Golgi-Cox Staining Research Articles

Mechanism of Gastrodin against neurotoxicity based on network pharmacology, molecular docking and experimental verification

BackgroundDisorders of glutamate metabolism and excessive release participat in multiple neuronal pathologies including ischemic stroke (IS), Alzheimer's disease (AD), or Parkinson's disease (PD). Recently, herbal medicines have been widely used and have shown satisfactory results in the treatment of neurological disorders. Gastrodin is a traditional Chinese medicine (TCM) used for the treatment of nerve injuries, spinal cord injuries, and some central nervous system diseases as well. This research examines the neuroprotective effects of Gastrodin against glutamate-induced neurotoxicity in neuronal cells. MethodsThe HERB database was used to explore the active ingredients and target genes of Gastrodia Elata. The STRING database and Cytoscape software were used to screen and construct the Protein-Protein Interaction (PPI). Furthermore, we used molecular docking to predict the potential targets of Gastrodin. The effects of Gastrodin were revealed by western blot, calcium imaging, membrane clamp, CCK8 and flow cytometry. Neuronal oxidative stress and damage were assessed by measuring malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity. Neuronal morphology was examined using Golgi-Cox staining. Finally, animal behavior was examined using novel object recognition and fear conditioning tests. ResultsWe have obtained 22 components such as TM10, TM17, TM25 (Gastrodin), and 281 targets such as AKT, EGFR, and CDK1 through network pharmacology. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed these genes were significantly enriched in protein phosphorylation, protein serine/threonine/tyrosine kinase activity, apoptosis and HIF-1 signaling pathways, etc. A higher affinity between Gastrodin and AKT was revealed by PPI analysis and molecular docking. Further, Gastrodin significantly inhibited Ca2+ influxes and excitatory synaptic transmission in cortical neurons. In addition, Gastrodin effectively alleviated neuron apoptosis, oxidative stress and damage. ConclusionGastrodin has neuroprotective effects against glutamate-induced neurotoxicity.

WuYou decoction effectively reduces neuronal damage, synaptic dysfunction, and Aβ production in rats exposed to chronic sleep deprivation by modulating the Aβ-related enzymes and SIRT1/Nrf2/NF-κB pathway

Ethnopharmacological relevanceChronic sleep deprivation (CSD) can result in neuronal damage, synaptic dysfunction, Aβ production, neuroinflammation, and ultimately cognitive deterioration. WuYou Decoction (WYD), a contemporary prescription, has shown promise in enhancing sleep quality and cognitive performance in individuals with insomnia. However, the specific molecular mechanisms responsible for the neuroprotective effects of WYD on CSD remain incompletely understood. Aim of the studyThis study aimed to investigate the neuroprotective effects of WYD on the CSD model and its molecular mechanism. Materials and methodsUHPLC-MS/MS analysis was utilized to analyze the active ingredients of WYD extract. The study employed the multi-platform water environment method to establish the CSD model in rats. Subsequent to treatment with varying doses of WYD in CSD rats, cognitive function and pathological alterations in hippocampus and cortex, including neuronal damage, synaptic dysfunction, Aβ production, and neuroinflammation, were evaluated through a combination of Morris Water Maze test, HE staining, Nissl staining, Golgi-Cox staining, Transmission electron microscope, ELISA, Immunohistochemistry staining, Immunofluorescence staining and Western blot. ResultsUHPLC-MS/MS analysis revealed a total of 99 active ingredients were identified from the WYD extract. The administration of WYD exhibited a mitigation of cognitive decline in the model of CSD, as evidenced by increased neuron count in the hippocampus and cortex, and improved density and length of dendritic spines in these brain regions. Furthermore, WYD was found to suppress the Aβ production, and inhibit the expression of BACE1, PS1, GFAP, IBA1, IL-1β, IL-6, TNF-α, phosphorylated IκBα (Ser32) and phosphorylated NF-κB p65 (Ser536) in the hippocampus and cortex, while also increasing the levels of PSD95, SYN1, ADAM10, IDE, SIRT1 and Nrf2. ConclusionsWYD exhibits neuroprotective properties in CSD, potentially through modulation of the Aβ-related enzymes and SIRT1/Nrf2/NF-κB pathway.

