Using the Morris water maze to assess spatial learning and memory in weanling mice

Specific Mode Electroacupuncture Stimulation Mediates the Delivery of NGF Across the Hippocampus Blood-Brain Barrier Through p65-VEGFA-TJs to Improve the Cognitive Function of MCAO/R Convalescent Rats

Cognitive impairment frequently presents as a prevalent consequence following stroke, imposing significant burdens on patients, families, and society. The objective of this study was to assess the effectiveness and underlying mechanism of nerve growth factor (NGF) in treating post-stroke cognitive dysfunction in rats with cerebral ischemia-reperfusion injury (MCAO/R) through delivery into the brain using specific mode electroacupuncture stimulation (SMES). From the 28th day after modeling, the rats were treated with NGF mediated by SMES, and the cognitive function of the rats was observed after treatment. Learning and memory ability were evaluated using behavioral tests. The impact of SMES on blood-brain barrier (BBB) permeability, the underlying mechanism of cognitive enhancement in rats with MCAO/R, including transmission electron microscopy, enzyme-linked immunosorbent assay, immunohistochemistry, immunofluorescence, and TUNEL staining. We reported that SMES demonstrates a safe and efficient ability to open the BBB during the cerebral ischemia repair phase, facilitating the delivery of NGF to the brain by the p65-VEGFA-TJs pathway.

Combined Effects of Arsenic and Bisphenol-A on Locomotor Activity and Oxidative Stress Mediated Neurotoxicity in Mice

Bisphenol A (BPA) is a monomer of plastic that can leach into water from scratched containers when used for an extended period. Arsenic (As) is an environmental toxicant, and people are exposed to both arsenic and BPA through drinking water and through scratched plastic containers used in contaminated areas. However, the combined effects of As and BPA on locomotor performance and neurobehavioral changes are yet to be investigated. Thus, this study was designed to assess the combined effect of As and BPA on locomotor activity and neurotoxicity through a mouse model. The neurobehavioral changes in experimental mice were evaluated using the different maze tests. Mice exposed to As or BPA exhibited higher anxiety-like behavior, decreased locomotor activity, and impaired learning and memory including social interaction compared with control mice. However, As + BPA-exposed mice showed a significantly reduced anxiety-like behavior, improved learning and memory including locomotor activity, and social interaction compared to individual As-exposed mice. Furthermore, mice exposed to As or BPA showed lower levels of antioxidant and cholinesterase enzymes activity, nuclear factor erythroid-2-related factor-2 (Nrf2), heme-oxygenase-1 (HO-1), and interleukin-10 (IL-10) in the brain and higher levels of interleukin-6 (IL-6) in the brain and lactate dehydrogenase (LDH) in the serum compared to control mice. However, combined exposure augmented antioxidant and cholinesterase enzymes activity, Nrf2, HO-1, IL-10 levels in the brain and reduced serum LDH activity and IL-6 in the brain compared to As exposure. Therefore, this study suggests that As and BPA may have antagonistic effects, and BPA could attenuate the As-induced neurobehavioral and biochemical changes in co-exposed mice.

Sigma-1 receptor modulation by fluvoxamine ameliorates valproic acid-induced autistic behavior in rats: Involvement of chronic ER stress modulation, enhanced autophagy and M1/M2 microglia polarization

Autism spectrum disorder (ASD) is a neurodevelopmental disorder. While, fluvoxamine (FVX) is an antidepressant and widely prescribed to ASD patients, clinical results are inconclusive and the mechanism of FVX in the management of ASD is unclear. This study determined the potential therapeutic impact of FVX, a sigma-1 receptor (S1R) agonist, against the valproic acid (VPA)-induced model of autism. On gestational day 12.5, Wistar pregnant rats were given a single intraperitoneal (i.p.) injection of either VPA (600 mg/kg) or normal saline (10 mL/kg, vehicle-control). Starting on postnatal day (PND) 21 to PND 50, FVX (30 mg/kg, P·O. daily) and NE-100, (S1R) antagonist, (1 mg/kg, i.p. daily) were given to male pups. Behavior tests and histopathological changes were identified at the end of the experiment. In addition, the cerebellum biomarkers of endoplasmic reticulum (ER) stress and autophagy were assessed. Microglial cell polarization to M1 and M2 phenotypes was also assessed. FVX effectively mitigated the histopathological alterations in the cerebellum caused by VPA. FVX enhanced sociability and stereotypic behaviors in addition to its noteworthy impact on autophagy enhancement, ER stress deterioration, and controlling microglial cell polarization. The current investigation confirmed that the S1R agonist, FVX, can lessen behavioral and neurochemical alterations in the VPA-induced rat model of autism.

Mitotic block and epigenetic repression underlie neurodevelopmental defects and neurobehavioral deficits in congenital heart disease

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease associated with microcephaly and poor neurodevelopmental outcomes. Here we show that the Ohia HLHS mouse model, with mutations in Sap130, a chromatin modifier, and Pcdha9, a cell adhesion protein, also exhibits microcephaly associated with mitotic block and increased apoptosis leading to impaired cortical neurogenesis. Transcriptome profiling, DNA methylation, and Sap130 ChIPseq analyses all demonstrate dysregulation of genes associated with autism and cognitive impairment. This includes perturbation of REST transcriptional regulation of neurogenesis, disruption of CREB signaling regulating synaptic plasticity, and defects in neurovascular coupling mediating cerebral blood flow. Adult mice harboring either the Pcdha9 mutation, which show normal brain anatomy, or forebrain-specific Sap130 deletion via Emx1-Cre, which show microcephaly, both demonstrate learning and memory deficits and autism-like behavior. These findings provide mechanistic insights indicating the adverse neurodevelopment in HLHS may involve cell autonomous/nonautonomous defects and epigenetic dysregulation.

Therapeutic Potential of Ocimum basilicum L. Extract in Alleviating Autistic-Like Behaviors Induced by Maternal Separation Stress in Mice: Role of Neuroinflammation and Oxidative Stress

A confluence of genetic, environmental, and epigenetic factors shapes autism spectrum disorder (ASD). Early-life stressors like MS play a contributing role in this multifaceted neurodevelopmental disorder. This research was to explore the efficacy of Ocimum basilicum L. (O.B.) extract in mitigating behaviors reminiscent of autism prompted by maternal separation (MS) stress in male mice, focusing on its impact on neuroinflammation and oxidative stress. MS mice were treated with O.B. extract at varying dosages (20, 40, and 60 mg/kg) from postnatal days (PND) 51-53 to PND 58-60. Behavioral experiments, including the Morris water maze, three-chamber test, shuttle box, and resident-intruder test, were conducted post-treatment. The method of maternal separation involved separating the pups from their mothers for 3 h daily, from PND 2 to PND 14. Molecular analysis of hippocampal tissue was performed to assess gene expression of Toll-like receptor 4 (TLR4), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). Hippocampal and serum malondialdehyde (MDA) levels and total antioxidant capacity (TAC) were measured. O.B. extract administration resulted in the amelioration of autistic-like behaviors in MS mice, as evidenced by improved spatial and passive avoidance memories and social interactions, as well as reduced aggression in behavioral tests. O.B. extract attenuated oxidative stress and neuroinflammation, as indicated by decreased MDA and increased TAC levels, as well as downregulation of TLR4, TNF-α, and IL-1β expression in the hippocampus. O.B. extract may offer a novel therapeutic avenue for ASD, potentially mediated through its anti-inflammatory and antioxidant properties.

Exploration of neuroprotective and cognition boosting effects of Mazus pumilus in Alzheimer's disease model

OBJECTIVES

Mazus pumilus (MP) an Asian flowering plant, known for various reported pharmacological activities including antioxidant, anti-nociceptive, anti-inflammatory, anticancer, antibacterial, antifungal, and hepatoprotective effects. This study focused on further exploring Mazus pumilus's methanol leaf extract (MPM) for bioactive principles and investigating its neuroprotective and cognition-enhancing potential in Alzheimer's disease models.

METHODS

For the phytochemical screening and identification, TLC, HPLC, and Fourier transform infrared (FTIR) were employed. In-vitro antioxidant potential was assayed by DPPH Free Radical Scavenging method, followed by in-vivo neuroprotective effect of MPM (100, 200, 300 mg/kg) using Wistar-albino rats, sodium azide for induction of AD and rivastigmine as standard. Over 21 days, we observed neurobehavioral changes and performed biochemical (GSH, CAT, SOD, and AchE activity) and histopathological evaluations.

RESULTS

Results revealed the presence of alkaloids, flavonoids, amino acids, terpenoids, glycosides, sterols, and saponins. HPLC analysis confirmed the presence of gallic acids, sinapic acid, and caffeic acid. DPPH confirmed the antioxidant effect of MPM, which served as a base for its potential neuroprotective activity. Biochemically, oxidative stress markers improved significantly post-treatment, with decreased GSH, SOD, CAT levels, and increased AchE activity, indicating a reversal of AD-induced changes. Behavioral assessments showed improvements in locomotion, memory, spatial learning, and cognition. Histologically, there was a dose-dependent reduction in neurodegenerative features like neurofibrillary tangles and amyloid beta plaques.

CONCLUSIONS

Hence, this study concluded MPM is a promising candidate for prophylaxis and treatment of behavioral deficits and cognitive dysfunction in Alzheimer's disease.

