Inhibition of endoplasmic reticulum stress alleviates secondary injury after traumatic brain injury

"Investigation of the potential cellular changes induced by magnesium sulfate and salubrinal in a lipopolysaccharide-induced chorioamnionitis model"

Chorioamnionitis is closely associated with preterm labor and poses a significant public health concern. In this pathological process where inflammation plays a key role, intracellular mechanisms such as endoplasmic reticulum stress are crucial. In this study, we aimed to explore the potential positive outcomes of the combined use of salubrinal (SLB) with magnesium (Mg) treatment in chorioamnionitis. Thirty pregnant rats were divided into 5 groups as: Control, LPS (1 mg/kg), LPS + SLB (1 mg/kg), LPS + Mg (Dhaka protocol), LPS + SLB + Mg. Rats were sacrificed 4 h after LPS administration, then placental and fetal brain tissues were collected. LPS administration enhanced the levels of tumor necrosis factor-alpha, vascular endothelial growth factor, caspase-3 immunoexpressions, BAX, eukaryotic initiation factor 2-alpha, s100, and glial fibrillary acidic protein expressions and lowered BCL2 expressions in the placenta or fetal brains. SLB and Mg treatments were observed to reverse all these findings, and the most significant positive effect was in the LPS + SLB + Mg group. The known anti-inflammatory activity of Mg, when used with SLB, preventing the transition to apoptosis and increasing antioxidant enzyme activity, as identified in this study, can contribute significantly to the literature. However, these results need to be supported by additional molecular studies.

Astragaloside IV ameliorated neuroinflammation and improved neurological functions in mice exposed to traumatic brain injury by modulating the PERK-eIF2α-ATF4 signaling pathway

Increasing evidence suggests that endoplasmic reticulum stress (ER stress) and neuroinflammation are involved in the complex pathological process of traumatic brain injury (TBI). However, the pathological mechanisms of their interactions in TBI remain incompletely elucidated. Therefore, investigating and ameliorating neuroinflammation and ER stress post-TBI may represent effective strategies for treating secondary brain injury. Astragaloside IV (AS-IV) has been reported as a potential neuroprotective and anti-inflammatory agent in neurological diseases. This study utilized a mouse TBI model to investigate the pathological mechanisms and crosstalk of ER stress, neuroinflammation, and microglial cell morphology in TBI, as well as the mechanisms and potential of AS-IV in improving TBI. The research revealed that post-TBI, inflammatory factors IL-6, IL-1β, and TNF-α increased, microglial cells were activated, and the specific inhibitor of PERK phosphorylation, GSK2656157, intervened to alleviate neuroinflammation and inhibit microglial cell activation. Post-TBI, levels of ER stress-related proteins (p-PERK, p-eIF2a, ATF4, ATF6, and p-IRE1a) increased. Following AS-IV treatment, neurological dysfunction in TBI mice improved. Levels of p-PERK, p-eIF2a, and ATF4 decreased, along with reductions in inflammatory factors IL-6, IL-1β, and TNF-α. Changes in microglial/macrophage M1/M2 polarization were observed. Additionally, the PERK activator CCT020312 intervention eliminated the impact of AS-IV on post-TBI inflammation and ER stress-related proteins p-PERK, p-eIF2a, and ATF4. These results indicate that AS-IV alleviates neuroinflammation and brain damage post-TBI through the PERK pathway, offering new directions and theoretical insights for TBI treatment.

GABAergic interneurons in the hippocampal CA1 mediate contextual fear generalization in PTSD rats

Fear overgeneralization is widely accepted as a pathogenic marker of post-traumatic stress disorder (PTSD). Recently, GABAergic interneurons have been regarded as key players in the regulation of fear memory. The role of hippocampal GABAergic interneurons in contextual fear generalization of PTSD remains incompletely understood. In the present study, we established a rat model of PTSD with inescapable foot shocks (IFS) and observed the loss of GABAergic interneuron phenotype in the hippocampal cornu ammonis-1 (CA1) subfield. To determine whether the loss of GABAergic interneuron phenotype was associated with fear generalization in PTSD rats, we used adeno-associated virus (AAV) to reduce the expression of GAD67 in CA1 and observed its effect on fear generalization. The results showed that the reduction of GAD67 in CA1 enhanced contextual fear generalization in rats. We investigated whether the PERK pathway was involved in the GABAergic interneuron injury. Increased expression of p-PERK, CHOP, and Caspase12 in GABAergic interneurons of PTSD rats was observed. Then, we used salubrinal, an endoplasmic reticulum stress inhibitor, to modulate the PERK pathway. The salubrinal treatment significantly protected the GABAergic interneurons and relieved fear generalization in PTSD rats. In addition, the results showed that salubrinal down-regulated the expression of CHOP and Caspase12 in GABAergic interneurons of PTSD rats. In conclusion, this study provided evidence that the loss of GABAergic interneuron phenotype in CA1 may contribute to contextual fear generalization in PTSD. The PERK pathway is involved in the GABAergic interneuron injury of PTSD rats and modulating it can protect GABAergic interneurons and constrain contextual fear generalization.

Sex-specific and cell-specific regulation of ER stress and neuroinflammation after traumatic brain injury in juvenile mice

Endoplasmic reticulum (ER) stress and neuroinflammation play an important role in secondary brain damage after traumatic brain injury (TBI). Due to the complex brain cytoarchitecture, multiple cell types are affected by TBI. However, cell type-specific and sex-specific responses to ER stress and neuroinflammation remain unclear. Here we investigated differential regulation of ER stress and neuroinflammatory pathways in neurons and microglia during the acute phase post-injury in a mouse model of impact acceleration TBI in both males and females. We found that TBI resulted in significant weight loss only in males, and sensorimotor impairment and depressive-like behaviors in both males and females at the acute phase post-injury. By concurrently isolating neurons and microglia from the same brain sample of the same animal, we were able to evaluate the simultaneous responses in neurons and microglia towards ER stress and neuroinflammation in both males and females. We discovered that the ER stress and anti-inflammatory responses were significantly stronger in microglia, especially in female microglia, compared with the male and female neurons. Whereas the degree of phosphorylated-tau (pTau) accumulation was significantly higher in neurons, compared with the microglia. In conclusion, TBI resulted in behavioral deficits and cell type-specific and sex-specific responses to ER stress and neuroinflammation, and abnormal protein accumulation at the acute phase after TBI in immature mice.

