SAH-induced Early Brain Injury Research Articles

Protective effect 3,4-dihydroxyphenylethanol in subarachnoid hemorrhage provoked oxidative neuropathy.

Clinical studies have indicated that early brain injury (EBI) following subarachnoid hemorrhage (SAH) is associated with fatal outcomes. Oxidative stress and brain edema are the characteristic pathological events in occurrence EBI following SAH. The present study aimed to examine the effect of 3,4-dihydroxyphenylethanol (DOPET) against SAH-induced EBI, and to demonstrate whether the effect is associated with its potent free radical scavenging property. SAH was induced in rats using an endovascular perforation technique, and 24 h later the rats displayed diminished neurological scores and brain edema. Furthermore, elevated malondialdehyde (an index of lipid peroxidation) and depleted levels of antioxidants were observed in the rat cerebral cortex tissue. Quantitative polymerase chain reaction analysis indicated the upregulated mRNA expression of the apoptotic markers caspase-3 and -9 in the cerebral cortex. Furthermore, the protein expression levels of the proinflammatory cytokines tumor necrosis factor-α, interleukin (IL)-1β and IL-6 were significantly upregulated in SAH-induced rats. By constrast, treatment with DOPET significantly attenuated EBI by reducing brain edema, elevation of antioxidant status, inhibition of apoptosis and inflammation. In this context, DOPET may be a potent agent in the treatment of EBI following SAH, as a result of its free radical scavenging capacity.

Pentoxifylline Alleviates Early Brain Injury in a Rat Model of Subarachnoid Hemorrhage.

Subarachnoid hemorrhage (SAH) is a severe cerebrovascular disease frequently caused by ruptured aneurysms. Early brain injury (EBI) is the primary cause of morbidity and mortality in patients diagnosed with SAH and is associated with increased intracranial pressure, decreased cerebral blood flow and cerebral ischemia. Pentoxifylline (PTX) is a methylxanthine derivative clinically proven to improve perfusion in the peripheral microcirculation and has been shown to have neuroprotective effects in brain trauma and global cerebral ischemia in experimental animal models. This study aimed to determine the effect of PTX in experimental SAH, which has not been investigated yet. An experimental SAH model was induced in male Wistar rats by autologous blood injection into the prechiasmatic cistern, and PTX was injected intraperitoneally immediately after SAH. The effects of PTX were evaluated 24h after SAH via assessing the cerebral ultrastructure via transmission electron microscopy (TEM). Brain edema, blood-brain barrier (BBB) permeability, red blood cell deformability, tumor necrosis factor-alpha (TNF-alpha), nitrite-nitrate levels and apoptotic neuron death were also determined 24h after SAH. The BBB permeability was measured by Evans blue (EB) extravasation, erythrocyte deformability was determined by filtration technique, and TNF-alpha and reactive nitrogen metobolites were analyzed in brain tissue by ELISA and spectral analysis, respectively. Apoptotic neurons were determined in brain sections by cleaved caspase-3 immunohistochemical analysis, and expression intensity was quantified using image J software. Cerebral ultrastructure in SAH group animals revealed intense perivascular edema and distortion in the astrocyte foot processes. PTX treatment attenuated structural deterioration due to SAH. Brain water content, BBB permeability, TNF-alpha, nitrite-nitrate levels and apoptotic neuronal death were significantly increased 24h after SAH and were significantly alleviated by PTX treatment. There was no significant change in red cell deformability after SAH. Our results show that PTX reduces brain edema, BBB permeability, TNF-alpha expression, reactive nitrogen metobolites and apopotosis in experimental SAH. Based on our findings we suggest that PTX exerts neuroprotection against SAH-induced EBI, which might be associated with the inhibition of inflammation and apoptotic neuronal cell death.