Zebrafish as a model organism to study sporadic Alzheimer's disease: Behavioural, biochemical and histological validation

Alzheimer's disease (AD) is a global burden to the healthcare system with no viable treatment options till date. Rodents and primates have been extensively used as models for understanding AD pathogenesis and identifying therapeutic targets. However, the focus is now shifting towards developing alternate models. Zebrafish is emerging as a preferred model for neurodegenerative conditions because of its simple nervous system, highly conserved genome and short duration required to model disease condition. The present study is aimed to develop streptozotocin (STZ)-induced model of sporadic AD (sAD) in zebrafish. STZ was administered to adult zebrafish (4–6 mo) at different doses (1 to 50 mg/kg body weight, intracerebroventricularly). Kaplan-Meier survival analysis revealed time and dose dependent mortality in the zebrafish administered with STZ. Based on survival analysis, 1 to 10 mg/kg body weight of STZ was selected for behavioural, molecular and histological studies. STZ administered fish had anxiety and stress-like behaviour in novel tank and light/dark preference tests. STZ-induced cognitive and memory deficits assessed using novel object recognition and spatial alternation tests. Further, expression of markers of amyloidogenic pathway (appa and bace1) were increased in terms of mRNA and protein levels in a time and dose dependent manner following STZ administration. However, expression of non-amyloidogenic pathway mediator (adam10) was reduced at both mRNA and protein level. Histological assessment using hematoxylin and eosin, and Nissl stain revealed loss of neurons in STZ administered fish. The ratio of phosphor-tauser396/total-tau was increased in STZ administered fish. Based on these findings, 5 mg/kg body weight of STZ was found to be most appropriate dose to exhibit sAD phenotype. Mass spectrometric analysis confirmed the presence of amyloid beta oligomers in brains of STZ administered fish. Transmission electron microscopy also showed the presence of higher order insoluble amyloid fibrils with twists. Immunohistochemical analysis revealed amyloid beta deposits in brain of STZ administered fish. Golgi-cox staining indicated decreased number of dendrites, whereas microglia had increased density, span ratio, soma area and lacunarity. The results of the present study demonstrate presence of AD hallmarks and phenotype in zebrafish 7 days post STZ administration (5 mg/kg). The study validates the potential of STZ-induced sAD in zebrafish as a reliable model for studying pathophysiology and rapid screening of therapeutic molecules against sAD.

Neonatal Cannabidiol Exposure Impairs Spatial Memory and Disrupts Neuronal Dendritic Morphology in Young Adult Rats.

Introduction: Early life is a sensitive period for brain development. Perinatal exposure to cannabis is increasingly linked to disruption of neurodevelopment; however, research on the effects of cannabidiol (CBD) on the developing brain is scarce. In this study, we aim to study the developmental effects of neonatal CBD exposure on behavior and dendritic architecture in young adult rats. Materials and Methods: Male and female neonatal Sprague Dawley rats were treated with CBD (50 mg/kg) intraperitoneally on postnatal day (PND) 1, 3, and 5 and evaluated for behavioral and neuronal morphological changes during early adulthood. Rats were subjected to a series of behavioral tasks to evaluate long-term effects of neonatal CBD exposure, including the Barnes maze, open field, and elevated plus maze paradigms to assess spatial memory and anxiety-like behavior. Following behavioral evaluation, animals were sacrificed, and neuronal morphology of the cortex and hippocampus was assessed using Golgi-Cox (GC) staining. Results: Rats treated with CBD displayed a sexually dimorphic response in spatial memory, with CBD-treated females developing a deficit but not males. CBD did not elicit alterations in anxiety-like behavior in either sex. Neonatal CBD caused an overall decrease in dendritic length and spine density (apical and basal) in cortical and hippocampal neurons in both sexes. Sholl analysis also revealed a decrease in dendritic intersections in the cortex and hippocampus, indicating reduced dendritic arborization. Conclusions: This study provides evidence that neonatal CBD exposure perturbs normal brain development and leads to lasting alterations in spatial memory and neuronal dendrite morphology in early adulthood, with sex-dependent sensitivity.

LT-102, an AMPA receptor potentiator, alleviates depression-like behavior and synaptic plasticity impairments in prefrontal cortex induced by sleep deprivation

