Subarachnoid Hemorrhage In Rats Research Articles

Transcription factor EB (TFEB) promotes autophagy in early brain injury after subarachnoid hemorrhage in rats.

Subarachnoid hemorrhage (SAH) has high mortality. Early brain injury (EBI) is responsible for unfavorable outcomes for patients with SAH. The protective involvement of autophagy in hemorrhagic stroke has been proposed. The transcription factor EB (TFEB) can increase autophagic flux by promoting autophagosome formation and autophagosome-lysosome fusion, and dysregulation of TFEB activity might induce the development of several diseases. However, the biological functions of TFEB in EBI after SAH remain unknown. We established an animal model of SAH by the modified endovascular perforation method. Expression of TFEB and autophagy required genes was measured by western blotting and immunofluorescence staining. SAH grading, brain water content and neurobehavioral functions were evaluated at 24h post-SAH. Neuronal apoptosis in cerebral cortex was assessed by TUNEL staining and Fluoro Jade B staining. TFEB was downregulated in SAH rats, and its overexpression reduced brain edema and ameliorated neurological deficits of SAH rats. Additionally, the neuronal apoptosis induced by SAH was inhibited by TFEB overexpression. Moreover, TFEB overexpression promoted autophagy after SAH. TFEB overexpression promotes autophagy to inhibit neuronal apoptosis, brain edema and neurological deficits post-SAH.

Peroxiredoxin-5 alleviates early brain injury after subarachnoid hemorrhage by reducing oxidative stress

Background and purposeFollowing subarachnoid hemorrhage (SAH), excessive activation of oxidative stress and cell apoptosis plays a critical role in early brain injury (EBI). Peroxiredoxin-5 (Prdx5), predominantly expressed in neuronal mitochondria, acts as an antioxidant. However, the role of Prdx5 in EBI after SAH remains unclear. This study aims to elucidate the antioxidative stress and anti-apoptotic effects of Prdx5 in rats following SAH. MethodsIn this study, an SAH model was established in Sprague-Dawley rats using endovascular perforation. Recombinant Prdx5 (rPrdx5) was administered intranasally to upregulate Prdx5 expression after SAH in rats. Prdx5 small interfering RNA (Prdx5 siRNA) was administered prior to SAH modelling. The neuroprotective effects of Prdx5 were validated through SAH grading, brain water content, blood-brain barrier permeability, neurobehavioral tests, immunofluorescence, TUNEL staining, and Western blotting. ResultsThe expression levels of endogenous Prdx5 significantly decreased after SAH. Treatment with rPrdx5 improved both short-term and long-term behaviour in rats, reduced brain water content and blood-brain barrier permeability, and exhibited anti-oxidative stress and anti-apoptotic effects. Measurements of oxidative stress-related indicators, including MDA, SOD, GSH-Px and GSH/GSSG, confirmed that Prdx5 can alleviate oxidative stress in rats after SAH. Western blot analysis showed that rPrdx5 significantly increased the expression of Bcl-XL and Bcl-2 and reduced the expression of Bax and Cleaved Caspase-3, thereby exerting anti-apoptotic effects. Additionally, Prdx5 siRNA reversed the neuroprotective effects of rPrdx5, exacerbated neuronal damage and blood-brain barrier permeability, and increased levels of oxidative stress and apoptosis. ConclusionIn conclusion, our study demonstrated that specifically upregulating the expression of Prdx5 can reduce oxidative stress and apoptosis in rats after SAH, while also improving both short-term and long-term neurological impairments. Prdx5 is primarily expressed in the mitochondria of neuronal cells and is a crucial target for reducing ROS after SAH. rPrdx5 treatment may offer a promising therapeutic approach for clinical SAH patients.

MiR-19-3p/GRSF1/COX1 axis attenuates early brain injury via maintaining mitochondrial function after subarachnoid haemorrhage

BackgroundGuanine-rich RNA sequence binding factor 1 (GRSF1) is an RNA-binding protein, which is eventually localised to mitochondria and promotes the translation of cytochrome C oxidase 1 (COX1) mRNA. However, the...