Inhibition of mammalian target of rapamycin attenuates early brain injury through modulating microglial polarization after experimental subarachnoid hemorrhage in rats

Here, we aimed to study the role and underlying mechanism of mTOR in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Experiment 1, the time course of mTOR activation in the cortex following SAH. Experiment 2, the role of mTOR in SAH-induced EBI. Adult SD rats were divided into four groups: sham group (n=18), SAH+vehicle group (n=18), SAH+rapamycin group (n=18), SAH+AZD8055 group (n=18). Experiment 3, we incubated enriched microglia with OxyHb. Rapamycin and AZD8055 were also used to demonstrate the mTOR's role on microglial polarization in vitro. The phosphorylation levels of mTOR and its substrates were significantly increased and peaked at 24h after SAH. Rapamycin or AZD8055 markedly decreased the phosphorylation levels of mTOR and its substrates and the activation of microglia in vivo, and promoted the microglial polarization from M1 phenotype to M2 phenotype. In addition, administration of rapamycin and AZD8055 following SAH significantly ameliorated EBI, including neuronal apoptosis, neuronal necrosis, brain edema and blood-brain barrier permeability. Our findings suggested that the rapamycin and AZD8055 could attenuate the development of EBI in this SAH model, possibly through inhibiting the activation of microglia by mTOR pathway.

Isoflurane postconditioning with cardiac support promotes recovery from early brain injury in mice after severe subarachnoid hemorrhage

AimsNeurocardiac dysfunction is a life-threatening systemic consequence of subarachnoid hemorrhage (SAH) that contributes to triggering delayed cerebral ischemia (DCI). This study aimed to determine the impact of dobutamine cardiac support during isoflurane postconditioning on post-SAH DCI. Main methodsMale C57BL/6 mice were subjected to SAH, SAH plus isoflurane postconditioning, or SAH plus isoflurane postconditioning with dobutamine. Severity of SAH was graded from 1 to 4 (mild, 1–2; severe, 3–4) based on T2*-weighted magnetic resonance imaging (MRI). Cardiac output (CO) measured by transthoracic pulsed wave Doppler-echocardiography was titrated at a supra-normal level with intravenous dobutamine infusion. Neurological function was examined daily by neurological score and Rotarod tests. DCI was analyzed 3days later by determining new infarction on diffusion-weighted MRI. In a separate experiment, mice were pretreated with hypoxia-inducible factor (HIF) inhibitor 2-methoxyestradiol (2ME2). Key findingsClinically relevant CO depression was notable in severe SAH grade mice, in which dobutamine CO management combined with isoflurane postconditioning showed earlier and improved functional recovery than postconditioning with single isoflurane inhalation. Incidence of infarction and volumes on day 3 reduced significantly in this subgroup. All of the effects during preconditioning were attenuated by 2ME2 pretreatment. SignificanceIsoflurane postconditioning under dobutamine cardiac support improves recovery from SAH-induced early brain injury, leading to reduced DCI resultant from severe experimental SAH. These results indicate the importance of neuro-cardiac protection, in which HIF may be acting as a critical mediator, as a promising therapeutic approach to SAH.

Pramipexole-Induced Hypothermia Reduces Early Brain Injury via PI3K/AKT/GSK3β pathway in Subarachnoid Hemorrhage rats.

Previous studies have shown neuroprotective effects of hypothermia. However, its effects on subarachnoid hemorrhage (SAH)-induced early brain injury (EBI) remain unclear. In this study, a SAH rat model was employed to study the effects and mechanisms of pramipexole-induced hypothermia on EBI after SAH. Dose-response experiments were performed to select the appropriate pramipexole concentration and frequency of administration for induction of mild hypothermia (33–36 °C). Western blot, neurobehavioral evaluation, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and Fluoro-Jade B (FJB) staining were used to detect the effects of pramipexole-induced hypothermia on SAH-induced EBI, as well as to study whether controlled rewarming could attenuate these effects. Inhibitors targeting the PI3K/AKT/GSK3β pathway were administered to determine whether the neuroprotective effect of pramipexole-induced hypothermia was mediated by PI3K/AKT/GSK3β signaling pathway. The results showed that intraperitoneal injection of pramipexole at 0.25 mg/kg body weight once per 8 hours was found to successfully and safely maintain rats at mild hypothermia. Pramipexole-induced hypothermia ameliorated SAH-induced brain cell death, blood-brain barrier damage and neurobehavioral deficits in a PI3K/AKT/GSK3β signaling-dependent manner. Therefore, we may conclude that pramipexole-induced hypothermia could effectively inhibit EBI after SAH in rats via PI3K/AKT/GSK3β signaling pathway.