Sestrin2 can alleviate endoplasmic reticulum stress to improve traumatic brain injury by activating AMPK/mTORC1 signaling pathway

Traumatic brain injury (TBI), as a serious central nervous system disease, can result in severe neurological dysfunction or even disability and death of patients. The early and effective intervention of secondary brain injury can improve the prognosis of TBI. Endoplasmic reticulum (ER) stress is one of the main reasons to recover TBI. ER stress inhibition may be beneficial in treating TBI. Sestrin2 is a crucial regulator of ER stress, and its activation can significantly improve TBI. In this paper, we analyze the biological function of sestrin2, the latest findings on ER stress, and the relationship between ER stress and TBI. We elucidate the relationship of sestrin2 inhibiting ER stress via activating the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (MTORC1) signaling. Finally, we elaborate on the possible role of sestrin2 in TBI and explain how its activation potentially improves TBI.

Endoplasmic reticulum stress and the unfolded protein response: emerging regulators in progression of traumatic brain injury

Traumatic brain injury (TBI) is a common trauma with high mortality and disability rates worldwide. However, the current management of this disease is still unsatisfactory. Therefore, it is necessary to investigate the pathophysiological mechanisms of TBI in depth to improve the treatment options. In recent decades, abundant evidence has highlighted the significance of endoplasmic reticulum stress (ERS) in advancing central nervous system (CNS) disorders, including TBI. ERS following TBI leads to the accumulation of unfolded proteins, initiating the unfolded protein response (UPR). Protein kinase RNA-like ER kinase (PERK), inositol-requiring protein 1 (IRE1), and activating transcription factor 6 (ATF6) are the three major pathways of UPR initiation that determine whether a cell survives or dies. This review focuses on the dual effects of ERS on TBI and discusses the underlying mechanisms. It is suggested that ERS may crosstalk with a series of molecular cascade responses, such as mitochondrial dysfunction, oxidative stress, neuroinflammation, autophagy, and cell death, and is thus involved in the progression of secondary injury after TBI. Hence, ERS is a promising candidate for the management of TBI.

Nervous System Response to Neurotrauma: A Narrative Review of Cerebrovascular and Cellular Changes After Neurotrauma

Neurotrauma is a significant cause of morbidity and mortality worldwide. For instance, traumatic brain injury (TBI) causes more than 30% of all injury-related deaths in the USA annually. The underlying cause and clinical sequela vary among cases. Patients are liable to both acute and chronic changes in the nervous system after such a type of injury. Cerebrovascular disruption has the most common and serious effect in such cases because cerebrovascular autoregulation, which is one of the main determinants of cerebral perfusion pressure, can be effaced in brain injuries even in the absence of evident vascular injury. Disruption of the blood-brain barrier regulatory function may also ensue whether due to direct injury to its structure or metabolic changes. Furthermore, the autonomic nervous system (ANS) can be affected leading to sympathetic hyperactivity in many patients. On a cellular scale, the neuroinflammatory cascade medicated by the glial cells gets triggered in response to TBI. Nevertheless, cellular and molecular reactions involved in cerebrovascular repair are not fully understood yet. Most studies were done on animals with many drawbacks in interpreting results. Therefore, future studies including human subjects are necessarily needed. This review will be of relevance to clinicians and researchers interested in understanding the underlying mechanisms in neurotrauma cases and the development of proper therapies as well as those with a general interest in the neurotrauma field.

Proposed mechanisms of tau: relationships to traumatic brain injury, Alzheimer's disease, and epilepsy

Traumatic brain injury (TBI), Alzheimer's disease (AD), and epilepsy share proposed mechanisms of injury, including neuronal excitotoxicity, cascade signaling, and activation of protein biomarkers such as tau. Although tau is typically present intracellularly, in tauopathies, phosphorylated (p-) and hyper-phosphorylated (hp-) tau are released extracellularly, the latter leading to decreased neuronal stability and neurofibrillary tangles (NFTs). Tau cleavage at particular sites increases susceptibility to hyper-phosphorylation, NFT formation, and eventual cell death. The relationship between tau and inflammation, however, is unknown. In this review, we present evidence for an imbalanced endoplasmic reticulum (ER) stress response and inflammatory signaling pathways resulting in atypical p-tau, hp-tau and NFT formation. Further, we propose tau as a biomarker for neuronal injury severity in TBI, AD, and epilepsy. We present a hypothesis of tau phosphorylation as an initial acute neuroprotective response to seizures/TBI. However, if the underlying seizure pathology or TBI recurrence is not effectively treated, and the pathway becomes chronically activated, we propose a "tipping point" hypothesis that identifies a transition of tau phosphorylation from neuroprotective to injurious. We outline the role of amyloid beta (Aβ) as a "last ditch effort" to revert the cell to programmed death signaling, that, when fails, transitions the mechanism from injurious to neurodegenerative. Lastly, we discuss targets along these pathways for therapeutic intervention in AD, TBI, and epilepsy.

Brief Oxygen Exposure after Traumatic Brain Injury Hastens Recovery and Promotes Adaptive Chronic Endoplasmic Reticulum Stress Responses

Traumatic brain injury (TBI) is a major public health concern, particularly in adolescents who have a higher mortality and incidence of visual pathway injury compared to adult patients. Likewise, we have found disparities between adult and adolescent TBI outcomes in rodents. Most interestingly, adolescents suffer a prolonged apneic period immediately post-injury, leading to higher mortality; therefore, we implemented a brief oxygen exposure paradigm to circumvent this increased mortality. Adolescent male mice experienced a closed-head weight-drop TBI and were then exposed to 100% O2 until normal breathing returned or recovered in room air. We followed mice for 7 and 30 days and assessed their optokinetic response; retinal ganglion cell loss; axonal degeneration; glial reactivity; and retinal ER stress protein levels. O2 reduced adolescent mortality by 40%, improved post-injury visual acuity, and reduced axonal degeneration and gliosis in optical projection regions. ER stress protein expression was altered in injured mice, and mice given O2 utilized different ER stress pathways in a time-dependent manner. Finally, O2 exposure may be mediating these ER stress responses through regulation of the redox-sensitive ER folding protein ERO1α, which has been linked to a reduction in the toxic effects of free radicals in other animal models of ER stress.

