Simvastatin activates Akt/glycogen synthase kinase-3beta signal and inhibits caspase-3 activation after experimental subarachnoid hemorrhage

c-Abl Tyrosine Kinase-Mediated Neuronal Apoptosis in Subarachnoid Hemorrhage by Modulating the LRP-1-Dependent Akt/GSK3β Survival Pathway

Accumulating evidence suggests that neuronal apoptosis plays a critical role in early brain injury (EBI) after subarachnoid hemorrhage (SAH), and the inhibition of apoptosis can induce neuroprotective effects in SAH animal models. c-Abl has been reported to promote neuronal apoptosis in Alzheimer's disease and cerebral ischemia, but its role in SAH had not been illuminated until now. In the present study, the effect of c-Abl on neuronal apoptosis induced by SAH was investigated. c-Abl protein levels and neuronal apoptosis were markedly increased 24 h after SAH, and the inhibition of endogenous c-Abl reduced neuronal apoptosis and mortality and ameliorated neurological deficits. Furthermore, c-Abl inhibition decreased the expression of cleaved caspase-3 (CC-3) after SAH. These results demonstrate the proapoptotic effect of c-Abl in EBI after SAH. Additionally, c-Abl inhibition further enhanced the SAH-induced phosphorylation of Akt and glycogen synthase kinase (GSK)3β. LY294002 abrogated the beneficial effects of targeting c-Abl and exacerbated neuronal apoptosis after SAH. SAH decreased LRP-1 levels and downregulated LRP-1 by RAP, and LRP-1 small interfering RNA (siRNA) induced a dramatic decrease in Akt/GSK3β activation in the presence of c-Abl siRNA. This is the first report showing that the c-Abl tyrosine kinase may play a key role in SAH-induced neuronal apoptosis by regulating the LRP-1-dependent Akt/GSK3β survival pathway. Thus, c-Abl has the potential to be a novel target for EBI therapy after SAH.

Bax inhibitor-1 suppresses early brain injury following experimental subarachnoid hemorrhage in rats

Early brain injury (EBI) following subarachnoid hemorrhage (SAH) is an important cause of high mortality and poor prognosis in SAH. B‑cell lymphoma 2‑associated X protein inhibitor‑1 (BI‑1) is an evolutionarily conserved antiapoptotic protein that is primarily located in the membranes of endoplasmic reticulum (ER). BI‑1 has been studied in certain nervous system‑associated diseases, but the role of this protein in SAH remains unclear. In the present study, the role of BI‑1 in EBI following SAH was investigated in rat models and its associated mechanisms were examined. The SAH rat model was generated by inserting nylon cords into the internal carotid artery from the external carotid artery. Samples were assessed using neurological scores, brain water content measurements, hematoxylin and eosin (H&E) staining, blood‑brain barrier (BBB) permeability, terminal deoxynucleotidyl transferase‑mediated dUTP nick‑end labeling and quantitative polymerase chain reaction assays, and western blot analyses. It was identified that the mRNA and protein levels of BI‑1 decreased markedly and were lowest at 24 h after SAH. BI‑1 overexpression and small hairpin RNA (shRNA)‑mediated silencing markedly suppressed or severely exacerbated EBI following SAH, respectively. BI‑1 overexpression in the SAH model improved neurological scores and decreased the brain water content, BBB permeability and levels of apoptosis compared with the control and sham groups following SAH. BI‑1 shRNA in the SAH model demonstrated contrary results. In addition, the mRNA or protein expression levels of ER stress‑associated genes (glucose regulated protein, 78 kDa, C/EBP homologous protein, Serine/threonine‑protein kinase/endoribonuclease IRE1, c‑Jun N terminal kinases and apoptotic signaling kinase‑1) were markedly suppressed or increased following BI‑1 overexpression and shRNA‑mediated silencing, respectively. The present study suggested that BI‑1 serves a neuroprotective role in EBI following SAH by attenuating BBB disruption, brain edema and apoptosis mediated by ER stress.

