Rat Model Of Subarachnoid Hemorrhage Research Articles

Rapid magnetic separation: An immunoassay platform for the SERS-based detection of subarachnoid hemorrhage biomarkers.

The blood-brain barrier (BBB) is of vital importance to the progression and prognosis of subarachnoid hemorrhage (SAH). The construction of a simple, sensitive, and accurate detection assay for measuring the biomarkers associated with BBB injury is still an urgent need owing to the complex pathogenesis of SAH and low expression levels of pathological molecules. Herein, we introduced surface-enhanced Raman scattering (SERS) label-embedded Fe3O4@Au core-shell nanoparticles as ideal SERS sensors for quantitative double detection of MMP-9 and occludin in SAH patients. Meanwhile, utilizing the SERS signals to dynamically estimate MMP-9 and occludin concentration in the rat SAH model is the first application in exploring the relationship of pathological MMP-9 and occludin molecular levels with neurobehavioral score. This method warrants reliable detection toward MMP-9 and occludin with a wide recognition range and a low detection limit in blood samples. Furthermore, the results monitored by the SERS assay exactly matched with those obtained through a traditional enzyme-linked immunosorbent assay (ELISA). The aforementioned results demonstrated this novel biosensor strategy has extensive application prospects in the quantitative measurement of multiple types of biomolecules in body fluid samples.

SIRT1 Activation Promotes Long-Term Functional Recovery After Subarachnoid Hemorrhage in Rats.

An increase in sirtuin 1 (SIRT1) reportedly attenuates early brain injury, delayed cerebral ischemia, and short-term neurologic deficits in rodent models of subarachnoid hemorrhage (SAH). This study investigates the effect of resveratrol, a SIRT1 activator, on long-term functional recovery in a clinically relevant rat model of SAH. Thirty male Wistar rats were subjected to fresh arterial blood injection into the prechiasmatic space and randomized to receive 7days of intraperitoneal resveratrol (20mg/kg) or vehicle injections. Body weight and rotarod performance were measured on days 0, 3, 7, and 34 post SAH. The neurologic score was assessed 7 and 34days post SAH. Morris water maze performance was evaluated 29-33days post SAH. Brain SIRT1 activity and CA1 neuronal survival were also assessed. Blood pressure rapidly increased in all SAH rats, and no between-group differences in blood pressure, blood gases, or glucose were detected. SAH induced weight loss during the first 7days, which gradually recovered in both groups. Neurologic score and rotarod performance were significantly improved after resveratrol treatment at 34days post SAH (p = 0.01 and 0.04, respectively). Latency to find the Morris water maze hidden platform was shortened (p = 0.02). In the resveratrol group, more CA1 neurons survived following SAH (p = 0.1). An increase in brain SIRT1 activity was confirmed in the resveratrol group (p < 0.05). Treatment with resveratrol for 1week significantly improved the neurologic score, rotarod performance, and latency to find the Morris water maze hidden platform 34days post SAH. These findings indicate that SIRT1 activation warrants further investigation as a mechanistic target for SAH therapy.

Correction to: CHOP Silencing Reduces Acute Brain Injury in the Rat Model of Subarachnoid Hemorrhage.

Correction to: CHOP Silencing Reduces Acute Brain Injury in the Rat Model of Subarachnoid Hemorrhage.

Exosome-Encapsulated microRNA-140-5p Alleviates Neuronal Injury Following Subarachnoid Hemorrhage by Regulating IGFBP5-Mediated PI3K/AKT Signaling Pathway.