Inhibitory effects of omega-3 fatty acids on early brain injury after subarachnoid hemorrhage in rats: Possible involvement of G protein-coupled receptor 120/β-arrestin2/TGF-β activated kinase-1 binding protein-1 signaling pathway

Omega-3 fatty acids have been reported to improve neuron functions during aging and in patients affected by mild cognitive impairment, and mediate potent anti-inflammatory via G protein-coupled receptor 120 (GPR120) signal pathway. Neuron dysfunction and inflammatory response also contributed to the progression of subarachnoid hemorrhage (SAH)-induced early brain injury (EBI). This study was to examine the effects of omega-3 fatty acids on SAH-induced EBI. Two weeks before SAH, 30% Omega-3 fatty acids was administered by oral gavage at 1g/kg body weight once every 24h. Specific siRNA for GPR120 was exploited. Terminal deoxynucleotidyl transferase dUTP nick end labeling, fluoro-Jade B staining, and neurobehavioral scores and brain water content test showed that omega-3 fatty acids effectively suppressed SAH-induced brain cell apoptosis and neuronal degradation, behavioral impairment, and brain edema. Western blot, immunoprecipitation, and electrophoretic mobility shift assays results showed that omega-3 fatty acids effectively suppressed SAH-induced elevation of inflammatory factors, including cyclooxygenase-2, monocyte chemoattractant protein-1, and inducible nitric oxide synthase. In addition, omega-3 fatty acids could inhibit phosphorylation of transforming growth factor β activated kinase-1 (TAK1), MEK4, c-Jun N-terminal kinase, and IkappaB kinase as well as activation of nuclear factor kappa B through regulating GPR120/β-arrestin2/TAK1 binding protein-1 pathway. Furthermore, siRNA-induced GPR120 silencing blocked the protective effects of omega-3 fatty acids. Here, we show that stimulation of GPR120 with omega-3 fatty acids pretreatment causes anti-apoptosis and anti-inflammatory effects via β-arrestin2/TAK1 binding protein-1/TAK1 pathway in the brains of SAH rats. Fish omega-3 fatty acids as part of a daily diet may reduce EBI in an experimental rat model of SAH.

Propofol Attenuates Early Brain Injury After Subarachnoid Hemorrhage in Rats.

Our previous studies demonstrated that propofol protects rat brain against focal cerebral ischemia. However, whether propofol attenuates early brain injury after subarachnoid hemorrhage in rats remains unknown until now. The present study was performed to evaluate the effect of propofol on early brain injury after subarachnoid hemorrhage in rats and further explore the potential mechanisms. Sprague-Dawley rats underwent subarachnoid hemorrhage (SAH) by endovascular perforation then received treatment with propofol (10 or 50 mg/kg) or vehicle after 2 and 12 h of SAH. SAH grading, neurological scores, brain water content, Evans blue extravasation, the myeloperoxidase activity, and malondialdehyde (MDA) content were measured 24 h after SAH. Expression of nuclear factor erythroid-related factor 2 (Nrf2), nuclear factor-kappa B (NF-κB) p65, and aquaporin 4 (AQP4) expression in rat brain were detected by Western blot. Expression of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9) were determined by reverse transcription-polymerase chain reaction (RT-PCR). Expressions of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were assessed by ELISA. Neurological scores, brain water content, Evans blue extravasation, the myeloperoxidase activity, and MDA content were significantly reduced by propofol. Furthermore, expression of Nrf2 in rat brain was upregulated by propofol, and expression of NF-κB p65, AQP4, COX-2, MMP-9, TNF-α, and IL-1β in rat brain were attenuated by propofol. Our results demonstrated that propofol improves neurological scores, reduces brain edema, blood-brain barrier (BBB) permeability, inflammatory reaction, and lipid peroxidation in rats of SAH. Propofol exerts neuroprotection against SAH-induced early brain injury, which might be associated with the inhibition of inflammation and lipid peroxidation.