Gender Differences in Dendritic Damage, Gut Microbiota Dysbiosis, and Cognitive Impairment During Aging Processes

BACKGROUND

Cognitive impairment is a common and feared characteristic of aging processes, and one key mechanism of cognition is hippocampal synaptic structure. Previous studies have reported that gut microbiota dysbiosis occurred in neurodegenerative diseases and other brain disorders with cognitive impairment. However, it is not clear how gender differences affect cognitive impairment in aging processes and whether they affect synaptic structure and gut microbiota. Here, we studied the gender differences in cognitive ability, dendritic morphology, and gut microbiota of adult, middle-, and old-aged rats.

METHODS

The cognitive ability of rats using was assessed by the Y-maze SAB test, the light/dark discrimination test, and the MWM test. Dendritic morphology was investegated by Golgi staining. Microbiota composition, diversity and richness were analyzed by 16S rRNA gene sequencing.

RESULTS

The results showed that the cognitive ability of old-aged rats was decreased than adult and middle-aged rats in the spontaneous alternation behavior test, the light/dark discrimination test in Y-maze, and the MWM test; males have better cognitive ability than the females for middle-aged rats. The neuronal dendritic structures of CA1, CA3, and DG regions of the hippocampus were damaged to different degrees during aging, and the spine loss of females was more than that of males in CA1 and CA3 of middle-aged rats. In addition, the microbial diversity of gut microbiota was significantly decreased in old-aged male rats; the distribution and composition of microbiota communities were different between male and female rats at different ages.

CONCLUSION

These findings revealed that cognitive impairment in aged rats might result from dendritic damage in the hippocampus and gut microbiota dysbiosis, which provides direct evidence that gender differences in dendritic damage and gut microbiota dysbiosis might associate with cognitive impairment in naturally aged rats.

Effect of JM-20 on Age-Related Cognitive Impairment in Mice

The decline in cognitive function associated with aging significantly impacts the well-being of elderly individuals and their families. This decline is a major recognized risk factor for neurodegenerative diseases, notably Alzheimer's disease. Animal models of aging provide a platform for evaluating drugs concerning aspects like memory and oxidative stress. JM-20 has demonstrated protective effects on short-term memory acquisition and consolidation, along with antioxidant properties and modulation of Acetylcholinesterase activity. This study assesses the potential protective JM-20 against cognitive decline and age-related memory loss. For the study, aged mice exhibiting aging-associated damage were initially selected. Experimental groups were then formed, and the effect of 8 mg/kg of JM-20 was evaluated for 40 days on aging-related behavior, such as spatial memory, novelty recognition memory, ambulatory activity, and anxiety. Subsequently, animals were sacrificed, and the hippocampal region was extracted for redox studies and to assess acetylcholinesterase activity. Results indicated that JM-20 at 8 mg/kg reversed damage to spatial working and reference memory, exhibiting performance comparable to untreated young adult animals. Furthermore, JM-20 preserved the enzymatic activity of superoxide dismutase, catalase, and total sulfhydryl levels in age-related cognitive impairment in mice, indicating a potent protective effect against oxidative events at the brain level. However, only young, healthy animals showed decreased acetylcholinesterase enzyme activity. These findings provide preclinical pharmacological evidence supporting the neuroprotective activity of JM-20, positioning it as a promising therapeutic candidate for treating memory disorders associated with aging.

Vitamin B12 supplementation improved memory impairment following nicotine withdrawal in adolescent male rats: The role of oxidative stress, inflammatory, BDNF, GFAP, and AChE activity

The present study aimed to assess the potential effect of vitamin B12 (Vit B12) on cognition impairment caused by nicotine (Nic) cessation in adolescent male rats. Adolescent male rats were categorized into two main groups as vehicle (normal saline, intraperitoneally), and Nic group in which received Nic (2 mg/kg) from 21 to 42 days of ages and then the Nic group were divided into three groups as withdrawal (the animals returned to regular diet without treatment), second and third groups received bupropion (20 mg/kg), and Vit B12 at three different doses including 0.5,1, and 1.5 mg/kg by oral gavage as treatments to attenuate Nic withdrawal symptoms. The last group including normal animals received the highest doses of Vit B12 just in the Nic abstinence period to compare the effect of that with vehicle. In MWM, Vit B12and bupropion increased the time spent in the target quadrant that is strongly associated with spatial memory as well as the more time spent with the NORT. Vit B12 and bupropion modulated both oxidant/antioxidant and inflammatory/anti-inflammatory balance, alongside inhibitory effect on AChE, and GFAP. However, BDNF and amyloid-B showed insignificant difference as compared to Vit B12 and bupropion. Considering the present results and similar related studies, Vit B12 can be introduced as a strong anti-oxidant, and anti-inflammatory agent by which probably improved memory impairment caused by Nic addiction accompanied by withdrawal. Further, other mechanisms including activity reduction of AChE, and GFAP should be considered; however, it needs further investigation and larger-scale evidences.

Yap1 alleviates sepsis associated encephalopathy by inhibiting hippocampus ferroptosis via maintaining mitochondrial dynamic homeostasis

Sepsis-associated encephalopathy (SAE) is a serious neurological complication accompanied by acute and long-term cognitive dysfunction. Ferroptosis is a newly discovered type of cell death that is produced by iron-dependent lipid peroxidation. As a key transcriptional coactivator in the Hippo signalling pathway, Yes-associated protein 1 (YAP1) could target ferroptosis-related genes. This study was aimed to determine whether Yap1 protects against SAE and inhibits ferroptosis via maintaining mitochondrial dynamic homeostasis. Caecal ligation puncture (CLP) was used to establish the SAE model, and LPS was applied in hippocampal cells to mimic the inflammatory model in vitro. The results showed that Yap1 conditional knockout in hippocampal caused lower survival in SAE mice and cognitive dysfunction, as proved by Morri's water maze (MWM) task, tail suspension test (TST), open field test (OFT) and elevated plus maze test (EPMT). After Yap1 knockout, the production of ROS, MDA and Fe2+ and proinflammatory cytokines in the hippocampus were increased, indicating that Yap1 deficiency exacerbates CLP-induced brain injury and hippocampus ferroptosis. Meanwhile, GPX4, SLC7A11, ferritin (FTH1) and GSH levels were decreased in the Yap1 knockout group. In vitro, Yap1 overexpression mitigated LPS-induced hippocampal cell ferroptosis and improved mitochondrial function by inhibiting mitochondrial fission, as evidenced by lower mitochondrial ROS, cell viability, Fe2+ and the expression of Fis1 and Drp1. Further, the present study suggested that Yap1 could inhibit ferritinophagy-mediated ferroptosis in the hippocampus via inhibiting mitochondrial fission, thus reducing cognitive dysfunction in SAE mice.

Ellagic acid improves the symptoms of early-onset Alzheimer's disease: Behavioral and physiological correlates

Oryza sativa is a globally recognized staple food, rich in essential phyto-phenolic compounds such as γ-Oryzanol (OZ), Ferulic acid (FA), and Ellagic acid (EA). These phytochemicals are known for their potential to beneficially modulate molecular biochemistry. The present investigation aimed to evaluate the neuroprotective and cognitive enhancement effects of Oryza sativa phyto-phenolics in a model of early-onset Alzheimer's disease (EOAD) induced by Aβ (1-42) in animals. In-silico studies suggested that FA, OZ, and EA have target specificity for Aβ, with EA being further selected based on its potent in-vitro Aβ anti-aggregatory effects for exploring neurodegenerative conditions. The in-vivo experiments demonstrated that EA exerts therapeutic effects in Aβ-induced EOAD, modulating both biochemical and behavioral outcomes. EA treatment at two dose levels, EA70 and EA140 (70 μM and 140 μM, respectively, administered i.c.v.), significantly counteracted Aβ aggregation and modulated the Ca2⁺/Calpain/GSK-3β/CDK5 signaling pathways, exhibiting anti-tauopathy effects. Additionally, EA was shown to exert anti-inflammatory effects by preventing astroglial activation, modulating FAIM-L expression, and protecting against TNF-α-induced apoptotic signals. Moreover, the neuromodulatory effects of EA were attributed to the regulation of CREB levels, Dnm-1 expression, and synaptophysin levels, thereby enhancing LTP and synaptic plasticity. EA also induced beneficial cytological and behavioral changes, improving both long-term and short-term spatial memory as well as associative learning behavior in the animal model, which underscores its cognitive enhancement properties.

Animal Models of Autistic-like Behavior in Rodents: A Scoping Review and Call for a Comprehensive Scoring System

Appropriate animal models of human diseases are a cornerstone in the advancement of science and medicine. To create animal models of neuropsychiatric and neurobehavioral diseases such as autism spectrum disorder (ASD) necessitates the development of sufficient neurobehavioral measuring tools to translate human behavior to expected measurable behavioral features in animals. If possible, the severity of the symptoms should also be assessed. Indeed, at least in rodents, adequate neurobehavioral and neurological tests have been developed. Since ASD is characterized by a number of specific behavioral trends with significant severity, animal models of autistic-like behavior have to demonstrate the specific characteristic features, namely impaired social interactions, communication deficits, and restricted, repetitive behavioral patterns, with association to several additional impairments such as somatosensory, motor, and memory impairments. Thus, an appropriate model must show behavioral impairment of a minimal number of neurobehavioral characteristics using an adequate number of behavioral tests. The proper animal models enable the study of ASD-like-behavior from the etiologic, pathogenetic, and therapeutic aspects. From the etiologic aspects, models have been developed by the use of immunogenic substances like polyinosinic-polycytidylic acid (PolyIC), lipopolysaccharide (LPS), and propionic acid, or other well-documented immunogens or pathogens, like Mycobacterium tuberculosis. Another approach is the use of chemicals like valproic acid, polychlorinated biphenyls (PCBs), organophosphate pesticides like chlorpyrifos (CPF), and others. These substances were administered either prenatally, generally after the period of major organogenesis, or, especially in rodents, during early postnatal life. In addition, using modern genetic manipulation methods, genetic models have been created of almost all human genetic diseases that are manifested by autistic-like behavior (i.e., fragile X, Rett syndrome, SHANK gene mutation, neuroligin genes, and others). Ideally, we should not only evaluate the different behavioral modes affected by the ASD-like behavior, but also assess the severity of the behavioral deviations by an appropriate scoring system, as applied to humans. We therefore propose a scoring system for improved assessment of ASD-like behavior in animal models.