Recent literature has highlighted the therapeutic implication of exosomes (Exos) released by adipose tissue-originated stromal cells (ADSCs) in regenerative medicine. Herein, the current study sought to examine the potential protective effects of ADSC-Exos on neuronal injury following subarachnoid hemorrhage (SAH) by delivering miR-140-5p. Firstly, isolated primary neurons were co-cultured together with well-identified ADSC-Exos. TDP-43-treated neurons were subsequently treated with PKH67-ADSC-Exos and Cy3-miR-140-5p to assess whether ADSC-Exos could transmit miR-140-5p to the recipient neurons to affect their behaviors. Moreover, a luciferase assay was carried out to identify the presumable binding of miR-140-5p to IGFBP5. IGFBP5 rescue experimentation was also performed to testify whether IGFBP5 conferred the impact of miR-140-5p on neuronal damage. The role of PI3K/AKT signaling pathway was further analyzed with the application of its inhibitor miltefosine. Lastly, SAH rat models were developed for in vivo validation. It was found that ADSC-Exos conferred protection against TDP-43-caused neuronal injury by augmenting viability and suppressing cell apoptosis. In addition, miR-140-5p was transmitted from ADSC-Exos to neurons and post-transcriptionally downregulated the expression of IGFBP5. As a result, by means of suppressing IGFBP5 and activating the PI3K/AKT signaling pathway, miR-140-5p from ADSC-Exos induced a neuroprotective effect. Furthermore, in vivo findings substantiated the aforementioned protective role of ADSC-Exos-miR-140-5p, contributing to protection against SAH-caused neurological dysfunction. Collectively, our findings indicated that ADSC-Exos-miR-140-5p could inhibit TDP-43-induced neuronal injury and attenuate neurological dysfunction of SAH rats by inhibiting IGFBP5 and activating the PI3K/Akt signaling pathway.

Activation of HIF-1α/VEGF-A pathway by deferoxamine ameliorates retinal hypoxia in a rat subarachnoid hemorrhage model.

Subarachnoid hemorrhage (SAH) is associated with sustained vasoconstriction in retinal vessels and vasoconstriction leads to retinal ischemia and hypoxia. Our previous finding also revealed the changes in hypoxia-related elements in the retina after SAH, further lending weight to the hypothesis that retinal vasospasm and hypoxia after SAH. Deferoxamine is a high-affinity iron chelator with reported neuroprotective effects against stroke. Here, we aimed to explore the effects of deferoxamine on retinal hypoxia after SAH. SAH was established and deferoxamine was injected intraperitoneally for 3 days in the treatment group. To detect retinal new vessels, platelet endothelial cell adhesion molecule (CD31) was labeled by immunofluorescence and immunohistochemistry. Furthermore, the effects of deferoxamine on the expression of vascular endothelial growth factor A (VEGF-A) and hypoxia-inducible factor-1α (HIF-1α) were revealed by western blot analysis. The immunofluorescence and immunohistochemical staining of CD31 revealed a marked increase in new vessels in the retinal ganglion cell layer after deferoxamine treatment. By western blot analysis, HIF-1α and VEGF-A increased gradually in the first day and then rebounded to a new level on day 7. A deferoxamine-induced increase in HIF-1α/VEGF-A expression was also confirmed by western blot. Our findings suggest that modulating the application of deferoxamine may offer therapeutic approaches to alleviate retinal complications after SAH.

6-Gingerol attenuates subarachnoid hemorrhage-induced early brain injury via GBP2/PI3K/AKT pathway in the rat model.

Numerous studies have elucidated the neuroprotective effect of 6-gingerol in central nervous system diseases. However, the potential role and mechanism of 6-gingerol on early brain injury (EBI) after subarachnoid hemorrhage (SAH) remains poorly understood. Here, we report that 6-gingerol exerts a neuroprotective effect on SAH-induced EBI through the GBP2/PI3K/AKT pathway. A SAH rat model was established by injecting femoral artery blood into the cisterna magna. 6-gingerol or vehicle was injected intraperitoneally 1 hour post-SAH induction. We found that the neurological function score and brain edema of SAH rats were significantly improved after 6-gingerol treatment, as well as neuronal apoptosis was attenuated in SAH rats by Nissl staining assay and TUNEL assay. To further explore potential molecular mechanisms associated with 6-gingerol, RNA sequencing was implemented to investigate the differences in transcriptomes between SAH rats with and without 6-gingerol treatment; and found that the expression of guanylate-binding protein 2 (GBP2) evidently was suppressed with 6-gingerol treatment compared to vehicle group. In addition, dual immunofluorescence was also employed to investigate changes in neurons, astrocytes, and microglia after 6-gingerol treatment. The results showed that GBP2 was expressed in neurons but not astrocytes or microglia. Western blotting analysis results demonstrated that the PI3K/AKT pathway was activated in the SAH rats treated with 6-gingerol. Furthermore, recombinant GBP2 protein and LY294002 (PI3K inhibitor) treatment reversed the effects of 6-gingerol treatment in SAH rats. These results indicate that 6-gingerol suppressed the expression of GBP2 to activate the PI3K/AKT pathway, improve neurologic outcomes, reduce brain edema and neuronal apoptosis. In summary, our findings suggest that 6-gingerol could attenuate EBI post-SAH in rats, and 6-gingerol may serve as a novel candidate neuroprotective drug for SAH-induced EBI.