Brief oxygen exposure after traumatic brain injury speeds recovery and promotes adaptive chronic endoplasmic reticulum stress responses

Traumatic brain injury (TBI) is a major public health concern particularly in adolescents who have a higher mortality and incidence of visual pathway injury compared to adult patients. Likewise, we have found disparities between adult and adolescent TBI outcomes in rodents. Most interestingly, adolescents suffer a prolonged apneic period immediately post injury leading to higher mortality; so, we implemented a brief oxygen exposure paradigm to circumvent this increased mortality. Adolescent male mice experienced a closed-head weight-drop TBI then were exposed to 100% O ₂ until normal breathing returned or recovered in room air. We followed mice for 7- and 30-days and assessed their optokinetic response; retinal ganglion cell loss; axonal degeneration; glial reactivity; and retinal ER stress protein levels. O ₂ reduced adolescent mortality by 40%, improved post-injury visual acuity, and reduced axonal degeneration and gliosis in optic projection regions. ER stress protein expression was altered in injured mice, and mice given O ₂ utilized different ER-stress pathways in a time dependent manner. Finally, O ₂ exposure may be mediating these ER stress responses through regulation of the redox-sensitive ER folding protein ERO1α, which has been linked to a reduction in the toxic effects of free radicals in other animal models of ER stress.

Increased Risk of Aging-Related Neurodegenerative Disease after Traumatic Brain Injury

Traumatic brain injury (TBI) survivors frequently suffer from chronically progressive complications, including significantly increased risk of developing aging-related neurodegenerative disease. As advances in neurocritical care increase the number of TBI survivors, the impact and awareness of this problem are growing. The mechanisms by which TBI increases the risk of developing aging-related neurodegenerative disease, however, are not completely understood. As a result, there are no protective treatments for patients. Here, we review the current literature surrounding the epidemiology and potential mechanistic relationships between brain injury and aging-related neurodegenerative disease. In addition to increasing the risk for developing all forms of dementia, the most prominent aging-related neurodegenerative conditions that are accelerated by TBI are amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Parkinson's disease (PD), and Alzheimer's disease (AD), with ALS and FTD being the least well-established. Mechanistic links between TBI and all forms of dementia that are reviewed include oxidative stress, dysregulated proteostasis, and neuroinflammation. Disease-specific mechanistic links with TBI that are reviewed include TAR DNA binding protein 43 and motor cortex lesions in ALS and FTD; alpha-synuclein, dopaminergic cell death, and synergistic toxin exposure in PD; and brain insulin resistance, amyloid beta pathology, and tau pathology in AD. While compelling mechanistic links have been identified, significantly expanded investigation in the field is needed to develop therapies to protect TBI survivors from the increased risk of aging-related neurodegenerative disease.

Brain injury triggers cell-type-specific and time-dependent endoplasmic reticulum stress responses

The unfolded protein response (UPR) is a signal transduction network that responds to endoplasmic reticulum (ER) stress by coordinating protein homeostasis to maintain cell viability. The UPR can also trigger cell death when adaptive responses fail to improve protein homeostasis. Despite accumulating evidence suggesting that the UPR plays a role in neurodegenerative diseases and brain insults, our understanding of how ER stress is induced under neuropathological conditions is limited. Here, we investigated the cell- and time-specific patterns of the ER stress response after brain injury using ER stress-activated indicator (ERAI) mice, which enable monitoring of the UPR in vivo via increased fluorescence of a spliced XBP-1 protein fused with the green fluorescent protein (GFP) variant Venus. Following cortical stab injury of ERAI mice, the GFP signal and number of GFP⁺ cells increased in the ipsilateral cortex throughout the observation period (6 h to 7 days post-injury), confirming the induction of the UPR. GFP signals were observed in injured neurons early (from 6 h) after brain injury. However, non-neuronal cells, mainly endothelial cells followed by astrocytes, accounted for the majority of GFP⁺ cells after brain injury. Similar results were obtained in a mouse model of focal cerebral ischemia. These findings suggest that activation of the UPR in both neuronal and non-neuronal cells, especially endothelial cells and astrocytes, may play an important role in and could be a potential therapeutic target for acute brain injuries.

Oxidative stress in the brain and retina after traumatic injury

The brain and the retina share many physiological similarities, which allows the retina to serve as a model of CNS disease and disorder. In instances of trauma, the eye can even indicate damage to the brain via abnormalities observed such as irregularities in pupillary reflexes in suspected traumatic brain injury (TBI) patients. Elevation of reactive oxygen species (ROS) has been observed in neurodegenerative disorders and in both traumatic optic neuropathy (TON) and in TBI. In a healthy system, ROS play a pivotal role in cellular communication, but in neurodegenerative diseases and post-trauma instances, ROS elevation can exacerbate neurodegeneration in both the brain and the retina. Increased ROS can overwhelm the inherent antioxidant systems which are regulated via mitochondrial processes. The overabundance of ROS can lead to protein, DNA, and other forms of cellular damage which ultimately result in apoptosis. Even though elevated ROS have been observed to be a major cause in the neurodegeneration observed after TON and TBI, many antioxidants therapeutic strategies fail. In order to understand why these therapeutic approaches fail further research into the direct injury cascades must be conducted. Additional therapeutic approaches such as therapeutics capable of anti-inflammatory properties and suppression of other neurodegenerative processes may be needed for the treatment of TON, TBI, and neurodegenerative diseases.

