Atorvastatin ameliorates early brain injury through inhibition of apoptosis and ER stress in a rat model of subarachnoid hemorrhage

Citrate-coated silver nanoparticles loaded with agomelatine provide neuronal therapy in acute cerebral ischemia/reperfusion of rats by inhibiting the oxidative stress, endoplasmic reticulum stress, and P2X7 receptor-mediated inflammasome

Cerebral ischemia and reperfusion are related to various situations like injuries after various traumas, oxidative stress, increased calcium ion, capillary hypoperfusion, microvascular hyperpermeability, leukocyte infiltration, and blood-brain barrier disruption. An antidepressant Agomelatine which is a melatonin receptor (MT1/MT2) agonist and serotonin receptor (5-HT2C) antagonist has been reported by studies to have antioxidant and anti-inflammatory effects. In our study, we aimed to detect the effects of citrate-coated silver nanoparticle-loaded agomelatine application on neurodegeneration, endoplasmic reticulum stress, autophagic and apoptotic cell death, inflammation, and P2X7R expression in the cerebral ischemia-reperfusion model to facilitate the passage of blood-brain barrier. Forty two Sprague-Dawley rats in total were divided into six equal groups (n:7) and applications were performed. Acute cerebral injury in the ischemia-reperfusion model was created 2 h after internal carotid artery ligation in rats and then at the 2nd hour of reperfusion citrate-coated silver nanoparticles loaded with Agomelatine were applied. Twenty four hours later, neurologic analysis on animals in experimental groups was performed, animals were decapitated and GSH, GPx, SOD, CAT, MDA, IL-1β, and TNF-α parameters were examined after taking blood and the cerebral tissue samples. As a result, it was determined that ischemia-reperfusion caused endoplasmic reticulum stress in the cerebral tissues and thus caused cellular injury.

Neuroprotective strategies for neonatal hypoxic-ischemic brain damage: Current status and challenges

Neonatal hypoxic-ischemic brain damage (HIBD) is a prominent contributor to both immediate mortality and long-term impairment in newborns. The elusive nature of the underlying mechanisms responsible for neonatal HIBD presents a significant obstacle in the effective clinical application of numerous pharmaceutical interventions. This comprehensive review aims to concentrate on the potential neuroprotective agents that have demonstrated efficacy in addressing various pathogenic factors associated with neonatal HIBD, encompassing oxidative stress, calcium overload, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory response, and apoptosis. In this review, we conducted an analysis of the precise molecular pathways by which these drugs elicit neuroprotective effects in animal models of neonatal hypoxic-ischemic brain injury (HIBD). Our objective was to provide a comprehensive overview of potential neuroprotective agents for the treatment of neonatal HIBD in animal experiments, with the ultimate goal of enhancing the feasibility of clinical translation and establishing a solid theoretical foundation for the clinical management of neonatal HIBD.

Atorvastatin prevents endoplasmic reticulum stress-mediated apoptosis via the Nrf2/HO-1 signaling pathway in TBI mice

BACKGROUND

Our present study evaluated the neuroprotection effects of atorvastatin by inhibiting TBI-induced ER stress, as well as the potential role of the Nrf2/HO-1 pathway in experimental TBI.

METHODS

First, the mice were divided into four groups:sham, TBI, TBI+Vehicle and TBI+atorvastatin groups. The mice received atorvastatin (10 mg/kg/day) through intragastric gavage once a day for 3 days before TBI. In addition, Nrf2 WT and Nrf2 knockout mice were randomly divided into four groups: Nrf2+/+ TBI, Nrf2+/+ TBI+atorvastatin, Nrf2-/- TBI, and Nrf2-/- TBI+atorvastatin groups. Several neurobehavioral parameters were assessed post-TBI using mNSS, brain edema and the rotarod test, and the brain was isolated for molecular and biochemical analysis conducted through TUNEL staining and western blotting.     .

RESULTS

The results showed that atorvastatin treatment significantly improved neurological deficits, alleviated brain edema, and apoptosis caused by TBI. Western blotting analysis showed that atorvastatin significantly suppressed ER stress and its related apoptotic pathway after TBI, which may be associated with the further activation of the Nrf2/HO-1 pathway. However, compared with the Nrf2+/+ TBI+Vehicle group, Nrf2 deficiency further aggravated neurological deficits and promoted ER stress-mediated apoptosis induced by TBI. Interestingly, atorvastatin failed to improve neurological deficits but reversed apoptosis, and the loss of the beneficial properties of anti-ER stress in the Nrf2-/- TBI mice.      .