The protective mechanism of protein kinase R to inhibit neuronal ferroptosis in cerebral injury from subarachnoid hemorrhage.

Purpose: To investigate the role and mechanism of protein kinase R (PKR) in subarachnoid hemorrhage (SAH)‐mediated ferroptosis. Methods: A rat SAH model was constructed and treated with PKR inhibitor C16 to observe SAH and neurological impairment in rats and to detect malonaldehyde (MDA), iron ions content, ferritin heavy polypeptide 1 (FTH1) and glutathione peroxidase 4 (GPX4), and other related ferroptosis indicators in brain tissue. RNA sequencing analysis was used to investigate the mechanism of PKR, affecting the ferroptosis network of SAH. Results: SAH caused severe fundic hemorrhage, neurological impairment, MDA and iron ion accumulation, and significant decrease in GPX4 and FTH1 levels in rats. C16 treatment significantly improved the above signs caused by SAH. By RNA‐seq analysis, brain tissue of SAH‐treated rats with SAH and C16 differentially expressed mRNA target genes enriched in stress response and organic developmental signaling pathways. Conclusion: Inhibition of PKR may improve cerebral injury after SAH by inhibiting ferroptosis, and RNA sequencing staged its mechanism of action may be related to the stress response.

TREM2 modulates neuroinflammation with elevated IRAK3 expression and plays a neuroprotective role after experimental SAH in rats

BackgroundThe modulation of neuroinflammation is a new direction that may alleviate the early brain injury after subarachnoid hemorrhage (SAH). Brain resident microglia/macrophages (Mi/MΦ) are the key drivers of neuroinflammation. Triggering receptor expressed on myeloid cells 2 (TREM2) has been reported to play a neuroprotective role by activating phagocytosis and suspending inflammatory response in experimental ischemic stroke and intracerebral hemorrhage. This study was designed to investigate the role of TREM2 on neuroinflammation and neuroprotective effects in a rat SAH model. MethodsAdult male Sprague-Dawley rats were induced SAH through endovascular perforation. Lentivirus vectors were administered by i.c.v. to induce TREM2 overexpression or knockdown 7 days before SAH induction. Short- and long-term neurobehavioral tests, western blotting, immunofluorescence, enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick end labeling and Nissl staining were performed to explore the neuroprotective role of TREM2 after SAH. ResultsThe expression of TREM2 elevated in a rat SAH model with a peak at 48 h after SAH and mainly expressed in Mi/MΦ in brain. TREM2 overexpression improved short- and long-term neurological deficits induced by SAH in rats, while TREM2 knockdown worsened neurological dysfunction. The rats with TREM2 overexpressed presented less neuronal apoptosis and more neuronal survival at 48 h after SAH, while the rats with TREM2 knockdown presented on the contrary. TREM2 overexpression manifested activated phagocytosis and suppressed inflammatory response, with the increase of CD206+/CD11b+ cells and IL-10 expression as well as the decrease of the infiltration of MPO+ cells and the expression of TNF-α, IL-1β. While TREM2 knockdown abolished these effects. The protein level of IRAK3, a negative regulatory factor of inflammation, was significantly elevated after TREM2 overexpression and declined after TREM2 knockdown. ConclusionsOur research suggested TREM2 played a neuroprotective role and improved the short- and long-term neurological deficits by modulating neuroinflammation after SAH. The modulation on neuroinflammation of TREM2 after SAH was related with the elevated protein level of IRAK3.

Isoliquiritigenin mitigates oxidative damage after subarachnoid hemorrhage in vivo and in vitro by regulating Nrf2-dependent Signaling Pathway via Targeting of SIRT1