Intranasally administered pitavastatin ameliorates pentylenetetrazol-induced neuroinflammation, oxidative stress and cognitive dysfunction

AIM

The present study aimed to evaluate the neuroprotective potential of intranasally administered pitavastatin in the PTZ-induced kindling model.

MATERIALS AND METHODS

Subconvulsant dose of PTZ (35 mg/kg, i.p) was administered on an alternate day until the development of kindling. Behavioural test, biochemical tests and inflammatory cytokines were estimated. Comparative molecular docking study of sodium valproate (VPA) and pitavastatin was performed to predict the binding affinity with GABA_A and GABA transaminase. Intranasally administered pitavastatin (0.5 mg/kg and 1 mg/kg) and VPA (200 mg/kg) were used to investigate its protective effect.

KEY FINDINGS

Comparative in-silico study showed docking score of -4.56 and -2.86 against GABA_A receptor whereas -5.56 and -1.86, against GABA transaminase. Root mean square deviation (RMSD) of 0.39A and 0.55A was found for pitavastatin and VPA, respectively. The present study showed the dose-dependent protective effect of intranasally administered pitavastatin and oral VPA against PTZ-induced seizure, cognitive impairment, oxidative stress, and neuroinflammation.

SIGNIFICANCE

Our findings suggest that the intranasally administered pitavastatin is potential therapeutic approach to managing PTZ-induced kindling and associated comorbid conditions via its antioxidant, anti-inflammatory, and anticonvulsant potential. Further, pitavastatin can modulate GABA_A receptor and GABA transaminase enzyme to ameliorate seizure. Meanwhile, more extensive studies are required to establish the molecular mechanism underlying the neuroprotective effect of pitavastatin.

Aloperine activates the Nrf2-ARE pathway when ameliorating early brain injury in a subarachnoid hemorrhage model

Aloperine (ALO) exhibits neuroprotective effects against oxidative stress in vitro; however, its protective effect in early brain injury (EBI) following experimental subarachnoid hemorrhage (SAH) remains to be elucidated. The aim of the current study was to evaluate the antioxidant activity of ALO in EBI, and its association with nuclear factor erythroid-related factor 2 and the antioxidant responsive element (Nrf2-ARE) survival pathway. In the present study, an experimental SAH model was induced in rats following a prechiasmatic cistern injection. All rats were randomly divided into five groups: Sham, SAH, SAH+ vehicle, and an SAH+ ALO group (including low and high doses). ALO was administrated intraperitoneally at 2 and 24 h following induction of the SAH model. Brain samples were collected from each group at 48 h after SAH induction. Subsequently, western blotting, immunohistochemistry and cell apoptosis assays were performed, along with assessments for brain edema, neurological deficit, and the activity of oxidant/antioxidant factors. It was observed that the expression of Nrf2-ARE pathway-associated agents, including Nrf2, and heme oxygenase-1, were markedly increased in the high concentration ALO group compared with that of the SAH group. In addition, the level of oxidative damage was reduced. Furthermore, early brain damage, including brain edema, neurological deficit and cellular apoptosis were significantly ameliorated. In conclusion, the results of the present study indicate that ALO can ameliorate oxidative damage against EBI following SAH, most likely via the Nrf2-ARE survival pathway.

Protective effects of PI3KCG gene on acute myocardial infarction

Background

To study the protective effects of recombinant phosphatidylinositol 3-kinase p110 gamma (rPLV-PI3KCG) lentiviral vector in Sprague-Dawley (SD) rats with acute myocardial infarction (AMI).

Method

The AMI rat models were established by ligaturing left anterior descending coronary artery. The rPLV-PI3KCG or empty lentiviral vectors were injected at the edge of the infarct zone. The experiment was divided randomly into four groups (n=8): (I) Sham group; (II) AMI group; (III) AMI + empty vector injection group (AMI + E group); and (IV) AMI + PLV-PI3KCG injection group (AMI + PLV-PI3KCG group). The ultrasonic cardiogram (UCG) was used to compare the structural or functional changes among the four groups after operation for 10 days. Meanwhile, the rats were sacrificed and HE staining was used to compare the myocardial tissue changes among the four groups. The immunofluorescence and western blots were performed to compare the angiogenesis in the infarct region and explore the mechanism of the protective effects of PI3KCG gene on AMI rats.