Dual-factor model of sleep and diet: a new approach to understanding central fatigue

Background

Numerous studies have recently examined the impact of dietary factors such as high-fat diets on fatigue. Our study aims to investigate whether high-fat diet (HFD) alone or combined with alternate-day fasting (ADF) can lead to the central fatigue symptoms and to investigate the potential integration of dietary and sleep variables in the development of central fatigue models.

Methods

Seventy-five male Wistar rats were divided into five groups: control, HFD, HFD + ADF, modified multiple platform method (MMPM), and MMPM+HFD + ADF. Each group underwent a 21-day modeling period according to their respective protocol. Their behavioral characteristics, fatigue biochemical markers, hippocampal pathological changes, mitochondrial ultrastructure, and oxidative stress damage were analyzed.

Results

Our findings demonstrate that using only HFD did not cause central fatigue, but combining it with ADF did. This combination led to reduced exercise endurance, decreased locomotor activity, impaired learning and memory abilities, along with alterations in serum levels of alanine aminotransferase (ALT), creatine kinase (CK), and lactate (LAC), as well as hippocampal pathological damage and other central fatigue symptoms. Moreover, the MMPM+HFD + ADF method led to the most obvious central fatigue symptoms in rats, including a variety of behavioral changes, alterations in fatigue-related biochemical metabolic markers, prominent pathological changes in hippocampal tissue, severe damage to the ultrastructure of mitochondria in hippocampal regions, changes in neurotransmitters, and evident oxidative stress damage. Additionally, it was observed that rats subjected to HFD + ADF, MMPM, and MMPM+HFD + ADF modeling method exhibited significant brain oxidative stress damage.

Conclusion

We have demonstrated the promotive role of dietary factors in the development of central fatigue and have successfully established a more stable and clinically relevant animal model of central fatigue by integrating dietary and sleep factors.

Examining individual learning patterns using generalised linear mixed models

Everyone learns differently, but individual performance is often ignored in favour of a group-level analysis. Using data from four different experiments, we show that generalised linear mixed models (GLMMs) and extensions can be used to examine individual learning patterns. Producing ellipsoids and cluster analyses based on predicted random effects, individual learning patterns can be identified, clustered and used for comparisons across various experimental conditions or groups. This analysis can handle a range of datasets including discrete, continuous, censored and non-censored, as well as different experimental conditions, sample sizes and trial numbers. Using this approach, we show that learning a face-named paired associative task produced individuals that can learn quickly, with the performance of some remaining high, but with a drop-off in others, whereas other individuals show poor performance throughout the learning period. We see this more clearly in a virtual navigation spatial learning task (NavWell). Two prominent clusters of learning emerged, one showing individuals who produced a rapid learning and another showing a slow and gradual learning pattern. Using data from another spatial learning task (Sea Hero Quest), we show that individuals' performance generally reflects their age category, but not always. Overall, using this analytical approach may help practitioners in education and medicine to identify those individuals who might need extra help and attention. In addition, identifying learning patterns may enable further investigation of the underlying neural, biological, environmental and other factors associated with these individuals.

Screening of active components of Ganoderma lucidum and decipher its molecular mechanism to improve learning and memory disorders

Learning and memory impairment (LMI), a common degenerative central nervous system disease. Recently, more and more studies have shown that Ganoderma lucidum (GL) can improve the symptoms of LMI. The active ingredients in GL and their corresponding targets were screened through TCMSP (Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform) and BATMAN-TCM (Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine) databases, and the potential LMI targets were searched for through GeneCard (GeneCards Human Gene Database) and DrugBank. Then, we construct a 'main active ingredient-target' network and a protein-protein interaction (PPI) network diagram.The GO (Gene Ontology) functional enrichment analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway annotation analysis were performed on the common targets through DAVID (Database for Annotation Visualization and Integrated Discovery) to clarify the potential molecular mechanism of action of active ingredients in GL. The tumor necrosis factor (TNF) protein was verified by Western blot; Twenty one active ingredients in GL and 142 corresponding targets were screened out, including 59 targets shared with LMI. The 448 biological processes shown by the GO functional annotation results and 55 signal pathways shown by KEGG enrichment analysis were related to the improvement of LMI by GL, among which the correlation of Alzheimer's disease pathway is the highest, and TNF was the most important protein; TNF can improve LMI. GL can improve LMI mainly by 10 active ingredients in it, and they may play a role by regulating Alzheimer's disease pathway and TNF protein.

Evaluating the Role of N-Acetyl-L-Tryptophan in the Aβ 1-42-Induced Neuroinflammation and Cognitive Decline in Alzheimer's Disease

Alzheimer's disease (AD), a neurodegenerative condition previously known to affect the older population, is also now seen in younger individuals. AD is often associated with cognitive decline and neuroinflammation elevation primarily due to amyloid β (Aβ) accumulation. Multiple pathological complications in AD call for therapies with a wide range of neuroprotection. Our study aims to evaluate the effect of N-acetyl-L-tryptophan (NAT) in ameliorating the cognitive decline and neuroinflammation induced by Aβ 1-42 oligomers and to determine the therapeutic concentration of NAT in the brain. We administered Aβ 1-42 oligomers in rats via intracerebroventricular (i.c.v.) injection to induce AD-like conditions. The NAT-treated animals lowered the cognitive decline in the Morris water maze characterized by shorter escape latency and increased path efficiency and platform entries. Interestingly, the hippocampus and frontal cortex showed downregulation of tumor necrosis factor, interleukin-6, and substance P levels. NAT treatment also reduced acetylcholinesterase activity and total and phosphorylated nuclear factor kappa B and Tau levels. Lastly, we observed upregulation of cAMP response element-binding protein 1 (CREB1) signaling. Surprisingly, our HPLC method was not sensitive enough to detect the therapeutic levels of NAT in the brain, possibly due to NAT concentrations being below the lowest limit of quantification of our validated method. To summarize, the administration of NAT significantly lowered cognitive decline, neuroinflammatory pathways, and Tau protein and triggered the upregulation of CREB1 signaling, suggesting its neuroprotective role in AD-like conditions.

Deciphering the Association of Epstein-Barr Virus and Its Glycoprotein M Peptide with Neuropathologies in Mice

The reactivation of ubiquitously present Epstein-Barr virus (EBV) is known to be involved with numerous diseases, including neurological ailments. A recent in vitro study from our group unveiled the association of EBV and its 12-amino acid peptide glycoprotein M146-157 (gM146-157) with neurodegenerative diseases, viz., Alzheimer's disease (AD) and multiple sclerosis. In this study, we have further validated this association at the in vivo level. The exposure of EBV/gM146-157 to mice causes a decline in the cognitive ability with a concomitant increase in anxiety-like symptoms through behavioral assays. Disorganization of hippocampal neurons, cell shrinkage, pyknosis, and apoptotic appendages were observed in the brains of infected mice. Inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were found to be elevated in infected mouse brain tissue samples, whereas TNF-α exhibited a decline in the serum of these mice. Further, the altered levels of nuclear factor-kappa B (NF-kB) and neurotensin receptor 2 affirmed neuroinflammation in infected mouse brain samples. Similarly, the risk factor of AD, apolipoprotein E4 (ApoE4), was also found to be elevated at the protein level in EBV/gM146-157 challenged mice. Furthermore, we also observed an increased level of myelin basic protein in the brain cortex. Altogether, our results suggested an integral connection of EBV and its gM146-157 peptide to the neuropathologies.

Quercetin modulates expression of serum exosomal long noncoding RNA NEAT1 to regulate the miR-129-5p/BDNF axis and attenuate cognitive impairment in diabetic mice

AIMS

Cognitive impairment poses a considerable health challenge in the context of type 2 diabetes mellitus (T2DM), emphasizing the need for effective interventions. This study delves into the therapeutic efficacy of quercetin, a natural flavonoid, in mitigating cognitive impairment induced by T2DM in murine models.

MATERIALS AND METHODS

Serum exosome samples were obtained from both T2DM-related and healthy mice for transcriptome sequencing, enabling the identification of differentially expressed mRNAs and long noncoding RNAs (lncRNAs). Subsequent experiments were conducted to ascertain the binding affinity between mmu-miR-129-5p, NEAT1 and BDNF. The structural characteristics and dimensions of isolated exosomes were scrutinized, and the expression levels of exosome-associated proteins were quantified. Primary mouse hippocampal neurons were cultured for in vitro validation, assessing the expression of pertinent genes as well as neuronal vitality, proliferation, and apoptosis capabilities. For in vivo validation, a T2DM mouse model was established, and quercetin treatment was administered. Changes in various parameters, cognitive ability, and the expression of insulin-related proteins, along with pivotal signaling pathways, were monitored.