Hydrogen Sulfide Ameliorates Early Brain Injury Following Subarachnoid Hemorrhage in Rats.

Increasing studies have demonstrated the neuroprotective effect of hydrogen sulfide (H2S) in central nervous system (CNS) diseases. However, the potential application value of H2S in the therapy of subarachnoid hemorrhage (SAH) is still not well known. This study was to investigate the potential effect of H2S on early brain injury (EBI) induced by SAH and explore the underlying mechanisms. The role of sodium hydrosulfide (NaHS), a donor of H2S, in SAH-induced EBI, was investigated in both in vivo and in vitro. A prechiasmatic cistern single injection model was used to produce experimental SAH in vivo. In vitro, cultured primary rat cortical neurons and human umbilical vein endothelial cells (HUVECs) were exposed to OxyHb at concentration of 10μM to mimic SAH. Endogenous production of H2S in the brain was significantly inhibited by SAH. The protein levels of the predominant H2S-generating enzymes in the brain, including cystathionineb-synthase (CBS) and 3-mercaptopyruvate sulfur transferase (3MST), were also correspondingly reduced by SAH, while treatment with NaHS restored H2S production and the expressions of CBS and 3MST. More importantly, NaHS treatment could significantly attenuate EBI (including brain edema, blood-brain barrier disruption, brain cell apoptosis, inflammatory response, and cerebral vasospasm) after SAH. In vitro, H2S protects neurons and endothelial function by functioning as an antioxidant and antiapoptotic mediator. Our results suggest that NaSH as an exogenous H2S donor could significantly reduce EBI induced by SAH.

Hydrogen-Rich Saline Attenuated Subarachnoid Hemorrhage-Induced Early Brain Injury in Rats by Suppressing Inflammatory Response: Possible Involvement of NF-κB Pathway and NLRP3 Inflammasome.

Early brain injury (EBI), highlighted with inflammation and apoptosis, occurring within 72h after subarachnoid hemorrhage (SAH), is associated with the prognosis of SAH. Recent studies have revealed that hydrogen-rich saline (HS) exerted multiple neuroprotective properties in many neurological diseases including SAH, involved to anti-oxidative and anti-apoptotic effect. We have previously reported that HS could attenuate neuronal apoptosis as well as vasospasm. However, the underlying mechanism of HS on inflammation in SAH-induced EBI remains unclear. In this study, we explored the influence of HS on nuclear factor-κB (NF-κB) pathway and nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome at early stage after SAH, by injecting HS intraperitoneally to SAH rats. One hundred and twenty-nine SD rats were randomly divided into four groups: sham group, SAH group, SAH+vehicle group, and SAH+HS group. SAH model was conducted using endovascular perforation method; all rats were sacrificed at 24h after SAH. Protein level of pIκBα, cytosolic and nuclear p65, NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, interleukin-1β (IL-1β), and cleaved caspase-3 were measured by western blot. mRNA level of IL-1β, interleukin-6 (IL-6), tumor necrosis factor-c (TNF-α) were evaluated by RT-PCR. Cellular injury and death was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Nissl staining, respectively. Our results showed that pIκBα, nuclear p65, NLRP3, ASC, caspase-1, IL-1β, cleaved caspase-3 proteins, as well as the mRNA of IL-1β, IL-6, and TNF-ɑ increased at 24h after SAH, while cytosolic p65 decreased. TUNEL and Nissl staining presented severe cellular injury at 24 h post-SAH. However, after HS administration, the changes mentioned above were reversed. In conclusion, HS may inhibit inflammation in EBI and improve neurobehavioral outcome after SAH, partially via inactivation of NF-κB pathway and NLRP3 inflammasome. Graphical Abstract Schematic representation of the mechanism of HS-mediated anti-inflammatory effect in EBI after SAH. The NF-κB inflammatory pathway and NLRP3 inflammasome are involved in the anti-neuroinflammatory effect of HS post-SAH. SAH-induced oxidative stress enhances the activation of NF-κB, thus promoting the translocation of p65 subunit into nucleus and increasing the mRNA level of its downstream proinflammatory cytokines (IL-1β, IN-6, TNF-α) and NLRP3. Elevated expression of NLRP3 mRNA increases the assembly of NLRP3 inflammasome. In addition, oxidative stress after SAH stimulates the activation of NLRP3 inflammasome, therefore, promoting caspase-1 activation and the cleavage of pro-IL-1β into mature IL-1β. Finally, activation of NF-κB pathway and NLRP3 inflammasome contribute to the inflammation response and cellular injury in EBI after SAH. HS treatment reversed the detrimental effect mentioned above via inactivation of NF-κB pathway and NLRP3 inflammasome. NF-κB nuclear factor-κB, IκB inhibitor of NF-κB, IKK Iκ kinase, NLRP3 nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3, ASC apoptosis-associated speck-like protein containing a caspase recruitment domain.