CONCLUSIONS

The results indicated that atorvastatin improves the neurologic functions and protects the brain from injury in the Nrf2+/+ TBI mice, primarily by counteracting ER stress-mediated apoptosis, which may be achieved through the activation of the Nrf2/HO-1 signaling pathway.

The mechanism and relevant mediators associated with neuronal apoptosis and potential therapeutic targets in subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a dominant cause of death and disability worldwide. A sharp increase in intracranial pressure after SAH leads to a reduction in cerebral perfusion and insufficient blood supply for neurons, which subsequently promotes a series of pathophysiological responses leading to neuronal death. Many previous experimental studies have reported that excitotoxicity, mitochondrial death pathways, the release of free radicals, protein misfolding, apoptosis, necrosis, autophagy, and inflammation are involved solely or in combination in this disorder. Among them, irreversible neuronal apoptosis plays a key role in both short- and long-term prognoses after SAH. Neuronal apoptosis occurs through multiple pathways including extrinsic, mitochondrial, endoplasmic reticulum, p53 and oxidative stress. Meanwhile, a large number of blood contents enter the subarachnoid space after SAH, and the secondary metabolites, including oxygenated hemoglobin and heme, further aggravate the destruction of the blood-brain barrier and vasogenic and cytotoxic brain edema, causing early brain injury and delayed cerebral ischemia, and ultimately increasing neuronal apoptosis. Even there is no clear and effective therapeutic strategy for SAH thus far, but by understanding apoptosis, we might excavate new ideas and approaches, as targeting the upstream and downstream molecules of apoptosis-related pathways shows promise in the treatment of SAH. In this review, we summarize the existing evidence on molecules and related drugs or molecules involved in the apoptotic pathway after SAH, which provides a possible target or new strategy for the treatment of SAH.

Autophagy and Apoptosis in Acute Brain Injuries: From Mechanism to Treatment

Significance: Autophagy and apoptosis are two important cellular mechanisms behind brain injuries, which are severe clinical situations with increasing incidences worldwide. To search for more and better treatments for brain injuries, it is essential to deepen the understanding of autophagy, apoptosis, and their interactions in brain injuries. This article first analyzes how autophagy and apoptosis participate in the pathogenetic processes of brain injuries respectively and mutually, then summarizes some promising treatments targeting autophagy and apoptosis to show the potential clinical applications in personalized medicine and precision medicine in the future. Recent Advances: Most current studies suggest that apoptosis is detrimental to brain recovery. Several studies indicate that autophagy can cause unnecessary death of neurons after brain injuries, while others show that autophagy is beneficial for acute brain injuries (ABIs) by facilitating the removal of damaged proteins and organelles. Whether autophagy is beneficial or detrimental in ABIs depends on many factors, and the results from different research groups are diverse or even controversial, making this topic more appealing to be explored further. Critical Issues: Neuronal autophagy and apoptosis are two primary pathological processes in ABIs. How they interact with each other and how their regulations affect the outcome and prognosis of brain injuries remain uncertain, making these answers more critical. Future Directions: Insights into the interplay between autophagy and apoptosis and the accurate regulations of their balance in ABIs may promote personalized and precise treatments in the field of brain injuries. Antioxid. Redox Signal. 38, 234-257.

Blocking postsynaptic density-93 binding to C-X3-C motif chemokine ligand 1 promotes microglial phenotypic transformation during acute ischemic stroke

We previously reported that postsynaptic density-93 mediates neuron-microglia crosstalk by interacting with amino acids 357-395 of C X3 C motif chemokine ligand 1 (CX3CL1) to induce microglia polarization. More importantly, the peptide Tat-CX3CL1 (comprising amino acids 357-395 of CX3CL1) disrupts the interaction between postsynaptic density-93 and CX3CL1, reducing neurological impairment and exerting a protective effect in the context of acute ischemic stroke. However, the mechanism underlying these effects remains unclear. In the current study, we found that the pro-inflammatory M1 phenotype increased and the anti-inflammatory M2 phenotype decreased at different time points. The M1 phenotype increased at 6 hours after stroke and peaked at 24 hours after perfusion, whereas the M2 phenotype decreased at 6 and 24 hours following reperfusion. We found that the peptide Tat-CX3CL1 (357-395aa) facilitates microglial polarization from M1 to M2 by reducing the production of soluble CX3CL1. Furthermore, the a disintegrin and metalloprotease domain 17 (ADAM17) inhibitor GW280264x, which inhibits metalloprotease activity and prevents CX3CL1 from being sheared into its soluble form, facilitated microglial polarization from M1 to M2 by inhibiting soluble CX3CL1 formation. Additionally, Tat-CX3CL1 (357-395aa) attenuated long-term cognitive deficits and improved white matter integrity as determined by the Morris water maze test at 31-34 days following surgery and immunofluorescence staining at 35 days after stroke, respectively. In conclusion, Tat-CX3CL1 (357-395aa) facilitates functional recovery after ischemic stroke by promoting microglial polarization from M1 to M2. Therefore, the Tat-CX3CL1 (357-395aa) is a potential therapeutic agent for ischemic stroke.