Activation of Piezo1 by intracranial hypertension induced neuronal apoptosis via activating hippo pathway.

Most of the subarachnoid hemorrhage (SAH) patients experienced the symptom of severe headache caused by intracranial hypertension. Piezo1 is a mechanosensitive ion channel protein. This study aimed to investigate the effect of Piezo1 on neurons in response to intracranial hypertension. The SAH rat model was performed by the modified endovascular perforation method. Piezo1 inhibitor GsMTx4 was administered intraperitoneally after SAH induction. To investigate the underlying mechanism, the selective Piezo1 agonist Yoda1, Piezo1 shRNA, and MY-875 were administered via intracerebroventricular injection before SAH induction. Invitro, we designed a pressurizing device to exclusively explore the effect of Piezo1 activation on primary neurons. Neurons were pretreated with Piezo1 inhibition followed by intracranial hypertension treatment, and then apoptosis-related proteins were detected. Piezo1 inhibition significantly attenuated neuronal apoptosis and improved the outcome of neurological deficits in rats after SAH. The Hippo pathway agonist MY-875 reversed the anti-apoptotic effects of Piezo1 knockdown. Invitro, intracranial hypertension mimicked by the pressurizing device induced Piezo1 expression, resulting in Hippo pathway activation and neuronal apoptosis. The Hippo pathway inhibitor Xmu-mp-1 attenuated Yoda1-induced neuronal apoptosis. In addition, the combination of hypertension and oxyhemoglobin treatment exacerbated neuronal apoptosis. Intracranial hypertension induced Piezo1 expression, neuronal apoptosis, and the Hippo pathway activation; the Hippo signaling pathway is involved in Piezo1 activation-induced neuronal apoptosis in respond to intracranial hypertension. Primary neurons treated with intracranial hypertension and oxyhemoglobin together can better characterize the circumstance of SAH invivo, which is contributed to construct an ideal invitro SAH model.

The potential of disulfiram as a drug to improve the prognosis after the onset of subarachnoid hemorrhage

Subarachnoid hemorrhage due to rupture of intracranial aneurysms has a poor outcome, making this disease being the social problem. Inflammation evoked by the increase in intracranial pressure and the clot in the subarachnoid space after the onset of SAH exacerbates neuronal death and vasospasm, resulting in the poor outcome and severe aftereffects. Here, FROUNT mediates CCR2 and CCR5 signaling as an intracellular molecule binding to these chemoattractant receptors which facilitate the migration of inflammatory cells, such as macrophages, in situ to trigger inflammation there. Animal model of subarachnoid hemorrhage was established in rats through intrathecal injection of autologous blood. The effect of the FROUNT inhibitor, disulfiram, on survival rate, neuronal death in hippocampus or vasospasm was then examined. The intrathecal administration of disulfiram significantly suppressed the infiltration of CD68-positive macrophages and myeloperoxidase-positive neutrophils toward the clot in the cistern in situ. In this condition, disulfiram ameliorated the death of animals after the onset of subarachnoid hemorrhage in rats. In addition, disulfiram suppressed both the two major events after subarachnoid hemorrhage, the neuronal death in hippocampus and vasospasm. The pharmacological inhibition of CCR2 and CCR5 signaling by disulfiram could thus be the therapeutic strategy to improve the outcome of subarachnoid hemorrhage.

