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Sleep is a fundamental state for maintaining the organism homeostasis. Disruptions in sleep patterns predispose to the appearance of memory impairments and mental disorders, including depression. Recent pre-clinical studies have highlighted the antidepressant-like properties of the synthetic compound 2-phenyl-3-(phenylselanyl)benzofuran (SeBZF1). To further investigate the neuromodulatory effects of SeBZF1, this study aimed to assess its therapeutic efficacy in ameliorating neurobehavioral impairments induced by sleep deprivation (SD) in mice. For this purpose, a method known as multiple platforms over water was used to induce rapid eye movement (REM) SD. Two hours after acute SD (24 h), male Swiss mice received a single treatment of SeBZF1 (5 mg/kg, intragastric route) or fluoxetine (a positive control, 20 mg/kg, intraperitoneal route). Subsequently, behavioral tests were conducted to assess spontaneous motor function (open-field test), depressive-like behavior (tail suspension test), and memory deficits (Y-maze test). Brain structures were utilized to evaluate oxidative stress markers, monoamine oxidase (MAO) and acetylcholinesterase (AChE) activities. Our findings revealed that SD animals displayed depressive-like behavior and memory impairments, which were reverted by SeBZF1 and fluoxetine treatments. SeBZF1 also reverted the increase in lipoperoxidation levels and glutathione peroxidase activity in the pre-frontal cortex in mice exposed to SD. Besides, the increase in hippocampal AChE activity induced by SD was overturned by SeBZF1. Lastly, cortical MAO-B activity was reestablished by SeBZF1 in mice that underwent SD. Based on the main findings of this study, it can be inferred that the compound SeBZF1 reverses the neurobehavioral alterations induced by sleep deprivation in male Swiss mice.
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Benzofuranos , Privação do Sono , Animais , Masculino , Camundongos , Privação do Sono/tratamento farmacológico , Benzofuranos/farmacologia , Benzofuranos/uso terapêutico , Comportamento Animal/efeitos dos fármacos , Depressão/tratamento farmacológico , Compostos Organosselênicos/farmacologia , Compostos Organosselênicos/uso terapêutico , Transtornos da Memória/tratamento farmacológico , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Aprendizagem em Labirinto/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacosRESUMO
The Aggie Figures Learning Test (AFLT) is a visual memory assessment tool, which was constructed as an analog to the Rey Auditory Verbal Learning Test (RAVLT). Since the test holds close resemblance to the RAVLT, it is possible to make meaningful comparisons between these two tests. These comparisons are notably relevant in the assessment of material-specific memory impairments in epilepsy. However, the AFLT convergent validity has not yet been established. OBJECTIVE: The purpose of the present study was to demonstrate the convergent validity of the AFLT and to provide norms for an adult population ranging from 18 to 58. METHOD: 140 healthy volunteers participated in the study. They ranged in age from 18 to 58 years, with 12 to 25 years of education. Subjects were assessed with a comprehensive neuropsychological battery which included the ALFT (A version) and the Rey-Osterrieth Complex Figure (ROCF). RESULTS: Positive correlations were found between the scores of both tests for recent memory (r = 0.606, p < 0.01), delayed free recall (r = 0.534, p < 0.01) and recognition memory (r = 0.202, p < 0.05). These results demonstrate the convergent validity of the AFLT. CONCLUSIONS: The AFLT is a visual memory assessment tool with adequate psychometric properties, which allows a comprehensive evaluation of visual memory processes.
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Obesity is a chronic disease caused by excessive fat accumulation that impacts the body and brain health. Insufficient leptin or leptin receptor (LepR) is involved in the disease pathogenesis. Leptin is involved with several neurological processes, and it has crucial developmental roles. We have previously demonstrated that leptin deficiency in early life leads to permanent developmental problems in young adult mice, including an imbalance in energy homeostasis, alterations in melanocortin and the reproductive system and a reduction in brain mass. Given that in humans, obesity has been associated with brain atrophy and cognitive impairment, it is important to determine the long-term consequences of early-life leptin deficiency on brain structure and memory function. Here, we demonstrate that leptin-deficient (LepOb) mice exhibit altered brain volume, decreased neurogenesis and memory impairment. Similar effects were observed in animals that do not express the LepR (LepRNull). Interestingly, restoring the expression of LepR in 10-week-old mice reverses brain atrophy, in addition to neurogenesis and memory impairments in older animals. Our findings indicate that leptin deficiency impairs brain development and memory, which are reversible by restoring leptin signalling in adulthood.