The role of the astrocyte in subarachnoid hemorrhage and its therapeutic implications

Subarachnoid hemorrhage (SAH) is an important public health concern with high morbidity and mortality worldwide. SAH induces cell death, blood−brain barrier (BBB) damage, brain edema and oxidative stress. As the most abundant cell type in the central nervous system, astrocytes play an essential role in brain damage and recovery following SAH. This review describes astrocyte activation and polarization after SAH. Astrocytes mediate BBB disruption, glymphatic–lymphatic system dysfunction, oxidative stress, and cell death after SAH. Furthermore, astrocytes engage in abundant crosstalk with other brain cells, such as endothelial cells, neurons, pericytes, microglia and monocytes, after SAH. In addition, astrocytes also exert protective functions in SAH. Finally, we summarize evidence regarding therapeutic approaches aimed at modulating astrocyte function following SAH, which could provide some new leads for future translational therapy to alleviate damage after SAH.

Cannabidiol’s Multifactorial Mechanisms Has Therapeutic Potential for Aneurysmal Subarachnoid Hemorrhage: a Review

Subarachnoid hemorrhage (SAH) is a major health burden that accounts for approximately 5% of all strokes. The most common cause of a non-traumatic SAH is the rupture of a cerebral aneurysm. The most common symptom associated with SAH is a headache, often described as “the worst headache of my life.” Delayed cerebral ischemia (DCI) is a major factor associated with patient mortality following SAH and is often associated with SAH-induced cerebral vasospasm (CV). Cannabidiol (CBD) is emerging as a potential drug for many therapeutic purposes, including epilepsy, anxiety, and pain relief. We aim to review the potential use of CBD as a treatment option for post-SAH critically ill patients. Through a literature review, we evaluated the known pharmacology and physiological effects of CBD and correlated those with the pathophysiological outcomes associated with cerebral vasospasm following subarachnoid hemorrhage. Although overlap exists, data were formatted into three major categories: anti-inflammatory, vascular, and neuroprotective effects. Based on the amount of information known about the actions of CBD, we hypothesize the anti-inflammatory effects are likely to be the most promising therapeutic mechanism. However, its cardiovascular effects through calcium regulation and its neuroprotective effects against cell death, excitotoxicity, and oxidative stress are all plausible mechanisms by which post-SAH critically ill patients may benefit from both early and late intervention with CBD. More research is needed to better understand if and how CBD might affect neurological and vascular functions in the brain following injury such as subarachnoid hemorrhage.

Hepatotoxicity in young adult mouse offspring after prenatal exposure to benzo(a)pyrene, and protective effect of atorvastatin

OBJECTIVES

Benzo[a]pyrene (BaP) is an environmental contaminant that interrupts the antioxidant defense and thus leads to oxidative stress and DNA damage in the liver. Atorvastatin (ATV) for reducing cholesterol has antioxidant and anti-apoptotic activities. This study investigated the effects of prenatal exposure of BaP on liver toxicity and the protective role of ATV in reducing liver toxicity.

MATERIALS AND METHODS

In this study, rats were distributed randomly to seven groups: I. Saline control; II. ATV (10 mg/kg); III. Corn oil; IV and V. BaP (10 and 20 mg/kg); VI and VII. ATV + BaP (10 and 20 mg/kg). BaP and ATV were administrated from gestation day 7-16 (GD7-GD16), orally. Ten weeks after the birth, female offspring were examined for oxidative stress markers, liver enzymes, and histology.

RESULTS

Data revealed that BaP significantly induced oxidative stress (decreased glutathione and increased malondialdehyde level), and disrupted the tissue structure of the liver. Moreover, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase increased in the offspring. ATV treatment along with BaP during gestation was able to bring the antioxidant status and serum liver enzymes levels relatively close to normal. As well as, histological findings showed that ATV was able to improve liver tissue structure caused by BaP.

CONCLUSION

Based on the above studies we concluded that ATV at a low dose during gestation was able to reduce liver damage caused by BaP with antioxidant properties.