PEDF-34 attenuates neurological deficit and suppresses astrocyte-dependent neuroinflammation by modulating astrocyte polarization via 67LR/JNK/STAT1 signaling pathway after subarachnoid hemorrhage in rats

BackgroundReactive astrocytes participate in various pathophysiology after subarachnoid hemorrhage (SAH), including neuroinflammation, glymphatic–lymphatic system dysfunction, brain edema, BBB disruption, and cell death. Astrocytes transform into two new reactive phenotypes with changed morphology, altered gene expression, and secretion profiles, termed detrimental A1 and beneficial A2. This study investigates the effect of 67LR activation by PEDF-34, a PEDF peptide, on neuroinflammation and astrocyte polarization after the experimental SAH.MethodsA total of 318 male adult Sprague-Dawley rats were used in experiments in vivo, of which 272 rats were subjected to the endovascular perforation model of SAH and 46 rats underwent sham surgery. 67LR agonist (PEDF-34) was administrated intranasally 1 h after SAH. 67LR-specific inhibitor (NSC-47924) and STAT1 transcriptional activator (2-NP) were injected intracerebroventricularly 48 h before SAH. Short- and long-term neurological tests, brain water content, immunostaining, Nissl staining, western blot, and ELISA assay were performed. In experiments in vitro, primary astrocyte culture with hemoglobin (Hb) stimulation was used to mimic SAH. The expression of the PEDF-34/67LR signaling pathway and neuro-inflammatory cytokines were assessed using Western blot, ELISA, and immunohistochemistry assays both in vivo and in vitro.ResultsEndogenous PEDF and 67LR expressions were significantly reduced at 6 h after SAH. 67LR was expressed in astrocytes and neurons. Intranasal administration of PEDF-34 significantly reduced brain water content, pro-inflammatory cytokines, and short-term and long-term neurological deficits after SAH. The ratio of p-JNK/JNK and p-STAT1/STAT1 and the expression of CFB and C3 (A1 astrocytes marker), significantly decreased after PEDF-34 treatment, along with fewer expression of TNF-α and IL-1β at 24 h after SAH. However, 2-NP (STAT1 transcriptional activator) and NSC-47924 (67LR inhibitor) reversed the protective effects of PEDF-34 in vivo and in vitro by promoting A1 astrocyte polarization with increased inflammatory cytokines.ConclusionPEDF-34 activated 67LR, attenuating neuroinflammation and inhibiting astrocyte A1 polarization partly via the JNK/STAT1 pathway, suggesting that PEDF-34 might be a potential treatment for SAH patients.Graphical

Retraction: Neuroprotective effect of protein phosphatase 2A/tristetraprolin following subarachnoid hemorrhage in rats.

[This retracts the article DOI: 10.3389/fnins.2018.00096.].

Diffuse microglial responses and persistent EEG changes correlate with poor neurological outcome in a model of subarachnoid hemorrhage

The mechanism by which subarachnoid hemorrhage (SAH) leads to chronic neurologic deficits is unclear. One possibility is that blood activates microglia to drive inflammation that leads to synaptic loss and impaired brain function. Using the endovascular perforation model of SAH in rats, we investigated short-term effects on microglia together with long-term effects on EEG and neurologic function for up to 3 months. Within the first week, microglia were increased both at the site of injury and diffusely across the cortex (2.5-fold increase in SAH compared to controls, p = 0.012). Concomitantly, EEGs from SAH animals showed focal increases in slow wave activity and diffuse reduction in fast activity. When expressed as a fast-slow spectral ratio, there were significant interactions between group and time (p < 0.001) with less ipsilateral recovery over time. EEG changes were most pronounced during the first week and correlated with neurobehavioral impairment. In vitro, the blood product hemin was sufficient to increase microglia phagocytosis nearly six-fold (p = 0.032). Immunomodulatory treatment with fingolimod after SAH reduced microglia, improved neurological function, and increased survival. These findings, which parallel many of the EEG changes seen in patients, suggest that targeting neuroinflammation could reduce long-term neurologic dysfunction following SAH.

