Enriched environment improves post-stroke cognitive impairment and inhibits neuroinflammation and oxidative stress by activating Nrf2-ARE pathway

Albiflorin alleviates neuroinflammation of rats after MCAO via PGK1/Nrf2/HO-1 signaling pathway

Ischemic stroke is acknowledged as one of the most frequent causes of death and disability, in which neuroinflammation plays a critical role. Emerging evidence supports that the PGK1/Nrf2/HO-1 signaling can modulate inflammation and oxidative injury. Albiflorin (ALB), a main component of Radix paeoniae Alba, possesses anti-inflammatory and antioxidative properties. However, how it exerts a protective role still needs further exploration. In our study, the middle cerebral artery occlusion (MCAO) model was established, and the Longa score was applied to investigate the degree of neurological impairment. Dihydroethidium (DHE) staining and Malondialdehyde (MDA) assay were used to detect the level of lipid peroxidation. 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining was used to measure the infarct area. Evans blue staining was employed to observe the integrality of the blood-brain barrier (BBB). The injury of brain tissue in each group was observed via HE staining. Immunofluorescence staining, enzyme-linked immunosorbent assay (ELISA) and western blot assay were used for the measurement of inflammatory factors and protein levels. We finally observed that ALB relieved cerebral infarction symptoms, attenuated oxidative damage in brain tissues, and reduced neuroinflammation and cell injury in MCAO rats. The overexpression of PGK1 abrogated the protective effect of ALB after experimental cerebral infarction. ALB promoted PGK1 degradation and induced Nrf2 signaling cascade activation for subsequent anti-inflammatory and antioxidant damage. Generally speaking, ALB exerted a protective role in treating cerebral ischemia, and it might target at PGK1/Nrf2/HO-1 signaling. Thus, ALB might be a potential therapeutic agent to alleviate neuroinflammation and protect brain cells after cerebral infarction.

Post-stroke cognitive impairment: exploring molecular mechanisms and omics biomarkers for early identification and intervention

Post-stroke cognitive impairment (PSCI) is a major stroke consequence that has a severe impact on patients' quality of life and survival rate. For this reason, it is especially crucial to identify and intervene early in high-risk groups during the acute phase of stroke. Currently, there are no reliable and efficient techniques for the early diagnosis, appropriate evaluation, or prognostication of PSCI. Instead, plenty of biomarkers in stroke patients have progressively been linked to cognitive impairment in recent years. High-throughput omics techniques that generate large amounts of data and process it to a high quality have been used to screen and identify biomarkers of PSCI in order to investigate the molecular mechanisms of the disease. These techniques include metabolomics, which explores dynamic changes in the organism, gut microbiomics, which studies host-microbe interactions, genomics, which elucidates deeper disease mechanisms, transcriptomics and proteomics, which describe gene expression and regulation. We looked through electronic databases like PubMed, the Cochrane Library, Embase, Web of Science, and common databases for each omics to find biomarkers that might be connected to the pathophysiology of PSCI. As all, we found 34 studies: 14 in the field of metabolomics, 5 in the field of gut microbiomics, 5 in the field of genomics, 4 in the field of transcriptomics, and 7 in the field of proteomics. We discovered that neuroinflammation, oxidative stress, and atherosclerosis may be the primary causes of PSCI development, and that metabolomics may play a role in the molecular mechanisms of PSCI. In this study, we summarized the existing issues across omics technologies and discuss the latest discoveries of PSCI biomarkers in the context of omics, with the goal of investigating the molecular causes of post-stroke cognitive impairment. We also discuss the potential therapeutic utility of omics platforms for PSCI mechanisms, diagnosis, and intervention in order to promote the area's advancement towards precision PSCI treatment.

The impact of enriched environments on cerebral oxidative balance in rodents: a systematic review of environmental variability effects

Introduction

The present review aimed to systematically summarize the impacts of environmental enrichment (EE) on cerebral oxidative balance in rodents exposed to normal and unfavorable environmental conditions.

Methods

In this systematic review, four databases were used: PubMed (830 articles), Scopus (126 articles), Embase (127 articles), and Science Direct (794 articles). Eligibility criteria were applied based on the Population, Intervention, Comparison, Outcomes, and Study (PICOS) strategy to reduce the risk of bias. The searches were carried out by two independent researchers; in case of disagreement, a third participant was requested. After the selection and inclusion of articles, data related to sample characteristics and the EE protocol (time of exposure to EE, number of animals, and size of the environment) were extracted, as well as data related to brain tissues and biomarkers of oxidative balance, including carbonyls, malondialdehyde, nitrotyrosine, oxygen-reactive species, and glutathione (reduced/oxidized).

Results

A total of 1,877 articles were found in the four databases, of which 16 studies were included in this systematic review. The results showed that different EE protocols were able to produce a global increase in antioxidant capacity, both enzymatic and non-enzymatic, which are the main factors for the neuroprotective effects in the central nervous system (CNS) subjected to unfavorable conditions. Furthermore, it was possible to notice a slowdown in neural dysfunction associated with oxidative damage, especially in the prefrontal structure in mice.

Discussion

In conclusion, EE protocols were determined to be valid tools for improving oxidative balance in the CNS. The global decrease in oxidative stress biomarkers indicates refinement in reactive oxygen species detoxification, triggering an improvement in the antioxidant network.

Enriched Environments in Stroke Units: Defining Characteristics and Limitations

BACKGROUND

Individuals with stroke rehabilitated in an enriched environment (EE) compared to a non-EE are more likely to participate in cognitive and social activities, promoting their rehabilitation and well-being. There is a need for a more comprehensive understanding of methods to implement EEs within complex health systems, particularly in stroke units.

OBJECTIVE

The aim of this systematic review was to compile the concept of an EE in stroke units.

METHODS

The literature was sourced from CINAHL, Embase, and Medline databases. A detailed screening and sifting process was used to identify relevant literature. Multiple reviewers independently appraised the identified literature using a Mixed-methods Appraisal Tool. After screening 336 studies, 11 were included.

RESULTS

This review reveals an EE is challenging to define and almost exclusively about activities based on access to individual and communal equipment. Generally, there are no common descriptions or conceptual agreements.

CONCLUSIONS

To the best of our knowledge, this is the first study to systematically review the concept of an EE in stroke units and shows that more studies on EEs are needed. The weak definitions and unclear theoretical backgrounds of an EE in the included studies could challenge operationalization. Future research should be based on more precise definitions of an EE and broader interventions that include changes to built and natural environments.

Environmental Enrichment in Stroke Research: an Update

Environmental enrichment (EE) refers to different forms of stimulation, where the environment is designed to improve the levels of sensory, cognitive, and motor stimuli, inducing stroke recovery in animal models. Stroke is a leading cause of mortality and neurological disability among older adults, hence the importance of developing strategies to improve recovery for such patients. This review provides an update on recent findings, compiling information regarding the parameters affected by EE exposure in both preclinical and clinical studies. During stroke recovery, EE exposure has been shown to improve both the cognitive and locomotor aspects, inducing important neuroplastic alterations, increased angiogenesis and neurogenesis, and modified gene expression, among other effects. There is a need for further research in this field, particularly in those aspects where the evidence is inconclusive. Moreover, it is necessary refine and adapt the EE paradigms for application in human patients.

Pentoxifylline protects against cerebral ischaemia-reperfusion injury through ferroptosis regulation via the Nrf2/SLC7A11/GPX4 signalling pathway

OBJECTIVE

To investigate whether pentoxifylline (PTX) attenuates cerebral ischaemia-reperfusion injury (IRI) in rats by inhibiting ferroptosis and to explore the underlying molecular mechanisms.

METHODS

Cerebral IRI was induced in male Sprague-Dawley (SD) rats using middle cerebral artery occlusion (MCAO). The effects of PTX on cerebral ischaemia-reperfusion brain samples were detected through neurological deficit score, staining and electron microscopy; levels of ferroptosis biomarkers from brain samples were detected using kits. Additionally, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), transferrin receptor protein 1, divalent metal transporter 1, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) were determined by immunohistochemistry, real-time quantitative polymerase chain reaction and western blotting.