Results

Compared with AMI group and AMI + E group, in the AMI + PLV-PI3KCG group, left ventricular end diastolic diameter (LVEDd) was decreased, left ventricular ejection fraction (LVEF%) was significantly increased, and vascular endothelial growth factor (VEGF) expression was significantly increased in the infarct region (P<0.05); PI3KCG, pAkt/Akt, HIF-1a, and Bcl-2/Bax protein expressions were significantly increased (P<0.05).

Conclusions

The rPLV-PI3KCG injection could improve the cardiac function, relieve the cardiac injury after the AMI operation. PI3KCG gene could play the protection role in the AMI process possibly by activating PI3K/Akt signal pathway, inhibiting apoptosis and promoting angiogenesis.

X-linked inhibitor of apoptosis inhibits apoptosis and preserves the blood-brain barrier after experimental subarachnoid hemorrhage

Early brain injury following subarachnoid hemorrhage (SAH) strongly determines the prognosis of patients suffering from an aneurysm rupture, and apoptosis is associated with early brain injury after SAH. This study was designed to explore the role of X-linked inhibitor of apoptosis (XIAP) in early brain injury following SAH. The expression of XIAP was detected using western blotting and real-time RT-PCR in an autologous blood injection model of SAH. We also studied the role of XIAP in early brain injury and detected apoptosis-related proteins. The results showed that XIAP was significantly up-regulated in the cortex and hippocampus and that XIAP was mainly expressed in neuronal cells following SAH. The inhibition of endogenous XIAP aggravated blood-brain barrier disruption, neurological deficits and brain edema. Recombinant XIAP preserved the blood-brain barrier, improved the neurological scores and ameliorated brain edema. Recombinant XIAP treatment also decreased the expression of cleaved caspase-3, caspase-8 and caspase-9, whereas there was no effect on the expression of p53, apoptosis-inducing factor or cytochrome c. These results show that XIAP acts as an endogenous neuroprotective and anti-apoptotic agent following SAH. The effects of XIAP on early brain injury was associated with the inhibition of the caspase-dependent apoptosis pathway.

Protective effect of simvastatin on impaired intestine tight junction protein ZO-1 in a mouse model of Parkinson's disease

Recently, several studies showed that gastrointestinal tract may be associated with pathophysiology of Parkinson's disease (PD). Intestine tight junction protein zonula occluden-1 (ZO-1) is an important component of intestinal barrier which can be degraded by matrix metallopeptidase 9 (MMP-9). In our previous study, a significant decline in ZO-1 was observed along with enhanced MMP-9 activity in the duodenum and distal colon of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. In this study, the protective effect of simvastatin on ZO-1 was investigated using an MPTP mouse model of PD. Seven days after the end of MPTP application, the expression level of ZO-1 was evaluated by immunohistochemistry. The protein expression levels of ZO-1 and MMP9 were detected by Western blotting. Meanwhile, MMP-9 activity was analyzed by gelatin zymography. MPTP treatment led to a decrease in the expression of ZO-1, which was accompanied by elevated MMP-9 activity. Treatment with simvastatin could partly reverse the MPTP-induced changes in ZO-1 expression and reduce MMP-9 protein and activity. Taken together, these findings suggest that simvastatin administration may partially reverse the impairment of ZO-1 induced by MPTP via inhibiting the activity of MMP9, fortify the impaired intestinal barrier and limit gut-derived toxins that pass across the intestinal barrier.

Preconditioning with pitavastatin, an HMG-CoA reductase inhibitor, attenuates C-Jun N-terminal kinase activation in experimental subarachnoid hemorrhage-induced apoptosis

BACKGROUND

Accumulating results have disclosed that early brain injury (EBI) may play a major role in the determination of the outcome of aneurysmal subarachnoid hemorrhage (SAH) patients. This study is of interest to examine the efficacy of pitavastatin, a 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) inhibitor, on SAH-induced apoptosis.