BackgroundSleep loss is closely related to the onset and development of depression, and the mechanisms involved may include impaired synaptic plasticity. Considering the important role of glutamate α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors (AMPARs) in synaptic plasticity as well as depression, we introduce LT-102, a novel AMPARs potentiator, to evaluate the potential of LT-102 in treating sleep deprivation-induced depression-like behaviors. MethodsWe conducted a comprehensive behavioral assessment to evaluate the effects of LT-102 on depression-like symptoms in male C57BL/6J mice. This assessment included the open field test to measure general locomotor activity and anxiety-like behavior, the forced swimming test and tail suspension test to assess despair behaviors indicative of depressive states, and the sucrose preference test to quantify anhedonia, a core symptom of depression. Furthermore, to explore the impact of LT-102 on synaptic plasticity, we utilized a combination of Western blot analysis to detect protein expression levels, Golgi-Cox staining to visualize neuronal morphology, and immunofluorescence to examine the localization of synaptic proteins. Additionally, we utilized primary cortical neurons to delineate the signaling pathway modulated by LT-102. ResultsTreatment with LT-102 significantly reduced depression-like behaviors associated with sleep deprivation. Quantitative Western blot (WB) analysis revealed a significant increase in GluA1 phosphorylation in the prefrontal cortex (PFC), triggering the Ca2+/calmodulin-dependent protein kinase II/cAMP response element-binding protein/brain-derived neurotrophic factor (CaMKII/CREB/BDNF) and forkhead box protein P2/postsynaptic density protein 95 (FoxP2/PSD95) signaling pathways. Immunofluorescence imaging confirmed that LT-102 treatment increased spine density and co-labeling of PSD95 and vesicular glutamate transporter 1 (VGLUT1) in the PFC, reversing the reductions typically observed following sleep deprivation. Golgi staining further validated these results, showing a substantial increase in neuronal dendritic spine density in sleep-deprived mice treated with LT-102. Mechanistically, application of LT-102 to primary cortical neurons, resulted in elevated levels of phosphorylated AKT (p-AKT) and phosphorylated glycogen synthase kinase-3 beta (p-GSK3β), key downstream molecules in the BDNF signaling pathway, which in turn upregulated FoxP2 and PSD95 expression. LimitationsIn our study, we chose to exclusively use male mice to eliminate potential influences of the estrous cycle on behavior and physiology. As there is no widely accepted positive drug control for sleep deprivation studies, we did not include one in our research. ConclusionOur results suggest that LT-102 is a promising therapeutic agent for counteracting depression-like behaviors and synaptic plasticity deficits induced by sleep deprivation, primarily through the activation of CaMKII/CREB/BDNF and AKT/GSK3β/FoxP2/PSD95 signaling pathways.

Protective effect of crocin-loaded nanoparticles in rats following epileptic seizures: Biochemical, behavioral and histopathological outcomes

Epilepsy is a condition resulting from complex interactions involving excessive neuronal electrical activity and oxidative stress, which can lead to chronic neurological conditions. This study evaluates crocin encapsulated in SLNC for neuroprotective and countering pentylenetetrazole (PTZ) -induced oxidative damage. The rats were pre-treated with SLNC and FC (25, 50 mg/kg/day; P.O.) for 28 days before being induced with PTZ. Various standard tests were conducted to assess their behavioral functions, such as Y-maze, Open field test (OFT), and elevated plus maze (EPM) tests. ELISA measured brain tissue catalase activity (CAT) and nitric oxide status (NO). The expression of Nuclear factor kappa B (NF-κB) and the number of dendrite spines were examined through Immunohistochemical and Golgi–Cox staining, respectively. The Pretreating rats with SLNC plus PTZ significantly boosted memory and reduced anxiety levels in Y-maze, OFT, and EPM tests. In addition, it decreased NO levels and increased CAT levels. SLNC also showed a significant decrease in NF-κB expression and an increase in neurons and the number of spines. The positive effects of SLNC in improving memory and learning deficits after PTZ injection can be attributed to its anti-inflammatory and anti-oxidative effects.

Neurophysiological, structural, and molecular alterations in the prefrontal and auditory cortices following noise-induced hearing loss

It is well established that hearing loss can lead to widespread plasticity within the central auditory pathway, which is thought to contribute to the pathophysiology of audiological conditions such as tinnitus and hyperacusis. Emerging evidence suggests that hearing loss can also result in plasticity within brain regions involved in higher-level cognitive functioning like the prefrontal cortex; findings which may underlie the association between hearing loss and cognitive impairment documented in epidemiological studies. Using the 40-Hz auditory steady state response to assess sound-evoked gamma oscillations, we previously showed that noise-induced hearing loss results in impaired gamma phase coherence within the prefrontal but not the auditory cortex. To determine whether region-specific structural or molecular changes accompany this differential plasticity following hearing loss, in the present study we utilized Golgi-Cox staining to assess dendritic organization and synaptic density, as well as Western blotting to measure changes in synaptic signaling proteins in these cortical regions. We show that following noise exposure, impaired gamma phase coherence within the prefrontal cortex is accompanied by alterations in pyramidal cell dendritic morphology and decreased expression of proteins involved in GABAergic (GAD65) and glutamatergic (NR2B) neurotransmission; findings that were not observed in the auditory cortex, where gamma phase coherence remained unchanged post-noise exposure. In contrast to the noise-induced effects we observed in the prefrontal cortex, plasticity in the auditory cortex was characterized by an increase in NR2B suggesting increased excitability, as well as increases in the synaptic proteins PSD95 and synaptophysin within the auditory cortex. Overall, our results highlight the disparate effect of noise-induced hearing loss on auditory and higher-level brain regions as well as potential structural and molecular mechanisms by which hearing loss may contribute to impaired cognitive and sensory functions mediated by the prefrontal and auditory cortices.

