RESUMO
Alcohol is the most consumed addictive substance worldwide that elicits multiple health problems. Consumption of alcoholic beverages by pregnant women is of great concern because pre-natal exposure can trigger fetal alcohol spectrum disorder (FASD). This disorder can significantly change the embryo's normal development, mainly by affecting the central nervous system (CNS), leading to neurobehavioral consequences that persist until adulthood. Among the harmful effects of FASD, the most reported consequences are cognitive and behavioral impairments. Alcohol interferes with multiple pathways in the brain, affecting memory by impairing neurotransmitter systems, increasing the rate of oxidative stress, or even activating neuroinflammation. Here, we aimed to evaluate the deleterious effects of alcohol on the cholinergic signaling and memory in a FASD zebrafish model, using inhibitory avoidance and novel object recognition tests. Four months after the embryonic exposure to ethanol, the behavioral tests indicated that ethanol impairs memory. While both ethanol concentrations tested (0.5â¯% and 1â¯%) disrupted memory acquisition in the inhibitory avoidance test, 1â¯% ethanol impaired memory in the object recognition test. Regarding the cholinergic system, 0.5â¯% ethanol decreased ChAT and AChE activities, but the relative gene expression did not change. Overall, we demonstrated that FASD model in zebrafish impairs memory in adult individuals, corroborating the memory impairment associated with embryonic exposure to ethanol. In addition, the cholinergic system was also affected, possibly showing a relation with the cognitive impairment observed.
Assuntos
Modelos Animais de Doenças , Etanol , Transtornos do Espectro Alcoólico Fetal , Transmissão Sináptica , Peixe-Zebra , Animais , Etanol/farmacologia , Etanol/efeitos adversos , Transtornos do Espectro Alcoólico Fetal/metabolismo , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Feminino , Memória/efeitos dos fármacos , Transtornos da Memória/induzido quimicamente , Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Masculino , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Depressores do Sistema Nervoso Central/farmacologia , GravidezRESUMO
Animal models of cerebral ischemia have improved our understanding of the pathophysiology and mechanisms involved in stroke, as well as the investigation of potential therapies. The potential of zebrafish to model human diseases has become increasingly evident. The availability of these models allows for an increased understanding of the role of chemical exposure in human conditions and provides essential tools for mechanistic studies of disease. To evaluate the potential neuroprotective properties of minocycline against ischemia and reperfusion injury in zebrafish and compare them with other standardized models. In vitro studies with BV-2 cells were performed, and mammalian transient middle cerebral artery occlusion (tMCAO) was used as a comparative standard with the zebrafish stroke model. Animals were subjected to ischemia and reperfusion injury protocols and treated with minocycline. Infarction size, cytokine levels, oxidative stress, glutamate toxicity, and immunofluorescence for microglial activation, and behavioral test results were determined and compared. Administration of minocycline provided significant protection in the three stroke models in different parameters analyzed. Both experimental models complement each other in their particularities. The proposal also strengthens the findings in the literature in rodent models and allows the validation of alternative models so that they can be used in further research involving diseases with ischemia and reperfusion injury.
Assuntos
Isquemia Encefálica , Fármacos Neuroprotetores , Traumatismo por Reperfusão , Acidente Vascular Cerebral , Animais , Humanos , Peixe-Zebra , Minociclina/farmacologia , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Isquemia Encefálica/tratamento farmacológico , Infarto da Artéria Cerebral Média/tratamento farmacológico , Traumatismo por Reperfusão/tratamento farmacológico , Modelos Animais de Doenças , MamíferosRESUMO
Maple Syrup Urine Disease (MSUD) is a metabolic disorder characterized by high levels in blood and urine of branched-chain amino acids leucine, isoleucine, and valine and their alpha-ketoacids, by a partial or total blockade in the activity of branched-chain complex alpha-keto acids dehydrogenase. The main symptoms in MSUD occur in the central nervous system, including cognitive deficits, locomotor, poor feeding, seizures, psychomotor delay, and mental retardation, but the mechanisms of neurotoxicity and behavior alteration due to this disease are poorly understood, thus this study aimed at showing the effects of leucine exposure on glutamate levels and behavior in zebrafish. For this, we analyzed the behavior using the social preference test and novel object recognition test, moreover, we analyse the glutamate levels and uptake using scintillation and high-performance liquid chromatography methods. Our results demonstrated a decrease in glutamate levels and uptake, accompanied by memory and social impairment. In conclusion, these results suggest that alterations in glutamate levels can be associated with behavior impairment, however, more studies are necessary to understand the mechanisms for brain damage in MSUD.
