22%) neonates. Follow-up was available for 29/34 (85%) long-term survivors with brain injury and the mean age at follow-up was 46 months. Neurodevelopmental impairment was present in 9/29 (31%) survivors with brain injury. Adverse outcome occurred in 28/53 (53%) TTTS individuals with brain injury. The risk of brain injury was increased after recurrent TTTS/post-laser twin anemia-polycythemia sequence (TAPS) (odds ratio (OR), 3.095 (95% CI, 1.581-6.059); P = 0.001) and lower gestational age at birth (OR per 1-week decrease in gestational age, 1.381 (95% CI, 1.238-1.541); P < 0.001). CONCLUSIONS: Based on dedicated neurosonography and limited use of MRI, brain injury was diagnosed in 2% of fetuses and 5% of neonates with TTTS. Adverse outcome was seen in over half of cases with brain injury. Brain injury was related to recurrent TTTS/post-laser TAPS and a lower gestational age at birth. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Distant neuroinflammation acutely induced by focal brain injury and its control by endocannabinoid system.

INTRODUCTION: We studied spatiotemporal features of acute transcriptional inflammatory response induced by a focal brain injury in distant uninjured neuronal tissue and a role of endocannabinoid (eCB) system in its control. MATERIALS AND METHODS: A focal excitotoxic lesion was induced by a unilateral injection of kainate in the dorsal hippocampus of awake Wistar rats. During acute post-injury period (3 h and 24 h post-injection), mRNA levels of genes associated with neuroinflammation (Il1b, Il6, Tnf, Ccl2; Cx3cl1, Zc3 h12a, Tgfb1) and eCB receptors of CB1 and CB2 types (Cnr1 and Cnr2) in intact regions of the hippocampus and neocortex were measured using qPCR. Occurrence of acute symptomatic seizures was controlled electrographically. To modulate eCB signaling during injury and acute post-injury period, antagonists (AM251, AM630) and agonist (WIN55-212-2) of eCB receptors were administered before the injury induction. RESULTS: Local intrahippocampal injury triggered widespread time- and region-dependent neuroinflammation in undamaged brain regions remote from the lesion site. The distant areas of the hippocampus and hippocampal meninges exhibited early (3 h) transient upregulation of pro- and anti-inflammatory cytokines simultaneously with occurrence of acute symptomatic seizures. The neocortex and its meninges showed minor neuroinflammation early after injury (3 h) but later (24 h) significantly upregulated several genes, mainly with anti-inflammatory properties. Focal lesion also changed expression of eCB receptors in the distant extra-lesional regions - CB1 receptors at 3 h and both CB1 and CB2 receptors at 24 h. Within the hippocampus, significant regional differences in constitutive and post-injury expression CB1 receptors were found. Pharmacological blockade of eCB receptors during injury and early post-injury period lengthened hippocampal neuroinflammation and reversed upregulation of anti-inflammatory molecules in the neocortex. CONCLUSION: The findings show that focal brain injury rapidly triggers widespread parenchymal and extraparenchymal neuroinflammation. The early injury-induced response is likely to represent neurogenic neuroinflammation produced by network hyperexcitability (acute symptomatic seizures). Activation of eCB signaling during acute phase of the brain injury is important for initiation of adaptive anti-inflammatory processes and prevention of chronic pathologic neuroinflammation in distant uninjured structures. However, the beneficial role of injury-induced eCB activity appears to depend on many factors including time, brain region, eCB tone etc.

Alpha-Asarone Ameliorates Neurological Dysfunction of Subarachnoid Hemorrhagic Rats in Both Acute and Recovery Phases via Regulating the CaMKII-Dependent Pathways.

Early brain injury (EBI) is the leading cause of poor prognosis for patients suffering from subarachnoid hemorrhage (SAH), particularly learning and memory deficits in the repair phase. A recent report has involved calcium/calmodulin-dependent protein kinase II (CaMKII) in the pathophysiological process underlying SAH-induced EBI. Alpha-asarone (ASA), a major compound isolated from the Chinese medicinal herb Acorus tatarinowii Schott, was proven to reduce secondary brain injury by decreasing CaMKII over-phosphorylation in rats' model of intracerebral hemorrhage in our previous report. However, the effect of ASA on SAH remains unclear, and the role of CaMKII in both acute and recovery stages of SAH needs further investigation. In this work, we first established a classic SAH rat model by endovascular perforation and intraperitoneally administrated different ASA doses (10, 20, and 40 mg/kg) 2 h after successful modeling. Then, the short- and long-term neurobehavioral performances were blindly evaluated to confirm ASA's efficacy against SAH. Subsequently, we explored ASA's therapeutic mechanism in both acute and recovery stages using histopathological examination, TUNEL staining, flow cytometry, Western-blot, double-immunofluorescence staining, and transmission electron microscopy (TEM) observation. Finally, KN93, a selective CaMKII inhibitor, was applied in oxyhemoglobin-damaged HT22 cells to explore the role of CaMKII in ASA's neuroprotective effect. The results demonstrated that ASA alleviated short- and long-term neurological dysfunction, reduced mortality and seizure rate within 24 h, and prolonged 14-day survival in SAH rats. Histopathological examination showed a reduction of neuronal damage and a restoration of the hippocampal structure after ASA treatment in both acute and recovery phases of SAH. In the acute stage, the Western-blot and flow cytometer analyses showed that ASA restored E/I balance, reduced calcium overload and CaMKII phosphorylation, and inhibited mitochondrion-involved apoptosis, thus preventing neuronal damage and apoptosis underlying EBI post-SAH. In the recovery stage, the TEM observation, double-immunofluorescence staining, and Western-blot analyses indicated that ASA increased the numbers of synapses and enhanced synaptic plasticity in the ipsilateral hippocampi, probably by promoting NR2B/CaMKII interaction and activating subsequent CREB/BDNF/TrkB signaling pathways. Furthermore, KN93 notably reversed ASA's neuroprotective effect on oxyhemoglobin-damaged HT22 cells, confirming CaMKII a potential target for ASA's efficacy against SAH. Our study confirmed for the first time that ASA ameliorated the SAH rats' neurobehavioral deterioration, possibly via modulating CaMKII-involved pathways. These findings provided a promising candidate for the clinical treatment of SAH and shed light on future drug discovery against SAH.