A Narrative Review on Translational Research in Acute Brain Injury

There has been a constant endeavor to reduce the mortality and morbidity associated with acute brain injury. The associated complex mechanisms involving biomechanics, markers, and neuroprotective drugs/measures have been extensively studied in preclinical studies with an ultimate aim to improve the patients' outcomes. Despite such efforts, only few have been successfully translated into clinical practice. In this review, we shall be discussing the major hurdles in the translation of preclinical results into clinical practice. The need is to choose an appropriate animal model, keeping in mind the species, age, and gender of the animal, choosing suitable outcome measures, ensuring quality of animal trials, and carrying out systematic review and meta-analysis of experimental studies before proceeding to human trials. The interdisciplinary collaboration between the preclinical and clinical scientists will help to design better, meaningful trials which might help a long way in successful translation. Although challenging at this stage, the advent of translational precision medicine will help the integration of mechanism-centric translational medicine and patient-centric precision medicine.

The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments

The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.

Traditional Chinese medicine use in the pathophysiological processes of intracerebral hemorrhage and comparison with conventional therapy

Intracerebral hemorrhage (ICH) refers to hemorrhage caused by non-traumatic vascular rupture in the brain parenchyma, which is characterized by acute onset, severe illness, and high mortality and disability. The influx of blood into the brain tissue after cerebrovascular rupture causes severe brain damage, including primary injury caused by persistent hemorrhage and secondary brain injury (SBI) induced by hematoma. The mechanism of brain injury is complicated and is a significant cause of disability after ICH. Therefore, it is essential to understand the mechanism of brain injury after ICH to develop drugs to prevent and treat ICH. Studies have confirmed that many traditional Chinese medicines (TCM) can reduce brain injury by improving neurotoxicity, inflammation, oxidative stress (OS), blood-brain barrier (BBB), apoptosis, and neurological dysfunction after ICH. Starting from the pathophysiological process of brain injury after ICH, this paper summarizes the mechanisms by which TCM improves cerebral injury after ICH and its comparison with conventional western medicine, so as to provide clues and a reference for the clinical application of TCM in the prevention and treatment of hemorrhagic stroke and further research and development of new drugs.

Beyond Lipid-Lowering: Effects of Statins on Cardiovascular and Cerebrovascular Diseases and Cancer

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, also known as statins, are administered as first-line therapy for hypercholesterolemia, both as primary and secondary prevention. Besides the lipid-lowering effect, statins have been suggested to inhibit the development of cardiovascular disease through anti-inflammatory, antioxidant, vascular endothelial function-improving, plaque-stabilizing, and platelet aggregation-inhibiting effects. The preventive effect of statins on atherothrombotic stroke has been well established, but statins can influence other cerebrovascular diseases. This suggests that statins have many neuroprotective effects in addition to lowering cholesterol. Furthermore, research suggests that statins cause pro-apoptotic, growth-inhibitory, and pro-differentiation effects in various malignancies. Preclinical and clinical evidence suggests that statins inhibit tumor growth and induce apoptosis in specific cancer cell types. The pleiotropic effects of statins on cardiovascular and cerebrovascular diseases have been well established; however, the effects of statins on cancer patients have not been fully elucidated and are still controversial. This review discusses the recent evidence on the effects of statins on cardiovascular and cerebrovascular diseases and cancer. Additionally, this study describes the pharmacological action of statins, focusing on the aspect of ‘beyond lipid-lowering’.

Modulation of Salubrinal-Mediated Endoplasmic Reticulum Stress in an Experimental Subarachnoid Hemorrhage Model

BACKGROUND

Perfusion abnormalities due to vasospasm remain a major cause of morbidity and mortality in subarachnoid hemorrhage (SAH). Despite a large number of clinical trials, therapeutic options with strong evidence for prevention and treatment of cerebral vasospasm are rare. In this study, we aimed to evaluate the neuroprotective effect of salubrinal (SLB) in endoplasmic reticulum stress-induced apoptosis, a catastrophic consequence of vasospasm.

METHODS

Thirty-two Wistar albino rats were divided into 4 groups of 8 rats each: control group, SAH, SAH+SLB, and SAH+nimodipine (NMN). In the SAH+SLB group, intraperitoneal SLB (1 mg/kg dose) administered 30 minutes after establishment of SAH, and in the SAH+NMN group, intraperitoneal NMN (0.1 mg/kg dose) was also administered 30 minutes after SAH.

RESULTS

Higher total antioxidant status level, lower oxidative stress index, and significantly higher vascular endothelial growth factor-A (VEGF-A) level were detected in the SAH+SLB and SAH+NMN groups compared with the SAH group. There was a significant increase in eukaryotic translation initiation factor-2 alpha (elF2α) level in the SAH+SLB group compared with the SAH group. Histopathological evaluation revealed decrease in the subarachnoid hemorrhagic area, as well as in cortical edema and apoptotic bodies in the SAH+SLB and SAH+NMN groups. There was a significant decrease in caspase-3 staining in the SAH+SLB group, and the levels were significantly less in the SAH+NMN group than the SAH and SAH+SLB groups.

