Search Results (340)

Background and Objectives: SARS-CoV-2 produces potentially pathogenic molecules, such as single-stranded RNA and spike proteins, which can potentially activate microglial cells. In this study, we aimed to investigate whether SARS-CoV-2 spike protein S1 and mRNA vaccines can cause neurotoxicity directly or through microglial involvement. Materials and Methods: Primary cerebellar granule cell cultures isolated from Wistar rats and organotypic hippocampal slice cultures from transgenic C57BL/6J mice were used in the experiments. Imaging and quantitative analysis of cell viability, proliferation, and phagocytic activity were performed using light and fluorescence microscopy. Results: The exogenous SARS-CoV-2 S1 protein at 50 µg/mL concentration induced neuronal cell death in neuronal–glial co-cultures and stimulated microglial proliferation during the first 3 days of exposure without an effect on inflammatory cytokine secretion. Single application of Tozinameran/Riltozinameran and Original/Omicron BA. 4–5 vaccines did not affect neuronal viability and total neuronal number in cell co-cultures after 7 days of exposure. In contrast, three repeated treatments with mRNA vaccines at 6 ng/mL caused microglial proliferation without affecting microglial phagocytosis and TNF-α release. In organotypic brain slice cultures, only Tozinameran/Riltozinameran stimulated microglial cell proliferation in female brain slices, while male brain slices remained unaffected by both vaccines, indicating sex-dependent effects. Conclusions: The findings suggest that mRNA vaccines do not exert neurotoxic effects in primary neuronal–glial co-cultures, but induce microglial proliferation, particularly in female brains in the absence of inflammatory cytokine release. SARS-CoV-2 S1 protein at high concentrations directly induces neuronal death. Full article

Simultaneously inhibiting beta-amyloid protein (Aβ) aggregation and reducing metal ion overload in the brain is a promising strategy for treating Alzheimer’s disease (AD). Aloe emodin (AE) is one of the major components of the traditional Chinese medicine rhubarb. Based on its reported pharmacological effects and its structural affinity for metal ions, this study aims to explore the potential of AE in improving AD pathology. Through the injection of Aβ or copper-Aβ complex in the bilateral hippocampus of rats, we constructed two kinds of nontransgenic animal models. Behavioral tests were used to evaluate cognitive impairment, and the effects of AE on neuronal damage and Aβ deposition were measured via Nissl staining and immunohistochemistry. Furthermore, we detected copper content in the serum and brain tissues as well as some biochemical indexes of Aβ cascade pathology in the brain tissues of model rats to explore the mechanism of action. AE treatment decreased copper accumulation and regulated Aβ metabolism in the brain of model rats, thereby improving Aβ deposition, memory impairment, hippocampal nerve cell damage, and related biochemical indicators. AE ameliorated the AD pathology of the model rats by targeting copper-induced Aβ toxicity, revealing a mechanism of action by which AE may exhibit good clinical efficacy in treating AD. Full article

Di-2-ethylhexyl phthalate (DEHP) is a widely used plasticizer with recognized sex-dependent neurotoxicity. However, research on adult neurotoxicity is scarce, especially in females. In this study, adult female rats were exposed to a high-dose experimental model of DEHP (500 mg/kg/day) for 28 days to systematically evaluate hippocampal neurotoxicity. We found that DEHP exposure significantly impaired spatial learning and memory. Transcriptomics revealed enrichment in oxidative stress, complement activation, and neurodegenerative pathways. Specifically, cellular and molecular analyses showed that DEHP induced mitochondrial structural defects and elevated markers of oxidative damage (8-OHdG and 3-NT). While the upregulation of mitochondrial and antioxidant proteins (COX4I1, SOD2, and NQO1) indicated an attempted compensatory response, it remained inadequate to restore redox homeostasis. Under this neurotoxic microenvironment, DEHP triggered early neurogenesis, marked by the upregulation of SOX2 and DCX; however, NeuN levels remained unchanged, suggesting that this compensatory effort failed to expand the mature neuronal population. Ultimately, these pathological processes culminated in neurodegeneration, as evidenced by reduced synaptic proteins, suppressed Olig1/2 expression, and increased tau phosphorylation. Collectively, this study provides a comprehensive neurotoxic profile of DEHP in adult female rats, filling a research gap in this field. Full article