RESULTS

Pre-treatment with PTX was found to improve neurological function, evidenced by reduced neurological deficit scores, decreased infarct volume and alleviated pathological features post-MCAO. This improvement was accompanied by reduced lipid peroxidation levels and mitigated mitochondrial damage. Notably, PTX's inhibitory effect on ferroptosis was characterised by enhanced Nrf2 nuclear translocation and regulation of ferroptosis-related proteins. Moreover, inhibition of Nrf2 using ML385 (an Nrf2-specific inhibitor) reversed PTX's neuroprotective effect on MCAO-induced ferroptosis via the SLC7A11/GPX4 signalling pathway.

CONCLUSIONS

Ferroptosis is evident following cerebral ischaemia-reperfusion in rats. Pentoxifylline confers protection against IRI in rats by inhibiting ferroptosis through the Nrf2/SLC7A11/GPX4 signalling pathway.

Naringenin alleviates cognitive dysfunction in rats with cerebral ischemia/reperfusion injury through up-regulating hippocampal BDNF-TrkB signaling: involving suppression in neuroinflammation and oxidative stress

Cognitive dysfunction is one of the common complications of cerebral ischemia-reperfusion (CI/R) injury after ischemic stroke. Neuroinflammation and oxidative stress are the core pathological mechanism of CI/R injury. The activation of brain derived neurotrophic factor (BDNF)-tyrosine receptor kinase B (TrkB) signaling antagonize cognitive dysfunction in a series of neuropathy. Naringenin (NAR) improves cognitive function in many diseases, but the role of NAR in CI/R injury-induced cognitive dysfunction remains unexplored. The study aimed to explore the potential protective effects of NAR in CI/R injury-induced cognitive dysfunction and underlying mechanism. The rats were exposed to transient middle cerebral artery occlusion (MCAO) and then treated with distilled water or NAR (50 or 100 mg/kg/day, p.o.) for 30 days. The Y-maze test, Novel object recognition test and Morris water maze test were performed to assess cognitive function. The levels of oxidative stress and inflammatory cytokines were measured by ELISA. The expressions of BDNF/TrkB signaling were detected by Western blot. NAR prevented cognitive impairment in MCAO-induced CI/R injury rats. Moreover, NAR inhibited oxidative stress (reduced levels of malondialdehyde and 4-hydroxynonenal, increased activities of superoxide dismutase and Glutathione peroxidase) and inflammatory cytokines (reduced levels of tumor necrosis factor-α, Interleukin-1β and Interleukin-6), up-regulated the expressions of BDNF and p-TrkB in hippocampus of MCAO-induced CI/R rats. NAR ameliorated cognitive dysfunction of CI/R rats via inhibiting oxidative stress, reducing inflammatory response, and up-regulating BDNF/TrkB signaling pathways in the hippocampus.

Exploring Research Trend and Hotspots on Oxidative Stress in Ischemic Stroke (2001-2022): Insights from Bibliometric

Oxidative stress is widely involved in the pathological process of ischemic stroke and ischemia-reperfusion. Several research have demonstrated that eliminating or reducing oxidative stress can alleviate the pathological changes of ischemic stroke. However, current clinical antioxidant treatment did not always perform as expected. This bibliometric research aims to identify research trends, topics, hotspots, and evolution on oxidative stress in the field of ischemic stroke, and to find potentially antioxidant strategies in future clinical treatment. Relevant publications were searched from the Web of Science (WOS) Core Collection databases (2001-2022). VOSviewer was used to visualize and analyze the development trends and hotspots. In the field of oxidative stress and ischemic stroke, the number of publications increased significantly from 2001 to 2022. China and the USA were the leading countries for publication output. The most prolific institutions were Stanford University. Journal of Cerebral Blood Flow and Metabolism and Stroke were the most cited journals. The research topics in this field include inflammation with oxidative stress, mitochondrial damage with oxidative stress, oxidative stress in reperfusion injury, oxidative stress in cognitive impairment and basic research and clinical translation of oxidative stress. Moreover, "NLRP3 inflammasome," "autophagy," "mitophagy," "miRNA," "ferroptosis," and "signaling pathway" are the emerging research hotspots in recent years. At present, multi-target regulation focusing on multi-mechanism crosstalk has progressed across this period, while challenges come from the transformation of basic research to clinical application. New detection technology and new nanomaterials are expected to integrate oxidative stress into the clinical treatment of ischemic stroke better.

An enriched environment ameliorates maternal sleep deprivation-induced cognitive impairment in aged mice by improving mitochondrial function via the Sirt1/PGC-1α pathway

BACKGROUND

Early life stress can cause cognitive impairment in aged offspring. Environmental enrichment (EE) is considered to be an effective non-pharmacological treatment for improving cognitive decline. The aim of this research was to evaluate the effect of EE, on cognitive impairment in aged offspring induced by maternal sleep deprivation (MSD) and the underlying mechanisms involved to investigate its potential value in clinical practice.

METHODS

CD-1 damns were subjected or not to sleep deprivation during late gestation. Twenty-one days after birth, the offspring were assigned to standard or EE cages. At 18 months-old, the learning and memory function of the offspring mice was evaluated using Morris water maze. The hippocampal and prefrontal cortical levels of protein, gene, proinflammation cytokines, and oxidative stress indicators was examined by Western blot, real-time polymerase chain reaction, enzyme linked immunosorbent assay, and biochemical assays.

RESULTS

Offspring in MSD group exhibited declined learning and memory abilities compared with control animals. Moreover, the hippocampal and prefrontal cortical levels of Sirtuin1 (Sirt1), peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), postsynaptic density protein-95, and synaptophysin were lower and those of proinflammation cytokines higher in the MSD group; meanwhile, the superoxide dismutase content was higher and the malondialdehyde and reactive oxygen species contents were lower. However, these deleterious changes were ameliorated by exposure to EE.

CONCLUSIONS

EE attenuates MSD-induced cognitive impairment, oxidative stress, and neuroinflammation and reverses the reduction in synaptic protein levels in aged offspring mice via the Sirt1/PGC-1α pathway.

Looking Upstream to Understand Race/Ethnicity as a Moderator for Poststroke Neuroinflammation and a Social Determinant for Poststroke Aphasia Outcomes

INTRODUCTION

Over the past decade, the stroke literature has begun to acknowledge and explore explanations for longstanding racial/ethnic differences in stroke outcomes. Poststroke cognitive impairment (PSCI) and poststroke aphasia are two such negative poststroke outcomes where racial/ethnic differences exist. Physiological differences, such as stroke type and lesion size, have been used to partially explain the variation in PSCI and aphasia. However, there is some evidence, although limited, that suggests neuroinflammatory processes as part of allostatic load may be a key contributor to the observed disparities.

METHOD

In this tutorial, we explore the influence of race differences in inflammation on poststroke cognitive outcomes. We suggest lifetime stress and other external determinants of health such as neighborhood environment and discriminatory practices through "weathering" explain differences in inflammation. While using an allostatic load framework, we explore the literature focusing specifically on the role of neuroinflammation on poststroke outcomes.

CONCLUSIONS

Examination of the immune response poststroke provides a foundation for understanding the mechanisms of PSCI and poststroke aphasia and the potential contributions of neuroinflammatory processes on poststroke cognitive outcomes. Furthermore, understanding of racial differences in those processes may contribute to a better understanding of racial disparities in general stroke outcomes as well as poststroke aphasia.

Impact of NQO1 dysregulation in CNS disorders

NAD(P)H Quinone Dehydrogenase 1 (NQO1) plays a pivotal role in the regulation of neuronal function and synaptic plasticity, cellular adaptation to oxidative stress, neuroinflammatory and degenerative processes, and tumorigenesis in the central nervous system (CNS). Impairment of the NQO1 activity in the CNS can result in abnormal neurotransmitter release and clearance, increased oxidative stress, and aggravated cellular injury/death. Furthermore, it can cause disturbances in neural circuit function and synaptic neurotransmission. The abnormalities of NQO1 enzyme activity have been linked to the pathophysiological mechanisms of multiple neurological disorders, including Parkinson's disease, Alzheimer's disease, epilepsy, multiple sclerosis, cerebrovascular disease, traumatic brain injury, and brain malignancy. NQO1 contributes to various dimensions of tumorigenesis and treatment response in various brain tumors. The precise mechanisms through which abnormalities in NQO1 function contribute to these neurological disorders continue to be a subject of ongoing research. Building upon the existing knowledge, the present study reviews current investigations describing the role of NQO1 dysregulations in various neurological disorders. This study emphasizes the potential of NQO1 as a biomarker in diagnostic and prognostic approaches, as well as its suitability as a target for drug development strategies in neurological disorders.