Assuntos
Doença da Urina de Xarope de Bordo , Peixe-Zebra , Animais , Leucina , Ácido Glutâmico , Doença da Urina de Xarope de Bordo/metabolismo , Aminoácidos de Cadeia Ramificada/farmacologiaRESUMO
Gallic acid (GA) is a secondary metabolite found in plants. It has the ability to cross the blood-brain barrier and, through scavenging properties, has a protective effect in a brain insult model. Alcohol metabolism generates reactive oxygen species (ROS); thus, alcohol abuse has a deleterious effect on the brain. The zebrafish is a vertebrate often used for screening toxic substances and in acute ethanol exposure models. The aim of this study was to evaluate whether GA pretreatment (24 h) prevents the changes induced by acute ethanol exposure (1 h) in the purinergic signaling pathway in the zebrafish brain via degradation of extracellular nucleotides and oxidative stress. The nucleotide cascade promoted by the nucleoside triphosphate diphosphohydrolase (NTPDase) and 5'-nucleotidase was assessed by quantifying nucleotide metabolism. The effect of GA alone at 5 and 10 mg L-1 did not change the nucleotide levels. Pretreatment with 10 mg L-1 GA prevented an ethanol-induced increase in ATP and ADP levels. No significant difference was found between the AMP levels of the two pretreatment groups. Pretreatment with 10 mg L-1 GA prevented ethanol-enhanced lipid peroxidation and dichlorodihydrofluorescein (DCFH) levels. The higher GA concentration was also shown to positively modulate against ethanol-induced effects on superoxide dismutase (SOD), but not on catalase (CAT). This study demonstrated that GA prevents the inhibitory effect of ethanol on NTPDase activity and oxidative stress parameters, thus consequently modulating nucleotide levels that may contribute to the possible protective effects induced by alcohol and purinergic signaling.
Assuntos
Etanol , Peixe-Zebra , Animais , Encéfalo/metabolismo , Etanol/metabolismo , Etanol/toxicidade , Ácido Gálico/metabolismo , Ácido Gálico/farmacologia , Nucleotídeos/metabolismo , Estresse Oxidativo , Purinas/metabolismo , Peixe-Zebra/metabolismoRESUMO
Fluoride is an essential chemical found in dental preparations, pesticides and drinking water. Excessive fluoride exposure is related to toxicological and neurological disruption. Zebrafish are used in translational approaches to understand neurotoxicity in both biomedical and environmental areas. However, there is no complete knowledge about the cumulative effects of fluoride on neurotransmission systems. Therefore, the aim of this study was to evaluate whether prolonged exposure to sodium fluoride (NaF) alters cholinergic and glutamatergic systems and oxidative stress homeostasis in the zebrafish brain. Adult zebrafish were used, divided into four experimental groups, one control group and three groups exposed to NaF at 30, 50 and 100 mg.L-1 for a period of 30 days. After NaF at 30 mg.L-1 exposure, there were significant decreases in acetylcholinesterase (29.8 %) and glutamate uptake (39.3 %). Furthermore, thiobarbituric acid-reactive species were decreased at NaF 50 mg.L-1 (32.7 %), while the group treated with NaF at 30 mg.L-1 showed an increase in dichlorodihydrofluorescein oxidation (41.4 %). NaF at 30 mg.L-1 decreased both superoxide dismutase (55.3 %) and catalase activities (26.1 %). The inhibitory effect observed on cholinergic and glutamatergic signalling mechanisms could contribute to the neurodegenerative events promoted by NaF in the zebrafish brain.
Assuntos
Encéfalo , Fluoretos , Estresse Oxidativo , Transmissão Sináptica , Peixe-Zebra , Acetilcolinesterase/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Fluoretos/efeitos adversos , Transmissão Sináptica/efeitos dos fármacos , Peixe-Zebra/metabolismoRESUMO
Status epilepticus (SE) develops from abnormal electrical discharges, resulting in neuronal damage. Current treatments include antiepileptic drugs. However, the most common drugs used to treat seizures may sometimes be ineffective and have many side effects. Melatonin is an endogenous physiological hormone that is considered an alternative treatment for neurological disorders because of its free radical scavenging property. Thus, this study aimed to determine the effects of melatonin pretreatment on SE by inducing glutamatergic hyperstimulation in zebrafish. Seizures were induced in zebrafish using kainic acid (KA), a glutamate analog, and the seizure intensity was recorded for 60 min. Melatonin treatment for 7 days showed a decrease in seizure intensity (28%), latency to reach score 5 (14 min), and duration of SE (29%). In addition, melatonin treatment attenuated glutamate transporter levels, which significantly decreased in the zebrafish brain after 12 h of KA-induced seizures. Melatonin treatment reduced the increase in oxidative stress by reactive oxygen species formation through thiobarbituric acid reactive substances and 2',7'-dichiorofluorescin, induced by KA-seizure. An imbalance of antioxidant enzyme activities such as superoxide dismutase and catalase was influenced by melatonin and KA-induced seizures. Our study indicates that melatonin promotes a neuroprotective response against the epileptic profile in zebrafish. These effects could be related to the modulation of glutamatergic neurotransmission, recovery of glutamate uptake, and oxidative stress parameters in the zebrafish brain.