KEY FINDINGS

Analysis of serum exosomes from T2DM mice revealed dysregulation of NEAT1, mmu-miR-129-5p, and BDNF. In vitro investigations demonstrated that NEAT1 upregulated BDNF expression by inhibiting mmu-miR-129-5p. Overexpression of mmu-miR-129-5p or silencing NEAT1 resulted in the downregulation of insulin-related protein expression, enhanced apoptosis, and suppressed neuronal proliferation. In vivo studies validated that quercetin treatment significantly ameliorated T2DM-related cognitive impairment in mice.

SIGNIFICANCE

These findings suggest that quercetin holds promise in inhibiting hippocampal neuron apoptosis and improving T2DM-related cognitive impairment by modulating the NEAT1/miR-129-5p/BDNF pathway within serum exosomes.

Astrocytic endothelin-1 overexpression impairs learning and memory ability in ischemic stroke via altered hippocampal neurogenesis and lipid metabolism

Vascular etiology is the second most prevalent cause of cognitive impairment globally. Endothelin-1, which is produced and secreted by endothelial cells and astrocytes, is implicated in the pathogenesis of stroke. However, the way in which changes in astrocytic endothelin-1 lead to poststroke cognitive deficits following transient middle cerebral artery occlusion is not well understood. Here, using mice in which astrocytic endothelin-1 was overexpressed, we found that the selective overexpression of endothelin-1 by astrocytic cells led to ischemic stroke-related dementia (1 hour of ischemia; 7 days, 28 days, or 3 months of reperfusion). We also revealed that astrocytic endothelin-1 overexpression contributed to the role of neural stem cell proliferation but impaired neurogenesis in the dentate gyrus of the hippocampus after middle cerebral artery occlusion. Comprehensive proteome profiles and western blot analysis confirmed that levels of glial fibrillary acidic protein and peroxiredoxin 6, which were differentially expressed in the brain, were significantly increased in mice with astrocytic endothelin-1 overexpression in comparison with wild-type mice 28 days after ischemic stroke. Moreover, the levels of the enriched differentially expressed proteins were closely related to lipid metabolism, as indicated by Kyoto Encyclopedia of Genes and Genomes pathway analysis. Liquid chromatography-mass spectrometry nontargeted metabolite profiling of brain tissues showed that astrocytic endothelin-1 overexpression altered lipid metabolism products such as glycerol phosphatidylcholine, sphingomyelin, and phosphatidic acid. Overall, this study demonstrates that astrocytic endothelin-1 overexpression can impair hippocampal neurogenesis and that it is correlated with lipid metabolism in poststroke cognitive dysfunction.

Enriched environment enhanced the astrocyte-derived BDNF and VEGF expression and alleviate white matter injuries of rats with ischemic stroke

OBJECTIVES

Numerous studies have shown that an enriched environment can promote ischemic stroke and improve cognitive function. In addition, white matter is closely related to cognitive function. The effects and mechanisms of the enriched environment on white matter recovery after stroke have not been elucidated. This study will analyse the effects of the enriched environment on white matter and cognitive function in the post-stroke brain from the perspective of astrocytes and their secretions.

METHODS

Stroke models were used for middle cerebral artery occlusion model. post-operative rats were divided into sham-operated, standard and enriched environment groups. The degree of cerebral infarction was assessed by TTC staining and the degree of white matter damage was assessed by Luxol-Fast Blue staining. The prognosis after stroke was assessed using the longa score and Morris water maze test. Western Blot and immunofluorescence were used to quantify and localize astrocytes and their associated secretory factors and myelin protein markers.

RESULTS

We found that ischemic stroke can cause severe demyelination. After EE treatment, there was a significant increase in cerebral remyelination and a significant improvement in neurological and cognitive functions. Astrocyte, BDNF, and VEGF expression were significantly higher than in rats in the standard circumstances of stroke model.

CONCLUSION

These data suggest that the enriched environment contributes to brain white matter recovery and improvement of cognitive function after stroke. The mechanism is related to astrocytes and their secretions. EE can activate astrocytes to secrete BDNF and VEGF, which may be crucial to promote white matter recovery.

Severe inflammation in C57/BL6 mice leads to prolonged cognitive impairment by initiating the IL-1β/TRPM2 pathway

BACKGROUND

Sepsis could lead to chronic cognitive impairment by unclear molecular mechanisms. Transient receptor potential melastatin-2 (TRPM2) is essential against immunity-related activities and inflammation. Our study attempted to decipher the relationship between cognitive impairment caused by severe inflammation and TRPM2 expression levels.

METHODS

Severe inflammation was induced by intraperitoneally injecting C57/BL6 mice with a high dosage (5 mg kg-1) of Lipopolysaccharide (LPS). Fear conditioning and a Morris water maze test were performed to examine the cognitive abilities of the mice. Moreover, the signaling and expression of pro-inflammatory cytokines and TRPM2 were measured using Western blotting and Reverse transcription-polymerase chain reaction (RT-PCR). Flow cytometry and immunofluorescence staining helped to determine the astrocyte apoptosis rate.

RESULTS

Severe inflammation can lead to long-term cognitive impairment in C57/BL6 mice. The interleukin-1 beta (IL-1β) levels intra-hippocampus were significantly elevated until P14 post-LPS introduction. At both P7 and P14, there is an up-regulation of TRPM2 expression within hippocampus. Administration of recombinant IL-1β to astrocytes results in a significant up-regulation of TRPM2 expression. IL-1β or TRPM2 level knockdown helped counter the cognitive impairment caused by significant inflammation.

CONCLUSIONS

A continuous increase in IL-1β levels within the hippocampus can lead to cognitive impairment by enhancing TRPM2 levels caused by severe inflammation.

Akkermansia muciniphila-derived small extracellular vesicles attenuate intestinal ischemia-reperfusion-induced postoperative cognitive dysfunction by suppressing microglia activation via the TLR2/4 signaling

Akkermansia muciniphila (AKK) bacteria improve the functions of theere intestinal and blood-brain barriers (BBB) via their extracellular vesicles (AmEvs). However, their role in postoperative cognitive dysfunction (POCD) and its underlying mechanisms remain unclear. To investigate, we used C57BL/6 J mice divided into five groups: Sham, POCD, POCD+Akk, POCD+Evs, and POCD+Evs + PLX5622. POCD was induced through intestinal ischemia-reperfusion (I/R). The mice's cognitive function was assessed using behavioral tests, and possible mechanisms were explored by examining gut and BBB permeability, inflammation, and microglial function. Toll-like receptor (TLR) 2/4 pathway-related proteins were also investigated both in vitro and in vivo. PLX5622 chow was employed to eliminate microglial cells. Our findings revealed a negative correlation between AKK abundance and POCD symptoms. Supplementation with either AKK or AmEvs improved cognitive function, improved the performance of the intestinal barrier and BBB, and decreased inflammation and microglial activation in POCD mice compared to controls. Moreover, AmEvs treatment inhibited TLR2/4 signaling in the brains of POCD mice and LPS-treated microglial cells. In microglial-ablated POCD mice, however, AmEvs failed to protect BBB integrity. Overall, AmEvs is a potential therapeutic strategy for managing POCD by enhancing gut and BBB integrity and inhibiting microglial-mediated TLR2/4 signaling.

Behavioral Analysis of NMDAR Function in Rodents: Tests of Long-Term Spatial Memory

NMDAR-dependent forms of synaptic plasticity in brain regions like the hippocampus are widely believed to provide the neural substrate for long-term associative memory formation. However, the experimental data are equivocal at best and may suggest a more nuanced role for NMDARs and synaptic plasticity in memory. Much of the experimental data available comes from studies in genetically modified mice in which NMDAR subunits have been deleted or mutated in order to disrupt NMDAR function. Behavioral assessment of long-term memory in these mice has involved tests like the Morris watermaze and the radial arm maze. Here we describe these behavioral tests and some of the different testing protocols that can be used to assess memory performance. We discuss the importance of distinguishing selective effects on learning and memory processes from nonspecific effects on sensorimotor or motivational aspects of performance.

The elderberry diet protection against intrahippocampal Aβ-induced memory dysfunction; the abrogated apoptosis and neuroinflammation

This study evaluates whether elderberry (EB) effectively decreases the inflammation and oxidative stress in the brain cells to reduce Aβ toxicity. In the Aβ + EB group, EB powder was added to rats' routine diet for eight consecutive weeks. Then, spatial memory, working memory, and long-term memory, were measured using the Morris water maze, T-maze, and passive avoidance test. Also, in this investigation immunohistopathology, distribution of hippocampal cells, and gene expression was carried out. Voronoi tessellation method was used to estimate the spatial distribution of the cells in the hippocampus. In addition to improving the memory functions of rats with Aβ toxicity, a reduction in astrogliosis and astrocytes process length and the number of branches and intersections distal to the soma was observed in their hippocampus compared to the control group. Further analysis indicated that the EB diet decreased the caspase-3 expression in the hippocampus of rats with Aβ toxicity. Also, EB protected hippocampal pyramidal neurons against Aβ toxicity and improved the spatial distribution of the hippocampal neurons. Moreover, EB decreased the expression of inflammatory and apoptotic genes. Overall, our study suggest that EB can be considered a potent modifier of astrocytes' reactivation and inflammatory responses.