Environmental Enrichment for Stroke and Traumatic Brain Injury: Mechanisms and Translational Implications

Acquired brain injuries, such as ischemic stroke, intracerebral hemorrhage (ICH), and traumatic brain injury (TBI), can cause severe neurologic damage and even death. Unfortunately, currently, there are no effective and safe treatments to reduce the high disability and mortality rates associated with these brain injuries. However, environmental enrichment (EE) is an emerging approach to treating and rehabilitating acquired brain injuries by promoting motor, sensory, and social stimulation. Multiple preclinical studies have shown that EE benefits functional recovery, including improved motor and cognitive function and psychological benefits mediated by complex protective signaling pathways. This article provides an overview of the enriched environment protocols used in animal models of ischemic stroke, ICH, and TBI, as well as relevant clinical studies, with a particular focus on ischemic stroke. Additionally, we explored studies of animals with stroke and TBI exposed to EE alone or in combination with multiple drugs and other rehabilitation modalities. Finally, we discuss the potential clinical applications of EE in future brain rehabilitation therapy and the molecular and cellular changes caused by EE in rodents with stroke or TBI. This article aims to advance preclinical and clinical research on EE rehabilitation therapy for acquired brain injury. © 2024 American Physiological Society. Compr Physiol 14:5291-5323, 2024.

Enriched environment alleviates neurological deficits via downregulation of Cx43 after experimental stroke

While it has been demonstrated that enriched environment (EE) can protect against cerebral ischemia/reperfusion (I/R) injury, the underlying mechanism remains largely unknown. Connexin 43 (Cx43) is a key component of gap junctions, which may mediate cell-to-cell communication in neural cells. This study aimed to investigate the neuroprotective effects of EE against cerebral I/R injury in rats by modulating Cx43. A rat model of cerebral I/R injury was established by middle cerebral artery occlusion (MCAO)/reperfusion. Rats were randomly divided into the sham, MCAO, MCAO + EE, MCAO + Gap19, and MCAO + EE + Gap19 groups. The modified neurological severity score test and Morris water maze assay were used to assess neurological deficits. The infarct volume was measured using triphenyltetrazolium chloride (TTC) staining. Neuronal survival was detected by immunofluorescence. The indices of oxidative stress were determined using ELISA, and the reactive oxygen species levels were determined using a dihydroethidium probe. Cx43 and inflammation-related protein expression levels were also measured using western blotting and immunohistochemistry. EE and Gap19 treatment significantly improved neurological deficits, reduced infarct volumes, attenuated neuronal injury, and suppressed inflammatory cytokine expression and oxidative stress. Furthermore, EE and Gap19 treatment notably downregulated the expression of Cx43 and the inflammation-related pathway TLR4/MyD88/NF-κB in the ischemic penumbra. Gap19, a Cx43 inhibitor, markedly enhanced the neuroprotective effects of EE in rats with cerebral I/R injury. EE treatment protects against cerebral I/R injury in rats via Cx43 downregulation. Our findings may shed light on the mechanism underlying the protective efficacy of EE.

Post-Stroke Brain Health Monitoring and Optimization: A Narrative Review

Significant advancements have been made in recent years in the acute treatment and secondary prevention of stroke. However, a large proportion of stroke survivors will go on to have enduring physical, cognitive, and psychological disabilities from suboptimal post-stroke brain health. Impaired brain health following stroke thus warrants increased attention from clinicians and researchers alike. In this narrative review based on an open timeframe search of the PubMed, Scopus, and Web of Science databases, we define post-stroke brain health and appraise the body of research focused on modifiable vascular, lifestyle, and psychosocial factors for optimizing post-stroke brain health. In addition, we make clinical recommendations for the monitoring and management of post-stroke brain health at major post-stroke transition points centered on four key intertwined domains: cognition, psychosocial health, physical functioning, and global vascular health. Finally, we discuss potential future work in the field of post-stroke brain health, including the use of remote monitoring and interventions, neuromodulation, multi-morbidity interventions, enriched environments, and the need to address inequities in post-stroke brain health. As post-stroke brain health is a relatively new, rapidly evolving, and broad clinical and research field, this narrative review aims to identify and summarize the evidence base to help clinicians and researchers tailor their own approach to integrating post-stroke brain health into their practices.

The Impact of Cerebral Ischemia on Antioxidant Enzymes Activity and Neuronal Damage in the Hippocampus

Cerebral ischemia and subsequent reperfusion, leading to reduced blood supply to specific brain areas, remain significant contributors to neurological damage, disability, and mortality. Among the vulnerable regions, the subcortical areas, including the hippocampus, are particularly susceptible to ischemia-induced injuries, with the extent of damage influenced by the different stages of ischemia. Neural tissue undergoes various changes and damage due to intricate biochemical reactions involving free radicals, oxidative stress, inflammatory responses, and glutamate toxicity. The consequences of these processes can result in irreversible harm. Notably, free radicals play a pivotal role in the neuropathological mechanisms following ischemia, contributing to oxidative stress. Therefore, the function of antioxidant enzymes after ischemia becomes crucial in preventing hippocampal damage caused by oxidative stress. This study explores hippocampal neuronal damage and enzymatic antioxidant activity during ischemia and reperfusion's early and late stages.

Environmental enrichment initiated in adolescence restores the reduced expression of synaptophysin and GFAP in the hippocampus of chronically stressed rats in a sex-specific manner

This study aims at investigating whether environmental enrichment (EE) initiated in adolescence can alter chronic unpredictable stress (CUS)-associated changes in astroglial and synaptic plasticity markers in male and female rats. To this end, we studied possible alterations in hippocampal glial fibrillary acidic protein (GFAP) and synaptophysin (SYN) in CUS rats previously housed in EE. Wistar rats on postnatal day (PND) 23 were housed for 10 weeks in standard housing (SH) or enriched conditions. On PND 66, animals were exposed to CUS for 4 weeks. SYN and GFAP expressions were evaluated in CA1 and CA3 subfields and dentate gyrus (DG). CUS reduced the expression of SYN in all hippocampal areas, whereas lower GFAP expression was evident only in CA1 and CA3. The reduced expression of SYN in DG and CA3 was evident to male SH/CUS rats, whereas the reduced GFAP expression in CA1 and CA3 was limited to SH/CUS females. EE housing increased the hippocampal expression of both markers and protected against CUS-associated decreases. Our findings indicate that the decreases in the expression of SYN and GFAP following CUS are region and sex-specific and underline the neuroprotective role of EE against these CUS-associated changes.

The mechanisms of minocycline in alleviating ischemic stroke damage and cerebral ischemia-reperfusion injury

Stroke is a group of diseases resulting from cerebral vascular rupture or obstruction and subsequent brain blood circulation disorder, leading to rapid neurological deficits. Ischemic stroke accounts for the majority of all stroke cases. The current treatments for ischemic stroke mainly include t-PA thrombolytic therapy and surgical thrombectomy. However, these interventions aimed at recanalizing cerebral vessels can paradoxically lead to ischemia-reperfusion injury, which exacerbates the severity of brain damage. Minocycline, a semi-synthetic tetracycline antibiotic, has been shown to possess a wide range of neuroprotective effects independent of its antibacterial activity. Here we summarize the mechanisms underlying the protective effects of minocycline against cerebral ischemia-reperfusion injury based on the pathogenesis of cerebral ischemia-reperfusion injury, including its modulation of oxidative stress, inflammatory response, excitotoxicity, programmed cell death and blood-brain barrier injury, and also introduce the role of minocycline in alleviating stroke-related complications, in order to provide a theoretical basis for the clinical application of minocycline in cerebral ischemia-reperfusion injury.