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Encéfalo , Leptina , Neurogênese , Receptores para Leptina , Animais , Receptores para Leptina/deficiência , Receptores para Leptina/genética , Receptores para Leptina/metabolismo , Camundongos , Encéfalo/metabolismo , Leptina/deficiência , Leptina/metabolismo , Neurogênese/fisiologia , Camundongos Knockout , Camundongos Endogâmicos C57BL , Masculino , Transtornos da Memória/metabolismo , Transtornos da Memória/genética , Atrofia/patologiaRESUMO
This study aimed to develop polysorbate 80-coated chitosan nanoparticles (PS80/CS NPs) as a delivery system for improved brain targeting of α-Melanocyte Stimulating Hormone analog (NDP-MSH). Chitosan nanoparticles loaded with NDP-MSH were surface-modified with polysorbate 80 ([NDP-MSH]-PS80/CS NP), which formed a flattened layer on their surface. Nanoparticle preparation involved ionic gelation, followed by characterization using scanning electron microscopy (SEM) for morphology, dynamic light scattering (DLS) for colloidal properties, and ATR-FTIR spectroscopy for structure. Intraperitoneal injection of FITC-PS80/CS NPs and [NDP-MSH]-PS80/CS NP in rats demonstrated their ability to cross the blood-brain barrier, reach the brain, and accumulate in CA1 neurons of the dorsal hippocampus within 2 h. Two experimental models of neuroinflammation were employed with Male Wistar rats: a short-term model involving high-fat diet (HFD) consumption for 5 days followed by an immune stimulus with LPS, and a long-term model involving HFD consumption for 8 weeks. In both models, [NDP-MSH]-PS80/CS NPs could reverse the decreased expression of contextual fear memory induced by the diets. These findings suggest that [NDP-MSH]-PS80/CS NPs offer a promising strategy to overcome the limitations of NDP-MSH regarding pharmacokinetics and enzymatic stability. By facilitating NDP-MSH delivery to the hippocampus, these nanoparticles can potentially mitigate the cognitive impairments associated with HFD consumption and neuroinflammation.
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Encéfalo , Quitosana , Disfunção Cognitiva , Dieta Hiperlipídica , Nanopartículas , Polissorbatos , Ratos Wistar , alfa-MSH , Animais , Quitosana/administração & dosagem , Quitosana/química , Masculino , alfa-MSH/administração & dosagem , alfa-MSH/análogos & derivados , Polissorbatos/química , Polissorbatos/administração & dosagem , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/tratamento farmacológico , Nanopartículas/administração & dosagem , Dieta Hiperlipídica/efeitos adversos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/tratamento farmacológico , RatosRESUMO
SUMMARY: We evaluated the role and mechanism of acteoside in the regulation of memory impairment induced by chronic unpredictable mild stress (CUMS). CUMS was used to induce depression in rats and the successful establishment of CUMS model were verified by forced swimming test and sucrose preference test. The Y-maze test and novel object recognition test assessed memory functions. The structural changes in the cortex and hippocampus were observed by hematoxylin and eosin (HE) staining. Immunofluorescence staining and western blotting determined the protein levels. Y-maze test and novel object recognition test showed that there was memory performance impairment in rats of CUMS group, which was improved by the acteoside treatment. HE staining showed that CUMS exposure damaged the structure in the cortex and hippocampus, while the acteoside treatment alleviated the structural changes. Compared with the control group, the levels of BNDF and CREB in the cortex and hippocampus of the CUMS group were significantly decreased. Acteoside significantly reversed the expressions of these proteins in CUMS rats. Meanwhile, compared with the control group, the levels of p-mTOR and p- P70S6K in the cortex and hippocampus of the CUMS group were significantly increased, and these changes were significantly reversed by acteoside. Nevertheless, the effect of acteoside on mTOR signaling was markedly blocked by rapamycin, a specific inhibitor of mTOR signaling. Acteoside can attenuate memory impairment and ameliorate neuronal damage and synaptic plasticity in depression rats probably via inhibiting the mTOR signaling pathway. Acteoside may serve as a novel reagent for the prevention of depression.
Evaluamos el papel y el mecanismo del acteoside en la regulación del deterioro de la memoria inducido por estrés leve crónico impredecible (ELCI). Se utilizó ELCI para inducir depresión en ratas y el establecimiento exitoso del modelo ELCI se verificó mediante una prueba de natación forzada y una prueba de preferencia de sacarosa. La prueba del laberinto en Y y la prueba de reconocimiento de objetos novedosos evaluaron las funciones de la memoria. Los cambios estructurales en la corteza y el hipocampo se observaron mediante tinción con hematoxilina y eosina (HE). La tinción por inmunofluorescencia y la transferencia Western determinaron los niveles de proteína. La prueba del laberinto en Y y la prueba de reconocimiento de objetos novedosos mostraron que había un deterioro del rendimiento de la memoria en ratas del grupo ELCI, que mejoró con el tratamiento con acteósidos. La tinción con HE mostró que la exposición a ELCI dañó la estructura de la corteza y el hipocampo, mientras que el tratamiento con actósidos alivió los cambios estructurales. En comparación con el grupo de control, los niveles de BNDF y CREB en la corteza y el hipocampo del grupo ELCI disminuyeron significativamente. Acteoside revirtió significativamente las expresiones de estas proteínas en ratas ELCI. Mientras tanto, en comparación con el grupo control, los niveles de p-mTOR y p-P70S6K en la corteza y el hipocampo del grupo ELCI aumentaron significativamente, y estos cambios fueron revertidos significativamente ELCI por el acteoside. Sin embargo, el efecto del acteoside sobre la señalización de mTOR fue notablemente bloqueado por la rapamicina, un inhibidor específico de la señalización de mTOR. El acteoside puede atenuar el deterioro de la memoria y mejorar el daño neuronal y la plasticidad sináptica en ratas con depresión, probablemente mediante la inhibición de la vía de señalización mTOR. Acteoside puede servir como un reactivo novedoso para la prevención de la depresión.