Excitable neurons are intrinsically capable of firing action potentials (AP), yet a state of hyperexcitability is prevented in the central nervous system by powerful GABAergic inhibition. For this inhibition to be effective, it must occur before excitatory signals can initiate runaway activity, implying the existence of a proactive control system. To test for such proactive inhibition, we used Ca²⁺ imaging and patch-clamp recording to measure how hippocampal neurons respond to depolarization and glutamatergic agonists. In mature hippocampal cultures (14 days in vitro (DIV)) and acute brain slices from two-month-old rats, neurons exhibited non-simultaneous responses to various excitatory stimuli, including KCl, NH₄Cl, forskolin, domoic acid, and glutamate. We observed that the Ca²⁺ rise occurred significantly earlier in GABAergic neurons than in glutamatergic neurons. This delay in glutamatergic neurons was abolished by GABA(A) receptor inhibitors, suggesting a mechanism of preliminary γ-aminobutyric acid (GABA) release. We further found that these early-responding GABAergic neurons express calcium-permeable kainate and AMPA receptors (CP-KARs and CP-AMPARs). Application of domoic acid induced an immediate Ca²⁺ increase in neurons expressing these receptors, but a delayed response in others. Crucially, when domoic acid was applied in the presence of the AMPA receptor inhibitors NBQX or GYKI-52466, the response delay in glutamatergic neurons was significantly prolonged. This confirms that CP-KARs on GABAergic neurons are responsible for the delayed excitation of glutamatergic neurons. In hippocampal slices from two-month-old rats, depolarization with 50 mM KCl revealed two distinct neuronal populations based on their calcium dynamics: a majority group (presumably glutamatergic) exhibited fluctuating Ca²⁺ signals, while a minority (presumably GABAergic) showed a steady, advancing increase in [Ca²⁺]i. This distinction was reinforced by the application of domoic acid. The “advancing-response” neurons reacted to domoic acid with a similar prompt increase, whereas the “fluctuating-response” neurons displayed an even more delayed and fluctuating reaction (80 s delay). Therefore, we identify a subgroup of hippocampal neurons—in both slices and cultures—that respond to depolarization and domoic acid with an early [Ca²⁺]_i signal. Consistent with our data from cultures, we conclude these early-responding neurons are GABAergic. Their early GABA release directly explains the delayed Ca²⁺ response observed in glutamatergic neurons. We propose that this proactive mechanism, mediated by CP-KARs on GABAergic neurons, is a primary means of protecting the network from hyperexcitation. Furthermore, the activity of these CP-KAR-expressing neurons is itself regulated by GABAergic neurons containing CP-AMPARs. Full article

Background/Objectives: Empagliflozin (EMPA) was repurposed for Alzheimer’s disease (AD) treatment via buccal delivery, exploiting novel nanofibers (NFs) integrating chitosan (Cs), silk fibroin (Fb), and poly(lactic acid) (PLA). Methods: EMPA-loaded Cs/Fb/PLA NFs were electrospun in different formulations to optimize the formulation parameters. The optimized formulation was then investigated for its enhanced in vivo effect. Results: Optimized nanofiber diameters ranged from 459 ± 173 to 668 ± 148 nm, possessing bead-free morphology confirmed by SEM and satisfactory mechanical properties. EMPA was successfully well-dispersed in the polymer matrix as evidenced by FTIR, XRD, and drug content. The optimized NFs displayed a hydrophilic surface (contact angle < 90°), and biphasic drug release with sustained EMPA liberation (84.98% over 24 h). In vivo, buccal EMPA-Cs/Fb/PLA NFs in an AlCl₃-induced AD rat model significantly reduced brain-amyloid-β, phosphorylated tau, IL-1β, and AGER expression by 2.88-, 2.64-, 2.87-, and 2.50-fold, respectively, compared to positive controls, and improved locomotor activity (1.86-fold) and cognitive performance (T-maze) (4.17-fold). Compared to pure EMPA, the nanofiber formulation achieved further reductions in amyloid-β (1.78-fold), p-tau (1.42-fold), IL-1β (1.89-fold), and AGER (1.38-fold), with efficacy comparable to memantine. Histopathological examination revealed preservation of the hippocampal neuronal structure. Conclusions: The findings suggest EMPA-loaded Cs/Fb/PLA NFs as a promising non-invasive, sustained-release buccal delivery platform for AD therapy, offering multimodal neuroprotection through modulation of the Aβ–AGER–p-tau axis. Full article