Theta oscillatory power decreases in humans are associated with spatial learning in a virtual water maze task

Theta oscillations (4-8 Hz) in humans play a role in navigation processes, including spatial encoding, retrieval and sensorimotor integration. Increased theta power at frontal and parietal midline regions is known to contribute to successful navigation. However, the dynamics of cortical theta and its role in spatial learning are not fully understood. This study aimed to investigate theta oscillations via electroencephalogram (EEG) during spatial learning in a virtual water maze. Participants were separated into a learning group (n = 25) who learned the location of a hidden goal across 12 trials, or a time-matched non-learning group (n = 25) who were required to simply navigate the same arena, but without a goal. We compared all trials, at two phases of learning, the trial start and the goal approach. We also compared the first six trials with the last six trials within-groups. The learning group showed reduced low-frequency theta power at the frontal and parietal midline during the start phase and largely reduced theta combined with a short increase at both midlines during the goal-approach phase. These patterns were not found in the non-learning group, who instead displayed extensive increases in low-frequency oscillations at both regions during the trial start and at the parietal midline during goal approach. Our results support the theory that theta plays a crucial role in spatial encoding during exploration, as opposed to sensorimotor integration. We suggest our findings provide evidence for a link between learning and a reduction of theta oscillations in humans.

Multilevel meta-analysis and dose-response analysis for bisphenol A (BPA) exposure on metabolic and neurobehavioral effects

Evidence suggests that oral exposure to bisphenol A (BPA) may result in adverse metabolic and neurobehavioral effects. The aim of the present meta-analysis is to examine this association based on systematically selected laboratory rodent studies published from 2012 to 2021 and sourced from Scopus, Web of Science, EmBase, and PubMed. Articles satisfying eligibility and inclusion criteria were included for the calculation of the summary standardised mean difference (SMD). Subgroup analysis and subsequent dose-response analysis were conducted if applicable. In total, 32 studies were analysed for 6 metabolic endpoints (cholesterol, triglycerides, insulin, glucose, leptin, and adiponectin) and 6 neurobehavioral endpoints (locomotor activity, exploratory, anxiety, depression, spatial learning and memory, non-spatial learning and memory). Summary SMDs implied that no significant effects were observed in endpoints considered. The dose was not determined as a significant moderator with regards to medium or high heterogeneity; however, there was significant impairment of spatial learning and memory at health-based guidance value ('HBGV') (0.05-9 mg (kg bw)-1 day-1) and 'High' (>9 mg (kg bw)-1 day-1) dose group. As a result, an indicative toxicological reference dose value of 0.034 mg (kg bw)-1 day-1 was proposed due to large variability. Potential harm to spatial learning and memory from BPA exposure requires further investigation. This study has provided some additional information on potential adverse metabolic and neurobehavioral effects of BPA from the perspective of meta-analysis which can inform the public, regulatory authorities, and policymakers.

The impact of early life stress and schizophrenia on motor and cognitive functioning: an experimental study

Background

Early life stress (ELS) and parental psychopathology, such as schizophrenia (SZ), have been associated with altered neurobiological and behavioral outcomes later in life. Previous studies have investigated the effects of ELS and parental SZ on various aspects of behavior, however, we have studied the combined effects of these stressors and how they interact, as individuals in real-life situations may experience multiple stressors simultaneously.

Objective

The aim of this study was to investigate the impact of ELS and schizophrenia on locomotor activity, anxiety-like behavior, exploratory tendencies, and spatial memory in Sprague Dawley (SD) rats.

Methods

Male and female SD pups were randomly assigned to eight groups: control, ELS, schizophrenia, and ELS + schizophrenia. ELS was induced by prenatal stress (maternal stress) and maternal separation (MS) during the first 2 weeks of life, while SZ was induced by subcutaneous administration of ketamine. Behavioral tests included an open field test (OFT) for motor abilities and a Morris water maze (MWM) for cognitive abilities. ANOVA and post hoc Tukey tests were utilized to analyze the data.

Results

Our results show that ELS and parental psychopathology had enduring effects on SZ symptoms, particularly psychomotor retardation (p < 0.05). The OFT revealed increased anxiety-like behavior in the ELS group (p = 0.023) and the parental psychopathology group (p = 0.017) compared to controls. The combined ELS and parental psychopathology group exhibited the highest anxiety-like behavior (p = 0.006). The MWM analysis indicated impaired spatial memory in the ELS group (p = 0.012) and the combined ELS and parental psychopathology group (p = 0.003) compared to controls. Significantly, the exposure to ELS resulted in a decrease in the population of glial fibrillary acidic protein-positive (GFAP+) astrocytes. However, this effect was reversed by positive parental mental health.

Conclusion

Our findings highlight the interactive effects of ELS and parental psychopathology on anxiety-like behavior and spatial memory in rats. ELS was linked to increased anxiety-like behavior, while SZ was associated with anhedonia-like behavior. Positive parenting augments neuroplasticity, synaptic function, and overall cognitive capacities.

Fenugreek seed powder protects mice against arsenic-induced neurobehavioral changes

The current study was designed to evaluate the protective effect of fenugreek seed powder against As-induced neurobehavioral and biochemical perturbations using a mouse model. Mice exposed to arsenic at 10 mg/kg body weight showed development of anxiety-like behavior and memory impairment compared to control mice in elevated plus maze and Morris water maze tests, respectively. A significantly decreased acetyl and butyrylcholinesterase, superoxide dismutase and glutathione reductase activities and brain-derived neurotrophic factor levels were found in the brain of arsenic-exposed mice compared to control mice. Interestingly, supplementation of fenugreek seed powder to arsenic-treated mice significantly restored the activity of cholinesterase and antioxidant enzymes (e.g. superoxide dismutase, glutathione reductase) as well as brain-derived neurotrophic factor levels in the brain tissue of arsenic-exposed mice. Consequently, reduced anxiety-like behavior, improved learning and memory were observed in fenugreek supplemented arsenic treated mice compared to only arsenic-exposed mice group. Thus, this study suggests that fenugreek seed powder reduces arsenic-induced neurotoxicity in mice.

Differential expression of SLC30A10 and RAGE in mouse pups by early life lead exposure

BACKGROUND

SLC30A10 and RAGE are widely recognized as pivotal regulators of Aβ plaque transport and accumulation. Prior investigations have established a link between early lead exposure and cerebral harm in offspring, attributable to Aβ buildup and amyloid plaque deposition. However, the impact of lead on the protein expression of SLC30A10 and RAGE has yet to be elucidated. This study seeks to confirm the influence of maternal lead exposure during pregnancy, specifically through lead-containing drinking water, on the protein expression of SLC30A10 and RAGE in mice offspring. Furthermore, this research aims to provide further evidence of lead-induced neurotoxicity.

METHODS

Four cohorts of mice were subjected to lead exposure at concentrations of 0 mM, 0.25 mM, 0.5 mM, and 1 mM over a period of 42 uninterrupted days, spanning from pregnancy to the weaning phase. On postnatal day 21, the offspring mice underwent assessments. The levels of lead in the blood, hippocampus, and cerebral cortex were scrutinized, while the mice's cognitive abilities pertaining to learning and memory were probed through the utilization of the Morris water maze. Furthermore, Western blotting and immunofluorescence techniques were employed to analyze the expression levels of SLC30A10 and RAGE in the hippocampus and cerebral cortex.

RESULTS

The findings revealed a significant elevation in lead concentration within the brains and bloodstreams of mice, mirroring the increased lead exposure experienced by their mothers during the designated period (P < 0.05). Notably, in the Morris water maze assessment, the lead-exposed group exhibited noticeably diminished spatial memory compared to the control group (P < 0.05). Both immunofluorescence and Western blot analyses effectively demonstrated the concomitant impact of varying lead exposure levels on the hippocampal and cerebral cortex regions of the offspring. The expression levels of SLC30A10 displayed a negative correlation with lead doses (P < 0.05). Surprisingly, under identical circumstances, the expression of RAGE in the hippocampus and cortex of the offspring exhibited a positive correlation with lead doses (P < 0.05).

CONCLUSION

SLC30A10 potentially exerts distinct influence on exacerbated Aβ accumulation and transportation in contrast to RAGE. Disparities in brain expression of RAGE and SLC30A10 may contribute to the neurotoxic effects induced by lead.

Gastrodin relieves cognitive impairment by regulating autophagy via PI3K/AKT signaling pathway in vascular dementia

Vascular dementia (VaD), the second most common type of dementia, is attributed to lower cerebral blood flow. To date, there is still no available clinical treatment for VaD. The phenolic glucoside gastrodin (GAS) is known for its neuroprotective effects, but the role and mechanisms of action on VD remains unclear. In this study, we aim to investigate the neuroprotective role and underlying mechanisms of GAS on chronic cerebral hypoperfusion (CCH)-mediated VaD rats and hypoxia-induced injury of HT22 cells. The study showed that GAS relieved learning and memory deficits, ameliorated hippocampus histological lesions in VaD rats. Additionally, GAS down-regulated LC3II/I, Beclin-1 levels and up-regulated P62 level in VaD rats and hypoxia-injured HT22 cells. Notably, GAS rescued the phosphorylation of PI3K/AKT pathway-related proteins expression, which regulates autophagy. Mechanistic studies verify that YP-740, a PI3K agonist, significantly resulted in inhibition of excessive autophagy and apoptosis with no significant differences were observed in the YP-740 and GAS co-treatment. Meantime, we found that LY294002, a PI3K inhibitor, substantially abolished GAS-mediated neuroprotection. These results revealed that the effects of GAS on VaD are related to stimulating PI3K/AKT pathway-mediated autophagy, suggesting a potentially beneficial therapeutic strategy for VaD.