BackgroundOxidative stress is a crucial factor leading to subarachnoid hemorrhage (SAH)-induced early brain injury (EBI). Isoliquiritigenin has been verified as a powerful anti-oxidant in a variety of diseases models and can activate sirtuin 1 and nuclear factor-erythroid 2-related factor 2 (Nrf2) pathways. However, the effects of isoliquiritigenin against EBI after SAH and the underlying mechanisms remain elusive. PurposeThe primary goal of this study is to verify the therapeutic effects of isoliquiritigenin on EBI after SAH and the possible molecular mechanisms. Study designA prechiasmatic cistern SAH model in rats and a hemoglobin incubation SAH model in primary neurons were established. Isoliquiritigenin was administered after SAH induction. EX527 was employed to inhibit sirtuin 1 activation and ML385 was used to suppress Nrf2 signaling. MethodsIn our study, neurological scores, brain edema, biochemical estimation, western blotting, and histopathological study were performed to explore the therapeutic action of isoliquiritigenin against SAH. ResultsOur data revealed that isoliquiritigenin significantly mitigated oxidative damage after SAH as evidenced by decreased reactive oxygen species overproduction and enhanced intrinsic anti-oxidative system. Concomitant with the reduced oxidative insults, isoliquiritigenin improved neurological function and reduced neuronal death in the early period after SAH. Additionally, isoliquiritigenin administration significantly enhanced Nrf2 and sirtuin 1 expressions. Inhibition of Nrf2 by ML385 reversed the anti-oxidative and neuroprotective effects of isoliquiritigenin against SAH. Moreover, inhibiting sirtuin 1 by EX527 pretreatment suppressed isoliquiritigenin-induced Nrf2-dependent pathway and abated the cerebroprotective effects of isoliquiritigenin. In primary cortical neurons, isoliquiritigenin treatment also ameliorated oxidative insults and repressed neuronal degeneration. The beneficial aspects of isoliquiritigenin were attributed to the promotion of sirtuin 1 and Nrf2 signaling pathways and were counteracted by EX527. ConclusionOur findings suggest that isoliquiritigenin exerts cerebroprotective effects against SAH-induced oxidative insults by modulating the Nrf2-mediated anti-oxidant signaling in part through sirtuin 1 activation. Isoliquiritigenin might be a new potential drug candidate for SAH.

Dexmedetomidine Inhibits Gasdermin D-Induced Pyroptosis via the PI3K/AKT/GSK3β Pathway to Attenuate Neuroinflammation in Early Brain Injury After Subarachnoid Hemorrhage in Rats.

Subarachnoid hemorrhage (SAH) is one kind of life-threatening stroke, which leads to severe brain damage. Pyroptosis plays a critical role in early brain injury (EBI) after SAH. Previous reports suggest that SAH-induced brain edema, cell apoptosis, and neuronal injury could be suppressed by dexmedetomidine (Dex). In this study, we used a rat model of SAH to investigate the effect of Dex on pyroptosis in EBI after SAH and to determine the mechanisms involved. Pyroptosis was found in microglia in EBI after SAH. Dex significantly alleviated microglia pyroptosis via reducing pyroptosis executioner GSDMD and inhibited the release of proinflammatory cytokines induced by SAH. Furthermore, the reduction of GSDMD by Dex was abolished by the PI3K inhibitor LY294002. In conclusion, our data demonstrated that Dex reduces microglia pyroptosis in EBI after SAH via the activation of the PI3K/AKT/GSK3β pathway.

Extracellular vesicles derived from bone marrow mesenchymal stem cells alleviate neurological deficit and endothelial cell dysfunction after subarachnoid hemorrhage via the KLF3-AS1/miR-83-5p/TCF7L2 axis

BackgroundNew data are accumulating on the effects of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in cerebrovascular diseases. We explored the potential role of KLF3-AS1-containing bone marrow MSC-EVs (BMSC-EVs) in a rat model of subarachnoid hemorrhage (SAH). MethodsA rat model of SAH was established by endovascular perforation method, into which KLF3-AS1-containing EVs from BMSCs or miR-183-5p mimic were injected. Further, brain microvascular endothelial cells (BMECs) were induced by oxyhemoglobin (OxyHb) to simulate in vitro setting, which were co-cultured with KLF3-AS1-containing EVs from BMSCs. Effects of KLF3-AS1 on neurological deficits in vivo and endothelial cell dysfunction in vitro were investigated. We also performed bioinformatics analysis to predict downstream factors miR-183-5p and TCF7L2, which were verified by RIP, RNA pull-down and luciferase activity assays. ResultsBMSC-EVs was demonstrated to alleviate neurological deficits in SAH rats and endothelial cell dysfunction in OxyHb-induced BMECs. In addition, BMSC-EVs were shown to deliver KLF3-AS1 to BMECs, where KLF3-AS1 bound to miR-183-5p and miR-183-5p targeted TCF7L2. In vivo results confirmed that BMSC-EVs regulated the KLF3-AS1/miR-183-5p/TCF7L2 signaling axis to attenuate neurological deficit and endothelial dysfunction after SAH. ConclusionOverall, KLF3-AS1 delivered by BMSC-EVs upregulate TCF7L2 expression by binding to miR-138-5p, thus attenuating neurological deficits and endothelial dysfunction after SAH.