Downregulated PGK1 attenuates cerebral ischemia-reperfusion injury by reversing neuroinflammation and oxidative stress through the Nrf2/ARE pathway

Understanding the role and mechanism of astrocytes in inflammation and oxidative response is crucial for developing therapeutic strategies to reduce inflammation and oxidative injury in cerebral ischemia-reperfusion injury (CIRI). In this study, we investigated the regulatory effects of phosphoglycerate kinase 1 (PGK1) on inflammation and oxidative response after CIRI in male adult Sprague-Dawley (SD) rats and using primary astrocytes obtained from neonatal SD rats, and explored its related mechanisms. We established a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R) by suture occlusion, and an oxygen-glucose deprivation/reoxygenation model of astrocytes using oxygen-free, glucose-free, and serum-free cultures. AAV8-PGK1-GFP was injected into the left ventricle 24 h before modeling. Real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, co-immunoprecipitation (CoIP) assay, fluorescence in situ hybridization (FISH), and western blotting were used to elucidate the in-depth mechanisms of PGK1 in CIRI. PGK1 overexpression significantly exacerbated neurological deficits, increased cerebral infarct volume, and aggravated nerve cell injury in rats after MCAO/R. Using FISH and CoIP assays, we verified the localization of PGK1 and Nrf2 in primary astrocytes. Further rescue experiments showed that Nrf2 knockdown eliminated the protective effect of CBR-470-1 (a PGK1 inhibitor) on CIRI. Lastly, we confirmed that PGK1 aggravates CIRI by inhibiting the Nrf2/ARE pathway. In conclusion, our findings suggest that inhibiting PGK1 attenuates CIRI by reducing the release of inflammatory and oxidative factors from astrocytes by activating the Nrf2/ARE signaling pathway.

Enriched Environment Induces Sex-Specific Changes in the Adult Neurogenesis, Cytokine and miRNA Expression in Rat Hippocampus

An enriched environment stimulates adult hippocampal plasticity, but the exact cellular and molecular mechanisms are complex, and thus a matter of debate. We studied the behavior and hippocampal neurogenesis in adult male and female Wistar rats that were housed in an enriched environment (EE) for two months. Both EE males and females performed better than control animals in a Barnes maze, meaning that EE enhances spatial memory. However, the expression levels of neurogenesis markers KI67, DCX, Nestin, and Syn1 increased only in EE females, while in EE males only KI67 and BDNF were higher than in the corresponding control. The number of DCX+ neurons on brain slices increased in the dentate gyrus of EE females only, i.e., the level of adult hippocampal neurogenesis was increased in female but not in male rats. The level of anti-inflammatory IL-10 and signaling pathway components was upregulated in EE females. Of 84 miRNAs tested, in the hippocampi of EE female rats we detected upregulation in the expression levels of 12 miRNAs related to neuronal differentiation and morphogenesis, while in EE males four miRNAs were upregulated and involved in the regulation of cell proliferation/differentiation, and one was downregulated and associated with the stimulation of proliferation. Taken altogether, our results point to sex-specific differences in adult hippocampal plasticity, IL-10 expression, and miRNA profiles induced by an enriched environment.

An enriched environment improves long-term functional outcomes in mice after intracerebral hemorrhage by mechanisms that involve the Nrf2/BDNF/glutaminase pathway

Post-stroke depression exacerbates neurologic deficits and quality of life. Depression after ischemic stroke is known to some extent. However, depression after intracerebral hemorrhage (ICH) is relatively unknown. Increasing evidence shows that exposure to an enriched environment (EE) after cerebral ischemia/reperfusion injury has neuroprotective effects in animal models, but its impact after ICH is unknown. In this study, we investigated the effect of EE on long-term functional outcomes in mice subjected to collagenase-induced striatal ICH. Mice were subjected to ICH with the standard environment (SE) or ICH with EE for 6 h/day (8:00 am-2:00 pm). Depressive, anxiety-like behaviors and cognitive tests were evaluated on day 28 with the sucrose preference test, tail suspension test, forced swim test, light-dark transition experiment, morris water maze, and novel object recognition test. Exposure to EE improved neurologic function, attenuated depressive and anxiety-like behaviors, and promoted spatial learning and memory. These changes were associated with increased expression of transcription factor Nrf2 and brain-derived neurotrophic factor (BDNF) and inhibited glutaminase activity in the perihematomal tissue. However, EE did not change the above behavioral outcomes in Nrf2-/- mice on day 28. Furthermore, exposure to EE did not increase BDNF expression compared to exposure to SE in Nrf2-/- mice on day 28 after ICH. These findings indicate that EE improves long-term outcomes in sensorimotor, emotional, and cognitive behavior after ICH and that the underlying mechanism involves the Nrf2/BDNF/glutaminase pathway.

Enriched environment ameliorates learning and memory deficits in hepatic encephalopathy mice by restoration of the structure of dendrites and dendritic spines

Cognitive impairment is one of the most common symptoms of hepatic encephalopathy (HE). However, there is a lack of easily implementable rehabilitation strategies. As an easy-to-implement strategy, numerous studies suggest that enriched environment (EE) can be beneficial for cognitive function. However, the effects of EE on learning and memory, as well as dendritic spines plasticity in HE is still unclear. Accordingly, in the present study, we evaluated the effects of EE on the behavior and dendritic spine morphology in an animal model of HE. Our results showed that HE mice have no movement disorder and anxiety, but they exhibit spatial learning and memory dysfunction. Further analysis revealed that the complexity of the dendrites and the maturity of the dendritic spines are reduced in the hippocampus of HE mice. After 4 weeks of housekeeping in EE, dendritic complexity, and dendritic spine maturity, as well as the spatial learning and memory function of HE mice were restored. In conclusion, exposure to EE can positively influence dendritic spines plasticity in the hippocampus and thereby elicit its beneficial effects on cognitive functions in HE.

Enriched environment can reverse chronic sleep deprivation-induced damage to cellular plasticity in the dentate gyrus of the hippocampus

Objective

We studied whether enriched environment (EE), a classic epigenetics paradigm, can prevent cellular plasticity damage caused by chronic sleep deprivation (SD).

Methods

We performed SD in mice by a modified multi-platform method (MMPM). Mice in the SD group were deprived of sleep for 18 h a day. In addition, half of the mice in the chronic SD group were exposed to EE stimuli for 6 h per day. Immunostaining analyzed neurogenesis and neural progenitor cell-differentiated phenotypes in the hippocampal dentate gyrus (DG) region.

Result

At 13 weeks, compared with the control group, SD severely impaired the proliferation and differentiation of neural stem cells, and EE completely reversed the process. SD can induce gliosis in the mouse hippocampus, and EE can delay the process.

Conclusion:

Our results suggest that chronic SD may damage the neurogenesis in the DG of the hippocampus. However, enrichment stimulation can reverse the processing by promoting neuronal repair related to neuronal plasticity.

Post-stroke cognitive impairment and synaptic plasticity: A review about the mechanisms and Chinese herbal drugs strategies

Post-stroke cognitive impairment, is a major complication of stroke, characterized by cognitive dysfunction, which directly affects the quality of life. Post-stroke cognitive impairment highlights the causal relationship between stroke and cognitive impairment. The pathological damage of stroke, including the increased release of excitatory amino acids, oxidative stress, inflammatory responses, apoptosis, changed neurotrophic factor levels and gene expression, influence synaptic plasticity. Synaptic plasticity refers to the activity-dependent changes in the strength of synaptic connections and efficiency of synaptic transmission at pre-existing synapses and can be divided into structural synaptic plasticity and functional synaptic plasticity. Changes in synaptic plasticity have been proven to play important roles in the occurrence and treatment of post-stroke cognitive impairment. Evidence has indicated that Chinese herbal drugs have effect of treating post-stroke cognitive impairment. In this review, we overview the influence of pathological damage of stroke on synaptic plasticity, analyze the changes of synaptic plasticity in post-stroke cognitive impairment, and summarize the commonly used Chinese herbal drugs whose active ingredient or extracts can regulate synaptic plasticity. This review will summarize the relationship between post-stroke cognitive impairment and synaptic plasticity, provide new ideas for future exploration of the mechanism of post-stroke cognitive impairment, compile evidence of applying Chinese herbal drugs to treat post-stroke cognitive impairment and lay a foundation for the development of novel formulas for treating post-stroke cognitive impairment.