Maternal antibiotic administration during gestation can affect the memory and brain structure in mouse offspring

Maternal antibiotics administration (MAA) is among the widely used therapeutic approaches in pregnancy. Although published evidence demonstrates that infants exposed to antibiotics immediately after birth have altered recognition memory responses at one month of age, very little is known about in utero effects of antibiotics on the neuronal function and behavior of children after birth. Therefore, this study aimed to evaluate the impact of MAA at different periods of pregnancy on memory decline and brain structural alterations in young mouse offspring after their first month of life. To study the effects of MAA on 4-week-old offspring, pregnant C57BL/6J mouse dams (2-3-month-old; n = 4/group) were exposed to a cocktail of amoxicillin (205 mg/kg/day) and azithromycin (51 mg/kg/day) in sterile drinking water (daily/1 week) during either the 2nd or 3rd week of pregnancy and stopped after delivery. A control group of pregnant dams was exposed to sterile drinking water alone during all three weeks of pregnancy. Then, the 4-week-old offspring mice were first evaluated for behavioral changes. Using the Morris water maze assay, we revealed that exposure of pregnant mice to antibiotics at the 2nd and 3rd weeks of pregnancy significantly altered spatial reference memory and learning skills in their offspring compared to those delivered from the control group of dams. In contrast, no significant difference in long-term associative memory was detected between offspring groups using the novel object recognition test. Then, we histologically evaluated brain samples from the same offspring individuals using conventional immunofluorescence and electron microscopy assays. To our knowledge, we observed a reduction in the density of the hippocampal CA1 pyramidal neurons and hypomyelination in the corpus callosum in groups of mice in utero exposed to antibiotics at the 2nd and 3rd weeks of gestation. In addition, offspring exposed to antibiotics at the 2nd or 3rd week of gestation demonstrated a decreased astrocyte cell surface area and astrocyte territories or depletion of neurogenesis in the dentate gyrus and hippocampal synaptic loss, respectively. Altogether, this study shows that MAA at different times of pregnancy can pathologically alter cognitive behavior and brain development in offspring at an early age after weaning.

The mediating role of gut microbiota in the associations of prenatal maternal combined exposure to lead and stress with neurodevelopmental deficits in young rats

Prenatal single and combined exposure to lead (Pb) and stress (Ps) impairs neurodevelopment. Prenatal single exposure to Pb or Ps affects the composition of intestinal microbiota, and bidirectional communication between gut microbiota and central nervous system has been well recognized. However, whether gut microbiota mediated the effects of prenatal Pb+Ps co-exposure on neurodevelopmental deficits remains unclear. This study established rat models with prenatal single and combined exposure to Ps and Pb. We investigated the effects of such prenatal single and combined exposure on hippocampal structures using morphological analyses, on learning/memory using the Morris-water-maze test, and on fecal microbiota using 16S rRNA sequencing. The mediating roles of gut microbiota were analyzed using the bootstrap method. The study found both single and combined exposure affected hippocampal ultra-structures and spatial learning/memory, and the most significant impairments were observed in the Pb+Ps group. Prenatal Pb+Ps co-exposure decreased fecal microbial alpha/beta-diversity. Significantly lower levels of B/F-ratio, class-Bacteroidia, order-Bacteroidales, and family-S24-7, and significantly higher levels of class-Bacilli, order-Lactobacillales, family-Lactobacillaceae, and genus-Lactobacillus were observed in the co-exposure group, compared with the controls. Increased relative abundances of genus-Helicobacter mediated the detrimental effect of prenatal Ps+Pb co-exposure on learning/memory [β (95%CI) for the total and indirect effects: - 10.70 (-19.19, -2.21) and - 4.65(-11.07, -1.85)], accounting for 43.47% of the total effect. As a result, increased relative abundances of genus-Lactobacillus alleviated the adverse effects of the co-exposure on learning/memory, and the alleviation effect accounted for 44.55% of the direct effect [β (95%CI) for the direct and indirect effects: - 0.28(-0.48, -0.08) and 0.13(0.01, 0.41)]. This study suggested that prenatal combined exposure to Pb and Ps induced more impairments in offspring gut microbiota and neurodevelopment than single exposure, and alterations in fecal microbiome may mediate the developmental neurotoxicity induced by such prenatal co-exposure.

LMP2 deficiency causes abnormal metabolism, oxidative stress, neuroinflammation, myelin loss and neurobehavioral dysfunctions

BACKGROUND

Substantial evidence suggests that immunoproteasome is implicated in the various neurological diseases such as stroke, multiple sclerosis and neurodegenerative diseases. However, whether the immunoproteasome itself deficiency causes brain disease is still unclear. Therefore, the aim of this study was to explore the contribution of the immunoproteasome subunit low molecular weight protein 2 (LMP2) in neurobehavioral functions.

METHODS

Male LMP2 gene completed knockout (LMP2-KO) and littermate wild type (WT) Sprague-Dawley (SD) rats aged 12-month-old were used for neurobehavioral testing and detection of proteins expression by western blotting and immunofluorescence. A battery of neurobehavioral test tools including Morris water maze (MWM), open field maze, elevated plus maze were used to evaluate the neurobehavioral changes in rats. Evans blue (EB) assay, Luxol fast blue (LFB) and Dihydroethidium (DHE) staining were applied to explore the blood-brain barrier (BBB) integrity, brain myelin damage and brain intracellular reactive oxygen species (ROS) levels, respectively.

RESULTS

We firstly found that LMP2 gene deletion did not cause significantly difference in rats' daily feeding activity, growth and development as well as blood routine, but it led to metabolic abnormalities including higher levels of low-density lipoprotein cholesterol, uric acid and blood glucose in the LMP2-KO rats. Compared with the WT rats, LMP2-KO rats displayed obviously cognitive impairment and decreased exploratory activities, increased anxiety-like behavior and without strong effects on gross locomotor abilities. Furthermore, multiple myelin loss, increased BBB leakage, downregulation of tight junction proteins ZO-1, claudin-5 and occluding, and enhanced amyloid-β protein deposition were observed in brain regions of LMP2-KO rats. In addition, LMP2 deficiency significantly enhanced oxidative stress with elevated levels of ROS, caused the reactivation of astrocytes and microglials and markedly upregulated protein expression levels of interleukin (IL)-1 receptor-associated kinase 1 (IRAK1), IL-6 and tumor necrosis factor-α (TNF-α) compared to the WT rats, respectively.

CONCLUSION

These findings highlight LMP2 gene global deletion causes significant neurobehavioral dysfunctions. All these factors including metabolic abnormalities, multiple myelin loss, elevated levels of ROS, increased BBB leakage and enhanced amyloid-β protein deposition maybe work together and eventually led to chronic oxidative stress and neuroinflammation response in the brain regions of LMP2-KO rats, which contributed to the initial and progress of cognitive impairment.

Clerodendrum viscosum leaves attenuate lead-induced neurotoxicity through upregulation of BDNF-Akt-Nrf2 pathway in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Clerodendrum viscosum is an important medicinal plant in Ayurveda in Bangladesh and its leaves are used as a remedy for various diseases such as anti-inflammatory, antibacterial, hyperglycemic, hepatoprotective effects.

AIM OF THE STUDY

The present study aimed to evaluate the protective effect of aqueous extract of C. viscosum leaves against Pb-induced neurobehavioral and biochemical changes in mice.

MATERIALS AND METHODS

Swiss albino mice were divided as a) control, b) lead treated (Pb) and c) C. viscosum leaves (Cle) d) Pb plus Cle groups. Pb-acetate (10 mg/kg body weight) was given to Pb and Pb + Cle groups mice, and water extract of leaves (50 mg/kg body weight) was provided as supplementation to Cle and Pb + Cle groups mice for 30 days. Elevated plus maze and Morris water maze tests were used for evaluating anxiety, spatial memory and learning, respectively. Status of cholinesterase, SOD, GSH enzyme activity and neurotoxicity markers such BDNF and Nrf2 levels were analyzed in the brain tissue of experimental mice.

RESULTS

Poorer learning, inferior spatial memory, and increased anxiety-like behavior in Pb-exposure mice were noted when compared to control mice in Morris water maze and elevated plus maze test, respectively. In addition, expression of BDNF and Nrf2, cholinesterase activity along with antioxidant activity were significantly reduced compared to control group (p < 0.01). Interestingly, C. viscosum leaves' aqueous extract supplementation in Pb-exposed mice provide a significant improved neurochemical and antioxidant properties through the augmentation of activity of cholinergic enzymes, and upregulation of BDNF and Nrf2 levels in the brain tissue compared to Pb-exposed mice.

CONCLUSIONS

This study suggested that C. viscosum leaves restore the cognitive dysfunction and reduce anxiety-like behavior through upregulation of BDNF mediated Akt-Nrf2 pathway in Pb-exposure mice.

Sex differences in hippocampal-dependent memory and the hippocampal lipidome in adolescent rats raised on diets with or without DHA

Recent studies suggest the effects of DHA supplementation on human memory may differ between females and males during infancy, adolescence, and early adulthood, but the underlying mechanisms are not clear. As a result, this study sought to examine the spatial memory and brain lipidomic profiles in female and male adolescent rats with or without a DHA-enriched diet that began perinatally with the supplementation of dams. Spatial learning and memory were examined in adolescent rats using the Morris Water Maze beginning at 6 weeks of age and animals were sacrificed at 7 weeks of age to permit isolation of brain tissue and blood samples. Behavioral testing showed that there was a significant diet x sex interaction for two key measures of spatial memory (distance to zone and time spent in the correct quadrant during the probe test), with female rats benefiting the most from DHA supplementation. Lipidomic analyses suggest levels of arachidonic acid (ARA) and n-6 docosapentaenoic acid (DPA) containing phospholipid species were lower in the hippocampus of DHA supplemented compared with control animals, and principal component analyses revealed a potential dietary treatment effect for hippocampal PUFA. Females fed DHA had slightly more PE P-18:0_22:6 and maintained levels of PE 18:0_20:4 in the hippocampus in contrast with males fed DHA. Understanding how DHA supplementation during the perinatal and adolescent periods changes cognitive function in a sex-specific manner has important implications for determining the dietary requirements of DHA. This study adds to previous work highlighting the importance of DHA for spatial memory and provides evidence that further research needs to consider how DHA supplementation can cause sex-specific changes.