CONCLUSIONS

SLB, selective inhibitor of eIF2α dephosphorylation, and NMN, a calcium channel blocker, can ameliorate SAH-induced damage. Inhibition of eIF2α dephosphorylation and enhanced VEGF-A production with SLB may protect brain tissue from apoptosis.

17β-oestradiol alleviates endoplasmic reticulum stress injury induced by chronic cerebral hypoperfusion through the Haemoglobin/HIF 1α signalling pathway in ovariectomized rats

Endoplasmic reticulum stress (ERS) is known to be an essential target in protecting against ischaemic brain injury. In this study, using a vascular dementia (VaD) animal model induced by bilateral common carotid artery occlusion (BCCAO), we evaluated the effect and mechanism of 17β-oestradiol (E2) against VaD by inhibiting ERS at the early stage (14 d, 21 d, 28 d) and late stage (3 m) after BCCAO in the hippocampal CA1 region of ovariectomized rats. The results showed that the activation of the PERK-eIF2α-ATF4-CHOP axis, a typical ERS pathway, was significantly increased at the early and late stages after BCCAO. JNK (c-Jun N-terminal kinase)-cJun, a pro-death pathway, also displayed the same pattern as the ERS axis. E2 treatment profoundly suppressed the impairments caused by BCCAO. Further mechanistic studies revealed that cerebral blood flow (CBF) was sharply decreased at 14 d and returned to the normal level at 21 d after BCCAO. E2 could not change CBF, while it unexpectedly enhanced the ability to carry oxygen. This is evidenced by the fact that the protein expression of haemoglobin α/β (Hα/β), an oxygen carrier, robustly increased at BCCAO 21 d and 3 m after E2 treatment. The oxygen carrier increased strongly after 21 d and 3 m of BCCAO treated with E2. Moreover, E2 correspondingly enhanced the protein expression of hypoxia-inducible factor 1α (HIF 1α) in both the early and late stage after BCCAO in the hippocampal CA1 region. Finally, E2 administration markedly decreased the activities of caspase-8, caspase-3, and caspase-12 and increased the number of NeuN-positive cells. These findings suggest that E2 serves as a neuroprotectant to alleviate VaD by suppressing ERS injury involving the haemoglobin/HIF 1α signalling pathway.

Ifenprodil Improves Long-Term Neurologic Deficits Through Antagonizing Glutamate-Induced Excitotoxicity After Experimental Subarachnoid Hemorrhage

Excessive glutamate leading to excitotoxicity worsens brain damage after SAH and contributes to long-term neurological deficits. The drug ifenprodil is a non-competitive antagonist of GluN1-GluN2B N-methyl-d-aspartate (NMDA) receptor, which mediates excitotoxic damage in vitro and in vivo. Here, we show that cerebrospinal fluid (CSF) glutamate level within 48 h was significantly elevated in aSAH patients who later developed poor outcome. In rat SAH model, ifenprodil can improve long-term sensorimotor and spatial learning deficits. Ifenprodil attenuates experimental SAH-induced neuronal death of basal cortex and hippocampal CA1 area, cellular and mitochondrial Ca²⁺ overload of basal cortex, blood-brain barrier (BBB) damage, and cerebral edema of early brain injury. Using in vitro models, ifenprodil declines the high-concentration glutamate-mediated intracellular Ca²⁺ increase and cell apoptosis in primary cortical neurons, reduces the high-concentration glutamate-elevated endothelial permeability in human brain microvascular endothelial cell (HBMEC). Altogether, our results suggest ifenprodil improves long-term neurologic deficits through antagonizing glutamate-induced excitotoxicity.

Astragalin alleviates ischemia/reperfusion‑induced brain injury via suppression of endoplasmic reticulum stress

Excessive apoptosis and neuronal dysfunction are pathological features of ischemic stroke. Previous studies have demonstrated that astragalin (AST) exerted both anti‑​apoptotic and anti‑inflammatory effects in several types of disease, although its potential effect in ischemic stroke remains unclear. The purpose of the present study was to investigate the effects of AST on cerebral ischemia/reperfusion (I/R)‑induced brain injury and the underlying mechanisms. Brain injury was assessed in an experimental rat model using measurement of neurological scores and inflammatory factors. To assess the role of AST in I/R‑induced brain injury and the potential mechanism of action, SH5Y were treated with thapsigargin and AST. Apoptotic rate and ER stress levels were measured by western blotting, reverse transcription‑quantitative PCR and immunofluorescence staining. It was discovered that AST significantly improved long‑term neurological outcomes in rats following cerebral I/R injury, through the attenuation of the expression levels of apoptotic proteins (Bax and cleaved‑caspase‑3) and the release of inflammatory cytokines, as well as upregulating the expression levels of the anti‑apoptotic protein Bcl‑2. Furthermore, AST attenuated the expression levels of the endoplasmic reticulum (ER) stress‑related protein, glucose‑regulated protein, 78 kDa, as well as its downstream apoptotic mediators (CHOP and caspase‑12). Thapsigargin‑induced ER stress activation and apoptosis were also attenuated by AST in an in vitro neuronal cell culture model. In conclusion, these results suggested that AST may protect against I/R‑induced brain injury, thus, highlighting its therapeutic potential in patients with ischemic stroke.