Protective Effects of Adropin in Experimental Subarachnoid Hemorrhage

Purpose: We aimed to investigate early effects of exogenously administered adropin (AD) on neurological function, endothelial nitric oxide synthase (eNOS) expression, nitrite/nitrate levels, oxidative stress, and apoptosis in subarachnoid hemorrhage (SAH). Methods: Following intracerebroventricular AD administration (10 µg/5 µl at a rate of 1 µl/min) SAH model was carried out in Sprague–Dawley rats by injection of autologous blood into the prechiasmatic cistern. The effects of AD were assessed 24 h following SAH. The modified Garcia score was employed to evaluate functional insufficiencies. Adropin and caspase-3 proteins were measured by ELISA, while nitrite/nitrate levels, total antioxidant capacity (TAC) and reactive oxygen/nitrogen species (ROS/RNS) were assayed by standard kits. eNOS expression and apoptotic neurons were detected by immunohistochemical analysis. Results: The SAH group performed notably lower on the modified Garcia score compared to sham and SAH + AD groups. Adropin administration increased brain eNOS expression, nitrite/nitrate and AD levels compared to SHAM and SAH groups. SAH produced enhanced ROS/RNS generation and reduced antioxidant capacity in the brain. Adropin boosted brain TAC and diminished ROS/RNS production in SAH rats and no considerable change amongst SHAM and SAH + AD groups were detected. Apoptotic cells were notably increased in intensity and number after SAH and were reduced by AD administration. Conclusions: Adropin increases eNOS expression and reduces neurobehavioral deficits, oxidative stress, and apoptotic cell death in SAH model. Presented results indicate that AD provides protection in early brain injury associated with SAH.

Transcriptomics and metabolomics reveal hypothalamic metabolic characteristics and key genes after subarachnoid hemorrhage in rats

Subarachnoid hemorrhage (SAH) is a serious hemorrhagic event with high mortality and morbidity. Multiple injurious events produced by SAH can lead to a series of pathophysiologic processes in the hypothalamus that can severely impact patients’ life. These pathophysiologic processes usually result in physiologic derangements and dysfunction of the brain and multiple organs. This dysfunction involved multiple dimensions of the genome and metabolome. In our study, we induced the SAH model in rats to obtain hypothalamic tissue and serum. The samples were subsequently analyzed by transcriptomics and metabolomics. Next, the functional enrichment analysis of the differentially expressed genes and metabolites were performed by GO and KEGG pathway analysis. Through transcriptomic analysis of hypothalamus samples, 263 up-regulated differential genes, and 207 down-regulated differential genes were identified in SAH groups compared to Sham groups. In the KEGG pathway analysis, a large number of differential genes were found to be enriched in IL-17 signaling pathway, PI3K-Akt signaling pathway, and bile secretion. Liquid chromatography-mass spectrometry metabolomics technology was conducted on the serum of SAH rats and identified 11 up-regulated and 26 down-regulated metabolites in positive ion model, and 1 up-regulated and 10 down-regulated metabolites in negative ion model. KEGG pathways analysis showed that differentially expressed metabolites were mainly enriched in pathways of bile secretion and primary bile acid biosynthesis. We systematically depicted the neuro- and metabolism-related biomolecular changes occurring in the hypothalamus after SAH by performing transcriptomics and metabolomics studies. These biomolecular changes may provide new insights into hypothalamus-induced metabolic changes and gene expression after SAH.

GPR30 alleviated subarachnoid hemorrhage-induced blood-brain barrier dysfunction by activating the PI3K/Akt and Nrf2/HO-1 pathways.