Targeting astrocytic TDAG8 with delayed CO2 postconditioning improves functional outcomes after controlled cortical impact injury in mice

T-cell death-associated gene 8 (TDAG8), a G-protein-coupled receptor sensing physiological or weak acids, regulates inflammatory responses. However, its role in traumatic brain injury (TBI) remains unknown. Our recent study showed that delayed CO2 postconditioning (DCPC) has neuroreparative effects after TBI. We hypothesized that activating astrocytic TDAG8 is a key mechanism for DCPC. WT and TDAG8−/− mice received DCPC daily by transiently inhaling 10% CO2 after controlled cortical impact (CCI). HBAAV2/9-GFAP-m-TDAG8-3xflag-EGFP was used to overexpress TDAG8 in astrocytes. The beam walking test, mNSS, immunofluorescence and Golgi-Cox staining were used to evaluate motor function, glial activation and dendritic plasticity. DCPC significantly improved motor function; increased total dendritic length, neuronal complexity and spine density; inhibited overactivation of astrocytes and microglia; and promoted the expression of astrocytic brain-derived neurotrophic factor in WT but not TDAG8−/− mice. Overexpressing TDAG8 in astrocytes surrounding the lesion in TDAG8−/− mice restored the beneficial effects of DCPC. Although the effects of DCPC on Days 14–28 were much weaker than those of DCPC on Days 3–28 in WT mice, these effects were further enhanced by overexpressing astrocytic TDAG8. Astrocytic TDAG8 is a key target of DCPC for TBI rehabilitation. Its overexpression is a strategy that broadens the therapeutic window and enhances the effects of DCPC.

Comparative utility of MRI and EEG for early detection of cortical dysmaturation after postnatal systemic inflammation in the neonatal rat

BackgroundExposure to postnatal systemic inflammation is associated with increased risk of brain injury in preterm infants, leading to impaired maturation of the cerebral cortex and adverse neurodevelopmental outcomes. However, the optimal method for identifying cortical dysmaturation is unclear. Herein, we compared the utility of electroencephalography (EEG), diffusion tensor imaging (DTI), and neurite orientation dispersion and density imaging (NODDI) at different recovery times after systemic inflammation in newborn rats. MethodsSprague Dawley rat pups of both sexes received single-daily lipopolysaccharide (LPS; 0.3 mg/kg i.p.; n = 51) or saline (n = 55) injections on postnatal days (P)1, 2, and 3. A subset of these animals were implanted with EEG electrodes. Cortical EEG was recorded for 30 min from unanesthetized, unrestrained pups at P7, P14, and P21, and in separate groups, brain tissues were collected at these ages for ex-vivo MRI analysis (9.4 T) and Golgi–Cox staining (to assess neuronal morphology) in the motor cortex. ResultsPostnatal inflammation was associated with reduced cortical pyramidal neuron arborization from P7, P14, and P21. These changes were associated with dysmature EEG features (e.g., persistence of delta waveforms, higher EEG amplitude, reduced spectral edge frequency) at P7 and P14, and higher EEG power in the theta and alpha ranges at P21. By contrast, there were no changes in cortical DTI or NODDI in LPS rats at P7 or P14, while there was an increase in cortical fractional anisotropy (FA) and decrease in orientation dispersion index (ODI) at P21. ConclusionsEEG may be useful for identifying the early evolution of impaired cortical development after early life postnatal systemic inflammation, while DTI and NODDI seem to be more suited to assessing established cortical changes.

Neonatal Diazepam Exposure Decreases Dendritic Arborization and Spine Density of Cortical Pyramidal Neurons in Rats.