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.

Bibliometric analysis of post-traumatic stress disorder in forensic medicine: Research trends, hot spots, and prospects

Background

Post-traumatic stress disorder (PTSD) has various risk factors, complex pathogenesis, and diverse symptoms, and is often comorbid with other injuries and diseases, making forensic diagnosis difficult.

Methods

To explore the current research status and trends of PTSD, we used the Web of Science Core Collection databases to screen PTSD-related literature published between 2010 and 2021 and CiteSpace to perform bibliometric analysis.

Results

In recent years, PTSD-related research has grown steadily. The countries and institutions with the most research results were the United States and England, and King's College London and Boston University, respectively. Publications were identified from 2,821 different journals, including 13 forensic-related journals, but the journal distribution was relatively scattered and there was a lack of professional core journals. Keyword co-occurrence and clustering identified many hot topics; "rat model," "mental health," and "satisfaction" were the topics most likely to have a clear effect on future research. Analysis extracted nine turning points from the literature that suggested that neural network centers, the hypothalamic-pituitary-adrenal axis, and biomarkers were new research directions. It was found that COVID-19 can cause severe psychological stress and induce PTSD, but the relationship needs further study. The literature on stress response areas and biomarkers has gradually increased over time, but specific systemic neural brain circuits and biomarkers remain to be determined.

Conclusion

There is a need to expand the collection of different types of biological tissue samples from patients with different backgrounds, screen PTSD biomarkers and molecular targets using multi-omics and molecular biology techniques, and establish PTSD-related molecular networks. This may promote a systematic understanding of the abnormal activation of neural circuits in patients with PTSD and help to establish a personalized, accurate, and objective forensic diagnostic standard.

TUDCA protects against tunicamycin-induced apoptosis of dorsal root ganglion neurons by suppressing activation of ER stress

The existence of endoplasmic reticulum (ER) stress in neurodegenerative diseases has been well established. Tauroursodeoxycholic acid (TUDCA) is a bile acid taurine conjugate derived from ursodeoxycholic acid, which has been reported to exert cytoprotective effects on several types of cells by inhibiting ER stress. The present study explored the effects of TUDCA on primary cultured rat dorsal root ganglion (DRG) neurons. Cell viability and apoptosis of DRG neurons treated with TUDCA and tunicamycin were detected by CellTiter-Blue assay and TUNEL staining, respectively. The protein levels and phosphorylation of apoptosis and ERS-related signaling pathway molecules were detected by western blot, and the mRNA levels of related genes were assessed by reverse transcription-quantitative PCR. Notably, TUDCA had no significant cytotoxic effect on DRG neurons at concentrations ≤250 µM. In addition, the apoptosis induced by tunicamycin exposure was markedly suppressed by TUDCA, as indicated by the percentage of TUNEL-positive cells, the activities of caspases and the changes in expression levels of critical apoptosis factors. Furthermore, the cytotoxicity of tunicamycin in DRG neurons was accompanied by an increase in malondialdehyde (MDA) content, reactive oxygen species (ROS) and lactate dehydrogenase (LDH) production, and a decrease in glutathione (GSH) levels. The changes in oxidative stress-related factors (ROS, LDH, MDA and GSH) were reversed by TUDCA. Furthermore, as determined by western blotting, the increase in C/EBP homologous protein, glucose-regulated protein 78 and cleaved caspase-12 expression following tunicamycin treatment suggested the activation of ER stress. Downregulation of ER stress components and unfolded protein response sensors by TUDCA confirmed the implication of ER stress in the effects of TUDCA on DRG neurons. In conclusion, the present study indicated that TUDCA may protect against tunicamycin-induced DRG apoptosis by suppressing the activation of ER stress. The protective effect and the therapeutic value of TUDCA in nervous system injury require further study in animal models.

Secondary Mechanisms of Neurotrauma: A Closer Look at the Evidence

Traumatic central nervous system injury is a leading cause of neurological injury worldwide. While initial neuroresuscitative efforts are focused on ameliorating the effects of primary injury through patient stabilization, secondary injury in neurotrauma is a potential cause of cell death, oxidative stress, and neuroinflammation. These secondary injuries lack defined therapy. The major causes of secondary injury in neurotrauma include endoplasmic reticular stress, mitochondrial dysfunction, and the buildup of reactive oxygen or nitrogenous species. Stress to the endoplasmic reticulum in neurotrauma results in the overactivation of the unfolded protein response with subsequent cell apoptosis. Mitochondrial dysfunction can lead to the release of caspases and the buildup of reactive oxygen species; several characteristics make the central nervous system particularly susceptible to oxidative damage. Together, endoplasmic reticulum, mitochondrial, and oxidative stress can have detrimental consequences, beginning moments and lasting days to months after the primary injury. Understanding these causative pathways has led to the proposal of various potential treatment options.

Endoplasmic Reticulum Stress-Associated Neuronal Death and Innate Immune Response in Neurological Diseases

Neuronal death and inflammatory response are two common pathological hallmarks of acute central nervous system injury and chronic degenerative disorders, both of which are closely related to cognitive and motor dysfunction associated with various neurological diseases. Neurological diseases are highly heterogeneous; however, they share a common pathogenesis, that is, the aberrant accumulation of misfolded/unfolded proteins within the endoplasmic reticulum (ER). Fortunately, the cell has intrinsic quality control mechanisms to maintain the proteostasis network, such as chaperone-mediated folding and ER-associated degradation. However, when these control mechanisms fail, misfolded/unfolded proteins accumulate in the ER lumen and contribute to ER stress. ER stress has been implicated in nearly all neurological diseases. ER stress initiates the unfolded protein response to restore proteostasis, and if the damage is irreversible, it elicits intracellular cascades of death and inflammation. With the growing appreciation of a functional association between ER stress and neurological diseases and with the improved understanding of the multiple underlying molecular mechanisms, pharmacological and genetic targeting of ER stress are beginning to emerge as therapeutic approaches for neurological diseases.