Paeoniflorin attenuates early brain injury through reducing oxidative stress and neuronal apoptosis after subarachnoid hemorrhage in rats

Paeoniflorin is a natural monoterpene glucoside from Paeoniae Radix with neuroprotective properties. However, it is still unclear whether paeoniflorin has neuroprotective effects on subarachnoid hemorrhage (SAH). This study explores the effect of paeoniflorin on early brain injury (EBI) using rat SAH model. We found that paeoniflorin significantly improves neurological deficits, attenuates brain water content and Evans blue extravasation at 72 h after SAH. Paeoniflorin attenuates the oxidative stress following SAH as evidenced by decrease of reactive oxygen species (ROS), malondialdehyde (MDA), 3-Nitrotyrosine, and 8-Hydroxy-2-deoxy guanosine (8-OHDG) level, increase of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase activity, and up-regulates the nuclear factor erythroid‑related factor 2 (Nrf2)/heme oxygenase‑1 (HO-1) pathway. Inhibition of microglia activation and neuro-inflammatory response both contributed to paeoniflorin's protective effects. Moreover, paeoniflorin treatment significantly reduces the ratio of Bax/Bcl-2, active caspase-3/ neuronal nuclei (NeuN) and TUNEL/DAPI positive cells at 72 h following SAH. Our results indicate that paeoniflorin may attenuate early brain injury after experimental SAH.

Endoplasmic reticulum stress mediates cortical neuron apoptosis after experimental subarachnoid hemorrhage in rats

OBJECTIVE

Neuronal apoptosis plays an important pathological process in early brain injury (EBI) after subarachnoid hemorrhage (SAH). This pathological process leads to a poor neurological prognosis for patients. This study aimed to investigate whether endoplasmic reticulum (ER) stress mediates cortical neuron apoptosis in EBI after SAH.

METHODS

Eighty-four male Sprague-Dawley rats were randomly assigned to different groups as follows: the control and the 3, 6, 12, 24, 48, and 72 h groups after SAH. The SAH model was established by injecting 0.3 mL of nonheparinized blood into the prechiasmatic cistern. Hematoxylin-eosin staining, Garcia scoring, Western blotting, transmission electron microscopy, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were performed.

RESULTS

SAH reduced the neurological scores and reached a trough at 24 h after the SAH. The GRP78 expression was significantly upregulated at 6 h after the SAH, peaked at 24 h after the SAH, and then decreased. By comparison, the CHOP, caspase-12, ASK1, and p-c-Jun N-terminal kinase expressions were significantly upregulated at 12 h after the SAH and peaked at 24 h after the SAH. The most serious swelling of the rough ER was observed at 24 h after the SAH and remained notably swollen at 72 h after the SAH. The number of TUNEL-positive cells substantially increased significantly at 12 h after the SAH, and the neuronal apoptosis decreased ratio after reaching a peak at 24 h after the SAH. The apoptosis ratio at 72 h after the SAH was still significantly different from the ratio in the control group.

CONCLUSION

Our study clearly demonstrated that ER stress mediates cortical neuron apoptosis after experimental subarachnoid hemorrhage in rats.

Targeting IL-10, ZO-1 gene expression and IL-6/STAT-3 trans-signaling by a combination of atorvastatin and mesalazine to enhance anti-inflammatory effects and attenuates progression of oxazolone-induced colitis