Benzodiazepines are extensively utilized in pediatric anesthesia and critical care for their anxiolytic and sedative properties. However, preclinical studies indicate that neonatal exposure to GABAergic drugs, including benzodiazepines, leads to long-term cognitive deficits, potentially mediated by altered GABAergic signaling during brain development. This preclinical study investigated the impact of early-life diazepam exposure on cortical neuronal morphology, specifically exploring dendritic arborization and spine density, crucial factors in synaptogenesis. Male and female Sprague Dawley rat pups were exposed to a single neonatal dose of diazepam (30mg/kg) or vehicle on postnatal day (PND) 7. Golgi-Cox staining was used to assess cortical pyramidal neuron development at 4 developmental stages: neonatal (PND8), infantile (PND15), juvenile (PND30), and adolescence (PND42). Animals were randomized equally to 4 groups: male-vehicle, male-diazepam, female-vehicle, and female-diazepam. Neuronal morphology was evaluated after reconstruction in neurolucida, and dendritic spine density was analyzed through high-power photomicrographs using ImageJ. Diazepam exposure resulted in decreased dendritic complexity in both sexes, with reduced arborization and spine density observed in cortical pyramidal neurons. Significant differences were found at each developmental stage, indicating a persistent impact. Dendritic length increased with age but was attenuated by diazepam exposure. Branching length analysis revealed decreased complexity after diazepam treatment. Spine density at PND42 was significantly reduced in both apical and basal dendrites after diazepam exposure. Neonatal diazepam exposure adversely affected cortical pyramidal neuron development, leading to persistent alterations in dendritic arborization and spine density. These structural changes suggest potential risks associated with early-life diazepam exposure. Further research is needed to unravel the functional consequences of these anatomic alterations.

Hippocampal Crhr1 conditional gene knockout ameliorated the depression-like behavior and pathological damage in male offspring mice caused by chronic stress during pregnancy

Numerous studies have demonstrated that chronic stress during pregnancy (CSDP) can induce depression and hippocampal damage in offspring. It has also been observed that high levels of corticotropin-releasing hormone (CRH) can damage hippocampal neurons, and intraperitoneal injection of a corticotropin releasing hormone receptor 1 (CRHR1) antagonist decreases depression-like behavior and hippocampal neuronal damage in a mouse depression model. However, whether CSDP causes hippocampal damage and depression in offspring through the interaction of CRH and hippocampal CRHR1 remains unknown and warrants further investigation. Therefore, hippocampal Crhr1 conditional gene knockout mice and C57/BL6J mice were used to study these questions. Depression-related indexs in male offspring mice were examined using the forced swim test (FST), sucrose preference test (SPT), tail suspension test (TST) and open field test (OFT). Serum CRH levels were measured by enzyme-linked immunosorbent assay (ELISA). Golgi-Cox staining was used to examine the morphological changes of hippocampal neuronal dendrites. Neuronal apoptosis in the hippocampal CA3 regions was detected by terminal deoxynucleotidy transferase dUTP nick end labeling (TUNEL) staining. The levels of mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR) and protein kinase B (AKT) proteins were measured by Western blot analysis. This study showed that CSDP induces depression-like behavior, hippocampal neuronal dendrite damage and apoptosis in male offspring mice. Conditional gene knockout of hippocampal Crhr1 in mice reduced CSDP-induced depression-like behavior, hippocampal neuronal dendrite damage and apoptosis in male offspring, and counteracted the CSDP-induced decreased expression of p-Akt and mTOR activity in male offspring hippocampus. These findings demonstrated that CSDP might inhibit the Akt/mTOR pathway by increasing the levels of CRH, leading to increased CRH-mediated activation of hippocampal CRHR1, thereby inducing synaptic impairment and apoptosis in hippocampal neurons, which in turn leads to depression-like behavior in offspring.

Targeting Neuronal GPR65 With Delayed BTB09089 Treatment Improves Neurorehabilitation Following Ischemic Stroke.

GPR65 (G protein-coupled receptor 65) can sense extracellular acidic environment to regulate pathophysiological processes. Pretreatment with the GPR65 agonist BTB09089 has been proven to produce neuroprotection in acute ischemic stroke. However, whether delayed BTB09089 treatment and neuronal GPR65 activation promote neurorestoration remains unknown. Ischemic stroke was induced in wild-type (WT) or GPR65 knockout (GPR65-/-) mice by photothrombotic ischemia. Male mice were injected intraperitoneally with BTB09089 every other day at days 3, 7, or 14 poststroke. AAV-Syn-GPR65 (adenoassociated virus-synapsin-GPR65) was utilized to overexpress GPR65 in the peri-infarct cortical neurons of GPR65-/- and WT mice. Motor function was monitored by grid-walk and cylinder tests. The neurorestorative effects of BTB09089 were observed by immunohistochemistry, Golgi-Cox staining, and Western blotting. BTB09089 significantly promoted motor outcomes in WT but not in GPR65-/- mice, even when BTB09089 was delayed for 3 to 7 days. BTB09089 inhibited the activation of microglia and glial scar progression in WT but not in GPR65-/- mice. Meanwhile, BTB09089 reduced the decrease in neuronal density in WT mice, but this benefit was abolished in GPR65-/- mice and reemerged by overexpressing GPR65 in peri-infarct cortical neurons. Furthermore, BTB09089 increased the GAP43 (growth-associated protein-43) and synaptophysin puncta density, dendritic spine density, dendritic branch length, and dendritic complexity by overexpressing GPR65 in the peri-infarct cortical neurons of GPR65-/- mice, which was accompanied by increased levels of p-CREB (phosphorylated cAMP-responsive element-binding protein). In addition, the therapeutic window of BTB09089 was extended to day 14 by overexpressing GPR65 in the peri-infarct cortical neurons of WT mice. Our findings indicated that delayed BTB09089 treatment improved neurological functional recovery and brain tissue repair poststroke through activating neuronal GRP65. GPR65 overexpression may be a potential strategy to expand the therapeutic time window of GPR65 agonists for neurorehabilitation after ischemic stroke.