TAT-HSP27 Peptide Improves Neurologic Deficits via Reducing Apoptosis After Experimental Subarachnoid Hemorrhage.

Cell apoptosis plays an important role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Heat shock protein 27 (HSP27), a member of the small heat shock protein (HSP) family, is induced by various stress factors and exerts protective role on cells. However, the role of HSP27 in brain injury after SAH needs to be further clarified. Here, we reported that HSP27 level of cerebrospinal fluid (CSF) is increased obviously at day 1 in patients with aneurysmal SAH (aSAH) and related to the grades of Hunt and Hess (HH), World Federation of Neurological Surgeons (WFNS), and Fisher score. In rat SAH model, HSP27 of CSF is first increased and then obviously declined; overexpression of HSP27, not knockdown of HSP27, attenuates SAH-induced neurological deficit and cell apoptosis in the basal cortex; and overexpression of HSP27 effectively suppresses SAH-elevated activation of mitogen-activated protein Kinase Kinase 4 (MKK4), the c-Jun N-terminal kinase (JNK), c-Jun, and caspase-3. In an in vitro hemolysate-damaged cortical neuron model, HSP2765−90 peptide effectively inhibits hemolysate-induced neuron death. Furthermore, TAT-HSP2765−90 peptide, a fusion peptide consisting of trans-activating regulatory protein (TAT) of HIV and HSP2765−90 peptide, effectively attenuates SAH-induced neurological deficit and cell apoptosis in the basal cortex of rats. Altogether, our results suggest that TAT-HSP27 peptide improves neurologic deficits via reducing apoptosis.

Roles of Rufy3 in experimental subarachnoid hemorrhage-induced early brain injury via accelerating neuronal axon repair and synaptic plasticity

RUN and FYVE domain-containing 3 (Rufy3) is a well-known adapter protein of a small GTPase protein family and is bound to the activated Ras family protein to maintain neuronal polarity. However, in experimental subarachnoid hemorrhage (SAH), the role of Rufy3 has not been investigated. Consequently, we aimed to investigate the potential role of Rufy3 in an in vivo model of SAH-induced early brain injury (EBI). In addition, we investigated the relevant brain-protective mechanisms. Oxyhemoglobin (OxyHb) stimulation of cultured primary neurons simulated vitro SAH condition. The SAH rat model was induced by infusing autologous blood into the optic chiasma pool and treating the rats with lentivirus-negative control 1 (LV-NC1), lentivirus-Rufy3 shRNA (LV-shRNA), lentivirus-negative control 2 (LV-NC2), lentivirus-Rufy3 (LV-Rufy3), or 8-pCPT-2′-O-Me-cAMP (8p-CPT) (Rap1 agonist). In experiment one, we found that the protein level of Rufy3 decreased and neuronal axon injury in the injured neurons but was rectified by LV-Rufy3 treatment. In experiment two, mRNA and protein levels of Rufy3 were downregulated in brain tissue and reached the lowest level at 24 h after SAH. In addition, the expression of Myelin Basic Protein was downregulated and that of anti-hypophosphorylated neurofilament H (N52) was upregulated after SAH. In experiments three and four, Rufy3 overexpression (LV-Rufy3) increased the interactions between Rufy3 and Rap1, the level of Rap1-GTP, and the ratio of Rap1-GTP/total GTP. In addition, LV-Rufy3 treatment inhibited axon injury and accelerated axon repair by activating the Rap1/Arap3/Rho/Fascin signaling pathway accompanied by upregulated protein expression levels of ARAP3, Rho, Fascin, and Facin. LV-Rufy3 also enhanced synaptic plasticity by activating the Rap1/MEK/ERK/synapsin I signaling pathway accompanied by upregulated protein expression levels of ERK1, p-ERK1, MEK1, p-MEK1, synaspin I, and p-synaspin I. Moreover, LV-Rufy3 also alleviated brain damage indicators, including cortical neuronal cell apoptosis and degeneration, brain edema, and cognitive impairment after SAH. However, the downregulation of Rufy3 had the opposite effect and aggravated EBI induced by SAH. Notably, the combined application of LV-Rufy3 and 8p-CPT showed a significant synergistic effect on the aforementioned parameters. Our findings suggest that enhanced Rufy3 expression may reduce EBI by inhibiting axon injury and promoting neuronal axon repair and synaptic plasticity after SAH.