Background: Epilepsy affects over 50 million people worldwide, and about 30% remain drug-resistant—underscoring the urgent need for new therapies. This study evaluated the neuroprotective effects of anodal transcranial direct current stimulation (tDCS) in PTZ-induced epilepsy at acute and chronic stages in rats. Methods: Sixty male Wistar Albino rats (12 per group) were randomly assigned to five groups: control, acute epilepsy, acute epilepsy+ tDCS, chronic epilepsy, and chronic epilepsy+ tDCS. Behavioral tests—including the open-field, novel-object recognition, and Y-maze—assessed locomotion, recognition, and spatial memory. Hippocampal tissues were analyzed for oxidative stress markers (SOD, MDA), inflammatory cytokines (IL-1β, TNF-α), histopathology, and mechanistic markers of astrocytic and nitric oxide-mediated neuronal damage (GFAP and nNOS immunohistochemistry). Results: PTZ-induced epilepsy resulted in cognitive deficits, increased oxidative stress, neuroinflammation, neuronal degeneration, and astrocytic activation. Specifically, SOD decreased, while MDA, IL-1β, and TNF-α increased; GFAP and nNOS upregulation indicated activation of astrocytes and nitric oxide-mediated neuronal damage. tDCS mitigated these effects by enhancing SOD, reducing MDA, IL-1β, and TNF-α, and modulating the NO/GFAP axis, which corresponded to decreased neuronal degeneration and vascular hyperemia. Behaviorally, tDCS improved recognition memory and partially rescued spatial memory deficits. Conclusions: Anodal tDCS exerts neuroprotective effects in acute and chronic epilepsy by modulating oxidative stress, neuroinflammation, and the astrocytic/nitric oxide pathways, supporting its potential as a non-invasive adjunct therapy for cognitive and cellular protection. Future studies should investigate its effects on hippocampal glutamatergic and GABAergic pathways, as well as calcium homeostasis. Full article

The cannabinoid 1-receptor (CB1R) is found in particularly high levels in the hippocampus (HPC). Increased CB1R density and binding are observed in patients with schizophrenia, and epidemiological studies suggest that regular cannabis use during adolescence is a risk factor for the disease. CB1R was shown to interfere with neuronal network oscillations and to impair sensory gating and memory function. Neuronal oscillations are essential in multiple cognitive functions, and their impairment was documented in neurological and psychiatric diseases. The aim of this study was to investigate how adolescent pre-treatment with the CB1R-selective agonist CP-55940 may lead to abnormalities in theta synchronization in adulthood. Rats were pre-treated with CP-55940 or vehicle during adolescence (daily injections in PND 32–36 or PND 42–46). They were then tested in adulthood (PND over 70) under urethane anesthesia. Hippocampal theta rhythm was elicited by brainstem stimulation at five intensity levels 1 hour before and up to 5 h after injection. We found a significant decrease in elicited theta power after CP-55940 in adult rats, which was aggravated further in rats pre-treated in adolescence with the CB1R agonist. The effect was significantly larger in rats pre-treated during early adolescence (PND 32–36) compared to the group pre-treated during late adolescence (PND 42–46). We conclude that (1) exposure to cannabis during adolescence leads to increased sensitivity to CB1R agonist in adulthood, and (2) early adolescence, a critical period for development of HPC networks generating theta rhythms, is particularly prone to this sensitivity. Full article