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Animais , Ratos , Depressão/tratamento farmacológico , Polifenóis/administração & dosagem , Glucosídeos/administração & dosagem , Transtornos da Memória/tratamento farmacológico , Estresse Psicológico/complicações , Western Blotting , Imunofluorescência , Ratos Sprague-Dawley , Aprendizagem em Labirinto , Reconhecimento Psicológico/efeitos dos fármacos , Modelos Animais de Doenças , Serina-Treonina Quinases TOR/antagonistas & inibidores , Polifenóis/uso terapêutico , Escala de Avaliação Comportamental , Inibidores de MTOR , Glucosídeos/uso terapêutico , Plasticidade Neuronal/efeitos dos fármacos , NeurôniosRESUMO
Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the Substantia nigra pars compacta (SNpc), which leads to motor and non-motor symptoms (NMS). NMS can appear many years before the classical motor symptoms and are associated with the neurodegeneration of several nuclei; in this work, we highlight the neurodegeneration of Locus coeruleus (LC) in PD. The aim was to investigate the effects of depleting SNpc and LC catecholaminergic neurons on behavioral and neurobiological endpoints. Here we used 6-hydroxydopamine (6-OHDA) in order to induced neurotoxic damage in three independent experimental groups: SNpc lesion group, which 6-OHDA was injected into CPu (CPu-6-OHDA), LC lesion group, which 6-OHDA was injected directly on LC to selectively caused a damage on this nucleus (LC-6-OHDA), and the combined SNpc and LC lesion group (CL-6-OHDA). Next, the behavioral studies were performed using the Morris water maze (MWM), open field (OF), and elevated plus maze (EPM). After stereotaxic surgeries, the animals showed a loss of 67% and 77% of Tyrosine hydroxylase (TH) reactive neurons in the SNpc and LC, respectively. The behavioral analysis showed the anxiety-like behavior in CL-6-OHDA group in the EPM test; in the MWM test, the combined lesions (CL-6-OHDA) showed an impairment in memory acquisition and spatial memory; and no changes were observed in locomotor activity in all the tests. Furthermore, our investigation demonstrating the effects of depleting SN and LC catecholaminergic neurons on behavioral and neurobiological parameters. All these data together lead us to believe that a bilateral PD model including a LC bilateral degeneration is potentially a more accurate model to evaluate the NMS in the pathological development of the disease in rodents.
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Doença de Parkinson , Animais , Oxidopamina/toxicidade , Doença de Parkinson/metabolismo , Roedores , Locus Cerúleo/metabolismo , Neurônios Dopaminérgicos , Substância Negra/metabolismo , Modelos Animais de DoençasRESUMO
N-nitrosodiethylamine (NDEA) is a potential carcinogen known to cause liver tumors and chronic inflammation, diabetes, cognitive problems, and signs like Alzheimer's disease (AD) in animals. This compound is classified as probably carcinogenic to humans. Usual sources of exposure include food, beer, tobacco, personal care products, water, and medications. AD is characterized by cognitive decline, amyloid-ß (Aß) deposit, tau hyperphosphorylation, and cell loss. This is accompanied by neuroinflammation, which involves release of microglial cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin 1ß (IL-1ß), by nuclear factor kappa B (NF-κB) upregulation; each are linked to AD progression. Weak PI3K/Akt insulin-signaling inhibits IRS-1 phosphorylation, activates GSK3ß and promotes tau hyperphosphorylation. Metformin, an antihyperglycemic agent, has potent anti-inflammatory efficacy. It reduces proinflammatory cytokines such as IL-6, IL-1ß, and TNF-α via NF-κB inhibition. Metformin also reduces reactive oxidative species (ROS) and modulates cognitive disorders reported due to brain insulin resistance links. Our study examined how NDEA affects spatial memory in Wistar rats. We found that all NDEA doses tested impaired memory. The 80 µg/kg dose of NDEA increased levels of Aß1-42, TNF-α, and IL-6 in the hippocampus, which correlated with memory loss. Nonetheless, treatment with 100 mg/kg of metformin attenuated the levels of pro-inflammatory cytokines and Aß1-42, and enhanced memory. It suggests that metformin may protect against NDEA-triggered memory issues and brain inflammation.