RETRACTED: A purine antimetabolite attenuates toll-like receptor-2, -4, and subarachnoid hemorrhage-induced brain apoptosis

BackgroundUpregulation of high-level toll-like receptors (TLRs) is observed in the serum of animals following experimental subarachnoid hemorrhage (SAH) and is highly related to SAH-induced early brain injury (EBI). The present study was of interest to examine the effect of 6-mercaptopurine (6-MP) on alternation of TLR-2, -3, and -4 in this model. MethodsA rodent SAH model was used. Administration with 6-MP (0.5/1/2 mg/kg/d) was initiated 1 h after the induction of SAH via an osmotic minipump. Cerebral cortex was harvested to measure TLRs messenger RNA and protein (reverse transcription polymerase chain reaction [rt-PCR] and Western blot). Cerebral cortex was harvested for activated caspases (rt-PCR) measurement. ResultsCellular evaluation revealed increased neuronal nuclei(+) neurons with vacuolated nuclear and glial fibrillary acidic protein(+) astrocytes in the SAH group, but absent in the 6-MP treatment and healthy controls. The TLR-3 levels were not significantly increased in animals subject to SAH, compared with the controls (no SAH). The levels of TLR-2 and -4 in the SAH only and SAH plus vehicle groups were significantly elevated (P < 0.01), and treatment with 6-MP reduced TLR-2, -3 (at 2 mg/kg), and -4 (dose-dependently) protein expression following SAH. Likewise, the TLR-4 messenger RNA levels were also significantly reduced in the 6-MP (at 1 mg/kg and 2 mg/kg) groups. Cleaved caspase-3 and caspase-9a were reduced at 2-mg/kg 6-MP treatment group. ConclusionsThese results show that 6-MP attenuates the expression of TLR-2, -4, especially TLR-4, which play an antiapoptotic effect on SAH-induced EBI. This finding supported that through modulating TLRs, 6-MP can attenuate SAH-induced EBI. Those results offer credit to the neuroprotective effect of 6-MP.