Pre-ischaemic Treatment with Enriched Environment Alleviates Acute Neuronal Injury by Inhibiting Endoplasmic Reticulum Stress-dependent Autophagy and Apoptosis

Enriched environment (EE) is effective in preventing cerebral ischemia-reperfusion (I/R) injury. However, little is known about the mechanism underlying the neuroprotection of EE preprocessing. Endoplasmic reticulum (ER) stress has been demonstrated to be extensively involved in I/R injury. We aimed to investigate the potential regulatory mechanism of ER stress in the neuroprotection of pre-ischemic EE. Rats were subjected to middle cerebral artery occlusion (MCAO) or sham surgery after 4 weeks of exposure in standard or enriched environments. We found that EE pretreatment alleviates acute neuronal injury after MCAO, as shown by reduced infarct volume and neurological deficit score. The expression of ER stress-related proteins, markers of autophagy, and apoptosis were detected to investigate the underlying mechanism. Our results showed that pre-ischemic EE inhibited the ER stress, as evidenced by the inactivation of activating transcription factor 6 (ATF6), protein kinase RNA (PKR)-like ER kinase (PERK), and inositol-requiring enzyme 1 (IRE1) pathways. Moreover, the rats reared in EE were detected with lower autophagic activity and apoptosis levels. The decrease in activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), and phospho-c-Jun N-terminal kinases (p-JNK) expression suggested EE pretreatment might inhibit autophagy and apoptosis via modulating ER stress-mediated PERK-ATF4-CHOP and IRE1-JNK signal pathways, which provides a new idea for the prevention of the deleterious cerebral and functional consequences of ischemic stroke.

DL-3-n-butylphthalide (NBP) alleviates poststroke cognitive impairment (PSCI) by suppressing neuroinflammation and oxidative stress

Currently, the recovery of cognitive function has become an essential part of stroke rehabilitation. DL-3-n-butylphthalide (NBP) is a neuroprotective reagent and has been used in stroke treatment. Clinical studies have confirmed that NBP can achieve better cognitive outcomes in ischemic stroke patients than in healthy controls. In this study, we aimed to investigate the influences of NBP on cognitive function in an ischemic reperfusion (I/R) rat model. Our results showed that NBP profoundly decreased neurological scores, reduced cerebral infarct areas and enhanced cerebral blood flow (CBF). NBP potently alleviated poststroke cognitive impairment (PSCI) including depression-like behavior and learning, memory and social cognition impairments, in I/R rats. NBP distinctly suppressed the activation of microglia and astrocytes and improved neuron viability in the ischemic brain. NBP inhibited the expression of inflammatory cytokines, including interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), by targeting the nuclear factor kappa B/inducible nitric oxide synthase (NF-κB/iNOS) pathway and decreased cerebral oxidative stress factors, including reactive oxygen species (ROS) and malondialdehyde (MDA), by targeting the kelch like ECH associated protein 1/nuclear factor-erythroid 2 p45-related factor 2 (Keap1/Nrf2) pathway in the ischemic brain. The current study revealed that NBP treatment improved neurological function and ameliorated cognitive impairment in I/R rats, possibly by synergistically suppressing inflammation and oxidative stress.

The Role of Nrf2 in Relieving Cerebral Ischemia-Reperfusion Injury

Ischemic stroke includes two related pathological damage processes: brain injury caused by primary ischemia and secondary ischemia reperfusion (I/R) injury. I/R injury has become a worldwide health problem. Unfortunately, there is still a lack of satisfactory drugs for ameliorating cerebral I/R damage. Nrf2 is a vital endogenous antioxidant protein, which combines with Keap1 to maintain a dormant state under physiological conditions. When pathological changes such as I/R occurs, Nrf2 dissociates from Keap1 and activates the expression of downstream antioxidant proteins to exert a protective effect. Recent research have shown that the activated Nrf2 not only effectively inhibits oxidative stress, but also performs the ability to repair the function of compromised mitochondria, alleviate endoplasmic reticulum stress, eliminate inflammatory response, reduce blood-brain barrier permeability, inhibit neuronal apoptosis, enhance the neural network remolding, thereby exerting significant protective effects in alleviating the injuries caused by cell oxygen-glucose deprivation, or animal cerebral I/R. However, no definite clinical application report demonstrated the efficacy of Nrf2 activators in the treatment of cerebral I/R. Therefore, further efforts are needed to elaborate the role of Nrf2 activators in the treatment of cerebral I/R. Here, we reviewed the possible mechanisms underlying its potential pharmacological benefits in alleviating cerebral I/R injury, so as to provide a theoretical basis for studying its mechanism and developing Nrf2 activators.

An enriched environment reduces hippocampal inflammatory response and improves cognitive function in a mouse model of stroke

An enriched environment is used as a behavioral intervention therapy that applies sensory, motor, and social stimulation, and has been used in basic and clinical research of various neurological diseases. In this study, we established mouse models of photothrombotic stroke and, 24 hours later, raised them in a standard, enriched, or isolated environment for 4 weeks. Compared with the mice raised in a standard environment, the cognitive function of mice raised in an enriched environment was better and the pathological damage in the hippocampal CA1 region was remarkably alleviated. Furthermore, protein expression levels of tumor necrosis factor receptor-associated factor 6, nuclear factor κB p65, interleukin-6, and tumor necrosis factor α, and the mRNA expression level of tumor necrosis factor receptor-associated factor 6 were greatly lower, while the expression level of miR-146a-5p was higher. Compared with the mice raised in a standard environment, changes in these indices in mice raised in an isolated environment were opposite to mice raised in an enriched environment. These findings suggest that different living environments affect the hippocampal inflammatory response and cognitive function in a mouse model of stroke. An enriched environment can improve cognitive function following stroke through up-regulation of miR-146a-5p expression and a reduction in the inflammatory response.

Multiplex array analysis of serum cytokines offers minimal predictive value for cognitive function in the subacute phase after stroke

OBJECTIVE

The effects of inflammation on post-stroke cognitive function are still unclear. This study investigated the correlation between the Th17-related cytokines in peripheral blood and post-stroke cognitive function after ischemic stroke in the subacute phase.

DESIGN

A retrospective cohort study.

SETTING

Academic acute inpatient rehabilitation facility.

PARTICIPANTS

One hundred and fourteen patients with first ischemic stroke were categorized as the poor cognitive recovery group (n = 58) or good cognitive recovery group (n = 56) based on their cognitive MRFS efficiency.

INTERVENTIONS

All subjects received routine physical, occupational, and speech-language pathology therapy.

MAIN OUTCOME MEASURES

Serum cytokines/chemokine (IL-1 β, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12p70, IL-13, IL-15, IL-17A, IL-17E, IL-17F, IL-21, IL-22, IL-23, IL-27, IL-28A, IL-31, IL-33, GM-CSF, IFN-γ, MIP-3 α, TNF-α, and TNF-β) levels were measured in duplicate using Human Th17 magnetic bead panel and multiplex array analysis (Luminex-200 system). The primary functional outcome was a gain in functional independence measure (FIM) cognitive subscore at discharge. The secondary outcome measures were FIM total score at discharge, length of stay in the hospital, and discharge destination. Cognitive Montebello Rehabilitation Factor Score (MRFS) and cognitive MRFS efficiency were calculated. Demographic and clinical characteristics were obtained from the medical record.

RESULTS

The good cognitive recovery group had an interesting trend of higher IL-13 than the poor cognitive recovery group (good cognitive recovery group 257.82 ± 268.76 vs. poor cognitive recovery group 191.67 ± 201.82, p = 0.049, unit: pg/ml). However, Pearson's correlation analysis showed no significant correlation between cytokine levels and gain of cognition, cognitive MRFS, or cognitive MRFS efficiency. Receiver operating characteristic (ROC) analysis of cytokines also suggested a low accuracy of prediction as a predictor for post-stroke cognitive recovery improvement.