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Doença de Alzheimer , Metformina , Animais , Ratos , Doença de Alzheimer/induzido quimicamente , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides , Carcinógenos , Citocinas , Dietilnitrosamina , Hipocampo , Interleucina-6 , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/tratamento farmacológico , Metformina/farmacologia , Metformina/uso terapêutico , NF-kappa B , Fosfatidilinositol 3-Quinases , Ratos Wistar , Fator de Necrose Tumoral alfaRESUMO
Tabernaemontana arborea (Apocynaceae) is a Mexican tree species known to contain ibogan type alkaloids. This study aimed at determining central nervous system-related activities of an alkaloid extract obtained from the root bark of T. arborea. A gas chromatography-mass spectrometry (GC-MS) analysis was performed to describe the alkaloid profile of the extract. A wide dosing range (0.1 to 56.2 mg/kg) of this extract was evaluated in different murine models. Electrical brain activity was examined by electroencephalography (EEG). The extract's effects on motor coordination, ambulatory activity, and memory were analyzed based on the rotarod, open field (OFT), and object recognition tests (ORT), respectively. Antidepressant and antinociceptive activities were determined using the forced swimming test (FST) and the formalin assay, respectively. In order to elucidate the underlying mechanisms of action, the 5-HT1A receptor antagonist WAY100635 (1 mg/kg) or the opioid receptor antagonist naloxone (1 mg/kg) was included in the latter experiments. GC-MS analysis (µg/mg extract) confirmed the presence of the monoterpenoid indole alkaloids (MIAs) voacangine (207.00), ibogaine (106.33), vobasine (72.81), coronaridine (30.72), and ibogamine (24.2) as principal constituents of the extract, which exhibited dose- and receptor-dependent antidepressant (0.1 to 1 mg/kg; 5-HT1A) and antinociceptive (30 and 56.2 mg/kg; opioid) effects, without altering motor coordination, ambulatory activity, and memory. EEG indicated CNS depressant activity at high doses (30 and 56.2 mg/kg). The root bark of T. arborea contains a mixture of alkaloids that may hold therapeutic value in pain relief and the treatment of psychiatric diseases without causing neurotoxic activity at effective doses.
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Antineoplásicos , Alcaloides de Triptamina e Secologanina , Tabernaemontana , Animais , Camundongos , Tabernaemontana/química , Modelos Animais de Doenças , Estrutura Molecular , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Sistema Nervoso Central , Analgésicos/farmacologia , Transmissão SinápticaRESUMO
Introduction: Functional Cognitive Disorder (FCD) is a non-degenerative, common cause of memory complaint in patients with high educational levels. FCD has been insufficiently described in individuals with low education. Here, we investigated the frequency of FCD among individuals with low education. Methods: We analyzed retrospectively all new referrals from primary care to a tertiary memory clinic from 2014 to 2021. Final diagnosis, diagnostic work-up, clinical and cognitive testing data were compared between FCD and other diagnoses, grouped as Neurodegenerative Disorders (NDD). A regression model was used to assess the effect of education on the diagnosis. Data is shown in Mean [SD]. Results: A total of 516 individuals (70.76 [10.3] years) with low educational attainment (4.5 [3.94] years) were divided into FCD (146, 28.3%) and NDD. Compared with NDD, FCD patients showed lower age at presentation (66.2 [9.4] vs. 72.6 [10.2], p < 0.001), higher Mini-Mental State Examination (MMSE) scores (22.4 [6.2] vs. 14.7 [7.8], p < 0.001) and Geriatric Depression Scale (GDS) scores (7.4 [5.4] vs. 5.3 [3.7], p = 0.0001). Discussion: Surprisingly, FCD was the most frequent diagnosis in a low educational setting. However, education was not associated with FCD. Individuals presenting FCD showed a distinct clinical profile, including younger age and higher depressive scores. Strategies to identify FCD in primary care settings may benefit both patients and healthcare systems.
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The present study evaluated the protective effect of 1-(7-chloroquinolin-4-yl)-5-methyl-N-phenyl-1H-1,2,3-triazole-4-carboxamide (QTCA-1) on seizure severity, oxidative stress, and memory disorder in a pentylenetetrazole (PTZ)-kindling model in mice. Male Swiss mice were treated with QTCA-1 (10 mg/kg, intragastrically (i.g.)) or phenobarbital (PHEN) (10 mg/kg; i.g.), 30 min before the injection of PTZ (35 mg/kg, intraperitoneally (i.p.)). Treatments with QCTA-1 or PHEN and PTZ were performed once every 48 h (on the 1st, 3rd, 5th, 7th, 9th and 11th days). After each PTZ injection, the animals were observed for 30 min to assess the stage of seizure intensity. Behavioral parameters were evaluated from the 12th day until the 16th day of the experimental protocol. On the 16th day, mice were euthanized, and the cerebral cortex and hippocampus of mice were removed to determine the thiobarbituric acid reactive species (TBARS) and reactive species (RS) levels, and superoxide dismutase (SOD), Na+/K+-ATPase and acetylcholinesterase (AChE) activities. Our results demonstrated that QTCA-1 significantly decreased the seizure stage score in PTZ-kindled mice. QCTA-1 protected against memory impairment induced by PTZ. QTCA-1 normalized oxidative stress and Na+/K+-ATPase activity in the cerebral structures of PTZ-kindled mice. The effect of QTCA-1 treatment was similar to the positive control used in this study (PHEN). AChE activity did not change in the cerebral structures in PTZ- kindling mice. In conclusion, QCTA-1 may be a promising tool for the treatment of epileptogenesis and epilepsy-associated comorbidity (memory impairment). QCTA-1 to prevent these alterations may involve the reduction of oxidative stress and normalization of Na+/K+-ATPase activity.