Ischemic brain injury in diabetes and endoplasmic reticulum stress

Diabetes is a widespread disease characterized by high blood glucose levels due to abnormal insulin activity, production, or both. Chronic diabetes causes many secondary complications including cardiovascular disease: a life-threatening complication. Cerebral ischemia-related mortality, morbidity, and the extent of brain injury are high in diabetes. However, the mechanism of increase in ischemic brain injury during diabetes is not well understood. Multiple mechanisms mediate diabetic hyperglycemia and hypoglycemia-induced increase in ischemic brain injury. Endoplasmic reticulum (ER) stress mediates both brain injury as well as brain protection after ischemia-reperfusion injury. The pathways of ER stress are modulated during diabetes. Free radical generation and mitochondrial dysfunction, two of the prominent mechanisms that mediate diabetic increase in ischemic brain injury, are known to stimulate the pathways of ER stress. Increased ischemic brain injury in diabetes is accompanied by a further increase in the activation of ER stress. As there are many metabolic changes associated with diabetes, differential activation of the pathways of ER stress may mediate pronounced ischemic brain injury in subjects suffering from diabetes. We presently discuss the literature on the significance of ER stress in mediating increased ischemia-reperfusion injury in diabetes.

Nrf2 loss of function exacerbates endoplasmic reticulum stress-induced apoptosis in TBI mice

Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in neuroprotection and recover. Our studies have showed that endoplasmic reticulum (ER) stress-induced apoptosis aggravates secondary damage following traumatic brain injury (TBI). Whether Nrf2 involved in ER stress and ER stress-mediated apoptosis is not clearly investigated. This present study explored the effect of Nrf2 knockout on ER stress and ER stress-induced apoptosis in TBI mice. A lateral fluid percussion injury (FPI)model of TBI was built based on Nrf2 knockout (Nrf2^(-/-)) mice and wild-type (Nrf2^(+/+)) mice, and the expressions of marker proteins of ER stress and ER stress-induced apoptosis were checked at 24 h following TBI. We found that Nrf2^(-/-) mice presented more severe neurological deficit, brain edema and neuronal cell apoptosis compared with Nrf2^(+/+) mice. And, the TBI Nrf2^(-/-) mice were significantly increased expression of marker proteins of ER stress and ER stress-induced apoptotic pathway including glucose regulated protein (GRP78), protein kinase RNA-like ER kinase (PERK), inositol requiring enzyme (IRE1), activating transcription factor 6 (ATF6), C/EBP homologous protein (CHOP), caspase-12 and caspase-3, compared with that in WT mice. These results suggest that Nrf2 could ameliorate TBI-induced second brain injury partly through ER stress signal pathway.

Selective activation of cannabinoid receptor-2 reduces white matter injury via PERK signaling in a rat model of traumatic brain injury

BACKGROUND AND PURPOSE

Traumatic brain injury (TBI) destroys white matter, and this destruction is aggravated by secondary neuroinflammatory reactions. Although white matter injury (WMI) is strongly correlated with poor neurological function, understanding of white matter integrity maintenance is limited, and no available therapies can effectively protect white matter. One candidate approach that may fulfill this goal is cannabinoid receptor 2 (CB2) agonist treatment. Here, we confirmed that a selective CB2 agonist, JWH133, protected white matter after TBI.

METHODS

The motor evoked potentials (MEPs), open field test, and Morris water maze test were used to assess neurobehavioral outcomes. Brain tissue loss, WM damage, Endoplasmic reticulum stress (ER stress), microglia responses were evaluated after TBI. The functional integrity of WM was measured by diffusion tensor imaging (DTI) and transmission electron microscopy (TEM). Primary microglia and oligodendrocyte cocultures were used for additional mechanistic studies.

RESULTS

JWH133 increased myelin basic protein (MBP) and neurofilament heavy chain (NF200) levels and anatomic preservation of myelinated axons revealed by DTI and TEM. JWH133 also increased the numbers of oligodendrocyte precursor cells and mature oligodendrocytes. Furthermore, JWH133 drove microglial polarization toward the protective M2 phenotype and modulated the redistribution of microglia in the striatum. Further investigation of the underlying mechanism revealed that JWH133 downregulated phosphorylation of the protein kinase R (PKR)-like endoplasmic reticulum (ER) kinase (PERK) signaling pathway and its downstream signals eukaryotic translation initiation factor 2 α (eIF2α), activating transcription factor 4 (ATF4) and Growth arrest and DNA damage-inducible protein (GADD34); this downregulation was followed by p-Protein kinase B(p-Akt) upregulation. In primary cocultures of microglia and oligodendrocytes, JWH133 decreased phosphorylated PERK expression in microglia stimulated with tunicamycin and facilitated oligodendrocyte survival. These data reveal that JWH133 ultimately alleviates WMI and improves neurological behavior following TBI. However, these effects were prevented by SR144528, a selective CB2 antagonist.

CONCLUSIONS

This work illustrates the PERK-mediated interaction between microglia and oligodendrocytes. In addition, the results are consistent with recent findings that microglial polarization switching accelerates WMI, highlighting a previously unexplored role for CB2 agonists. Thus, CB2 agonists are potential therapeutic agents for TBI and other neurological conditions involving white matter destruction.

Synergistic effects of brain injury and aging: common mechanisms of proteostatic dysfunction

The aftermath of TBI is associated with an acute stress response and the accumulation of insoluble protein aggregates. Even after the symptoms of TBI are resolved, insidious molecular processes continue to develop, which often ultimately result in the development of age-associated neurodegenerative disorders. The precise molecular cascades that drive unhealthy brain aging are still largely unknown. In this review, we discuss proteostatic dysfunction as a converging mechanism contributing to accelerated brain aging after TBI. We examine evidence from human tissue and in vivo animal models, spanning both the aging and injury contexts. We conclude that TBI has a sustained debilitating effect on the proteostatic machinery, which may contribute to the accelerated pathological and cognitive hallmarks of aging that are observed following injury.

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.