METHODS

A rodent double SAH model was employed. Pitavastatin was administered orally. CSF IL-1β, IL-6, IL-8 and TNF-α were measured (rt-PCR). Basilar arteries were harvested for C-Jun N-terminal kinase p46/p55 (cJNK (p46/p55)), matrix metallopeptidase-9 (MMP-9) (Western blot), caspase and Bcl-2 (rt-PCR) evaluation.

RESULTS

Pitavastatin reduced the bioexpression of cJNK p55 compared with the SAH groups. Cleaved caspase-9a was significantly reduced in the pitavastatin-preconditioned group compared with the SAH group (p > 0.05). IL-1β and TNF-α levels were reduced in the pitavastatin-preconditioned group. Pretreatment with pitavastatin significantly reduced activated MMP-9, capsase-9a and B-cell lymphoma 2(Bcl) mRNA.

CONCLUSION

Preconditioning with pitavastatin exerts its neuroprotective effect through the dual action of inhibiting cJNK(p46/p55) activation and reducing cleaved caspase-9a expression. Besides, the bioinhibition of MMP-9 may partially contribute to the neuroprotective effect. This study lends credence to the theory that statins, especially in the preconditioning status, may attenuate SAH-induced neuron apoptosis.

The single and double blood injection rabbit subarachnoid hemorrhage model

Over the past 30 years, the rabbit subarachnoid hemorrhage model (SAH) has been used for investigating the post-hemorrhage pathology, especially with respect to understanding of the mechanisms of cerebral vasospasm. However, the molecular mechanisms of cerebral vasospasm remain to be elucidated. Furthermore, it is not clear whether the rabbit SAH model is suitable for the investigation of pathological conditions other than cerebral vasospasm, such as early brain injury. Therefore, the properties of the rabbit SAH model need to be validated, and the reasons for using the rabbit should be clarified. This review explores the settings and technical issues of establishing a rabbit cisterna magna single and double blood injection SAH model and discusses the characteristics and feasibilities of the models.

Carnosine attenuates early brain injury through its antioxidative and anti-apoptotic effects in a rat experimental subarachnoid hemorrhage model

Carnosine (β-alanyl-L-histidine) has been demonstrated to provide antioxidative and anti-apoptotic roles in the animal of ischemic brain injuries and neurodegenerative diseases. The aim of this study was to examine whether carnosine prevents subarachnoid hemorrhage (SAH)-induced early brain injury (EBI) in rats. We found that intraperitoneal administration of carnosine improved neurobehavioral deficits, attenuated brain edema and blood-brain barrier permeability, and decreased reactive oxygen species level at 48 h following SAH in rat models. Carnosine treatment increased tissue copper/zinc superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GSH-Px) enzymatic activities, and reduced post-SAH elevated lactate dehydrogenase (LDH) activity, the concentration of malondialdehyde (MDA), 3-nitrotyrosine (3-NT), 8-hydroxydeoxyguanosine (8-OHDG), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in rats. Furthermore, carnosine treatment attenuated SAH-induced microglia activation and cortical neuron apoptosis. These results indicated that administration of carnosine may provide neuroprotection in EBI following SAH in rat models.

Early brain injury, an evolving frontier in subarachnoid hemorrhage research

Subarachnoid hemorrhage (SAH), predominantly caused by a ruptured aneurysm, is a devastating neurological disease that has a morbidity and mortality rate higher than 50%. Most of the traditional in vivo research has focused on the pathophysiological or morphological changes of large-arteries after intracisternal blood injection. This was due to a widely held assumption that delayed vasospasm following SAH was the major cause of delayed cerebral ischemia and poor outcome. However, the results of the CONSCIOUS-1 trial implicated some other pathophysiological factors, independent of angiographic vasospasm, in contributing to the poor clinical outcome. The term early brain injury (EBI) has been coined and describes the immediate injury to the brain after SAH, before onset of delayed vasospasm. During the EBI period, a ruptured aneurysm brings on many physiological derangements such as increasing intracranial pressure (ICP), decreased cerebral blood flow (CBF), and global cerebral ischemia. These events initiate secondary injuries such as blood-brain barrier disruption, inflammation, and oxidative cascades that all ultimately lead to cell death. Given the fact that the reversal of vasospasm does not appear to improve patient outcome, it could be argued that the treatment of EBI may successfully attenuate some of the devastating secondary injuries and improve the outcome of patients with SAH. In this review, we provide an overview of the major advances in EBI after SAH research.