Edaravone Dexborneol Treatment Attenuates Neuronal Apoptosis and Improves Neurological Function by Suppressing 4-HNE-Associated Oxidative Stress After Subarachnoid Hemorrhage.

Edaravone dexborneol is a novel neuroprotective drug that comprises edaravone and (+)-borneol in a 4:1 ratio. Phase II and III studies have demonstrated that Chinese patients treated with edaravone dexborneol within 48 h of AIS onset have better functional outcomes than those treated with edaravone alone. However, the effect of edaravone dexborneol on subarachnoid hemorrhage (SAH) has not yet been elucidated. This study aimed to investigate the therapeutic effects of edaravone dexborneol on SAH-induced brain injury and long-term behavioral deficits and to explore the possible mechanisms. The experimental rat SAH model was induced by an intraluminal puncture of the left middle cerebral artery (MCA). Edaravone dexborneol or edaravone at a clinical dose was infused into the tail vein for 3 days post-SAH surgery. Behavioral outcomes were assessed by a modified Garcia scoring system and rotarod, foot-fault, and corner tests. Immunofluorescence, Western blot, and ELISA methods were used to evaluate neuronal damage and oxidative stress. Our results showed that a post-SAH therapeutic regimen with edaravone dexborneol helped improve neurological function up to 21 days after SAH surgery and demonstrated a greater beneficial effect than edaravone alone, accompanied by an obvious inhibition of neuronal apoptosis in the CA1 hippocampus and basal cortex regions. Mechanistically, edaravone dexborneol not only suppressed the lipid peroxidation product malondialdehyde (MDA) but also improved the total antioxidant capability (TAC) 3 days after SAH. Notably, edaravone dexborneol treatment significantly inhibited the expression of another lipid peroxidation product, 4-hydroxynonenal (4-HNE), in the CA1 hippocampus and basal cortex, which are vital participants in the process of neuronal oxidative damage and death after SAH because of their acute cytotoxicity. Together, our results demonstrate that edaravone dexborneol confers neuroprotection and stabilizes long-term behavioral ability after SAH injury, possibly by suppressing 4-HNE-associated oxidative stress. These results may help develop new clinical strategies for SAH treatment.

Glibenclamide reduces secondary brain injury in a SAH rat model by reducing brain swelling and modulating inflammatory response.

Early brain injury (EBI) after subarachnoid hemorrhage (SAH) is a new therapeutic target. Sulfonylurea receptor 1 (SUR1) is expressed in nerve cells, glial cells, and vascular endothelial cells in EBI. SUR1 promotes intracellular inflow of Na and Ca ions, resulting in cell swelling and depolarization, and finally cell death. Glibenclamide reduced cerebral edema and mortality in a basic study of cerebral ischemia. However, the effects of glibenclamide on EBI have not been fully elucidated. This study examined the inhibitory effect of glibenclamide on EBI. Rats were divided into the sham group, SAH-control group, and SAH-glibenclamide group. The water content of the brain was measured using the dry-wet method. In addition, the brain was divided into the cortex, putamen, and hippocampus, and expression of inflammatory cytokines was evaluated by the polymerase chain reaction method. In addition, microglia in the brain were evaluated immunohistologically. Water content of the brain was significantly decreased in the SAH-glibenclamide group compared to the SAH-control group. Interleukin-1beta (IL-1β), tumor necrosis factor alpha (TNFα), and nuclear factor-kappa B significantly increased in the cerebral cortex after SAH. IL-1β and TNFα in the cortex were significantly decreased in the SAH-glibenclamide group compared to the SAH-control group. Immunohistochemical staining confirmed that SAH causes extensive microglial activation in the brain, which was suppressed by glibenclamide. The present study showed that glibenclamide suppressed cerebral edema and activation of microglia and hypersecretion of inflammatory cytokines. Glibenclamide is a potential therapeutic method which may significantly improve the functional prognosis.