The blood-brain barrier (BBB) plays a critical role in the development and outcome of subarachnoid hemorrhage (SAH). This study focuses on the potential mechanism by which G-protein-coupled estrogen receptor 30 (GPR30) affects the BBB after SAH. A rat SAH model was established using an intravascular perforation approach. G1 (GPR30 agonist) was administered to investigate the mechanism of BBB damage after SAH. Brain water content, Western blotting, Evans blue leakage, and immunofluorescence staining were performed. Brain microvascular endothelial cells were induced by hemin to establish SAH model in vitro. By adding LY294002 [a phosphatidylinositol 3-kinase (PI3K) blocker] and zinc protoporphyrin IX (ZnPP IX) [a heme oxygenase 1 (HO-1) antagonist], the mechanism of improving BBB integrity through the activation of GPR30 was studied. In vivo, GPR30 activation improved BBB disruption, as evidenced by decreased cerebral edema, downregulated albumin expression, and reduced extravasation of Evans blue and IgG after G1 administration in SAH rats. Moreover, SAH downregulated the levels of tight junction (TJ) proteins, whereas treatment with G1 reversed the effect of SAH. The protective effect of G1 on BBB integrity in vitro was consistent with that in vivo, as evidenced by G1 reducing the impact of hemin on transendothelial electrical resistance (TEER) value, dextran diffusivity, and TJ protein levels in brain microvascular endothelial cells. In addition, G1 activated the PI3K/ protein kinase B (Akt) and nuclear factor erythroid 2-related factor 2 (Nrf2)/HO-1 pathways both in vivo and in vitro. Furthermore, the administration of LY294002 and ZnPP IX partially reversed the protective effect of G1 on BBB integrity in hemin-stimulated cells. We demonstrated that the activation of GPR30, at least partly through the PI3K/Akt and Nrf2/HO-1 pathways, alleviated BBB damage both in vivo and in vitro. This study introduced a novel therapeutic approach for protecting the BBB after SAH.NEW & NOTEWORTHY The PI3K/Akt and Nrf2/HO-1 pathways might be potential mechanisms by which GPR30 protected the integrity of the BBB in SAH models. Therefore, treatment of SAH with GPR30 activator might be a promising therapeutic strategy.

Electroacupuncture enhances cerebral blood perfusion by inhibiting HIF-1α in rat subarachnoid hemorrhage

ObjectiveCerebral blood perfusion (CBP) reduction is a prevalent complication following subarachnoid hemorrhage (SAH) in clinical practice, often associated with long-term cognitive impairment and prognosis. Electroacupuncture (EA), a widely utilized traditional Chinese therapy for central nervous system disorders, has demonstrated promising therapeutic effects. This study aims to investigate the therapeutic potential of EA in restoring CBP in SAH rats and to explore the mechanisms involving HIF-1α in this process. MethodsRats were randomly assigned to one of five groups, including Sham, SAH, EA, EA + Saline, and EA + dimethyloxallyl glycine (DMOG) groups. EA treatment was administered for 10 min daily, while DMOG were intraperitoneally injected. Behavioral tests, cerebral blood flow monitoring, vascular thickness measurement, western blotting, and immunofluorescence staining were conducted to assess the therapeutic effects of EA on cerebral blood flow. ResultsSAH resulted in elevated levels of HIF-1α, endothelin (ET), ICAM-1, P-SELECTIN, E-SELECTIN, and decreased level of eNOS in the brain. This led to cerebral vasospasm, decreased CBF, and cognitive deficits in the rat SAH model. EA intervention downregulated the expression of HIF-1α, ET, ICAM-1, P-SELECTIN, and E-SELECTIN, while increasing eNOS expression. This alleviated cerebral vasospasm, restored CBF, and improved cognitive function. However, the administration of the HIF-1α stabilizer (DMOG) counteracted the therapeutic effects of EA. ConclusionEA promotes the recovery of cerebral blood flow after SAH injury, attenuates cerebral vasospasm, and accelerates the recovery of cognitive dysfunction, and its mechanism of action may be related to the inhibition of the HIF-1α signaling pathway.

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.