Polydatin alleviates severe traumatic brain injury induced acute lung injury by inhibiting S100B mediated NETs formation

Severe traumatic brain injury (sTBI)-induced acute lung injury (sTBI-ALI) is regarded as the most common complication of sTBI that is an independent predictor of poor outcomes in patients with sTBI and strongly increases sTBI mortality. Polydatin (PD) has been shown to have a potential therapeutic effect on sTBI-induced neurons injury and sepsis-induced acute lung injury (ALI), therefore, it is reasonable to believe that PD has a protective effect on sTBI-ALI. Here, to clarify the PD protective effect following sTBI-ALI, a rat brain injury model of lateral fluid percussion was established to mimic sTBI. As a result, sTBI induced ALI, and caused an increasing of wet/dry weight ratio and lung vascular permeability, as well as sTBI promoted oxidative stress response in the lung; sTBI caused inflammatory cytokines release, such as IL-6, IL-1β, TNF-α and MCP-1; and sTBI promoted NETs formation, mainly including an increasing expression of MPO, NE and CitH3. Simultaneously, sTBI induced a significant increase in the level of S100B; however, when inhibition of S100B, the expression of MPO, NE and CITH3 were significantly inhibited following sTBI. Inhibition of S100B also promoted lung vascular permeability recovery and alleviated oxidative stress response. Furthermore, PD treatmentreduced the pathological lung damage, promoted lung vascular permeability recovery, alleviated oxidative stress response and inflammatory cytokines release; more importantly, PD inhibited the expression of S100B, and NETs formation in the lung following sTBI. These results indicate that PD alleviates sTBI-ALI by inhibiting S100B mediated NETs formation. Thus, PD may be valuable in sTBI-ALI treatment.

Preclinical Western Blot in the Era of Digital Transformation and Reproducible Research, an Eastern Perspective

The current research is an interdisciplinary endeavor to develop a necessary tool in preclinical protein studies of diseases or disorders through western blotting. In the era of digital transformation and open access principles, an interactive cloud-based database called East-West Blot ( https://rancs-lab.shinyapps.io/WesternBlots ) is designed and developed. The online interactive subject-specific database built on the R shiny platform facilitates a systematic literature search on the specific subject matter, here set to western blot studies of protein regulation in the preclinical model of TBI. The tool summarizes the existing publicly available knowledge through a data visualization technique and easy access to the critical data elements and links to the study itself. The application compiled a relational database of PubMed-indexed western blot studies labeled under HHS public access, reporting downstream protein regulations presented by fluid percussion injury model of traumatic brain injury. The promises of the developed tool include progressing toward implementing the principles of 3Rs (replacement, reduction, and refinement) for humane experiments, cultivating the prerequisites of reproducible research in terms of reporting characteristics, paving the ways for a more collaborative experimental design in basic science, and rendering an up-to-date and summarized perspective of current publicly available knowledge.

Assessment of the Effects of Stretch-Injury on Primary Rat Microglia

Mechanical stretch-injury is a prominent force involved in the etiology of traumatic brain injury (TBI). It is known to directly cause damage and dysfunction in neurons, astrocytes, and endothelial cells. However, the deleterious effects of stretch-injury on microglia, the brain's primary immunocompetent cell, are currently unknown. The Cell Injury Controller II (CICII), a validated cellular neurotrauma model, was used to induce a mechanical stretch-injury in primary rat microglia. Statistical analysis utilized Student's t test and one- and two-way ANOVAs with Tukey's and Sidak's multiple comparisons, respectively. Cells exposed to stretch-injury showed no signs of membrane permeability, necrosis, or apoptosis, as measured by media-derived lactate dehydrogenase (LDH) and cleaved-caspase 3 immunocytochemistry, respectively. Interestingly, injured cells displayed a functional deficit in nitric oxide production (NO), identified by media assay and immunocytochemistry, at 6, 12, 18, and 48 h post-injury. Furthermore, gene expression analysis revealed the expression of inflammatory cytokines IL-6 and IL-10, and enzyme arginase-1 was significantly downregulated at 12 h post-injury. Time course evaluation of migration, using a cell exclusion zone assay, showed stretch-injured cells display decreased migration into the exclusion zone at 48- and 72-h post-stretch. Lastly, coinciding with the functional immune deficits was a significant change in morphology, with process length decreasing and cell diameter increasing following an injury at 12 h. Taken together, the data demonstrate that stretch-injury produces significant alterations in microglial function, which may have a marked impact on their response to injury or their interaction with other cells.

Acute Neural and Proteostasis Messenger Ribonucleic Acid Levels Predict Chronic Locomotor Recovery after Contusive Spinal Cord Injury

One of the difficulties in identifying novel therapeutic strategies to manage central nervous system (CNS) trauma is the need for behavioral assays to assess chronic functional recovery. In vitro assays and/or acute behavioral assessments cannot accurately predict long-term functional outcome. Using data from 13 independent T9 moderate contusive spinal cord injury (SCI) studies, we asked whether the ratio of acute (24-72 h post-injury) changes in the levels of neuron-, oligodendrocyte-, astrocyte-specific and/or endoplasmic reticulum stress response (ERSR) messenger ribonucleic acids (mRNAs) could predict the extent of chronic functional recovery. Increased levels of neuron, oligodendrocyte, and astrocyte mRNAs all correlated with enhanced Basso Mouse Scale (BMS) scores. Reduced levels of the ERSR mRNAs Atf4 and Chop correlate with improved chronic locomotor function. Neither neural or ERSR mRNAs were predictive for chronic recovery across all behavioral changes. The ratio of oligodendrocyte/ERSR mRNAs, however, did predict "improved," "no change," or "worse" functional recovery. Neuronal/ERSR mRNA ratios predicted functional improvement, but could not distinguish between worse or no change outcomes. Astrocyte/ERSR mRNA ratios were not predictive. This approach can be used to confirm biological action of injected drugs in vivo and to optimize dose and therapeutic window. It may prove useful in cervical and lumbar SCI and in other traumatic CNS injuries such as traumatic brain injury and stroke, where prevention of neuronal loss is paramount to functional recovery. Although the current analysis was directed toward ERSR whose activity was targeted in all but one study, acute mRNA markers for other pathophysiological cascades may be as predictive of chronic recovery when those cascades are targeted for neuroprotection.