Action mechanism of early cerebral injuries after spontaneous subarachnoid hemorrhage by silence Ghrelin and angiogenic factor with G-patch and FHA domain 1

ABSTRACT The objective of the research was to investigate action mechanism of oxidative stress and cerebral injuries after subarachnoid hemorrhage (SAH) by Ghrelin and angiogenic factor G-patch and FHA domain 1 (Aggf1) and offer new research ideas to SAH clinical treatment and SAH-induced early cerebral injuries. SAH rat models were prepared by prechiasmatic anterior cistern injection. Specific Ghrelin and Aggf1 small interfering ribonucleic acid (siRNA) were designed and injected into silence Ghrelin or Aggf1 in rat left lateral ventricles. Rats were divided randomly into sham-operated (sham), SAH model, negative control siRNA, Ghrelin silence (Ghrelin(-/-)), and Aggf1 silence groups. Changes of rat neurological impairment, encephaledema, cerebral tissue phosphorylated protein kinase (p-Akt), and content changes of caspase-3 protein and oxidative stress indexes were observed, including glutathione (GSH) and oxidized glutathione (GSSG). Results showed scores of neurological impairment and water content in SAH model group were reduced compared with sham group, while p-Akt protein and GSH contents were enhanced. However, caspase-3 protein and GSSG contents were declined, showing statistically meaningful difference (P < 0.05). Compared with SAH model group, scores of neurological impairment, cerebral tissue water content, and caspase-3 protein and GSSG contents in silence Ghrelin and Aggf1 groups were increased, while p-Akt protein and GSH contents were decreased, demonstrating statistically meaningful difference (P < 0.05). To conclude, silence Ghrelin and Aggf1 aggravated early cerebral injuries after SAH, revealing that Ghrelin and Aggf1 could protect brains to some degree.

Trigeminal Nerve Stimulation Improves Cerebral Macrocirculation and Microcirculation After Subarachnoid Hemorrhage: An Exploratory Study.

Delayed cerebral ischemia (DCI) is the most consequential secondary insult after aneurysmal subarachnoid hemorrhage (SAH). It is a multifactorial process caused by a combination of large artery vasospasm and microcirculatory dysregulation. Despite numerous efforts, no effective therapeutic strategies are available to prevent DCI. The trigeminal nerve richly innervates cerebral blood vessels and releases a host of vasoactive agents upon stimulation. As such, electrical trigeminal nerve stimulation (TNS) has the capability of enhancing cerebral circulation. To determine whether TNS can restore impaired cerebral macrocirculation and microcirculation in an experimental rat model of SAH. The animals were randomly assigned to sham-operated, SAH-control, and SAH-TNS groups. SAH was induced by endovascular perforation on Day 0, followed by KCl-induced cortical spreading depolarization on day 1, and sample collection on day 2. TNS was delivered on day 1. Multiple end points were assessed including cerebral vasospasm, microvascular spasm, microthrombosis, calcitonin gene-related peptide and intercellular adhesion molecule-1 concentrations, degree of cerebral ischemia and apoptosis, and neurobehavioral outcomes. SAH resulted in significant vasoconstriction in both major cerebral vessels and cortical pial arterioles. Compared with the SAH-control group, TNS increased lumen diameters of the internal carotid artery, middle cerebral artery, and anterior cerebral artery, and decreased pial arteriolar wall thickness. Additionally, TNS increased cerebrospinal fluid calcitonin gene-related peptide levels, and decreased cortical intercellular adhesion molecule-1 expression, parenchymal microthrombi formation, ischemia-induced hypoxic injury, cellular apoptosis, and neurobehavioral deficits. Our results suggest that TNS can enhance cerebral circulation at multiple levels, lessen the impact of cerebral ischemia, and ameliorate the consequences of DCI after SAH.

Inhibition of caspase-1-mediated inflammasome activation reduced blood coagulation in cerebrospinal fluid after subarachnoid haemorrhage.