Background/Objective: Alzheimer’s disease (AD) is a neurodegenerative condition characterized by oxidative stress, neuroinflammation, amyloidogenesis, and tau-related pathology. This study investigated the macronutrient and phytochemical composition of strawberry (S), lemon (L), and lemon juice-assisted strawberry (S/L) extracts and evaluated their neuroprotective efficacy relative to selenium (Se) in an aluminum chloride (AlCl₃)-induced rat model of AD. Methods: Macronutrients and phenolics were quantified in S, L, and S/L, and the extracts were profiled using high-performance liquid chromatography and electrospray ionization tandem mass-spectrometry. Male Sprague–Dawley rats received AlCl₃ with or without S, L, S/L, or Se, and their cognitive performance was assessed using the Morris water maze, Y-maze, and conditioned avoidance tests. Markers of oxidative status, inflammation, cholinergic function, apoptotic signaling, and Wnt3/β-catenin pathway activity were quantified in the brain tissue, and cortico-hippocampal morphology was examined. Results: The S/L extract showed the highest carbohydrate, protein, and lipid content. The total phenolic content was highest in S/L (60.46 mg gallic acid equivalents/g), followed by L (55.08) and S (44.75), with S/L also being the richest in gallic, ellagic, and chlorogenic acids. S/L attenuated AlCl₃-induced cognitive deficits, restored antioxidant status, suppressed neuroinflammation, improved cholinergic indices, modulated apoptotic signaling, and downregulated amyloidogenic and NLRP3 inflammasome markers, consistent with histological evidence of neuronal preservation. Conclusions: Lemon juice-assisted extraction enhanced the macronutrient and phenolic richness and multitarget neuroprotection of strawberries. S/L co-extracts represent promising functional food–derived adjuvants for AD management and support integrative compositional–mechanistic profiling to optimize natural product–based interventions. Full article

Background/Objectives: Cerebral ischemia and reperfusion injury, induced by bilateral common carotid artery occlusion and reperfusion (BCCAO/R), cause extensive neuronal damage and cognitive impairment. Bouvardia ternifolia (BtD), a plant known for its anti-inflammatory and neuroprotective effects, may offer therapeutic benefits against ischemic injury. This study aimed to evaluate the neuroprotective effects of BtD root extract on neuronal integrity, oxidative stress, and p53 protein expression following global cerebral ischemia in rats. Methods: Adult male Sprague Dawley rats were subjected to the BCCAO/R procedure for 60 min, followed by six days of reperfusion. Experimental groups included BCCAO/R+BtD, BCCAO/R+silymarin (reference control), BCCAO/R+vehicle, and sham controls. Neuronal morphology in the cortex, striatum, hippocampus, and cerebellum was assessed histologically. Oxidative stress markers, including reactive oxygen species (ROS), lipid peroxidation (LPO), reduced glutathione (GSH), and superoxide dismutase (SOD), were measured, along with the expression of p53 protein. Results: Treatment with BtD significantly decreased oxidative stress markers—LPO (82.2%), ROS (88.2%), GSH (66.5%), and SOD (54%)—and reduced p53 expression levels by 75%. Histological evaluation revealed that neurons in the BCCAO/R+BtD and BCCAO/R+silymarin groups maintained normal morphology, characterized by elongated cells and well-defined nuclei. In contrast, the BCCAO/R+vehicle group exhibited marked neuronal damage, including pyknosis, nuclear fragmentation, and interstitial edema, particularly in the hippocampal CA1 and cortical regions. BtD treatment significantly preserved neuronal structure and enhanced antioxidant defenses. Conclusions:Bouvardia ternifolia extract demonstrates neuroprotective potential in cerebral ischemia by maintaining neuronal architecture, reducing oxidative stress, and modulating p53 expression, supporting its therapeutic relevance in ischemia–reperfusion injury. Full article

Febrile seizures (FS) are a common childhood neurological event associated with an increased risk of long-term cognitive and emotional deficits, though the precise mechanisms remain elusive. Using a rat model, we investigated the long-term effects of FS induced on postnatal day 10, assessing outcomes in young adulthood (P45-55). We report region-specific neuronal loss in the hippocampus, more extensive in the ventral segment. Molecular analysis revealed a broad downregulation of genes encoding ionotropic and metabotropic glutamate receptors and excitatory amino acid transporters. These alterations were most severe and persistent in the ventral hippocampus and medial prefrontal cortex. Behaviorally, rats with neonatal FS exhibited a hyperanxious phenotype, characterized by reduced locomotor and exploratory activity and impaired habituation to a novel environment. In contrast, spatial working memory and social behavior remained intact. Our results provide the first comprehensive evidence that neonatal FS trigger long-term, region-specific disruptions of the glutamatergic system within hippocampal–prefrontal circuits. These findings identify vulnerable molecular targets and precise neurobiological mechanisms that may underlie the heightened risk of anxiety-related disorders following early-life FS, suggesting new avenues for therapeutic intervention. Full article