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Excitação Neurológica , Pentilenotetrazol , Acetilcolinesterase/metabolismo , Animais , Anticonvulsivantes/farmacologia , Antioxidantes/farmacologia , Encéfalo/metabolismo , Comorbidade , Masculino , Camundongos , Estresse Oxidativo , Pentilenotetrazol/farmacologia , QuinolinasRESUMO
Doxorubicin (DOX) is known to cause cognitive impairments in patients submitted to long-term chemotherapy (deficits also known as chemobrain). Therefore, there is an urgent need for therapeutic strategies capable of returning cancer survivors back to their previous quality of life. The present study investigated whether resveratrol (RSV) or curcumin (CUR) administration could affect mnemonic function and brain morphological changes following DOX administration in rats. Male Wistar rats were divided into 4 groups: DOX group (2.5 mg/kg/week for 4 weeks, i.p., plus distilled water for 28 days, oral gavage - OG), DOX + RSV group (DOX, 2.5 mg/kg/week for 4 weeks, i.p., plus RSV, 10 mg/kg/day for 28 days, OG), DOX + CUR group (DOX, 2.5 mg/kg/week for 4 weeks, i.p., plus CUR, 100 mg/kg/day for 28 days, OG) and control (CTR) group (0.9% saline solution weekly for 4 weeks, i.p., plus distilled water for 28 days, OG). Behavioral analyses (open field - OF - and the novel object recognition test - NORT) were performed. Brains were collected and analyzed by hematoxylin-eosin and luxol fast blue staining techniques and by immunohistochemistry for GFAP (glial fibrillary acidic protein) expression in astrocytes and Iba1 (ionized calcium-binding adaptor molecule 1) expression in microglia. DOX-injected rats presented short-term and long-term memory impairments as seen in the NORT at 3 and 24 h after habituation and increased GFAP and Iba1 expression, respectively, in astrocytes and microglia of the frontal cortex, hypothalamus and hippocampus. Such cognitive deficits were prevented by CUR at both periods and by RSV at 24 h. DOX-induced astrogliosis and microgliosis were avoided by RSV and CUR. No signs of demyelination or neuronal loss were found in any group. Thus, CUR and RSV prevented memory loss, astrogliosis and microgliosis induced by DOX monotherapy.
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Disfunção Cognitiva , Curcumina , Animais , Disfunção Cognitiva/induzido quimicamente , Disfunção Cognitiva/tratamento farmacológico , Curcumina/farmacologia , Curcumina/uso terapêutico , Doxorrubicina/toxicidade , Masculino , Qualidade de Vida , Ratos , Ratos Wistar , ResveratrolRESUMO
Survivors of sepsis often develop long-term cognitive impairments. This review aimed at exploring the results of the behavioral tools and tests which have been used to evaluate cognitive dysfunction in different animal models of sepsis. Two independent investigators searched for sepsis- and cognition-related keywords. 6323 publications were found, of which 355 were selected based on their title, and 226 of these were chosen based on manuscript review. LPS was used to induce sepsis in 171 studies, while CLP was used in 55 studies. Inhibitory avoidance was the most widely used method for assessing aversive memory, followed by fear conditioning and continuous multi-trial inhibitory avoidance. With regard to non-aversive memory, most studies used the water maze, open-field, object recognition, Y-maze, plus maze, and radial maze tests. Both CLP and LPS models of sepsis were effective in inducing short- and long-term behavioral impairment. Our findings help elucidate the mechanisms involved in the pathophysiology of sepsis-induced cognitive changes, as well as the available methods and tests used to study this in animal models.