Controversies and evolving new mechanisms in subarachnoid hemorrhage

Despite decades of study, subarachnoid hemorrhage (SAH) continues to be a serious and significant health problem in the United States and worldwide. The mechanisms contributing to brain injury after SAH remain unclear. Traditionally, most in vivo research has heavily emphasized the basic mechanisms of SAH over the pathophysiological or morphological changes of delayed cerebral vasospasm after SAH. Unfortunately, the results of clinical trials based on this premise have mostly been disappointing, implicating some other pathophysiological factors, independent of vasospasm, as contributors to poor clinical outcomes. Delayed cerebral vasospasm is no longer the only culprit. In this review, we summarize recent data from both experimental and clinical studies of SAH and discuss the vast array of physiological dysfunctions following SAH that ultimately lead to cell death. Based on the progress in neurobiological understanding of SAH, the terms "early brain injury" and "delayed brain injury" are used according to the temporal progression of SAH-induced brain injury. Additionally, a new concept of the vasculo-neuronal-glia triad model for SAH study is highlighted and presents the challenges and opportunities of this model for future SAH applications.

Therapeutic implications of estrogen for cerebral vasospasm and delayed cerebral ischemia induced by aneurysmal subarachnoid hemorrhage

Cerebral vasospasm (CV) remains the leading cause of delayed morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). However, increasing evidence supports etiologies of delayed cerebral ischemia (DCI) other than CV. Estrogen, specifically 17 β -estradiol (E2), has potential therapeutic implications for ameliorating the delayed neurological deterioration which follows aneurysmal SAH. We review the causes of CV and DCI and examine the evidence for E2-mediated vasodilation and neuroprotection. E2 potentiates vasodilation by activating endothelial nitric oxide synthase (eNOS), preventing increased inducible NOS (iNOS) activity caused by SAH, and decreasing endothelin-1 production. E2 provides neuroprotection by increasing thioredoxin expression, decreasing c-Jun N-terminal kinase activity, increasing neuroglobin levels, preventing SAH-induced suppression of the Akt signaling pathway, and upregulating the expression of adenosine A2a receptor. The net effect of E2 modulation of these various effectors is the promotion of neuronal survival, inhibition of apoptosis, and decreased oxidative damage and inflammation. E2 is a potentially potent therapeutic tool for improving outcomes related to post-SAH CV and DCI. However, clinical evidence supporting its benefits remains lacking. Given the promising preclinical data available, further studies utilizing E2 for the treatment of patients with ruptured intracranial aneurysms appear warranted.

Role of Akt signaling pathway in delayed cerebral vasospasm after subarachnoid hemorrhage in rats

BACKGROUND

Akt plays an important role in cell survival, proliferation, apoptosis and other activities. It also has been involved in maintaining smooth muscle cell contraction phenotypes in vitro and in vivo. Recent studies have focused on the inhibition of Akt in acute vasospasm and neuronal apoptosis after subarachnoid hemorrhage (SAH). However, its role in delayed cerebral vasospasm (DCVS) has not been reported.

METHODS

In this study, using a "two-hemorrhage" rat model of SAH, we examined the expression of p-Akt and the formation of vasospasm in the basilar arteries. To investigate the possible role of Akt in phenotypic switching, we performed immunohistochemical staining to examine expressions of SMα-actin and proliferating cell nuclear antigen (PCNA), markers of smooth muscle phenotypic switching.

RESULTS

We found that the basilar arteries exhibited vasospasm after SAH and that vasospasm became most severe on day 7 after SAH. Elevated protein expression of p-Akt was detected 4 days after SAH induction, peaked on day 7, and recovered on day 21, which was in a parallel time course to the development of DCVS. Moreover, results of immunohistochemical staining revealed enhanced expression of PCNA but gradual reduction in expression of SMα-actin from day 1 to day 7 after SAH; then, the expressions of PCNA and SMα-actin gradually recovered until day 21.