CONCLUSION

Our preliminary findings suggested that the level of serum cytokines had minimal predictive value for the recovery of cognitive function during the subacute inpatient rehabilitation after stroke.

The effects and mechanism of environmental enrichment on MK-801 induced cognitive impairment in rodents with schizophrenia

Schizophrenia is a severe mental disorder characterized by positive, negative, and cognitive symptoms. Cognitive symptoms are a kind of symptoms with high incidence and great impact on patients. There is no effective treatment in clinical practice. N-methyl-d-aspartic acid (NMDA) receptor hypofunction may be an important cause of cognitive symptoms. MK-801 (also named Dizocilpine), a noncompetitive antagonist of NMDA receptor, is often used to construct a model of NMDA receptor dysfunction. In terms of treatment, environmental enrichment (EE) as an environmental intervention can effectively improve the symptoms of cognitive impairment in rodents. In this paper, we first briefly introduce the background of cognitive symptoms and EE in schizophrenia, and then investigate the manifestations of MK-801 induced cognitive impairment, the improvement of EE on these cognitive impairments based on the MK-801 induced schizophrenia rodent models, and the possible mechanism of EE in improving cognitive symptoms. This article reviews the literature in recent years, which provides an important reference for MK-801 to construct a cognitive symptom model of schizophrenia and the mechanism of EE in improving cognitive symptoms of schizophrenia.

Rodent Models of Post-Stroke Dementia

Post-stroke cognitive impairment is one of the most common complications in stroke survivors. Concomitant vascular risk factors, including aging, diabetes mellitus, hypertension, dyslipidemia, or underlying pathologic conditions, such as chronic cerebral hypoperfusion, white matter hyperintensities, or Alzheimer’s disease pathology, can predispose patients to develop post-stroke dementia (PSD). Given the various clinical conditions associated with PSD, a single animal model for PSD is not possible. Animal models of PSD that consider these diverse clinical situations have not been well-studied. In this literature review, diverse rodent models that simulate the various clinical conditions of PSD have been evaluated. Heterogeneous rodent models of PSD are classified into the following categories: surgical technique, special structure, and comorbid condition. The characteristics of individual models and their clinical significance are discussed in detail. Diverse rodent models mimicking the specific pathomechanisms of PSD could provide effective animal platforms for future studies investigating the characteristics and pathophysiology of PSD.

Preweaning environmental enrichment alters neonatal ultrasonic vocalisations in a rat model for prenatal infections

OBJECTIVE

Maternal infections are a well-known risk factor for neurodevelopmental defects. Such defects are associated with a range of symptoms, and environmental enrichment (EE) could be a promising approach to rehabilitate these. We used the well-established prenatal poly I:C (polyinosinic-polycytidylic acid) model in rats to examine the effects of preweaning EE on rat pups' ultrasonic vocalisations (USVs) when separated from their mothers. USVs are one of the earliest indicators of a pup's functional level and, thus, well-suited as a marker of neurodevelopmental abnormalities.

METHODS

We used a two-by-two factorial design in which pregnant Sprague-Dawley rats received either saline or the viral mimic poly I:C, and one group of pups was exposed to preweaning enrichment. We measured maternal separation-induced USVs both before postnatal day (PND) 7 and after preweaning enrichment on PND 14.

RESULTS

Poly I:C significantly reduced the number of USVs on PND 7. EE interacted with the poly I:C treatment in that poly I:C pups in the enrichment group called more, whereas saline pups in the enriched environment called less on PND 14 than the respective controls.

CONCLUSION

We showed that the effects of maternal poly I:C on the offspring's USVs could be reduced by early EE. If replicated, it could open novel and safe avenues for treating children of mothers who were exposed to infections during pregnancy.

Role of Neuropilin 1 in COVID-19 Patients with Acute Ischemic Stroke

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection can trigger the adaptive and innate immune responses, leading to uncontrolled inflammatory reactions and associated local and systematic tissue damage, along with thromboembolic disorders that may increase the risk of acute ischemic stroke (AIS) in COVID-19 patients. The neuropilin (NRP-1) which is a co-receptor for the vascular endothelial growth factor (VEGF), integrins, and plexins, is involved in the pathogenesis of AIS. NRP-1 is also regarded as a co-receptor for the entry of SARS-CoV-2 and facilitates its entry into the brain through the olfactory epithelium. NRP-1 is regarded as a cofactor for binding of SARS-CoV-2 with angiotensin-converting enzyme 2 (ACE2), since the absence of ACE2 reduces SARS-CoV-2 infectivity even in presence of NRP-1. Therefore, the aim of the present study was to clarify the potential role of NRP-1 in COVID-19 patients with AIS. SARS-CoV-2 may transmit to the brain through NRP-1 in the olfactory epithelium of the nasal cavity, leading to different neurological disorders, and therefore about 45% of COVID-19 patients had neurological manifestations. NRP-1 has the potential capability to attenuate neuroinflammation, blood–brain barrier (BBB) permeability, cerebral endothelial dysfunction (ED), and neuronal dysfunction that are uncommon in COVID-19 with neurological involvement, including AIS. Similarly, high NRP-1 serum level is linked with ED, oxidative stress, and the risk of pulmonary thrombosis in patients with severe COVID-19, suggesting a compensatory mechanism to overcome immuno-inflammatory disorders. In conclusion, NRP-1 has an important role in the pathogenesis of COVID-19 and AIS, and could be the potential biomarker linking the development of AIS in COVID-19. The present findings cannot provide a final conclusion, and thus in silico, experimental, in vitro, in vivo, preclinical, and clinical studies are recommended to confirm the potential role of NRP-1 in COVID-19, and to elucidate the pharmacological role of NRP-1 receptor agonists and antagonists in COVID-19.

Effects of musk volatile compounds on attenuated nerve injury and improving post-cerebral ischemic exercise functions

BACKGROUND

Reperfusion Injury Acute ischemic stroke is increasing in people recently and Musk, as a commonly used Traditional Chinese Medicine (TCM), has been suggested as a potential agent against acute ischemic stroke, but the efficacies and underlying mechanisms of it remain unknown.

OBJECTIVE

This study was aimed to tested the hypotheses that volatile compounds of musk could attenuate nerve injury and identify the bioactive compounds and potential mechanisms of Musk.

METHOD

Transient middle cerebral artery occlusion (MCAO) model in vivo in Sprague-Dawley rats (SD rats) was used to test this hypothesis. Collecting ingredients of Musk and their related targets were discerned from the Gas chromatography-olfactory mass spectrometry (GC-O-MS) experiment. Then the potential mechanisms and targets of the compounds were searched by network pharmacology techniques. Finally, the pathway was verified by Western Bolt (WB).

RESULTS

First, Musk treatment significantly up-regulated the relative levels of AKT1, PI3KA, and VEGFA in the hippocampus, and improved the sport functions in the post-MCAO ischemic rats in vivo. Next, twenty potential flavor active compounds were recognized by GC-O-MS. A total of 89 key targets including HIF-1, PIK3CA, TNF signaling pathway, and VEGF were identified. AKT1, HIF1A, PIK3CA, and VEGFA were viewed as the most important genes, which were validated by molecular docking simulation.

CONCLUSION

The Volatile compounds of musk can attenuate nerve injury and improving post-cerebral ischemic exercise functions by HIF1A pathways, and the combined data provide novel insight for Musk volatile compounds developed as new drug for improving reperfusion injury in acute ischemic stroke.