Zinc supplementation alleviates endoplasmic reticulum stress during porcine oocyte in vitro maturation by upregulating zinc transporters

Endoplasmic reticulum (ER) stress is a major contributor to embryonic development failure. Mammalian oocytes have a high risk of exposure to cellular stress during in vitro embryo production. We investigated the effects of zinc supplementation during in vitro maturation under ER stress. We evaluated cumulus expansion, embryonic development derived by parthenogenetic activation, reactive oxygen species, protein expression of X-box binding protein 1 (XBP1), and expression of genes related to ER stress. Supplementation with 1 μg/ml zinc significantly increased the nuclear maturation of oocytes, cleavage and blastocyst formation rates, and total blastocyst cell number (p < .05). Under ER stress, zinc significantly reduced protein expression of XBP1, and increased cleavage and blastocyst rates (p < .05). Concomitantly, zinc supplementation upregulated the expression of zinc transporters (SLC39A14 and SLC39A10), PTGS2, and downregulated ER stress-related genes (sXBP1, uXBP1, ATF4, and PTPN1/PTP1B), and caspase 3. These results suggest that zinc supplementation alleviates ER stress by providing essential metal-ion transporters for oocyte maturation and subsequent embryonic development.

Ferroptosis-relevant mechanisms and biomarkers for therapeutic interventions in traumatic brain injury

Traumatic brain injury (TBI) is one of the most significant health care problems worldwide, causing disability and death especially among young individuals. Although a large range of agents and therapies have been proved beneficial to lesions post-TBI to some extent, effective treatments have not been translated to the clinic. As a newly discovered form of iron-dependent regulated cell death, ferroptosis has been implicated in TBI. In this review, we update the current state of knowledge related to second injuries post-TBI, including ferroptosis, oxidative stress, mitochondrial dysfunction, neuroinflammation and so on, which often lead to chronic symptoms and long-term disability. This review systematically summarizes the latest progress in the pathophysiological mechanisms of TBI, with a focus on providing references for proposing new multi-molecular targets for comprehensive therapeutic strategies based on ferroptosis-relevant mechanisms. In addition, biomarkers are essential diagnostic and prognostic tools in TBI. Several biomarkers associated with the outcome of TBI have been listed in this article, such as Pde10a, MDA, UCH-L1, S100A9, S100B, ALDOC, ACSL4, MBP and F2-Isoprostane. Therefore, the understating of ferroptosis-relevant mechanisms and biomarkers may contribute to development of promising therapies for TBI clinical trials.

Endoplasmic reticulum stress signaling in cancer and neurodegenerative disorders: Tools and strategies to understand its complexity

The endoplasmic reticulum (ER) comprises a network of tubules and vesicles that constitutes the largest organelle of the eukaryotic cell. Being the location where most proteins are synthesized and folded, it is crucial for the upkeep of cellular homeostasis. Disturbed ER homeostasis triggers the activation of a conserved molecular machinery, termed the unfolded protein response (UPR), that comprises three major signaling branches, initiated by the protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1) and the activating transcription factor 6 (ATF6). Given the impact of this intricate signaling network upon an extensive list of cellular processes, including protein turnover and autophagy, ER stress is involved in the onset and progression of multiple diseases, including cancer and neurodegenerative disorders. There is, for this reason, an increasing number of publications focused on characterizing and/or modulating ER stress, which have resulted in a wide array of techniques employed to study ER-related molecular events. This review aims to sum up the essentials on the current knowledge of the molecular biology of endoplasmic reticulum stress, while highlighting the available tools used in studies of this nature.

Aberrant ER Stress Induced Neuronal-IFNβ Elicits White Matter Injury Due to Microglial Activation and T-Cell Infiltration after TBI

Persistent endoplasmic reticulum (ER) stress in neurons is associated with activation of inflammatory cells and subsequent neuroinflammation following traumatic brain injury (TBI); however, the underlying mechanism remains elusive. We found that induction of neuronal-ER stress, which was mostly characterized by an increase in phosphorylation of a protein kinase R-like ER kinase (PERK) leads to release of excess interferon (IFN)β due to atypical activation of the neuronal-STING signaling pathway. IFNβ enforced activation and polarization of the primary microglial cells to inflammatory M1 phenotype with the secretion of a proinflammatory chemokine CXCL10 due to activation of STAT1 signaling. The secreted CXCL10, in turn, stimulated the T-cell infiltration by serving as the ligand and chemoattractant for CXCR3⁺ T-helper 1 (Th1) cells. The activation of microglial cells and infiltration of Th1 cells resulted in white matter injury, characterized by impaired myelin basic protein and neurofilament NF200, the reduced thickness of corpus callosum and external capsule, and decline of mature oligodendrocytes and oligodendrocyte precursor cells. Intranasal delivery of CXCL10 siRNA blocked Th1 infiltration but did not fully rescue microglial activation and white matter injury after TBI. However, impeding PERK-phosphorylation through the administration of GSK2656157 abrogated neuronal induction of IFNβ, switched microglial polarization to M2 phenotype, prevented Th1 infiltration, and increased Th2 and Treg levels. These events ultimately attenuated the white matter injury and improved anxiety and depressive-like behavior following TBI.SIGNIFICANCE STATEMENT A recent clinical study showed that human brain trauma patients had enhanced expression of type-1 IFN; suggests that type-1 IFN signaling may potentially influence clinical outcome in TBI patients. However, it was not understood how TBI leads to an increase in IFNβ and whether induction of IFNβ has any influence on neuroinflammation, which is the primary reason for morbidity and mortality in TBI. Our study suggests that induction of PERK phosphorylation, a characteristic feature of ER stress is responsible for an increase in neuronal IFNβ, which, in turn, activates microglial cells and subsequently manifests the infiltration of T cells to induce neuroinflammation and subsequently white matter injury. Blocking PERK phosphorylation using GSK2656157 (or PERK knockdown) the whole cascade of neuroinflammation was attenuated and improved cognitive function after TBI.