CONCLUSIONS

These results support a novel mechanism in which the Akt signaling pathway plays an important role in the proliferation of smooth muscle cells (SMCs) rather than inducing phenotype switching in basilar arteries, which promotes the development of DCVS after SAH.

17β-Estradiol attenuates secondary injury through activation of Akt signaling via estrogen receptor alpha in rat brain following subarachnoid hemorrhage

BACKGROUND

Apoptosis is implicated in vasospasm and the long-term sequelae of subarachnoid hemorrhage (SAH). This study tested the hypothesis that attenuation of SAH-induced apoptosis after 17β-estradiol (E2) treatment is associated with an increase in phosphorylation of Akt via estrogen receptor-α (ER-α) in rats.

MATERIALS AND METHODS

We examined the expression of phospho-Akt, ERα and ERβ, and apoptosis in cerebral cortex, hippocampus, and dentate gyrus in a two-hemorrhage SAH model in rats. We subcutaneously implanted other rats with a silicone rubber tube containing E2; they received daily injections of nonselective estrogen receptor antagonist (ICI 182,780), selective ERα-selective antagonist (methyl-piperidino-pyrazole), or ERβ-selective antagonist (R,R-tetrahydrochrysene) after the first hemorrhage.

RESULTS

At 7 d after the first SAH, protein levels of phospho-Akt and ERα were significantly decreased and caspase-3 was significantly increased in the dentate gyrus. The cell death assay revealed that DNA fragmentation was significantly increased in the dentate gyrus. Those actions were reversed by E2 and blocked by ICI 182,780 and methyl-piperidino-pyrazole, but not R,R-tetrahydrochrysene. However, there were no significant changes in the expression of the protein levels of phospho-Akt, ERα, ERβ, and caspase-3, and DNA fragmentation after SAH.

CONCLUSIONS

The present study shows that a beneficial effect of E2 in attenuating SAH-induced apoptosis is associated with activation of the expression of phospho-Akt and ERα, and alteration in caspase-3 protein expression via an ERα-dependent mechanism in the dentate gyrus. These data support further the investigation of E2 in the treatment of SAH in humans.

Role of autophagy in early brain injury after subarachnoid hemorrhage in rats

Early brain injury (EBI) occurred after aneurismal subarachnoid hemorrhage (SAH) strongly determined the patients' prognosis. Autophagy was activated in neurons in the acute phase after SAH, while its role in EBI has not been examined. This study was designed to explore the effects of autophagy on EBI post-SAH in rats. A modified endovascular perforating SAH model was established under monitoring of intracranial pressure. Extent of autophagy was regulated by injecting autophagy-regulating drugs (3-methyladenine, wortmannin and rapamycin) 30 min pre-SAH intraventricularly. Simvastatin (20 mg/kg) was prophylactically orally given 14 days before SAH induction. Mortality, neurological scores, brain water content and blood-brain barrier (BBB) permeability were evaluated at 24 h post-SAH. Microtubule-associated protein light chain-3 (LC3 II/I) and beclin-1 were detected for monitoring of autophagy flux. Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling, expression of cleaved caspase-3 and cytoplasmic histone-associated DNA fragments were used to detect apoptosis. The results showed that mortality was reduced in rapamycin and simvastatin treated animals. When autophagy was inhibited by 3-methyladenine and wortmannin, the neurological scores were decreased, brain water content and BBB permeability were further aggravated and neuronal apoptosis was increased when compared with the SAH animals. Autophagy was further activated by rapamycin and simvastatin, and apoptosis was inhibited and EBI was ameliorated. The present results indicated that activation of autophagy decreased neuronal apoptosis and ameliorated EBI after SAH. Aiming at autophagy may be a potential effective target for preventing EBI after SAH.