Pre-Exposure to Environmental Enrichment Protects against Learning and Memory Deficits Caused by Infrasound Exposure

With the development of industrialization in recent years, infrasound has become an important component of public noise. To date, diverse studies have revealed the negative effects of infrasound on the central nervous system (CNS), especially the learning and memory ability. It is widely reported that environmental enrichment (EE) ameliorates the learning and memory deficits in different models of brain injury. Therefore, the present study was designed to determine the possible benefits of pre-exposure to EE in preventing functional deficits following infrasound exposure and their related mechanism. Adult male rats were given enriched or standard housing for 30 days. Following enrichment, the rats were exposed to 16 Hz, 130 dB infrasound for 14 days, and then their learning and memory ability was assessed. Changes to neuroinflammation, apoptosis, and oxidative stress in the hippocampus were also detected. Our results showed that the infrasound-induced deficit in learning and memory was attenuated significantly in EE pre-exposed rats. Pre-exposure to EE could induce a decrease in proinflammatory cytokines and increased anti-inflammatory cytokines and antioxidant properties in the hippocampus. Moreover, pre-exposure to EE also exerted antiapoptosis functions by upregulating the B-cell lymphoma/leukemia-2 (Bcl-2) level and downregulating the P53 level in the hippocampus. In conclusion, the results of the present study suggested that EE is neuroprotective when applied before infrasound exposure, resulting in an improved learning and memory ability by enhancing antioxidant, anti-inflammatory, and antiapoptosis capacities.

Rehmannioside A improves cognitive impairment and alleviates ferroptosis via activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway after ischemia

ETHNOPHARMACOLOGICAL RELEVANCE

Rehmannioside A is derived from Rehmannia glutinosa Libosch, which is widely used as an important ingredient in diverse traditional Chinese medicines to treat diseases caused by "kidney deficiency" such as cerebral arteriosclerosis, aging-related stroke and dementia in China. Recent studies have proved that Rehmannia glutinosa Libosch and Rehmannioside A can improve memory capability and recover nerve damage.

AIM OF THE STUDY

To investigate the effect of Rehmannioside A on cognitive impairment after ischemia in rats and SH-SY5Y cells, and further evaluate the anti-oxidative and anti-ferroptosis mechanisms.

MATERIALS AND METHODS

Differentially expressed proteins (DEPs) in patients after cerebral ischemic stroke were revealed by a RayBio protein array. Cognitive impairment model was established by middle cerebral artery occlusion and reperfusion (MCAO) 14 days in rats. Rehmannioside A was administered intraperitoneally injection at dose of 80 mg/kg. The SH-SY5Y cells were exposed to H2O2 for 24 h and treated with Rehmannioside A (80 μM) for 24 h. The neuroprotecion of Rehmannioside A were evaluated by infarct volume (TTC), neurological defects (Garcia score) and learning memory (Morris water maze test) in vivo, and cell viability (CCK-8 or LDH) in vitro. Superoxide dismutase (SOD), malondialdehyde (MDA) and myeloperoxidase (MPO) activity of rats, glutathione (GSH), oxidized glutathione (GSSG) and nicotinamide adenine dinucleotide phosphate (NADPH) of cells were detected by biochemical assay. Intracellular reactive oxygen species (ROS) were measured by DCFH-DA assay. Myeloperoxidase (MPO), PI3 kinase (PI3K), p-PI3K, Akt, p-Akt, heme oxygenase-1 (HO-1), nuclear factor-E2-related factor 2 (Nrf2), SLC7A11, glutathione peroxidase 4 (GPX4) of the cerebral cortex in rats or SH-SY5Y cells were examined by western blotting.

RESULTS

Compared with model group, the cognitive impairment and neurological deficits of Rehmannioside A group were significantly improved, and the cerebral infarction was reduced in MCAO rats. Moreover, the cell viability obviously increased and the H2O2-induced toxicity was reduced in Rehmannioside A group. Further research indicated that the expression of p-PI3K, p-Akt, nuclear Nrf2, HO-1 and SLC7A11 in Rehmannioside A group was significantly higher than model group.

CONCLUSION

Rehmannioside A has neuroprotection effect and improves cognitive impairment after cerebral ischemia by inhibiting ferroptosis and activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway. These findings provide valuable insight into the pathogenesis and therapeutic target of ischemic stroke.

Enriched Environment Effects on Myelination of the Central Nervous System: Role of Glial Cells

Myelination is regulated by various glial cells in the central nervous system (CNS), including oligodendrocytes (OLs), microglia, and astrocytes. Myelination of the CNS requires the generation of functionally mature OLs from OPCs. OLs are the myelin-forming cells in the CNS. Microglia play both beneficial and detrimental roles during myelin damage and repair. Astrocyte is responsible for myelin formation and regeneration by direct interaction with oligodendrocyte lineage cells. These glial cells are influenced by experience-dependent activities such as environmental enrichment (EE). To date, there are few studies that have investigated the association between EE and glial cells. EE with a complex combination of sensorimotor, cognitive, and social stimulation has a significant effect on cognitive impairment and brain plasticity. Hence, one mechanism through EE improving cognitive function may rely on the mutual effect of EE and glial cells. The purpose of this paper is to review recent research into the efficacy of EE for myelination and glial cells at cellular and molecular levels and offers critical insights for future research directions of EE and the treatment of EE in cognitive impairment disease.

Traditional Chinese Medicine for Post-Stroke Cognitive Impairment: A Systematic Review and Meta-Analysis

Background: Post-stroke cognitive impairment (PSCI) affects more than one-third of stroke patients, and causes much greater harm to long-term function than the initial brain damage. No conventional Western medications have shown convincing clinical effectiveness for treating PSCI. Research shows that Traditional Chinese medicine (TCM) can improve cognitive function in patients. However, the clinical efficacy and safety remain controversial. The aim of this study was to examine the effectiveness and harmful effects of TCMs in the treatment of PSCI. Method: We searched seven databases and two clinical registration websites for randomized controlled trials (RCTs). The revised Cochrane risk of bias tool (RoB 2.0) was used to evaluate the methodological quality and RevMan 5.4 was used for data analysis. This study has been submitted to PROSPERO with registration number is CRD42020149299. Results: We included 34 studies in this review. The results of this study showed that TCM adjuvant therapy improved scores on the MoCA [MD = 2.55, 95% CI (1.56, 3.53), p < 0.00001; MD = 3.07, 95% CI (1.98, 4.17), p < 0.00001 at treatment duration of <3 and 3 months, respectively], MMSE [MD = 2.55, 95% CI (1.99, 3.10), p < 0.00001; MD = 2.53, 95% CI (1.59, 3.47), p < 0.00001; MD = 2.91, 95% CI (1.26, 4.56), p = 0.0006; MD = 3.11, 95% CI (-0.04, 6.27), p = 0.05 at treatment duration of <3, 3, 4, and 6 months, respectively], and BI [MD = 7.34, 95% CI (3.83, 10.85), p < 0.0001; MD = 8.98, 95% CI (4.76, 13.21), p < 0.0001 at treatment duration of <3 and 3 months, respectively] and reduced scores on the ADL (MD = -8.64, 95% CI (-9.83, -7.45), p < 0.00001; MD = -2.00, 95% CI (-2.94, -1.06), p < 0.0001 at treatment duration of 3 and 4 months, respectively], NIHSS [MD = -2.48, 95% CI (-4.97, 0.00), p = 0.05; MD = -3.81, 95% CI (-6.21, -1.40), p = 0.002 at treatment duration of <3 and 3 months, respectively], and CSS [MD = -2.47, 95% CI (-3.49, -1.45), p < 0.00001 at a treatment duration of 3 months]. No serious adverse reactions were observed. Conclusion: Despite the significant positive results, the present evidence supports, to a limited extent because of the methodological flaws and herbal heterogeneity, that TCM adjuvant therapy can be used for patients with PSCI. While, further rigorous RCTs are warranted to confirm the efficacy and safety of TCM. Systematic Review Registration: https://www.crd.york.ac.uk/prospero, identifier CRD42020149299.

Gamma-glutamyl transferase levels are associated with the occurrence of post-stroke cognitive impairment: a multicenter cohort study

Background

Gamma-glutamyl transferase (GGT) is involved in maintenance of physiological concentrations of glutathione in cells, and protects them from oxidative stress-induced damage. However, its role in post-stroke cognitive impairment (PSCI) remains unknown. Here, we investigated the effects of serum GGT on PSCI.