Ulcerative colitis (UC) is a chronic inflammatory disease characterized by diffused inflammation of the colon and rectum mucosa. The pathogenesis of UC is multifactorial, and the exact underlying mechanisms remain poorly understood. This study aims to investigate the effect of mesalazine and atorvastatin combination in enhancing anti-inflammatory effects and attenuates progression of oxazolone colitis in rats. In the present study, male albino rats (N = 60) were divided into six groups (10 rats each), the first two groups served as normal control and a control saline group. Colitis was induced by intra-rectal administration of oxazolone in the 5th and 7th days after pre-sensitization. Then, rats were divided into untreated group, groups treated with mesalazine or atorvastatin or their combination. Colitis was assessed by colon length, body weight, and incidence of diarrhea, rectal bleeding, and histopathology of colon tissue. Colon tissues were used for measuring interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), IL-13, signal transducer and activator of transcription-3 (STAT-3), myeloperoxidase activity (MPO), reduced glutathione(GSH), and tissue expression of IL-10, tight junction protein zonula occludens (ZO-1), and caspase-3 genes. The combination therapy significantly attenuated progression of UC by decreasing incidence of diarrhea, rectal bleeding, weight loss, IL-13, IL-6, TNF-α, STAT-3, caspase-3, and MPO activity and significantly increased IL-10, ZO-1, colon length, and GSH content, and these effects were more superior to single drugs. These findings showed that combination therapy was able to ameliorate progression of UC and enhance anti-inflammatory effects possibly by restoring IL-10 and ZO-1 levels and limiting IL-6/STAT-3 trans-signaling.

An early neuroprotective effect of atorvastatin against subarachnoid hemorrhage

Atorvastatin has been shown to reduce early brain edema and neuronal death after subarachnoid hemorrhage, but its mechanism is not clear. In this study, rat models of subarachnoid hemorrhage were established by autologous blood injection in the cisterna magna. Rat models were intragastrically administered 20 mg/kg atorvastatin 24 hours before subarachnoid hemorrhage, 12 and 36 hours after subarachnoid hemorrhage. Compared with the controls, atorvastatin treatment demonstrated that at 72 hours after subarachnoid hemorrhage, neurological function had clearly improved; brain edema was remarkably relieved; cell apoptosis was markedly reduced in the cerebral cortex of rats; the number of autophagy-related protein Beclin-1-positive cells and the expression levels of Beclin-1 and LC3 were increased compared with subarachnoid hemorrhage only. The ultrastructural damage of neurons in the temporal lobe was also noticeably alleviated. The similarities between the effects of atorvastatin and rapamycin were seen in all the measured outcomes of subarachnoid hemorrhage. However, these were contrary to the results of 3-methyladenine injection, which inhibits the signaling pathway of autophagy. These findings indicate that atorvastatin plays an early neuroprotective role in subarachnoid hemorrhage by activating autophagy. The experimental protocol was approved by the Animal Ethics Committee of Anhui Medical University, China (904 Hospital of Joint Logistic Support Force of PLA; approval No. YXLL-2017-09) on February 22, 2017.

Controlled Decompression Attenuates Brain Injury in a Novel Rabbit Model of Acute Intracranial Hypertension

Background

In the past, standard rapid decompressive craniectomy was used to alleviate the secondary damage caused by high intracranial pressure. Recent clinical studies showed that controlled decompression may have a better curative effect than rapid decompression. However, the effect on controlled decompression in animals is unclear.

Material/Methods

Totally 80 healthy male New Zealand rabbits were randomly divided into a sham group (n=20), a rapid decompression group (n=30), and a controlled decompression group (n=30). An intracranial hypertension model was induced by injecting saline into an epidural balloon catheter and reducing ICP slowly and gradually by use of a pressure pump. The model was evaluated and analyzed by general observations, imaging examination, ICP values, behavioral score, brain water content, Nissl staining, and caspase-3 protein detection.

Results

The mortality rate was 36.7% (11/30) in the rapid group, 20% (6/30) in the controlled group, and 5% (1/20) in the sham group. The incidence of epidural hematoma in the controlled group was lower than in the rapid group (p<0.01). The ICP was significantly lower in the controlled group than in the rapid group (p<0.001), and the behavioral score in the rapid group was higher than in the controlled group (p<0.05). There was a marked difference in brain water content between the controlled group and the rapid group (p<0.01). Nissl staining demonstrated that the ratio of Nissl body in the controlled group was significantly higher than in the rapid group (p<0.01). WB detection showed the expression of Caspase-3 in the controlled group was lower than in the rapid group (p<0.05).

Conclusions

The results show the advantages of use of controlled decompression with intracranial hypertension. The animal model we developed provides a platform for further research on controlled decompression.

Atorvastatin attenuates spinal cord injury by chronic fluorosis in rats

The aim of the study was to explore the effect of atorvastatin on improvement of the function of the spinal cord in rats with chronic fluorosis. Sixty 3-month-old Wistar rats were separated randomly into three groups: normal group (N group), control group (C group) and atorvastatin group (A group). The Basso Beattie and Bresnahan scale and oblique board test showed that the rats in A group got higher score and better hind-limb motor function than C group. Immunohistochemistry and western blotting revealed that compared with N group, matrix metalloproteinase 9 (MMP-9) and p53 were highly expressed and myelin basic protein (MBP) was low expressed in spinal cord of C group. Meanwhile, MMP-9 and p53 expression were decreased and MBP was upregulated by atorvastatin compared with C group. In conclusion, the improvement of the function of the spinal cord in rats can be found when they were treated with atorvastatin.