Enhancing Rab7 Activity by Inhibiting TBC1D5 Expression Improves Mitophagy in Alzheimer's Disease Models.

Mitochondrial dysfunction exists in Alzheimer's disease (AD) brain, and damaged mitochondria need to be removed by mitophagy. Small GTPase Rab7 regulates the fusion of mitochondria and lysosome, while TBC1D5 inhibits Rab7 activation. However, it is not clear whether the regulation of Rab7 activity by TBC1D5 can improve mitophagy and inhibit AD progression. To investigate the role of TBC1D5 in mitophagy and its regulatory mechanism for Rab7, and whether activation of mitophagy can inhibit the progression of AD. Mitophagy was determined by western blot and immunofluorescence. The morphology and quantity of mitochondria were tracked by TEM. pCMV-Mito-AT1.03 was employed to detect the cellular ATP. Amyloid-β secreted by AD cells was detected by ELISA. Co-immunoprecipitation was used to investigate the binding partner of the target protein. Golgi-cox staining was applied to observe neuronal morphology of mice. The Morris water maze test and Y-maze were performed to assess spatial learning and memory, and the open field test was measured to evaluate motor function and anxiety-like phenotype of experimental animals. Mitochondrial morphology was impaired in AD models, and TBC1D5 was highly expressed. Knocking down TBC1D5 increased the expression of active Rab7, promoted the fusion of lysosome and autophagosome, thus improving mitophagy, and improved the morphology of hippocampal neurons and the impaired behavior in AD mice. Knocking down TBC1D5 increased Rab7 activity and promoted the fusion of autophagosome and lysosome. Our study provided insights into the mechanisms that bring new possibilities for AD therapy targeting mitophagy.

FMOD Alleviates Depression-Like Behaviors by Targeting the PI3K/AKT/mTOR Signaling After Traumatic Brain Injury

Depression frequently occurs following traumatic brain injury (TBI). However, the role of Fibromodulin (FMOD) in TBI-related depression is not yet clear. Previous studies have suggested FMOD as a potential key factor in TBI, yet its association with depression post-TBI and underlying mechanisms are not well understood. Serum levels of FMOD were measured in patients with traumatic brain injury using qPCR. The severity of depression was assessed using the self-depression scale (SDS). Neurological function, depressive state, and cognitive function in mice were assessed using the modified Neurological Severity Score (mNSS), forced swimming test (FST), tail suspension test (TST), Sucrose Preference Test (SPT), and morris water maze (MWM). The morphological features of mouse hippocampal synapses and neuronal dendritic spines were revealed through immunofluorescence, transmission electron microscopy, and Golgi-Cox staining. The protein expression levels of FMOD, MAP2, SYP, and PSD95, as well as the phosphorylation levels of the PI3K/AKT/mTOR signaling pathway, were detected through Western blotting. FMOD levels were decreased in TBI patients’ serum. Overexpression of FMOD preserved neuronal function and alleviated depression-like behaviour, increased synaptic protein expression, and induced ultrastructural changes in hippocampal neurons. The increased phosphorylation of PI3K, AKT, and mTOR suggested the involvement of the PI3K/AKT/mTOR signaling pathway in FMOD’s protective effects. FMOD exhibits potential as a therapeutic target for depression related to TBI, with its protective effects potentially mediated through the PI3K/AKT/mTOR signaling pathway.