Epidural Pulsation Accelerates the Drainage of Brain Interstitial Fluid

Unhindered transportation of substances in the brain extracellular space (ECS) is essential for maintaining brain function. Regulation of transportation is a novel strategy for treating ECS blockage-related brain diseases, but few techniques have been developed to date. In this study, we established a novel approach for accelerating the drainage of brain interstitial fluid (ISF) in the ECS using minimally invasive surgery, in which a branch of the external carotid artery is separated and implanted epidurally (i.e., epidural arterial implantation [EAI]) to promote a pulsation effect on cerebrospinal fluid (CSF) in the frontoparietal region. Tracer-based magnetic resonance imaging was used to evaluate the changes in ISF drainage in rats 7 and 15 days post-EAI. The drainage of the traced ISF from the caudate nucleus to ipsilateral cortex was significantly accelerated by EAI. Significant increases in the volume fraction of the ECS and molecular diffusion rate were demonstrated using the D_ECS-mapping technique, which may account for the mechanisms underlying the changes in brain ISF. This study provides a novel perspective for encephalopathy treatment via the brain ECS.

Docosahexaenoic acid improves cognition and hippocampal pyroptosis in rats with intrauterine growth restriction

Background and Objective

Intrauterine growth restriction (IUGR) is defined as the failure of a fetus to reach its genetic growth potential in utero resulted by maternal, placental, fetal, and genetic factors. Previous studies have reported that IUGR is associated with a high incidence of neurological damage, although the precise causes of such damage remain unclear. We aimed to investigate whether cognitive impairment in rats with IUGR is related to pyroptosis of hippocampal neurons and determine the effect of early intervention with docosahexaenoic acid (DHA).

Methods

Learning and memory function was assessed using the Morris water maze test. The morphological structure and ultrastructure of the hippocampus was examined via hematoxylin and eosin staining and electron microscopy respectively. The pyroptosis of hippocampal neuron was detected by gasdermin-D (GSDMD) immunofluorescence staining, mRNA and protein expression of nuclear localization leucine-rich-repeat protein 1 (NLRP1), caspase-1, GSDMD, and quantification of inflammatory cytokines interleukin (IL)-1β and IL-18 in the hippocampus.

Results

IUGR rats exhibited decreased learning and memory function, morphological structure and ultrastructural changes in hippocampus compared to controls. IUGR rats also exhibited increased hippocampal quantification of GSDMD immunofluorescence staining, increased mRNA and protein expression of NLRP1, caspase-1, and GSDMD, and increased quantification of IL-1β and IL-18 in the hippocampus. Intervention with DHA attenuated these effects.

Conclusion

Cognitive impairment in rats with IUGR may be related to pyroptosis of hippocampal neurons. Early intervention with DHA may attenuate cognitive impairment and reduce hippocampal pyroptosis in rats with IUGR.

Epilepsy and its neurobehavioral comorbidities: Insights gained from animal models

It is well established that epilepsy is associated with numerous neurobehavioral comorbidities, with a bidirectional relationship; people with epilepsy have an increased incidence of depression, anxiety, learning and memory difficulties, and numerous other psychosocial challenges, and the occurrence of epilepsy is higher in individuals with those comorbidities. Although the cause-and-effect relationship is uncertain, a fuller understanding of the mechanisms of comorbidities within the epilepsies could lead to improved therapeutics. Here, we review recent data on epilepsy and its neurobehavioral comorbidities, discussing mainly rodent models, which have been studied most extensively, and emphasize that clinically relevant information can be gained from preclinical models. Furthermore, we explore the numerous potential factors that may confound the interpretation of emerging data from animal models, such as the specific seizure induction method (e.g., chemical, electrical, traumatic, genetic), the role of species and strain, environmental factors (e.g., laboratory environment, handling, epigenetics), and the behavioral assays that are chosen to evaluate the various aspects of neural behavior and cognition. Overall, the interplay between epilepsy and its neurobehavioral comorbidities is undoubtedly multifactorial, involving brain structural changes, network-level differences, molecular signaling abnormalities, and other factors. Animal models are well poised to help dissect the shared pathophysiological mechanisms, neurological sequelae, and biomarkers of epilepsy and its comorbidities.

Esmolol inhibits cognitive impairment and neuronal inflammation in mice with sepsis-induced brain injury

Sepsis is a potentially fatal organ failure resulting from a dysregulated host response to infection. It can be a substantial financial burden on families and society due to the high cost of medical care. The study aims to investigate the protective roles of Esmolol in mice with sepsis-induced brain injuries against cognitive dysfunction and neuronal inflammation. Male C57BL/6J mice were intraperitoneally injected with LPS (10 mg/kg, L2630, Sigma) to establish a septic encephalopathy model. Esmolol (15 mg/kg/h, HY-B1392, MedChemExpress) was subcutaneously infused using osmotic mini-pumps for 6 h before LPS injection. Morris water maze and novel object recognition tests evaluated LPS-induced cognitive impairment and behavioral phenotypes. Cytokines and protein expression were assessed using ELISA assay and RT-qPCR. Esmolol treatment potentially improved cognitive impairment in septic mice. Esmolol administration markedly diminished the abnormal hippocampal neuronal structure, and the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α was significantly downregulated in the hippocampal tissue. Esmolol treatment significantly reduced apoptotic TUNEL-positive cells and reversed the related gene expression (BAX and BCL-2). The effects of esmolol on the reactive oxidative species and oxidative stress markedly reduce malondialdehyde MDA content and increase superoxide dismutase and catalase in hippocampal tissues. In addition, esmolol significantly reduced the percentage and density of Iba-1 + microglia in septic mice. Our results demonstrated that esmolol potentially improved cognitive impairment and neuronal inflammation in mice with sepsis-induced brain injury.

NUDT21 relieves sevoflurane-induced neurological damage in rats by down-regulating LIMK2

Postoperative cognitive dysfunction (POCD) is a common complication of cognitive decline after surgery and anesthesia. Sevoflurane, as a commonly used anesthetic, was found to cause POCD. Nudix Hydrolase 21 (NUDT21), a conserved splicing factor, has been reported to exert important functions in multiple diseases' progression. In this study, the effect of NUDT21 on sevoflurane-induced POCD was elucidated. Results showed that NUDT21 was down-regulated in the hippocampal tissue of sevoflurane-induced rats. Morris water maze test results revealed that overexpression of NUDT21 improved sevoflurane-induced cognitive impairment. In addition, TUNEL assay results indicated that enhanced NUDT21 alleviated sevoflurane-induced apoptosis of hippocampal neurons. Furthermore, overexpression of NUDT21 suppressed the sevoflurane-induced LIMK2 expression. Taken together, NUDT21 alleviates sevoflurane-induced neurological damage in rats by down-regulating LIMK2, providing a novel target for the prevention of sevoflurane-induced POCD.

Mechanisms Underlying Cognitive Impairment Induced by Prenatal Alcohol Exposure

Alcohol is one of the most commonly used illicit substances among pregnant women. Clinical and experimental studies have revealed that prenatal alcohol exposure affects fetal brain development and ultimately results in the persistent impairment of the offspring's cognitive functions. Despite this, the rate of alcohol use among pregnant women has been progressively increasing. Various aspects of human and animal behavior, including learning and memory, are dependent on complex interactions between multiple mechanisms, such as receptor function, mitochondrial function, and protein kinase activation, which are especially vulnerable to alterations during the developmental period. Thus, the exploration of the mechanisms that are altered in response to prenatal alcohol exposure is necessary to develop an understanding of how homeostatic imbalance and various long-term neurobehavioral impairments manifest following alcohol abuse during pregnancy. There is evidence that prenatal alcohol exposure results in vast alterations in mechanisms such as long-term potentiation, mitochondrial function, and protein kinase activation in the brain of offspring. However, to the best of our knowledge, there are very few recent reviews that focus on the cognitive effects of prenatal alcohol exposure and the associated mechanisms. Therefore, in this review, we aim to provide a comprehensive summary of the recently reported alterations to various mechanisms following alcohol exposure during pregnancy, and to draw potential associations with behavioral changes in affected offspring.