Expression signatures of long non-coding RNAs in early brain injury following experimental subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is an important cause of mortality in stroke patients. Long non-coding RNAs (LncRNAs) have important functions in brain disease, however their expression profiles in SAH remain to be elucidated. The present study aimed to investigate the expression signatures of LncRNAs and mRNAs in early brain injury (EBI) following SAH in a rat model. Male Wistar rats were randomly divided into an SAH group and a sham operation group. The expression signatures of the LncRNAs and mRNAs in the temporal lobe cortex were investigated using a rat LncRNAs array following experimental SAH. The results revealed that there were 144 downregulated and 64 upregulated LncRNAs and 181 downregulated and 221 upregulated mRNAs following SAH. Additionally, two upregulated (BC092207, MRuc008hvl) and three downregulated (XR_006756, MRAK038897, MRAK017168) LncRNAs were confirmed using reverse transcription quantitative polymerase chain reaction. The differentially expressed mRNAs were further analyzed using the Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The pathway analysis results provided by the KEGG database indicated that eight pathways associated with inflammation were involved in EBI following SAH. In conclusion, these results demonstrated that the expression profiles of the LncRNAs and mRNAs were significantly different between the SAH-induced EBI group and the sham operation group. These differently expressed LncRNAs may be important in EBI following SAH.

Curcumin, encapsulated in nano-sized PLGA, down-regulates nuclear factor κB (p65) and subarachnoid hemorrhage induced early brain injury in a rat model

BackgroundMore and more evidence revealed early brain injury (EBI) may determine the final outcome in aneurismal subarachnoid hemorrhage (SAH) patients. This study is of interest to examine the efficacy of nano-particle curcumin (nanocurcumin), a diarylheptanoid, on a SAH-induced EBI model. MethodsA rodent double hemorrhage model was employed. Nanocurcumin (75/150/300μg/kg/day) was administered via osmotic mini-pump post-SAH. CSF samples were collected to examine IL-1β, IL-6, IL-8 and TNF-α (rt-PCR). Cerebral cortex was harvested for NF-κB (p50/p65) (western blot), caspases (rt-PCR) measurement. ResultsNanocurcumin significantly reduced the bio-expression of NF-κB (p65), when compared with the SAH groups. The levels of IL-1β and IL-6 were increased in animals subjected to SAH, compared with the healthy controls, but absent in the high dose nanocurcumin+SAH group. Moreover, the levels of TNF-α in the SAH groups were significantly elevated. Treatment with nanocurcumin (300μg/kg) reduced the level to the healthy control. The cleaved caspase-3 and -9a was significantly reduced in 300μg/kg nanocurcumin treatment groups (P<0.05). ConclusionTreatment with nanocurcumin exerts its neuroprotective effect through the upward regulation of NF-κB (p65) and also reduced mitochondrion related caspase-9a expression. Besides, nanocurcumin decreased CSF levels of TNF-α and IL-1β, which may contribute to the extrinsic antiapoptotic effect. This study shows promise to support curcuminin, in a nano-particle, could attenuate SAH induced EBI.

Evidence for the role of phosphatidylcholine-specific phospholipase in experimental subarachnoid hemorrhage in rats

Neuron apoptosis and inflammatory responses contribute to subarachnoid hemorrhage (SAH)-induced early brain injury (EBI), which is the main aspect that affects patients' outcome. Previous research has demonstrated that phosphatidylcholine-specific phospholipase C (PC-PLC) plays critical roles in cell apoptosis and various inflammatory responses, and that tricyclodecan-9-yl-xanthogenate (D609), a well known PC-PLC inhibitor, is a powerful agent to protect brain from cerebral ischemic injury and SAH-induced cerebral vasospasm. However, the association between PC-PLC and SAH-induced EBI is undetermined. Therefore, we sought to investigate whether PC-PLC was implicated in SAH-induced EBI. Compared with sham group, an upregulation of PC-PLC activity was detected in the brain tissue and serum of SAH group. Pharmacological blockade of PC-PLC by D609 attenuated neurological behavior impairment, brain edema and blood–brain barrier (BBB) damage induced by SAH. In addition, D609 treatment significantly inhibited SAH-induced inflammatory response and neuron apoptosis. Furthermore, inhibition of PC-PLC in primary-cultured rat cortical neurons attenuated oxyhemoglobin (OxyHb)-induced apoptosis morphology and decrease in survival rate. In conclusion, our data suggest that PC-PLC participates in SAH-induced EBI.