A large body of evidence suggests that flaxseed oil (FSO), one of the richest sources of essential omega-3 fatty acids, has neuroprotective properties. Purinergic signaling plays a crucial role in pathophysiological processes in the nervous system. There is a lack of evidence regarding the effects of FSO on the purinergic system under both physiological and neurotoxic conditions. Here we report the effects of dietary FSO consumption in a rat model of trimethyltin (TMT) intoxication. Exposure to TMT selectively induces hippocampal neuronal damage and glial reactivation associated with oxidative stress and neuroinflammation, causing severe behavioral impairments. When administered orally (1 mL/kg) before and during TMT intoxication (single dose 8 mg/kg, i.p.) to female Wistar rats, FSO effectively prevented the behavioral disturbances induced by TMT. FSO selectively increased CAT-mRNA level in both healthy and TMT-intoxicated animals, while preventing TMT-induced upregulation of Nrf2, NF-κB, and GPx1 without affecting SOD2 or Gsr-mRNA levels. FSO prevented microgliosis, microglial NTPDase1-eN upregulation, and the increase in purinergic receptors involved in microglial reactivity. Pretreatment with FSO in TMT-intoxicated rats maintained the activity and expression of NTPDase1 at control level, while the activity and expression of eN and ADA were increased. FSO upregulated eN, A₁R, A_2BR, A₃R, ADA, and NGF, while downregulating NTPDase1, A_2AR, and ENT1 in TMT-intoxicated rats. This suggests complex modulation of purinergic signaling, particularly the adenosine system. These findings may contribute to a better understanding of the effects of FSO, highlighting the impact of the dietary intake of this oil on the brain. Full article

Diverse neuronal nicotinic acetylcholine receptor (nAChR) subtypes are expressed in hippocampal interneurons. Single-cell analysis of mRNA expression previously revealed prominent co-expression of the α3 and β2 subunits within rat interneurons in the CA1 region. Although the α3 subunit (traditionally expressed together with β4) is usually associated with the peripheral nervous system, its significant co-expression with the β2 subunit in hippocampal interneurons suggests a distinct, potentially novel central nervous system nAChR subtype. We demonstrate that the human α3 and β2 subunits injected into Xenopus laevis oocytes can assemble into at least two functionally distinct subtypes of nAChRs based on different subunit stoichiometries. These subtypes exhibit similar reversal potentials but differ significantly in their desensitization kinetics and acetylcholine (ACh) affinities. The response obtained from a 1:5 α3:β2 mRNA injection ratio shows a higher affinity for ACh and significantly greater desensitization during prolonged ACh application compared to the response obtained from a 5:1 α3:β2 mRNA injection ratio. The identification of distinct functional α3β2 subtypes, characterized by differential desensitization kinetics and ACh affinity, could represent novel targets for the potential development of highly selective cognitive therapeutics for conditions such as Alzheimer’s disease, autism spectrum disorder, and attention deficit hyperactivity disorder, where hippocampal nAChRs are implicated. Full article