WITHDRAWN: Recombinant osteopontin stabilizes the blood brain barrier following subarachnoid hemorrhage in rats

Background and PurposeRecombinant osteopontin (rOPN) decreases neuronal cell death and brain edema and improves the neurological scores following subarachnoid hemorrhage (SAH) in rats. The molecular mechanisms of the preservation of blood-brain barrier of rOPN following SAH in rats were examined in this study. MethodsAdult rats were divided into 3 groups: sham, vehicle, and treatment groups. Each animal in the SAH group underwent a surgical procedure to induce SAH, and the brains was harvested at 24 hours for analysis. For the mechanism part of the study two additional groups were operated and treated with Fib-14 and Wortmannin additional to rOPN. rOPN was administered via the nasal route and neurological scores as well as brain water content were evaluated at 24 hours after SAH induction. The blood brain barrier (BBB) permeability was evaluated using Evans Blue dye extravasation. The expressions of tight junction proteins claudin-3, claudin-5, occludin and the phosphorylation of β-catenin were examined using Western blot analysis. ResultsrOPN improved neurological scores and reduced brain edema at 24 hours after SAH. The BBB preservation action of rOPN is mediated in part through stabilizing β-catenin and increasing expression of tight junction proteins, claudin-3, claudin-5, and occludin. rOPN is thought to exert its effects through FAK activated PI3K-Akt pathway. ConclusionSince BBB disruption is one of the major pathophysiology of EBI after SAH, rOPN may be a promising drug to maintain BBB integrity and functions in SAH treatment.

LAMC1 attenuates neuronal apoptosis via FAK/PI3K/AKT signaling pathway after subarachnoid hemorrhage

Background and purposeThe poor prognosis in patients with subarachnoid hemorrhage (SAH) is often attributed to neuronal apoptosis. Recent evidence suggests that Laminin subunit gamma 1 (LAMC1) is essential for cell survival and proliferation. However, the effects of LAMC1 on early brain injury after SAH and the underlying mechanisms are unknown. The current study aimed to reveal the anti-neuronal apoptotic effect and the potential mechanism of LAMC1 in the rat and in the in vitro SAH models. MethodsThe SAH model of Sprague–Dawley rats was established by endovascular perforation. Recombinant LAMC1 (rLAMC1) was administered intranasally 30 min after modeling. LAMC1 small interfering RNA (LAMC1 siRNA), focal adhesion kinase (FAK)-specific inhibitor Y15 and PI3K-specific inhibitor LY294002 were administered before SAH modeling to explore the neuroprotection mechanism of rLAMC1. HT22 cells were cultured and stimulated by oxyhemoglobin to establish an in vitro model of SAH. Subsequently, SAH grades, neurobehavioral tests, brain water content, blood-brain barrier permeability, western blotting, immunofluorescence, TUNEL, and Fluoro-Jade C staining were performed. ResultsThe expression of endogenous LAMC1 was markedly decreased after SAH, both in vitro and in vivo. rLAMC1 significantly reduced the brain water content and blood-brain barrier permeability, improved short- and long-term neurobehavior, and decreased neuronal apoptosis. Furthermore, rLAMC1 treatment significantly increased the expression of p-FAK, p-PI3K, p-AKT, Bcl-XL, and Bcl-2 and decreased the expression of Bax and cleaved caspase -3. Conversely, knockdown of endogenous LAMC1 aggravated the neurological impairment, suppressed the expression of Bcl-XL and Bcl-2, and upregulated the expression of Bax and cleaved caspase-3. Additionally, the administration of Y15 and LY294002 abolished the protective roles of rLAMC1. In vitro, rLAMC1 significantly reduced neuronal apoptosis, and the protective effects were also abolished by Y15 and LY294002. ConclusionExogenous LAMC1 treatment improved neurological deficits after SAH in rats, and attenuated neuronal apoptosis in both in vitro and in vivo SAH models, at least partially through the FAK/PI3K/AKT pathway.

Subarachnoid Hemorrhage Depletes Calcitonin Gene-Related Peptide Levels of Trigeminal Neurons in Rat Dura Mater.