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Disfunção Cognitiva , Sepse , Animais , Cognição , Disfunção Cognitiva/etiologia , Modelos Animais de Doenças , Aprendizagem em Labirinto , Sepse/complicaçõesRESUMO
BACKGROUND: Evidence has revealed an association between familial hypercholesterolemia and cognitive impairment. In this regard, a connection between cognitive deficits and hippocampal blood-brain barrier (BBB) breakdown was found in low-density lipoprotein receptor knockout mice (LDLr-/-), a mouse model of familial hypercholesterolemia. OBJECTIVE: Herein we investigated the impact of a hypercholesterolemic diet on cognition and BBB function in C57BL/6 wild-type and LDLr-/-mice. METHODS: Animals were fed with normal or high cholesterol diets for 30 days. Thus, wild-type and LDLr-/-mice were submitted to memory paradigms. Additionally, BBB integrity was evaluated in the mice's prefrontal cortices and hippocampi. RESULTS: A tenfold elevation in plasma cholesterol levels of LDLr-/-mice was observed after a hypercholesterolemic diet, while in wild-type mice, the hypercholesterolemic diet exposure increased plasma cholesterol levels only moderately and did not induce cognitive impairment. LDLr-/-mice presented memory impairment regardless of the diet. We observed BBB disruption as an increased permeability to sodium fluorescein in the prefrontal cortices and hippocampi and a decrease on hippocampal claudin-5 and occludin mRNA levels in both wild-type and LDLr-/-mice treated with a hypercholesterolemic diet. The LDLr-/-mice fed with a regular diet already presented BBB dysfunction. The BBB-increased leakage in the hippocampi of LDLr-/-mice was related to high microvessel content and intense astrogliosis, which did not occur in the control mice. CONCLUSION: Therefore, LDLr-/-mice seem to be more susceptible to cognitive impairments and BBB damage induced by exposure to a high cholesterol diet. Finally, BBB disruption appears to be a relevant event in hypercholesterolemia-induced brain alterations.
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Barreira Hematoencefálica , Colesterol/metabolismo , Disfunção Cognitiva/metabolismo , Hipercolesterolemia/metabolismo , Animais , Cognição , Dieta , Modelos Animais de Doenças , Gliose/metabolismo , Hipocampo/metabolismo , Masculino , Memória , Transtornos da Memória/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Córtex Pré-Frontal/metabolismo , Receptores de LDLRESUMO
Obesity has been associated with cognitive decline, atrophy of brain regions related to learning and memory, and higher risk of developing dementia. However, the molecular mechanisms underlying these neurological alterations are still largely unknown. Here, we investigate the effects of palmitate, a saturated fatty acid present at high amounts in fat-rich diets, in the brain. Palmitate is increased in the cerebrospinal fluid (CSF) of overweight and obese patients with amnestic mild cognitive impairment. In mice, intracerebroventricular infusion of palmitate impairs synaptic plasticity and memory. Palmitate induces astroglial and microglial activation in the mouse hippocampus, and its deleterious impact is mediated by microglia-derived tumor necrosis factor alpha (TNF-α) signaling. Our results establish that obesity is associated with increases in CSF palmitate. By defining a pro-inflammatory mechanism by which abnormal levels of palmitate in the brain impair memory, the results further suggest that anti-inflammatory strategies may attenuate memory impairment in obesity.
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Transtornos da Memória/etiologia , Obesidade/líquido cefalorraquidiano , Palmitatos/líquido cefalorraquidiano , Fator de Necrose Tumoral alfa/metabolismo , Animais , Humanos , Transtornos da Memória/patologia , Camundongos , Obesidade/patologiaRESUMO
Familial hypercholesterolemia (FH) is a genetic disorder caused by dysfunction of low density lipoprotein receptors (LDLr), resulting in elevated plasma cholesterol levels. FH patients frequently exhibit cognitive impairment, a finding recapitulated in LDLr deficient mice (LDLr-/-), an animal model of FH. In addition, LDLr-/- mice are more vulnerable to the deleterious memory impact of amyloid-ß (Aß), a peptide linked to Alzheimer's disease. Here, we investigated whether the expression of proteins involved in Aß metabolism are altered in the brains of adult or middle-aged LDLr-/- mice. After spatial memory assessment, Aß levels and gene expression of LDLr related-protein 1, proteins involved in Aß synthesis, and apoptosis-related proteins were evaluated in prefrontal cortex and hippocampus. Moreover, the location and cell-specificity of apoptosis signals were evaluated. LDLr-/- mice presented memory impairment, which was more severe in middle-aged animals. Memory deficit in LDLr-/- mice was not associated with altered expression of proteins involved in Aß processing or changes in Aß levels in either hippocampus or prefrontal cortex. We further found that the expression of Bcl-2 was reduced while the expression of Bax was increased in both prefrontal cortex and hippocampus in 3- and 14-month-old LDLr-/-mice Finally, LDLr-/- mice presented increased immunoreactivity for activated caspase-3 in the prefrontal cortex and hippocampus. The activation of caspase 3 was predominantly associated with neurons in LDLr-/- mice. Cognitive impairment in LDLr-/- mice is thus accompanied by an exacerbation of neuronal apoptosis in brain regions related to memory formation, but not by changes in Aß processing or levels.
Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Apoptose/genética , Química Encefálica/genética , Receptores de LDL/deficiência , Receptores de LDL/genética , Envelhecimento/metabolismo , Envelhecimento/psicologia , Animais , Caspase 3 , Colesterol/sangue , Expressão Gênica , Hipocampo/metabolismo , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Córtex Pré-Frontal/metabolismoRESUMO
Low-exploratory (LE) and high-exploratory (HE) rodents mimic human depressive and hyperthymic temperaments, respectively. Mood disorders (MD) may be developed by the exposure of these temperaments to environmental stress (ES). Psychiatric symptoms severity in MD patients is related to the magnitude of memory impairment. Thus, we aimed at studying the consequences of the exposure of LE and HE male Wistar rats, during periadolescence, to a combination of ES, namely, paradoxical sleep deprivation (PSD) and unpredictable stress (US), on anxiety-related behavior in the plus maze test, working (WM) and declarative memory (DM) performance. We also evaluated hippocampal immune-inflammatory/oxidative, as consequences of ES, and prevention of ES-induced alterations by the mood-stabilizing drugs, lithium and valproate. Medium exploratory (ME) control rats were used for comparisons with HE- and LE-control rats. We observed that HE-controls presented increased anxiolytic behavior that was significantly increased by ES exposure, whereas LE-controls presented increased anxiety-like behavior relative to ME-controls. Lithium and valproate prevented anxiolytic alterations in HE+ES rats. HE+ES- and LE+ES-rats presented WM and DM deficits. Valproate and lithium prevented WM deficits in LE-PSD+US rats. Lithium prevented DM impairment in HE+ES-rats. Hippocampal levels of reduced glutathione (GSH) increased four-fold in HE+ES-rats, being prevented by valproate and lithium. All groups of LE+ES-rats presented increased levels of GSH in relation to controls. Increments in lipid peroxidation in LE+ES- and HE+ES-rats were prevented by valproate in HE+ES-rats and by both drugs in LE+ES-rats. Nitrite levels were increased in HE+ES- and LE+ES-rats (five-fold increase), which was prevented by both drugs in LE+ES-rats. HE+ES-rats presented a two-fold increase in the inducible nitric oxide synthase (iNOS) expression that was prevented by lithium. HE+ES-rats showed increased hippocampal and plasma levels of interleukin (IL)-1ß and IL-4. Indoleamine 2, 3-dioxygenase 1 (IDO1) was increased in HE+ES- and LE+ES-rats, while tryptophan 2,3-dioxygenase (TDO2) was increased only in HE+ES-rats. Altogether, our results showed that LE- and HE-rats exposed to ES present distinct anxiety-related behavior and similar memory deficits. Furthermore, HE+ES-rats presented more brain and plasma inflammatory alterations that were partially prevented by the mood-stabilizing drugs. These alterations in HE+ES-rats may possibly be related to the development of mood symptoms.
RESUMO
Introduction. With age, there is a growing risk of vitamin D deficiency and cognitive impairment. Maintaining the older people's health is socially relevant to health systems in the light of the population ageing trend. The study was aimed at identifying the relationship of vitamin D levels and symptoms of moderate cognitive impairment in older people. Methods. The authors conducted a cross-sectional screening of vitamin D status and cognitive impairment using the memory impairment screen (MIS) questionnaire, as well as the clinical, placebo-controlled study of vitamin D intake at a dose of 2,000 IU/day for 6 months. Results. The frequency of vitamin D deficiency in older patients with signs of cognitive impairment totaled 90.91 %, which was significantly more frequently compared with the group without cognitive impairment, where vitamin D deficiency was found only in 11.36 % of cases. In the dynamics on the background of the vitamin D intake for 6 months, the concentration in the intervention group amounted to 52.34 ± 2.43 ng/ml vs 14.71 ± 1.54 ng/ ml in the placebo group. The results of the study of cognitive impairment using MIS for the treatment group were 3.63 ± 0.01 points, which was significantly higher compared with the placebo group 1.78 ± 0.22 points. A correlation analysis of vitamin D levels and MIS points showed a strong positive relationship, with a correlation coefficient of 0.92. Conclusion. The study identified a positive relationship of increasing vitamin D levels and reducing the symptoms of mild cognitive impairment in older people. Achieving vitamin D levels of over 40 ng/ ml greatly reduces the symptoms of cognitive impairment identified by the MIS questionnaire, however, the issue of treatment of impaired cognitive functions with vitamin D remains debatable.
Assuntos
Humanos , Idoso , Idoso de 80 Anos ou mais , Vitamina D/administração & dosagem , Deficiência de Vitamina D/tratamento farmacológico , Estudos Transversais , Resultado do Tratamento , Avaliação de Resultados em Cuidados de Saúde , Ensaio Clínico Controlado , Disfunção Cognitiva/terapiaRESUMO
Chronic cerebral hypoperfusion (CCH) may be involved in the etiology of aging-related dementias, and several risk factors contribute to their development and/or aggravation. We previously reported on the development of the 4-VO/ICA model of CCH, and the impact of hypertension on the cognitive and histological outcomes of CCH. Here, we advanced those studies by investigating how 4-VO/ICA alone or in combination with diabetes affects survival, body weight and cognitive performance in both young and middle-aged rats. Subsequently, middle-aged rats were examined for the impact of diabetes on CCH-induced neurodegeneration, white matter damage, and glial cells response. Diabetes alone reduced body weight and increased mortality rate slightly in young rats; these effects were striking, however, in the older animals. After CCH alone, neither body weight nor mortality rate changed significantly in both age groups. However, when CCH was combined with diabetes, mortality rate increased significantly in both aged groups. Young rats were cognitively asymptomatic to CCH, but they became 'mildly' impaired after CCH combined with diabetes. In middle-aged rats, CCH severely impaired memory, which was significantly worsened by diabetes. Moreover, diabetes aggravated neurodegeneration in the hippocampus and white matter injury in the corpus callosum and it promoted glial activation in the hippocampus and white matter of CCH middle-aged rats. These data suggest that diabetes interacts synergistically with age and reduces the capacity of the brain to adequately respond to CCH and highlight the importance of associating risk factors in the preclinical investigation of age-related cerebrovascular diseases physiopathology and potential therapies.