Parecoxib, A Selective Cyclooxygenase Inhibitor, Attenuates C-Jun N-Terminal Kinase Activation in Experimental Subarachnoid Hemorrhage Induced Early Brain Injury

Background: Increased evidence has disclosed early brain injury (EBI) might determine the outcome of patients suffering from aneurismal subarachnoid hemorrhage (SAH). This study is of interest to examine the efficacy of parecoxib, a cyclooxygenase-2(COX-2) inhibitor, on SAH-induced EBI. Methods: The rodent SAH model was employed. 500/1000/2000ug/kg/day parecoxib was administered via osmotic mini-pump. CSF samples were collected to examine IL-1β, IL-6, IL-8 and TNF-α. Cerebral cortex was harvested for C-Jun N-terminal kinase (cJNK), NMDARs (western blot), B-cell lymphoma 2 (Bcl-2), caspases (rt- PCR) measurement. Results: Parecoxib dose-dependently reduced the bio-expression of cJNK when compared with the SAH groups. No significant differences were found in the levels of IL-8 among the experimental groups. The levels of IL-1β, IL-6 and TNF-α were increased in animals subjected to SAH, compared with healthy controls, but not in the medium- and high-dose parecoxib treatment group. Moreover, the levels of TNF-α in the SAH-only and SAH-plus vehicle groups were significantly elevated, and treatment with parecoxib (1000ug/kg) reduced the level of healthy controls. Cleaved caspase-3 and -9a were both significantly reduced in 2000ug/kg parecoxib treatment groups. Likewise, NMDAR-2a was significantly suppressed in parecoxib treatment SAH groups (p <0.01). Conclusion: Treatment with parecoxib exerts its neuroprotective effect through the dual effect of inhibiting cJNKactivated neuro-inflammation and reduced mitochondrion-related caspase-9a expression. Besides, parecoxib decreased CSF levels of TNF-α and IL-1β, which contributes to the anti-delayed vasoconstriction effect. This study lends credence to support the COX-2 inhibitor could attenuate SAH-induced EBI.

Recombinant human erythropoietin (rhEPO) alleviates early brain injury following subarachnoid hemorrhage in rats: Possible involvement of Nrf2–ARE pathway

Recombinant human erythropoietin (rhEPO) has demonstrated beneficial effects against vasospasm and brain damage at the late stage of subarachnoid hemorrhage (SAH); however few investigations have been done about the effect of rhEPO on SAH-induced early brain injury (EBI) and also the underlying mechanisms remain unclear. This study was undertaken to evaluate the influence of rhEPO on the nuclear factor erythroid 2-related factor 2 and antioxidant responsive element (Nrf2–ARE) pathway and early brain injury in rats after SAH. Adult male SD rats were divided into four groups: (1) control group ( n = 18); (2) SAH group ( n = 18); (3) SAH + vehicle group ( n = 18); and (4) SAH + rhEPO group ( n = 18). The rat SAH model was induced by injection of 0.3 ml fresh arterial, non-heparinized blood into the prechiasmatic cistern in 20 s. In SAH + rhEPO group, rhEPO was administered i.p. at 1000 U/kg starting 5 min after the induction of SAH and repeated every 8 h for 48 h. Brain samples were extracted at 48 h after SAH. As a result, we found that treatment with rhEPO markedly increased expressions of Nrf2–ARE pathway related agents, such as Nrf2, heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase-1 (NQO1), and glutathione S-transferase α-1 (GST-α1). Administration of rhEPO following SAH significantly ameliorated EBI, such as cortical apoptosis, brain edema, and blood–brain barrier (BBB) impairment. In conclusion, post-SAH rhEPO administration may attenuate EBI in this SAH model, possibly through activating Nrf2–ARE pathway and modulating cerebral oxidative stress by inducing antioxidant and detoxifying enzymes.