Subarachnoid hemorrhage (SAH) remains a major cause of cerebrovascular morbidity, eliciting severe headaches and vasospasms that have been shown to inversely correlate with vasodilator calcitonin gene-related peptide (CGRP) levels. Although dura mater trigeminal afferents are an important source of intracranial CGRP, little is known about the effects of SAH on these neurons in preclinical models. The present study evaluated changes in CGRP levels and expression in trigeminal primary afferents innervating the dura mater 72 h after experimentally induced SAH in adult rats. SAH, eliciting marked damage revealed by neurological examination, significantly reduced the density of CGRP-immunoreactive nerve fibers both in the dura mater and the trigeminal caudal nucleus in the medulla but did not affect the total dural nerve fiber density. SAH attenuated ex vivo dural CGRP release by ~40% and in the trigeminal ganglion, reduced both CGRP mRNA levels and the number of highly CGRP-immunoreactive cell bodies. In summary, we provide novel complementary evidence that SAH negatively affects the integrity of the CGRP-expressing rat trigeminal neurons. Reduced CGRP levels suggest likely impaired meningeal neurovascular functions contributing to SAH complications. Further studies are to be performed to reveal the importance of impaired CGRP synthesis and its consequences in central sensory processing.

Tat-NR2B9c attenuates oxidative stress via inhibition of PSD95-NR2B-nNOS complex after subarachnoid hemorrhage in rats

Oxidative stress plays important roles in the pathogenesis of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Tat-NR2B9c has shown efficacy as a neuroprotective agent in several studies. Here, we identified the neuroprotective role of Tat-NR2B9c after SAH and its related mechanisms. The results showed that Tat-NR2B9c treatment attenuated oxidative stress, therefore alleviated neuronal apoptosis and neurological deficits after SAH. Tat-NR2B9c treatment could alleviate mitochondrial vacuolization induced by SAH. Compared to SAH + vehicle group, Tat-NR2B9c resulted in the decrease of Acetylated superoxide dismutase2 (Ac-SOD2), Bcl-2-associated X protein (Bax) and cleaved-caspase3 (CC3) protein expression, and the up-regulation of Sirtunin 3 (Sirt3) and Bcl-2 protein level. Moreover, Tat-NR2B9c attenuated excitotoxicity by inhibiting the interaction of PSD95-NR2B-nNOS. Our results demonstrated that Tat-NR2B9c inhibited oxidative stress via inhibition of PSD95-NR2B-nNOS complex formation after SAH. Tat-NR2B9c may serve as a potential treatment for SAH induced brain injury.

LPCAT3 exacerbates early brain injury and ferroptosis after subarachnoid hemorrhage in rats

AimsLysophosphatidylcholine acyltransferase 3 (LPCAT3) is known to play a pivotal role in lipid metabolism, but its role in the early brain injury (EBI) following subarachnoid hemorrhage (SAH) remains unclear. This study provides insights into LPCAT3 expression alterations and functional implications in EBI following SAH. MethodsSAH models of adult male Sprague-Dawley (SD) rats were established by intravascular perforation. Lentivirus vectors were administered by intracerebroventricular injection (i.c.v.) to either induce LPCAT3 overexpression or knockdown 14 days before SAH induction. Western blot, immunofluorescence, Nissl staining, MDA detection, ROS detection, iron content detection, and short-term and long-term neurobehavioral tests were performed to investigate the effects of regulated-LPCAT3 after SAH. ResultsLPCAT3 levels were found to be significantly elevated in SAH. Suppression of LPCAT3 expression via shRNA improved oxidative stress, reduced brain edema, alleviated behavioral and cognitive deficits following SAH and decreased neuronal death, while upregulating LPCAT3 expression showed opposing effects. ConclusionLPCAT3 is involved in SAH-induced EBI and associated with ferroptosis. Our findings provide a referential basis for potential therapeutic interventions aimed at alleviating EBI following SAH.

Investigation of the protective effects of piceatannol on experimental subarachnoid hemorrhage in rats.