Assuntos
Envelhecimento/fisiologia , Isquemia Encefálica/patologia , Artéria Carótida Interna/patologia , Cognição/fisiologia , Amnésia Retrógrada/fisiopatologia , Animais , Isquemia Encefálica/complicações , Isquemia Encefálica/mortalidade , Doenças das Artérias Carótidas/complicações , Doenças das Artérias Carótidas/patologia , Transtornos Cognitivos/metabolismo , Transtornos Cognitivos/fisiopatologia , Modelos Animais de Doenças , Hipocampo/patologia , Hipocampo/fisiopatologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Transtornos da Memória/patologia , Ratos WistarRESUMO
Maple Syrup Urine Disease (MSUD) is biochemically characterized by elevated levels of leucine, isoleucine and valine, as well as their corresponding transaminated branched-chain α-keto acids in tissue and biological fluids. Neurological symptoms and cerebral abnormalities, whose mechanisms are still unknown, are typical of this metabolic disorder. In the present study, we evaluated the early effects (1 h after injection) and long-term effects (15 days after injection) of a single intracerebroventricular administration of α-ketoisocaproic acid (KIC) on oxidative stress parameters and cognitive and noncognitive behaviors. Our results showed that KIC induced early and long-term effects; we found an increase in TBARS levels, protein carbonyl content and DNA damage in the hippocampus, striatum and cerebral cortex both one hour and 15 days after KIC administration. Moreover, SOD activity increased in the hippocampus and striatum one hour after injection, whereas after 15 days, SOD activity decreased only in the striatum. On the other hand, KIC significantly decreased CAT activity in the striatum one hour after injection, but 15 days after KIC administration, we found a decrease in CAT activity in the hippocampus and striatum. Finally, we showed that long-term cognitive deficits follow the oxidative damage; KIC induced impaired habituation memory and long-term memory impairment. From the biochemical and behavioral findings, it we presume that KIC provokes oxidative damage, and the persistence of brain oxidative stress is associated with long-term memory impairment and prepulse inhibition.
Assuntos
Comportamento Animal/efeitos dos fármacos , Cognição/efeitos dos fármacos , Cetoácidos/administração & dosagem , Cetoácidos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Catalase/metabolismo , Injeções Intraventriculares , Masculino , Doença da Urina de Xarope de Bordo/psicologia , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/psicologia , Carbonilação Proteica , Ratos , Ratos Wistar , Reflexo de Sobressalto/efeitos dos fármacos , Superóxido Dismutase-1/metabolismo , Natação/psicologia , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Cerebral malaria (CM) is a life-threatening complication of Plasmodium falciparum infection, which can result in long-term cognitive and behavioral deficits despite successful anti-malarial therapy. Due to the substantial social and economic burden of CM, the development of adjuvant therapies is a scientific goal of highest priority. Apart from vascular and immune responses, changes in glutamate system have been reported in CM pathogenesis suggesting a potential therapeutic target. Based on that, we hypothesized that interventions in the glutamatergic system induced by blockage of N-methyl-D-aspartate (NMDA) receptors could attenuate experimental CM long-term cognitive and behavioral outcomes. Before the development of evident CM signs, susceptible mice infected with Plasmodium berghei ANKA (PbA) strain were initiated on treatment with dizocilpine maleate (MK801, 0.5 mg/kg), a noncompetitive NMDA receptor antagonist. On day 5 post-infection, mice were treated orally with a 10-day course chloroquine (CQ, 30 mg/kg). Control mice also received saline, CQ or MK801 + CQ therapy. After 10 days of cessation of CQ treatment, magnetic resonance images (MRI), behavioral and immunological assays were performed. Indeed, MK801 combined with CQ prevented long-term memory impairment and depressive-like behavior following successful PbA infection resolution. In addition, MK801 also modulated the immune system by promoting a balance of TH1/TH2 response and upregulating neurotrophic factors levels in the frontal cortex and hippocampus. Moreover, hippocampus abnormalities observed by MRI were partially prevented by MK801 treatment. Our results indicate that NMDA receptor antagonists can be neuroprotective in CM and could be a valuable adjuvant strategy for the management of the long-term impairment observed in CM.