Neuroprotective effect of Cyclosporin A on the development of early brain injury in a subarachnoid hemorrhage model: a pilot study

Cyclosporin A (CsA) has been demonstrated to be neuroprotective in ischemic and traumatic brain injuries by inhibiting mitochondrial permeability transition pore (mPTP) opening, thereby maintaining mitochondrial homeostasis and inhibiting pro-apoptotic protein release. The effects of CsA on early brain injury (EBI) after subarachnoid hemorrhage (SAH), however, have not been investigated. This study was designed to explore the effects of CsA on apoptotic signaling pathways and EBI after experimental SAH using four equal groups (n=36) of adult male SD rats, including the sham group, SAH+vehicle group, SAH+CsA2 group, and SAH+CsA10 group. The rat SAH model was induced by injection of 0.3ml non-heparinized arterial blood into the prechiasmatic cistern. In the SAH+CsA2 and SAH+CsA10 groups, a dose of 2mg/kg and 10mg/kg CsA was directly administered by intercarotid injection at 15min and again 24h after SAH induction. Cerebral tissue samples were extracted 48h after SAH. Increased expressions of Cytochrome C, apoptosis-inducing factor (AIF), and cleaved caspase-3 were observed in the cerebral cortex after SAH. Treatment with high dose (10mg/kg) CsA markedly decreased expressions of Cytochrome C, AIF, and cleaved caspase-3, and inhibited apoptosis pathways. Administration of CsA following SAH significantly ameliorated EBI, including cortical apoptosis, brain edema, blood-brain barrier (BBB) impairment, and neurobehavioral deficits. These findings suggest that early administration of CsA may ameliorate EBI and provide neuroprotection in the SAH model through potential mechanisms that include blockage of mPTP opening and inhibition of apoptotic cell death pathways.

CHOP silencing reduces acute brain injury in the rat model of subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Endoplasmic reticulum stress triggers apoptotic cascades in neurons of the central nervous system after subarachnoid hemorrhage. The aim of this work was to study the mechanism of neuroprotection conferred by targeting cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in the acute brain injury following subarachnoid hemorrhage.

METHODS

A total of 172 rats were used. Endovascular perforation induced subarachnoid hemorrhage. Two small interfering RNAs for CHOP were injected 24 hours before hemorrhage induction. At 24 or 72 hours, rats were neurologically evaluated and euthanized. The brains were recovered for molecular biology and histology studies.

RESULTS

Western blot analysis revealed effective silencing of CHOP associated with suppression of Bim-Caspase-3 apoptotic pathway. Moreover, the antiapoptotic Bcl2 was found upregulated with CHOP siRNA treatment. A reduced number of TUNEL-positive cells in the subcortex and in the hippocampus reflected histological protection. CHOP siRNA treatment ameliorated intracranial sequelae of and improved functional performance.

CONCLUSIONS

We conclude that CHOP silencing alleviates early brain injury following subarachnoid hemorrhage via inhibiting apoptosis and that CHOP siRNA treatment has a clinical potential for patients with this type of hemorrhagic stroke.

α7 nicotinic acetylcholine receptor agonist PNU-282987 attenuates early brain injury in a perforation model of subarachnoid hemorrhage in rats

BACKGROUND AND PURPOSE

Early brain injury is an important pathological process after subarachnoid hemorrhage (SAH). The goal of this study was to evaluate whether the α7 nicotinic acetylcholine receptor (α7nAChR) agonist PNU-282987 attenuates early brain injury after SAH and whether α7nAChR stimulation is associated with down-regulation of caspase activity via phosphatidylinositol 3-kinase-Akt signaling.

METHODS

The perforation model of SAH was performed, and neurological score, body weight loss, and brain water content were evaluated 24 and 72 hours after surgery. Western blot and immunohistochemistry were used for quantification and localization of phosphorylated Akt and cleaved caspase 3. Neuronal cell death was quantified with TUNEL staining. α7nAChR antagonist methylcaconitine and phosphatidylinositol 3-kinase inhibitor wortmannin were used to manipulate the proposed pathway, and results were quantified with Western blot.