Subarachnoid hemorrhage (SAH) is one of the most prevalent brain injuries in humans which has poor prognosis and high mortality rates. Due to several medical or surgical treatment methods, a gold standard method doesn't exist for SAH treatment. Piceatannol (PCN), a natural analog of resveratrol, was reported to reduce inflammation and apoptosis promising a wide range of therapeutic alternatives. In this study, we aimed to investigate the effects of PCN in an experimental SAH model. The alleviating effects of PCN in the hippocampus in an experimental SAH model were investigated for the first time. In this study, 27 Wistar Albino male rats (200-300g; 7-8week) were used. Animals were divided into three groups; SHAM, SAH, and SAH + PCN. SAH model was created with 120µl of autologous arterial tail blood to prechiasmatic cisterna. 30mg/kg PCN was administered intraperitoneally at 1st h after SAH. Neurological evaluation was performed with Garcia's score. RT-PCR was performed for gene expression levels in the hippocampus. Pyknosis, edema, and apoptosis were evaluated by H&E and TUNEL staining. Our results indicated that PCN administration reduced apoptosis (P < 0.01), cellular edema, and pyknosis (P < 0.05) in the hippocampus after SAH. Moreover, PCN treatment significantly decreased the expression levels of TNF-α (P < 0.01), IL-6 (P < 0.05), NF-κB (P < 0.05), and Bax (P < 0.05) in the hippocampus. Our results demonstrated that PCN might be a potential therapeutic adjuvant agent for the treatment of early brain injury (EBI) following SAH. Further studies are required to clarify the underlying mechanisms and treatment options of SAH.

Remote Ischemic Post-conditioning Reduces Cognitive Impairment in Rats Following Subarachnoid Hemorrhage: Possible Involvement in STAT3/STAT5 Phosphorylation and Th17/Treg Cell Homeostasis.

The inflammatory response following subarachnoid hemorrhage (SAH) may lead to Early Brain Injury and subsequently contribute to poor prognosis such as cognitive impairment in patients. Currently, there is a lack of effective strategies for SAH to ameliorate inflammation and improve cognitive impairment in clinical. This study aims to examine the inhibitory impact of remote ischemic post-conditioning (RIPostC) on the body's inflammatory response by regulating Th17/Treg cell homeostasis after SAH. The ultimate goal is to search for potential early treatment targets for SAH. The rat SAH models were made by intravascular puncture of the internal carotid artery. The intervention of RIPostC was administered for three consecutive days immediately after successful modeling. Behavioral experiments including the Morris water maze and Y-maze tests were conducted to assess cognitive functions such as spatial memory, working memory, and learning abilities 2weeks after successful modeling. The ratio of Th17 cells and Treg cells in the blood was detected using flow cytometry. Immunofluorescence was used to observe the infiltration of neutrophils into the brain. Signal transducers and activators of transcription 5 (STAT5) and signal transducers and activators of transcription 3 (STAT3) phosphorylation levels, receptor-related orphan receptor gamma-t (RORγt), and forkhead box protein P3 (Foxp3) levels were detected by Western blot. The levels of anti-inflammatory factors (IL-2, IL-10, IL-5, etc.) and pro-inflammatory factors (IL-6, IL-17, IL-18, TNF-α, IL-14, etc.) in blood were detected using Luminex Liquid Suspension Chip Assay. RIPostC significantly improved the cognitive impairment caused by SAH in rats. The results showed that infiltration of Th17 cells and neutrophils into brain tissue increased after SAH, leading to the release of pro-inflammatory factors (IL-6, IL-17, IL-18, and TNF-α). This response can be inhibited by RIPostC. Additionally, RIPostC facilitates the transfer of Treg from blood to the brain and triggers the release of anti-inflammatory (IL-2, IL-10, and IL-5) factors to suppress the inflammation following SAH. Finally, it was found that RIPostC increased the phosphorylation of STAT5 while decreasing the phosphorylation of STAT3. RIPostC reduces inflammation after SAH by partially balancing Th17/Treg cell homeostasis, which may be related to downregulation of STAT3 and upregulation of STAT5 phosphorylation, which ultimately alleviates cognitive impairment in rats. Targeting Th17/Treg cell homeostasis may be a promising strategy for early SAH treatment.