Selective mGluR1 Negative Allosteric Modulator Reduces Blood-Brain Barrier Permeability and Cerebral Edema After Experimental Subarachnoid Hemorrhage

The blood-brain barrier (BBB) disruption leads to the vasogenic brain edema and contributes to the early brain injury (EBI) after subarachnoid hemorrhage (SAH). However, the mechanisms underlying the BBB damage following SAH are poorly understood. Here we reported that the neurotransmitter glutamate of cerebrospinal fluid (CSF) was dramatically increased in SAH patients with symptoms of cerebral edema. Using the rat SAH model, we found that SAH caused the increase of CSF glutamate level and BBB permeability in EBI, intracerebroventricular injection of exogenous glutamate deteriorated BBB damage and cerebral edema, while intraperitoneally injection of metabotropic glutamate receptor 1(mGluR1) negative allosteric modulator JNJ16259685 significantly attenuated SAH-induced BBB damage and cerebral edema. In an in vitro BBB model, we showed that glutamate increased monolayer permeability of human brain microvascular endothelial cells (HBMEC), whereas JNJ16259685 preserved glutamate-damaged BBB integrity in HBMEC. Mechanically, glutamate downregulated the level and phosphorylation of vasodilator-stimulated phosphoprotein (VASP), decreased the tight junction protein occludin, and increased AQP4 expression at 72 h after SAH. However, JNJ16259685 significantly increased VASP, p-VASP, and occludin, and reduced AQP level at 72 h after SAH. Altogether, our results suggest an important role of glutamate in disruption of BBB function and inhibition of mGluR1 with JNJ16259685 reduced BBB damage and cerebral edema after SAH.

The effect of HMG-CoA reductase inhibitors on thrombolysis-induced haemorrhagic transformation

Thrombolysis-induced haemorrhagic transformation is the most challenging preventable complication in thrombolytic therapy. This condition is often associated with poor functional outcome and long-term disease burden. Statins, or 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are controversially suggested to either increase or decrease the odds of better primary outcomes compared to treatment without statins after thrombolysis in patients or animals; statins are thought to act by influencing lipid levels, the inflammatory response, blood brain barrier permeability and cell apoptosis. Statins are the cornerstone of secondary prevention of cardiovascular and cerebrovascular diseases. However, the role of statins in acute phase stroke, and the necessity of their use, remains unclear. Currently, whether statins can increase the risk of haemorrhagic transformation is of great concern for patients treated with tissue plasminogen activator (t-PA). Herein, we thoroughly summarize the recent advances that address whether the administration of statins in ischaemic stroke increases haemorrhagic transformation in patients or animals who received thrombolysis at an early stage and the related mechanisms. This review will provide more clinical and preclinical evidence to address questions regarding the exercise of caution in the use of high dose statins in patients who received thrombolysis and if low dose statins may be beneficial in decreasing thrombolysis-induced haemorrhagic transformation.

The role and therapeutic potential of heat shock proteins in haemorrhagic stroke

Heat shock proteins (HSPs) are induced after haemorrhagic stroke, which includes subarachnoid haemorrhage (SAH) and intracerebral haemorrhage (ICH). Most of these proteins function as neuroprotective molecules to protect cerebral neurons from haemorrhagic stroke and as markers to indicate cellular stress or damage. The most widely studied HSPs in SAH are HSP70, haeme oxygenase-1 (HO-1), HSP20 and HSP27. The subsequent pathophysiological changes following SAH can be divided into two stages: early brain injury and delayed cerebral ischaemia, both of which determine the outcome for patients. Because the mechanisms of HSPs in SAH are being revealed and experimental models in animals are continually maturing, new agents targeting HSPs with limited side effects have been suggested to provide therapeutic potential. For instance, some pharmaceutical agents can block neuronal apoptosis signals or dilate cerebral vessels by modulating HSPs. HO-1 and HSP70 are also critical topics for ICH research, which can be attributed to their involvement in pathophysiological mechanisms and therapeutic potential. However, the process of HO-1 metabolism can be toxic owing to iron overload and the activation of succedent pathways, for example, the Fenton reaction and oxidative damage; the overall effect of HO-1 in SAH and ICH tends to be protective and harmful, respectively, given the different pathophysiological changes in these two types of haemorrhagic stroke. In the present study, we focus on the current understanding of the role and therapeutic potential of HSPs involved in haemorrhagic stroke. Therefore, HSPs may be potential therapeutic targets, and new agents targeting HSPs are warranted.