SummaryBackgroundNeuroinflammation and blood coagulation responses in cerebrospinal fluid (CSF) contribute to the poor outcome associated with subarachnoid haemorrhage (SAH). We explored the role of caspase-1-mediated inflammasome activation on extrinsic blood coagulation in CSF after SAH.MethodsPost-SAH proteomic changes and correlation between caspase-1 with extrinsic coagulation factors in human CSF after SAH were analysed. Time course and cell localisation of brain inflammasome and extrinsic coagulation proteins after SAH were explored in a rat SAH model. Pharmacological inhibition of caspase-1 via VX-765 was used to explore the role of caspase-1 in blood clearance and CSF circulation after SAH in rats. Primary astrocytes were used to evaluate the role of caspase-1 in haemoglobin-induced pyroptosis and tissue factor (TF) production/release.FindingsNeuroinflammation and blood coagulation activated after SAH in human CSF. The caspase-1 levels significantly correlated with the extrinsic coagulation factors. The activated caspase-1 and extrinsic coagulation initiator TF was increased on astrocytes after SAH in rats. VX-765 attenuated neurological deficits by accelerating CSF circulation and blood clearance through inhibiting pyroptotic neuroinflammation and TF-induced fibrin deposition in the short-term, and improved learning and memory capacity by preventing hippocampal neuronal loss and hydrocephalus in the long-term after SAH in rats. VX-765 reduced haemoglobin-induced pyroptosis and TF production/release in primary astrocytes.InterpretationInhibition of caspase-1 by VX-765 appears to be a potential treatment against neuroinflammation and blood coagulation in CSF after SAH.FundingThis study was supported by National Institutes of Health of United States of America, and National Natural Science Foundation of China.

2-PMAP Ameliorates Cerebral Vasospasm and Brain Injury after Subarachnoid Hemorrhage by Regulating Neuro-Inflammation in Rats.

A subarachnoid hemorrhage (SAH), leading to severe disability and high fatality in survivors, is a devastating disease. Neuro-inflammation, a critical mechanism of cerebral vasospasm and brain injury from SAH, is tightly related to prognoses. Interestingly, studies indicate that 2-[(pyridine-2-ylmethyl)-amino]-phenol (2-PMAP) crosses the blood–brain barrier easily. Here, we investigated whether the vasodilatory and neuroprotective roles of 2-PMAP were observed in SAH rats. Rats were assigned to three groups: sham, SAH and SAH+2-PMAP. SAHs were induced by a cisterna magna injection. In the SAH+2-PMAP group, 5 mg/kg 2-PMAP was injected into the subarachnoid space before SAH induction. The administration of 2-PMAP markedly ameliorated cerebral vasospasm and decreased endothelial apoptosis 48 h after SAH. Meanwhile, 2-PMAP decreased the severity of neurological impairments and neuronal apoptosis after SAH. Furthermore, 2-PMAP decreased the activation of microglia and astrocytes, expressions of TLR-4 and p-NF-κB, inflammatory markers (TNF-α, IL-1β and IL-6) and reactive oxygen species. This study is the first to confirm that 2-PMAP has vasodilatory and neuroprotective effects in a rat model of SAH. Taken together, the experimental results indicate that 2-PMAP treatment attenuates neuro-inflammation, oxidative stress and cerebral vasospasm, in addition to ameliorating neurological deficits, and that these attenuating and ameliorating effects are conferred through the TLR-4/NF-κB pathway.

Apelin-13 attenuates early brain injury through inhibiting inflammation and apoptosis in rats after experimental subarachnoid hemorrhage.

Early brain injury (EBI) has been considered as the major contributor to the neurological dysfunction and poor clinical outcomes of subarachnoid hemorrhage (SAH). Studies showed that apelin-13 exhibits a neuroprotective effect in brain damage induced by cerebral ischemia. However, it remains unclear whether apelin-13 could exhibit the protective functions following SAH. The present study aimed to validate the neuroprotective role of apelin-13 in SAH, and further investigated the underlying mechanisms. We constructed SAH rat model and we found that apelin-13 significantly alleviated neurological disorder and brain edema, improved memory deficits in SAH rats. Apelin-13 treatment decreased contents of TNF-α and IL-1β in cerebral spinal fluid of SAH rat by using ELISA. Apelin-13 treatment promoted the expression of APJ and Bcl-2, and decreased the level of active caspase-3 and Bax in the temporal cortex after SAH by using western blot. Also, apelin-13 attenuated the cortical cell death and neuronal degeneration as shown by TUNEL, FJB and Nissl staining. However, ML221, an inhibitor of APJ, significantly reversed all the above neuroprotective effects of apelin-13. Moreover, a neuron-microglia co-culture system, which mimic SAH in vitro, confirmed the protective effect of apelin-13 on neurons and the inhibitory effect on inflammation through apoptosis-related proteins. These data demonstrated that apelin-13 exhibit a neuroprotective role after SAH through inhibition of apoptosis in an APJ dependent manner.