Astragaloside IV mediates radiation-induced neuronal damage through activation of BDNF-TrkB signaling

BackgroundElectromagnetic radiation is relevant to human life, and radiation can trigger neurodegenerative diseases by altering the function of the central nervous system through oxidative stress, mitochondrial dysfunction, and protein degradation. Astragaloside IV (AS-IV) is anti-oxidative, anti-apoptotic, activates the BDNF-TrkB pathway and enhances synaptic plasticity in radiated mice, which can exert its neuroprotection. However, the exact molecular mechanisms are still unclear. PurposeThis study investigated whether AS-IV could play a neuroprotective role by regulating BDNF-TrkB pathway in radiation damage and its underlying molecular mechanisms. MethodsTransgenic mice (Thy1-YFP line H) were injected with AS-IV (40 mg/kg/day body weight) by intraperitoneal injection daily for 4 weeks, followed by X-rays. PC12 cells and primary cortical neurons were also exposed to UVA after 24 h of AS-IV treatment (25 μg/ml and 50 μg/ml) in vitro. The impact of radiation on learning and cognitive functions was visualized in the Morris water maze assay. Subsequently, Immunofluorescence and Golgi-Cox staining analyses were utilized to investigate the structural damage of neuronal dendrites and the density of dendritic spines. Transmission electron microscopy was performed to examine how the radiation affected the ultrastructure of neurons. Finally, western blotting analysis and Quantitative RT-PCR were used to evaluate the expression levels and locations of proteins in vitro and in vivo. ResultsRadiation induced BDNF-TrkB signaling dysregulation and decreased the levels of neuron-related functional genes (Ngf, Bdnf, Gap-43, Ras, Psd-95, Arc, Creb, c-Fos), PSD-95 and F-actin, which subsequently led to damage of neuronal ultrastructure and dendrites, loss of dendritic spines, and decreased dendritic complexity index, contributing to spatial learning and memory deficits. These abnormalities were prevented by AS-IV treatment. In addition, TrkB receptor antagonists antagonized these neuroprotective actions of AS-IV. 7,8-dihydroxyflavone and AS-IV had neuroprotective effects after radiation. ConclusionAS-IV inhibits morphological damage of neurons and cognitive dysfunction in mice after radiation exposure, resulting in a neuroprotective effect, which were mediated by activating the BDNF-TrkB pathway.

Melatonin mitigates cisplatin-induced cognitive impairment in rats and improves hippocampal dendritic spine density.

Cisplatin-induced cognitive impairment (chemobrain) affects a considerable percentage of cancer patients and has no established pharmacological treatment. Chemobrain can be associated with neuroinflammation and oxidative stress. Melatonin, a pineal hormone, is known to have antioxidant, anti-inflammatory and neuroprotective potential. In this study, we investigated cisplatin-induced cognitive impairment in rats and whether melatonin can improve or reverse this impairment. Behavioral testing involved measuring working memory using the novel location recognition test (NLRT) under conditions of cisplatin or cisplatin + melatonin treatment, followed by the collection of rats' brains. The brains were subsequently stained with Golgi-Cox stain and then the hippocampus area CA3 of each one was examined, and dendritic spine density was calculated. Treatment with cisplatin resulted in deficits in the rats' performance in the NLRT (P < 0.05). These deficits were prevented by the coadministration of melatonin (P < 0.05). Cisplatin also reduced the density of dendritic spines in the hippocampus (P < 0.0001), specifically CA3 area, while the coadministration of melatonin significantly reversed this reduction (P < 0.001). This study showed that melatonin can ameliorate cisplatin-induced spatial memory deficits and dendritic spines density abnormalities in rats. Given that melatonin is a safe and wildly used supplement, it is feasible to explore its use as a palliative intervention in cancer treatment.

Genetic deletion of zinc transporter ZnT3 induces progressive cognitive deficits in mice by impairing dendritic spine plasticity and glucose metabolism.

Zinc transporter 3 (ZnT3) is abundantly expressed in the brain, residing in synaptic vesicles, where it plays important roles in controlling the luminal zinc levels. In this study, we found that ZnT3 knockout in mice decreased zinc levels in the hippocampus and cortex, and was associated with progressive cognitive impairments, assessed at 2, 6, and 9-month of age. The results of Golgi-Cox staining demonstrated that ZnT3 deficiency was associated with an increase in dendritic complexity and a decrease in the density of mature dendritic spines, indicating potential synaptic plasticity deficit. Since ZnT3 deficiency was previously linked to glucose metabolism abnormalities, we tested the expression levels of genes related to insulin signaling pathway in the hippocampus and cortex. We found that the Expression of glucose transporters, GLUT3, GLUT4, and the insulin receptor in the whole tissue and synaptosome fraction of the hippocampus of the ZnT3 knockout mice were significantly reduced, as compared to wild-type controls. Expression of AKT (A serine/threonine protein kinase) and insulin-induced AKT phosphorylation was also reduced in the hippocampus of ZnT3 knockout mice. We hypothesize that the ZnT3 deficiency and reduced brain zinc levels may cause cognitive impairment by negatively affecting glycose metabolism via decreased expression of key components of insulin signaling, as well as via changes in synaptic plasticity. These finding may provide new therapeutic target for treatments of neurodegenerative disorders.