Polydatin prevents the induction of secondary brain injury after traumatic brain injury by protecting neuronal mitochondria

Polydatin is thought to protect mitochondria in different cell types in various diseases. Mitochondrial dysfunction is a major contributing factor in secondary brain injury resulting from traumatic brain injury. To investigate the protective effect of polydatin after traumatic brain injury, a rat brain injury model of lateral fluid percussion was established to mimic traumatic brain injury insults. Rat models were intraperitoneally injected with polydatin (30 mg/kg) or the SIRT1 activator SRT1720 (20 mg/kg, as a positive control to polydatin). At 6 hours post-traumatic brain injury insults, western blot assay was used to detect the expression of SIRT1, endoplasmic reticulum stress related proteins and p38 phosphorylation in cerebral cortex on the injured side. Flow cytometry was used to analyze neuronal mitochondrial superoxide, mitochondrial membrane potential and mitochondrial permeability transition pore opened. Ultrastructural damage in neuronal mitochondria was measured by transmission electron microscopy. Our results showed that after treatment with polydatin, release of reactive oxygen species in neuronal mitochondria was markedly reduced; swelling of mitochondria was alleviated; mitochondrial membrane potential was maintained; mitochondrial permeability transition pore opened. Also endoplasmic reticulum stress related proteins were inhibited, including the activation of p-PERK, spliced XBP-1 and cleaved ATF6. SIRT1 expression and activity were increased; p38 phosphorylation and cleaved caspase-9/3 activation were inhibited. Neurological scores of treated rats were increased and the mortality was reduced compared with the rats only subjected to traumatic brain injury. These results indicated that polydatin protectrd rats from the consequences of traumatic brain injury and exerted a protective effect on neuronal mitochondria. The mechanisms may be linked to increased SIRT1 expression and activity, which inhibits the p38 phosphorylation-mediated mitochondrial apoptotic pathway. This study was approved by the Animal Care and Use Committee of the Southern Medical University, China (approval number: L2016113) on January 1, 2016.

Vitamin B12 Enhances Nerve Repair and Improves Functional Recovery After Traumatic Brain Injury by Inhibiting ER Stress-Induced Neuron Injury

Traumatic brain injury (TBI) is one of the most common causes of neurological damage in young human populations. Vitamin B₁₂ has been reported to promote axon growth of neuronal cells after peripheral nerve injury, which is currently used for the treatment of peripheral nerve damage in the clinical trial. Thus, we hypothesized that TBI can be attenuated by vitaminB₁₂ treatment through its beneficial role on axon regeneration after nerve injury. To confirm it, the biological function of vitaminB₁₂ was characterized using hematoxylin and eosin (H&E) staining, Luxol fast blue (LFB) staining, western blot analysis, and immunohistochemistry staining. The results showed that the neurological functional recovery was improved in the VitaminB₁₂-treated group after TBI, which may be due to downregulation of the endoplasmic reticulum stress-related apoptosis signaling pathway. Moreover, the microtubule stabilization, remyelination and myelin reparation were rescued by vitamin B₁₂, which was consistent with the treatment of 4-phenylbutyric acid (4-PBA), an endoplasmic reticulum stress inhibitor. The study suggests that vitamin B₁₂ may be useful as a novel neuroprotective drug for TBI.

Resveratrol reduces brain injury after subarachnoid hemorrhage by inhibiting oxidative stress and endoplasmic reticulum stress

Previous studies have shown that resveratrol, a bioactive substance found in many plants, can reduce early brain injury after subarachnoid hemorrhage, but how it acts is still unclear. This study explored the mechanism using the experimental subarachnoid hemorrhage rat model established by injecting autologous blood into the cerebellomedullary cistern. Rat models were treated with an intraperitoneal injection of 60 mg/kg resveratrol 2, 6, 24 and 46 hours after injury. At 48 hours after injury, their neurological function was assessed using a modified Garcia score. Brain edema was measured by the wet-dry method. Neuronal apoptosis in the prefrontal cortex was detected by terminal deoxyribonucleotidyl transferase-mediated biotin-16-dUTP nick-end labeling assay. Levels of reactive oxygen species and malondialdehyde in the prefrontal cortex were determined by colorimetry. CHOP, glucose-regulated protein 78, nuclear factor-erythroid 2-related factor 2 and heme oxygenase-1 mRNA expression levels in the prefrontal cortex were measured by reverse transcription polymerase chain reaction. Tumor necrosis factor-alpha content in the prefrontal cortex was detected by enzyme linked immunosorbent assay. Immunohistochemical staining was used to detect the number of positive cells of nuclear factor-erythroid 2-related factor 2, heme oxygenase 1, glucose-regulated protein 78, CHOP and glial fibrillary acidic protein. Western blot assay was utilized to analyze the expression levels of nuclear factor-erythroid 2-related factor 2, heme oxygenase 1, glucose-regulated protein 78 and CHOP protein expression levels in the prefrontal cortex. The results showed that resveratrol treatment markedly alleviated neurological deficits and brain edema in experimental subarachnoid hemorrhage rats, and reduced neuronal apoptosis in the prefrontal cortex. Resveratrol reduced the levels of reactive oxygen species and malondialdehyde, and increased the expression of nuclear factor-erythroid 2-related factor 2, heme oxygenase-1 mRNA and protein in the prefrontal cortex. Resveratrol decreased glucose-regulated protein 78, CHOP mRNA and protein expression and tumor necrosis factor-alpha level. It also activated astrocytes. The results suggest that resveratrol exerted neuroprotective effect on subarachnoid hemorrhage by reducing oxidative damage, endoplasmic reticulum stress and neuroinflammation. The study was approved by the Animals Ethics Committee of Shandong University, China on February 22, 2016 (approval No. LL-201602022).