Methods

We conducted a prospective, multicenter cohort study. A total of 1, 957 participants with a minor ischemic stroke or transient ischemic attack whose baseline GGT levels were measured were enrolled from the Impairment of Cognition and Sleep (ICONS) study of the China National Stroke Registry-3 (CNSR-3). They were categorized into four groups according to quartiles of baseline GGT levels. Cognitive functions were assessed using the Montreal Cognitive Assessment (MoCA) approach. Multiple logistic regression models were performed to evaluate the relationship between GGT and PSCI at 3 months follow-up.

Results

Among the 1957 participants, 671 (34.29%) patients suffered PSCI at 3 months follow-up. The highest GGT level quartile group exhibited a lower risk of PSCI in the fully adjusted model [OR (95% CI): 0.69 (0.50-0.96)], relative to the lowest group. Moreover, incorporation of GGT to the conventional model resulted in slight improvements in PSCI outcomes after 3 months (NRI: 12.00%; IDI: 0.30%).

Conclusions

Serum GGT levels are inversely associated with the risk of PSCI, with extremely low levels being viable risk factors for PSCI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02587-4.

Environmental Enrichment Protects Against Sepsis-Associated Encephalopathy-Induced Learning and Memory Deficits by Enhancing the Synthesis and Release of Vasopressin in the Supraoptic Nucleus

Background

As a severe complication of sepsis, sepsis-associated encephalopathy (SAE) usually manifests as impaired learning and memory ability in survivors. Previous studies have reported that environmental enrichment (EE) can increase the learning and memory ability in different brain injury models. However, there has been no research on the possible positive effect of EE on SAE.

Aim

The present study aimed to test the effect of EE on SAE-induced impairment of learning and memory and its related mechanisms.

Methods

A Morris water maze test (MWM) was used to evaluate the learning and memory ability of SAE rats that received EE housing or not. The expression of vasopressin (VP) was assessed using immunofluorescence microscopy and enzyme-linked immunosorbent assays (ELISAs). The synthesis of VP in the supraoptic nucleus (SON) was determined using quantitative real-time reverse transcription-PCR analysis. Moreover, inflammatory markers and brain-derived neurotrophic factor (BDNF) were detected using ELISA.

Results

The results showed that SAE induced a decreased learning and memory ability, while EE reversed this impairment. EE also enhanced the synthesis and secretion of VP in the SON. Blocking the action of VP in the hippocampus interrupted the EE-induced amelioration of learning and memory impairment. Moreover, EE induced changes to the levels of BDNF and cytokines in the hippocampus and these effects were mediated by VP binding to the VP receptor 1a.

Conclusion

Our findings demonstrated that the enhanced synthesis and secretion of VP in the SON are a key determinant responsible for EE-induced alleviation of learning and memory deficits caused by SAE.

A novel viewpoint in glaucoma therapeutics: enriched environment

Glaucoma is one of the world's most frequent visual impairment causes and leads to selective damage to retinal ganglion cells and their axons. Despite glaucoma's most accepted risk factor is increased intraocular pressure (IOP), the mechanisms behind the disease have not been fully elucidated. To date, IOP lowering remains the gold standard; however, glaucoma patients may still lose vision regardless of effective IOP management. Therefore, the exclusive IOP control apparently is not enough to stop the disease progression, and developing new resources to protect the retina and optic nerve against glaucoma is a goal of vast clinical importance. Besides pharmacological treatments, environmental conditions have been shown to prevent neurodegeneration in the central nervous system. In this review, we discuss current concepts on key pathogenic mechanisms involved in glaucoma, the effect of enriched environment on these mechanisms in different experimental models, as well as recent evidence supporting the preventive and therapeutic effect of enriched environment exposure against experimental glaucomatous damage. Finally, we postulate that stimulating vision may become a non-invasive and rehabilitative therapy that could be eventually translated to the human disease, preventing glaucoma-induced terrible sequelae resulting in permanent visual disability.

Enriched environment and visual stimuli protect the retinal pigment epithelium and photoreceptors in a mouse model of non-exudative age-related macular degeneration

Non-exudative age-related macular degeneration (NE-AMD), the main cause of blindness in people above 50 years old, lacks effective treatments at the moment. We have developed a new NE-AMD model through unilateral superior cervical ganglionectomy (SCGx), which elicits the disease main features in C57Bl/6J mice. The involvement of oxidative stress in the damage induced by NE-AMD to the retinal pigment epithelium (RPE) and outer retina has been strongly supported by evidence. We analysed the effect of enriched environment (EE) and visual stimulation (VS) in the RPE/outer retina damage within experimental NE-AMD. Exposure to EE starting 48 h post-SCGx, which had no effect on the choriocapillaris ubiquitous thickness increase, protected visual functions, prevented the thickness increase of the Bruch’s membrane, and the loss of the melanin of the RPE, number of melanosomes, and retinoid isomerohydrolase (RPE65) immunoreactivity, as well as the ultrastructural damage of the RPE and photoreceptors, exclusively circumscribed to the central temporal (but not nasal) region, induced by experimental NE-AMD. EE also prevented the increase in outer retina/RPE oxidative stress markers and decrease in mitochondrial mass at 6 weeks post-SCGx. Moreover, EE increased RPE and retinal brain-derived neurotrophic factor (BDNF) levels, particularly in Müller cells. When EE exposure was delayed (dEE), starting at 4 weeks post-SCGx, it restored visual functions, reversed the RPE melanin content and RPE65-immunoreactivity decrease. Exposing animals to VS protected visual functions and prevented the decrease in RPE melanin content and RPE65 immunoreactivity. These findings suggest that EE housing and VS could become an NE-AMD promising therapeutic strategy.

Effect of environmental enrichment and isolation on behavioral and histological indices following focal ischemia in old rats

Stroke is a disease of aging. In stroke patients, the enriched group that received stimulating physical, eating, socializing, and group activities resulted in higher activity levels including spending more time on upper limb, communal socializing, listening and iPad activities. While environmental enrichment has been shown to improve the behavioral outcome of stroke in young animals, the effect of an enriched environment on behavioral recuperation and histological markers of cellular proliferation, neuroinflammation, and neurogenesis in old subjects is not known. We used behavioral testing and immunohistochemistry to assess the effect of environment on post-stroke recovery of young and aged rats kept either in isolation or stimulating social, motor, and sensory environment (( +)Env). We provide evidence that post-stroke animals environmental enrichment ( +)Env had a significant positive effect on recovery on the rotating pole, the inclined plane, and the labyrinth test. Old age exerted a small but significant effect on lesion size, which was independent of the environment. Further, a smaller infarct volume positively correlated with better recovery of spatial learning based on positive reinforcement, working and reference memory of young, and to a lesser extent, old animals kept in ( +)Env. Histologically, isolation/impoverishment was associated with an increased number of proliferating inflammatory cells expressing ED1 cells in the peri-infarcted area of old but not young rats. Further, ( +)Env and young age were associated with an increased number of neuroepithelial cells expressing nestin/BrdU as well as beta III tubulin cells in the damaged brain area which correlated with an increased performance on the inclined plane and rotating pole. Finally, ( +)Env and an increased number of neurons expressing doublecortin/BrdU cells exerted a significant effect on performance for working memory and performance on the rotating pole in both age groups. A stimulating social, motor and sensory environment had a limited beneficial effect on behavioral recovery (working memory and rotating pole) after stroke in old rats by reducing neuroinflammation and increasing the number of neuronal precursors expressing doublecortin. Old age however, exerted a small but significant effect on lesion size, which was independent of the environment.

Changes in Gene Expression and Neuroinflammation in the Hippocampus after Focal Brain Ischemia: Involvement in the Long-Term Cognitive and Mental Disorders

Ischemic brain injuries are accompanied by the long-term changes in gene expression in the hippocampus, the limbic system structure, involved in the regulation of key aspects of the higher nervous activity, such as cognitive functions and emotions. The altered expression of genes and proteins encoded by them may be related to the development of post-ischemic psycho-emotional and cognitive disturbances. Activation of neuroinflammation following stroke in the hippocampus has been suggested to play an essential role in induction of long-lasting consequences. Identification of changes in the gene expression patterns after ischemia and investigation of the dynamics of these changes in the hippocampus are the necessary first steps toward understanding molecular pathways responsible for the development of post-stroke cognitive impairments and mental pathologies.