Visual EMDR stimulation mitigates acute varied stress effects on morphology of hippocampal neurons in male Wistar rats.

Stress is a pervasive health concern known to induce physiological changes, particularly impacting the vulnerable hippocampus and the morphological integrity of its main residing cells, the hippocampal neurons. Eye Movement Desensitization and Reprocessing (EMDR), initially developed to alleviate emotional distress, has emerged as a potential therapeutic/preventive intervention for other stress-related disorders. This study aimed to investigate the impact of Acute Variable Stress (AVS) on hippocampal neurons and the potential protective effects of EMDR. Rats were exposed to diverse stressors for 7 days, followed by dendritic morphology assessment of hippocampal neurons using Golgi-Cox staining. AVS resulted in significant dendritic atrophy, evidenced by reduced dendritic branches and length. In contrast, rats receiving EMDR treatment alongside stress exposure exhibited preserved dendritic morphology comparable to controls, suggesting EMDR's protective role against stressinduced dendritic remodeling. These findings highlight the potential of EMDR as a neuroprotective intervention in mitigating stress-related hippocampal alterations.

Terminalia chebula attenuates restraint stress-induced memory impairment and synaptic loss in the dentate gyrus of the hippocampus and the basolateral and central nuclei of the amygdala by inhibiting oxidative damage

Chronic restraint stress induces cognitive abnormalities through changes in synapses and oxidant levels in the amygdala and hippocampus. Given the neuroprotective effects of fruit of Terminalia chebula (Halileh) in different experimental models, the present investigation aimed to address whether Terminalia chebula is able to reduce chronic restraint stress-induced behavioral, synaptic and oxidant markers in the rat model. Thirty-two male Wistar rats were randomly divided into four groups as follows: control (did not receive any treatment and were not exposed to stress), stress (restraint stress for 2 h a day for 14 consecutive days), Terminalia chebula (received 200 mg/kg hydroalcoholic extract of Terminalia chebula), and stress + Terminalia chebula groups (received 200 mg/kg extract of Terminalia chebula twenty minutes before stress) (n = 8 in each group). We used the shuttle box test to assess learning and memory, Golgi-Cox staining to examine dendritic spine density in the dentate gyrus region of the hippocampus and the basolateral and central nuclei of the amygdala, and total antioxidant capacity (TAC) and total oxidant status (TOS) in the brain. The shuttle box test results demonstrated that Terminalia chebula treatment had a profound positive effect on memory parameters, including step-through latency (STL) and time spent in the dark room, when compared to the stress group. Daily oral treatment with Terminalia chebula effectively suppressed the loss of neural spine density in the dentate gyrus region of the hippocampus and the basolateral and central nuclei of the amygdala caused by chronic restraint stress, as demonstrated by Golgi-Cox staining. Additionally, the results indicate that Terminalia chebula significantly reduced the TOS and increased TAC in the brain compared to the stress group. In conclusion, our results suggest that Terminalia chebula improved memory impairment and synaptic loss in the dentate gyrus of the hippocampus and the basolateral and central nuclei of the amygdala induced by restraint stress via inhibiting oxidative damage.

Low-frequency repetitive transcranial magnetic stimulation alleviates abnormal behavior in valproic acid rat model of autism through rescuing synaptic plasticity and inhibiting neuroinflammation

Autism is a complex neurodevelopmental disorder with no effective treatment available currently. Repetitive transcranial magnetic stimulation (rTMS) is emerging as a promising neuromodulation technique to treat autism. However, the mechanism how rTMS works remains unclear, which restrict the clinical application of magnetic stimulation in the autism treatment. In this study, we investigated the effect of low-frequency rTMS on the autistic-like symptoms and explored if this neuroprotective effect was associated with synaptic plasticity and neuroinflammation in the hippocampus. A rat model of autism was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats and male offspring were treated with 1 Hz rTMS daily for two weeks continuously. Behavior tests were performed to identify behavioral abnormality. Synaptic plasticity was measured by in vivo electrophysiological recording and Golgi-Cox staining. Synapse and inflammation associated proteins were detected by immunofluorescence and Western blot analyses. Results showed prenatal VPA-exposed rats exhibited autistic-like and anxiety-like behaviors, and cognitive impairment. Synaptic plasticity deficits and the abnormality expression of synapse-associated proteins were found in the hippocampus of prenatal VPA-exposed rats. Prenatal VPA exposure increased the level of inflammation cytokines and promoted the excessive activation of microglia. rTMS significantly alleviated the prenatal VPA-induced abnormalities including behavioral and synaptic plasticity deficits, and excessive neuroinflammation. TMS maybe a potential strategy for autism therapy via rescuing synaptic plasticity and inhibiting neuroinflammation.