Chronic social isolation (CSIS), a known risk factor for the development of major depressive disorders, is associated with hippocampal dysfunction. In rodent models, CSIS produces two phenotypes: CSIS-susceptible, which develop depressive- and anxiety-like behaviors, and CSIS-resilient, which maintain normal behavior despite stress. However, the biological mechanisms underlying resilience to stress remain elusive. Mitochondria, as central regulators of neuronal energy metabolism and redox balance, are potential mediators of stress susceptibility and resilience. This review summarizes comparative proteomic analyses of hippocampal nonsynaptic mitochondria (NSM) and synaptosome-enriched mitochondria from CSIS-susceptible and CSIS-resilient rats along with controls. In NSM of resilient rats relative to susceptible rats, remodeling enhanced energy production, limited reactive oxygen species, stabilized phosphate transport, and promoted removal of damaged components. Compared with controls, these changes optimized energy production, and selectively downregulated oxidative stress-promoting proteins. Conversely, synaptosome-enriched mitochondria from resilient rats showed downregulation of proteins related to synaptic energy metabolism and redox balance relative to CSIS-susceptible rats, but demonstrated upregulation of bioenergetic and antioxidant enzymes, molecular chaperones, and neuroprotective factors compared with controls. These proteomic signatures both highlight mitochondrial adaptability in promoting stress resilience and identify mitochondria as promising targets for the development of novel antidepressant therapies. Full article

Background: Traumatic brain injury (TBI) disrupts hippocampal neurogenesis and dendritic structure. Objective: The objective was to assess whether fractal and multifractal analyses can sensitively quantify dendritic complexity changes in newly formed dentate gyrus neurons following TBI and hyperbaric oxygen therapy (HBO). Methods: Adult rats underwent sham surgery with HBO (SHBO), lesion-induced TBI (L), or lesion-induced TBI with HBO (LHBO). Dendritic morphology was evaluated using Euclidean, monofractal, and multifractal metrics. Results: Lesioned animals exhibited marked reductions in dendritic complexity across multiple metrics compared to both HBO-treated groups. HBO treatment partially restored complexity to near-sham levels, with multifractal spectra revealing subtle structural differences between SHBO and LHBO. Conclusions: Fractal and multifractal analyses provide sensitive tools for detecting TBI-induced morphological changes and therapeutic effects. Our findings support HBO as a potential neuroprotective intervention and demonstrate the utility of mathematical modeling in evaluating therapeutic efficacy in neurotrauma. Full article

Background/Objectives: Radiotherapy can cause severe and irreversible brain damage, including cognitive impairment, increased dementia risk, debilitating depression, and other neuropsychiatric disorders. Current radioprotective drugs face limitations, such as single-target inefficacy or manufacturing hurdles. Isoliquiritigenin (ISL), a natural flavonoid derived from licorice root, exhibits broad bioactivities. It exhibits anti-inflammatory, anti-cancer, immunoregulatory, hepatoprotective, and cardioprotective activities. This study aimed to elucidate ISL’s neuronal radiation mitigation effects and key targets. Methods: In vitro and in vivo models of radiation-induced neuronal injury were established. ISL’s bioactivities were evaluated through cellular cytotoxicity assays, LDH release, ROS, ATP, glutamate, and GSH levels. In vivo, ISL’s radiation mitigation effect was evaluated with sucrose preference test, IL-β level, histopathological analysis, and Golgi-Cox staining analysis. Proteomics, pathway enrichment, and ensemble models (four machine learning models, weighted gene co-expression network, protein–protein interaction) identified core targets. Molecular docking and dynamic simulations validated ISL’s binding stability with key targets. Results: ISL attenuated radiation-induced cellular cytotoxicity, reduced LDH/ROS, restored ATP, elevated GSH, and mitigated glutamate accumulation. In rats, ISL alleviated anhedonia-like phenotypes and hippocampal synaptic loss. ISL also significantly suppressed radiation-induced neuroinflammation, as evidenced by reduced levels of the pro-inflammatory cytokine IL-1β. Proteomic analysis revealed that ISL’s main protective pathways included the synaptic vesicle cycle, glutamatergic synapse, MAPK signaling pathway, SNARE interactions in vesicular transport, insulin signaling pathway, and insulin secretion. Grm8, Grik3, and Grin3a were identified as key targets using the integrated models. The expression of these targets was upregulated post-radiation and restored by ISL. Molecular docking and dynamic simulations indicated that ISL showed stable binding to these receptors compared to native ligands. Conclusions: ISL demonstrates multi-scale radiation mitigation activities in vitro and in vivo by modulating synaptic and inflammatory pathways, with glutamate receptors as core targets. This work nominates ISL as an important natural product for mitigating radiotherapy-induced neural damage. Full article