RESULTS

PNU-282987 improved neurological deficits both 24 and 72 hours after surgery and reduced brain water content in left hemispheres 24 hours after surgery. PNU-282987 significantly increased phosphorylated Akt levels and significantly decreased cleaved caspase 3 levels in ipsilateral hemispheres after SAH. Methylcaconitine and wortmannin reversed effects of treatment. Phosphorylated Akt and cleaved caspase 3 were colocalized to neurons in the ipsilateral basal cortex. Phosphorylated Akt was mainly localized in TUNEL-negative cells. PNU-282987 significantly reduced neuronal cell death in the ipsilateral basal cortex.

CONCLUSIONS

α7nAChR stimulation decreased neuronal cell death and brain edema and improved neurological status in a rat perforation model of SAH. α7nAChR stimulation is associated with increasing phosphorylation of Akt and decreasing cleaved caspase 3 levels in neurons.

Atorvastatin treatment reduces exercise capacities in rats: involvement of mitochondrial impairments and oxidative stress

Physical exercise exacerbates the cytotoxic effects of statins in skeletal muscle. Mitochondrial impairments may play an important role in the development of muscular symptoms following statin treatment. Our objective was to characterize mitochondrial function and reactive oxygen species (ROS) production in skeletal muscle after exhaustive exercise in atorvastatin-treated rats. The animals were divided into four groups: resting control (CONT; n = 8) and exercise rats (CONT+EXE; n = 8) as well as resting (ATO; n = 10) and exercise (ATO+EXE; n = 8) rats that were treated with atorvastatin (10 mg·kg(-1)·day(-1) for 2 wk). Exhaustive exercise showed that the distance that was covered by treated animals was reduced (P < 0.05). Using dihydroethidium staining, we showed that the ROS level was increased by 60% in the plantaris muscle of ATO compared with CONT rats and was highly increased in ATO+EXE (226%) compared with that in CONT+EXE rats. The maximal mitochondrial respiration (V(max)) was decreased in ATO rats compared with that in CONT rats (P < 0.01). In CONT+EXE rats, V(max) significantly increased compared with those in CONT rats (P < 0.05). V(max) was significantly lower in ATO+EXE rats (-39%) compared with that in CONT+EXE rats (P < 0.001). The distance that was covered by rats significantly correlated with V(max) (r = 0.62, P < 0.01). The glycogen content was decreased in ATO, CONT+EXE, and ATO+EXE rats compared with that in CONT rats (P < 0.05). GLUT-4 mRNA expression was higher after exhaustive exercise in CONT+EXE rats compared with the other groups (P < 0.05). Our results show that exhaustive exercise exacerbated metabolic perturbations and ROS production in skeletal muscle, which may reduce the exercise capacity and promote the muscular symptoms in sedentary atorvastatin-treated animals.

Statins in the management of aneurysmal subarachnoid hemorrhage: an overview of animal research, observational studies, randomized controlled trials and meta-analyses

BACKGROUND

the pathophysiology of delayed neurological deficits (DNDs) following aneurysmal subarachnoid hemorrhage (SAH) is complex, and is not limited to arterial narrowing (vasospasm) and classical ischemia. Thus, combined drug approaches, or therapies with multiple effects, may have the greatest potential for benefit. Statins are known to have pleiotropic vascular effects, some of which may interrupt the pathogenesis of DNDs. Based on promising preliminary reports, many clinicians routinely administer statins to prevent DNDs.

METHODS

a systematic review was performed to identify and summarize all animal research, observational studies, randomized controlled trials (RCTs) and meta-analyses which have evaluated the use of statins in the management of SAH.

RESULTS

nine animal studies, nine observational (cohort and case-control) studies, six RCTs and three meta-analyses were identified. Animal studies have generally administered statin doses that, when adjusted for body weight, are 10-80 times larger than what is used in humans. Nevertheless, these models have consistently reported statins to reduce vasospasm and to demonstrate additional neuroprotective effects. However, observational studies have not revealed an association between statin-use and reduced DNDs or improved neurological outcomes. Results of RCTs have been inconsistent and limited by small sample size, but together suggest that statins may reduce DNDs, with no clear impact on mortality or neurological recovery. Optimal drug administration strategies (timing of initiation, most effective dose and duration) have not been clarified.

CONCLUSIONS

the role of statins in the management of patients with SAH remains unclear. Although promising, statins should not, at this time, be considered standard care.