Mulberry leaves juice attenuates arsenic-induced neurobehavioral and hepatic disorders in mice

Arsenic (As) poisoning has caused an environmental catastrophe in Bangladesh as millions of people are exposed to As-contaminated drinking water. Chronic As-exposure causes depression, memory impairment, and liver injury in experimental animals. This study was carried out to assess the protective effect of mulberry leaves juice (Mul) against As-induced neurobehavioral and hepatic dysfunctions in Swiss albino mice. As-exposed mice spent significantly reduced time in open arms and increased time spent in closed arms in the elevated plus maze (EPM) test, whereas they took significantly longer time to find the hidden platform in the Morris water maze (MWM) test and spent significantly less time in the desired quadrant when compared to the control mice. A significant reduction in serum BChE activity, an indicator of As-induced neurotoxicity-associated behavioral changes, was noted in As-exposed mice compared to control mice. Supplementation of Mul to As-exposed mice significantly increased serum BChE activity, increased the time spent in open arms and reduced time latency to find the hidden platform, and stayed more time in the target quadrant in EPM and MWM tests, respectively, compared to As-exposed-only mice. Also, a significantly reduced activity of BChE, AChE, SOD, and GSH in brain, and elevated ALP, AST, and ALT activities in serum were noted in As-exposed mice when compared to control mice. Mul supplementation significantly restored the activity of these enzymes and also recovered As-induced alterations in hepatic tissue in As-exposed mice. In conclusion, this study suggested that mulberry leaves juice attenuates As-induced neurobehavioral and hepatic dysfunction in mice.

Disrupted metabolic and spontaneous neuronal activity of hippocampus in sepsis associated encephalopathy rats: A study combining magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging

BACKGROUND

The diagnosis of sepsis associated encephalopathy (SAE) remains challenging in clinical settings because of a lack of specific biomarkers. Functional magnetic resonance imaging (fMRI) and proton magnetic resonance spectroscopy (1H-MRS) can be used to aid in the diagnosis of cognition related diseases. This study investigated changes in functional activities and brain metabolites in the hippocampus in SAE rats by fMRI and 1H-MRS.

MATERIALS AND METHODS

Sepsis associated encephalopathy rats underwent cecal ligation and perforation (CLP) surgery. The Morris water maze (MWM) test was then used to evaluate cognitive function. Resting state-fMRI and 1H-MRS scanning were performed 7 and 14 days after CLP surgery to reveal spontaneous neuronal activity and metabolite changes in the hippocampus. The amplitude of low-frequency fluctuation (ALFF) was used to evaluate spontaneous neuronal activity in the hippocampus. Creatine (Cr), Myo-inositol (mI), and glutamine/glutamate (Glx) levels were measured with 1H-MRS scanning. Immunofluorescence and levels of interleukin (IL)-1β, interleukin (IL)-6, and C-reactive protein (CRP) in the hippocampus were additionally detected to evaluate microglial mediated inflammatory responses. Statistical analysis was performed to evaluate correlations between hippocampal metabolism and behavioral findings.

RESULTS

Cecal ligation and perforation treated rats exhibited impaired learning and memory function in the MWM test at days 7 and 14. Elevation of IL-1β in the hippocampus, as well as immunofluorescence results, confirmed severe neuro inflammation in the hippocampus in SAE rats. Compared with the sham group, the ALFF of the right CA-1 area of the hippocampus was higher at day 7after CLP surgery. The Glx/Cr and mI/Cr ratios were enhanced at day 7 after CLP surgery and slightly lower at day 14 after CLP surgery. The ALFF value, and Glx/Cr and mI/Cr ratios were negatively correlated with time spent in the target quadrant in the MWM test.

CONCLUSION

Spontaneous neuronal activity and metabolites showed significant alterations in SAE rats. The elevated ALFF value, Glx/Cr ratio, and mI/Cr ratio in the hippocampus were positively associated with cognitive deficits. Changes in ALFF and metabolites in hippocampus may serve as potential neuroimaging biomarkers of cognitive disorders in patients with SAE.

The Inhibition of Zinc Excitotoxicity and AMPK Phosphorylation by a Novel Zinc Chelator, 2G11, Ameliorates Neuronal Death Induced by Global Cerebral Ischemia

AMP-activated protein kinase (AMPK) is necessary for maintaining a positive energy balance and essential cellular processes such as glycolysis, gene transcription, glucose uptake, and several other biological functions. However, brain injury-induced energy and metabolic stressors, such as cerebral ischemia, increase AMPK phosphorylation. Phosphorylated AMPK contributes to excitotoxicity, oxidative, and metabolic problems. Furthermore, brain disease-induced release of zinc from synaptic vesicles contributes to neuronal damage via mechanisms including ROS production, apoptotic cell death, and DNA damage. For this reason, we hypothesized that regulating zinc accumulation and AMPK phosphorylation is critical for protection against global cerebral ischemia (GCI). Through virtual screening based on the structure of AMPK subunit alpha 2, we identified a novel compound, 2G11. In this study, we verified that 2G11 administration has neuroprotective effects via the blocking of zinc translocation and AMPK phosphorylation after GCI. As a result, we demonstrated that 2G11 protected hippocampal neurons against GCI and OGD/R-derived cellular damage. In conclusion, we propose that AMPK inhibition and zinc chelation by 2G11 may be a promising tool for preventing GCI-induced hippocampal neuronal death.

Evaluation of Neurotoxicity in BALB/c Mice following Chronic Exposure to Polystyrene Microplastics

BACKGROUND

The toxicity of microplastics (MPs) has attracted wide attention from researchers. Previous studies have indicated that MPs produce toxic effects on a variety of organs in aquatic organisms and mammals. However, the exact neurotoxicity of MPs in mammals is still unclear.

OBJECTIVES

We aimed to confirm the neurotoxicity of chronic exposure to polystyrene MPs (PS-MPs) at environmental pollution concentrations.

METHODS

In the present study, mice were provided drinking water containing 100μg/L and 1,000μg/L PS-MPs with diameters of 0.5, 4, and 10μm for 180 consecutive days. After the exposure period, the mice were anesthetized to gain brain tissues. The accumulation of PS-MPs in brain tissues, integrity of the blood-brain barrier, inflammation, and spine density were detected. We evaluated learning and memory ability by the Morris water maze and novel object recognition tests.

RESULTS

We observed the accumulation of PS-MPs with various particle diameters (0.5, 4, and 10μm) in the brains of exposed mice. Meanwhile, exposed mice also exhibited disruption of the blood-brain barrier, higher level of dendritic spine density, and an inflammatory response in the hippocampus. In addition, exposed mice exhibited cognitive and memory deficits compared with control mice as determined using the Morris water maze and novel object recognition tests, respectively. There was a concentration-dependent trend, but no particle size-dependent differences were seen in the neurotoxicity of MPs.

CONCLUSIONS

Collectively, our results suggested that PS-MPs exposure can lead to learning and memory dysfunctions and induce neurotoxic effects in mice, findings which have wide-ranging implications for the public regarding the potential risks of MPs. https://doi.org/10.1289/EHP10255.

The effects of inactivated SARS-CoV-2 vaccination and subsequent infection of pregnant mice on the behaviors of offspring

The mass inoculation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines to induce herd immunity is one of the most effective measures we can deploy in the fight against coronavirus disease 2019 (COVID-19). Pregnant women are prone to a higher risk of COVID-19, and maternal infection is a risk factor for a range of neurological disorders leading to abnormal behavior in adulthood. However, there are limited clinical data to support whether vaccination or infection post-immunization in pregnant women can affect the behavioral cognition of fetuses in adulthood. In this study, human angiotensin-converting enzyme 2 pregnant mice (F0 generation) were immunized with CoronaVac and then infected with SARS-CoV-2. Subsequently, we analyzed the behavioral cognition of their adult offspring (F1 generation) using the open-field test and Morris water maze test. The adult F1 generation did not exhibit any impairments in spontaneous locomotor activity or spatial reference memory.

GLP-1 receptor nitration contributes to loss of brain pericyte function in a mouse model of diabetes

AIMS/HYPOTHESIS

We have previously shown that diabetes causes pericyte dysfunction, leading to loss of vascular integrity and vascular cognitive impairment and dementia (VCID). Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs), used in managing type 2 diabetes mellitus, improve the cognitive function of diabetic individuals beyond glycaemic control, yet the mechanism is not fully understood. In the present study, we hypothesise that GLP-1 RAs improve VCID by preventing diabetes-induced pericyte dysfunction.

METHODS

Mice with streptozotocin-induced diabetes and non-diabetic control mice received either saline (NaCl 154 mmol/l) or exendin-4, a GLP-1 RA, through an osmotic pump over 28 days. Vascular integrity was assessed by measuring cerebrovascular neovascularisation indices (vascular density, tortuosity and branching density). Cognitive function was evaluated with Barnes maze and Morris water maze. Human brain microvascular pericytes (HBMPCs), were grown in high glucose (25 mmol/l) and sodium palmitate (200 μmol/l) to mimic diabetic conditions. HBMPCs were treated with/without exendin-4 and assessed for nitrative and oxidative stress, and angiogenic and blood-brain barrier functions.

RESULTS

Diabetic mice treated with exendin-4 showed a significant reduction in all cerebral pathological neovascularisation indices and an improved blood-brain barrier (p<0.05). The vascular protective effects were accompanied by significant improvement in the learning and memory functions of diabetic mice compared with control mice (p<0.05). Our results showed that HBMPCs expressed the GLP-1 receptor. Diabetes increased GLP-1 receptor expression and receptor nitration in HBMPCs. Stimulation of HBMPCs with exendin-4 under diabetic conditions decreased diabetes-induced vascular inflammation and oxidative stress, and restored pericyte function (p<0.05).

CONCLUSIONS/INTERPRETATION

This study provides novel evidence that brain pericytes express the GLP-1 receptor, which is nitrated under diabetic conditions. GLP-1 receptor activation improves brain pericyte function resulting in restoration of vascular integrity and BBB functions in diabetes. Furthermore, the GLP-1 RA exendin-4 alleviates diabetes-induced cognitive impairment in mice. Restoration of pericyte function in diabetes represents a novel therapeutic target for diabetes-induced cerebrovascular microangiopathy and VCID.