Assuntos
Sistema X-AG de Transporte de Aminoácidos/metabolismo , Ácido Glutâmico/metabolismo , Ácido Caínico/toxicidade , Melatonina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Estado Epiléptico/prevenção & controle , Animais , Antioxidantes/farmacologia , Catalase/metabolismo , Glutationa/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/metabolismo , Superóxido Dismutase/metabolismo , Peixe-ZebraRESUMO
Gold nanoparticles (GNP) have emerged as an alternative to biomaterials in biomedical applications. Research has clearly demonstrated the relative safety and low toxicity of these molecules. However, the possible neuroprotective effect of GNP on the central nervous system (CNS) and its relationship with neurological and psychiatric disorders remain unclear. Zebrafish is a reliable model to investigate the impact of ethanol (EtOH) consumption on the CNS, including reward signaling such as the cholinergic neurotransmission system. Here, we investigated whether cotreatment or pretreatment with GNP prevented EtOH-induced changes in acetylcholinesterase activity and oxidative stress in the brain of zebrafish. We exposed adult zebrafish to 2.5â¯mg·L-1 GNP 1â¯h prior to EtOH (1% v/v) treatment for 1â¯h, and cotreated adult zebrafish simultaneously with both substances for 1â¯h. Pretreatment with GNP did not prevent EtOH-induced increase in the acetylcholinesterase activity, whereas cotreatment with 2.5â¯mg·L-1 GNP and EtOH protected against this increase. The results also suggested similar protective effect on oxidative stress parameters in the zebrafish pretreated with GNP at 2.5â¯mg·L-1. GNP significantly decreased the levels of thiobarbituric acid reactive species and dihydrodichlorofluorescein levels when cotreated with EtOH. GNP also prevented EtOH-induced increase in superoxide dismutase and catalase activities, suggesting a modulatory role of GNP in enzymatic antioxidant defenses. Our results showed that GNP was able to modulate the disruption of cholinergic and oxidative homeostasis in the brain of zebrafish. These findings indicate for the first time that zebrafish is an interesting perspective to investigate nanoparticles against disorders related to alcohol abuse.
Assuntos
Nanopartículas Metálicas , Peixe-Zebra , Acetilcolinesterase/metabolismo , Animais , Etanol/toxicidade , Ouro , Estresse Oxidativo , Peixe-Zebra/metabolismoRESUMO
Gallic acid (GA) is a polyphenolic compound that has attracted significant interest due to its antioxidant action through free radical elimination and metal chelation. Ethanol is a highly soluble psychoactive substance, and its toxicity is associated with oxidative stress. In this context, the purpose of the present study was to investigate the effect of GA on neurochemical changes in zebrafish brains exposed to ethanol. GA was first analyzed in isolation by treating the animals at concentrations of 5, 10, and 20â¯mg/L for 24â¯h and 48â¯h. The results revealed that the group exposed to 20â¯mg/L over a 24/48â¯h period exhibited increases in thiobarbituric acid reactive substance (TBA-RS) levels and 2',7'-dichlorofluorescein (DCFH) oxidation, demonstrating a pro-oxidant profile. Moreover, decrease in acetylcholinesterase (AChE) enzyme activity was observed. To investigate the effects of GA after ethanol exposure, the animals were divided into four groups: control; those exposed to 0.5% ethanol for 7â¯days; those exposed to 0.5% ethanol for 7â¯days and treated with GA at 5 and 10â¯mg/L on day 8. Treatment with GA at 5 and 10â¯mg/L reversed impairment of choline acetyltransferase activity and the damage to TBA-RS levels, DCFH oxidation, and superoxide dismutase activity induced by ethanol. Results of the present study suggest that GA treatment (20â¯mg/L) appeared to disrupt oxidative parameters in the zebrafish brain. GA treatment at 5 and 10â¯mg/L reversed alterations to the cholinergic system induced by prolonged exposure to ethanol in the zebrafish brain, probably through an antioxidant mechanism.
Assuntos
Encéfalo , Etanol , Ácido Gálico , Animais , Antioxidantes/farmacologia , Encéfalo/efeitos dos fármacos , Etanol/toxicidade , Ácido Gálico/farmacologia , Estresse Oxidativo , Peixe-ZebraRESUMO
Chronic and/or excessive consumption of alcohol followed by reduced consumption or abstention can result in Alcohol Withdrawal Syndrome. A number of behavioral changes and neurological damage result from ethanol (EtOH) withdrawal. Ceftriaxone (Cef) modulates the activity of excitatory amino acid transporters by increasing their gene expression. Zebrafish are commonly used to study alcohol exposure. The aim of this study was to evaluate the influence of Cef (100 µM) on behavior patterns, glutamate transport activity, and oxidative stress in zebrafish brains subjected to EtOH (0.3% v/v) withdrawal. The exploratory tests using Novel tank showed that EtOH withdrawal promoted a decrease in the time spent and number of entries of in the bottom displaying an anxiety-like behavior. In contrast, treatment with Cef resulted in recovery of exploratory behavioral patterns. Ceftriaxone treatment resulted in increased glutamate uptake in zebrafish subjected to EtOH withdrawal. Furthermore, EtOH withdrawal increased reactive species, as determined using thiobarbituric acid and dichlorodihydrofluorescein assays. Treatment with Cef reversed these effects. Ceftriaxone promoted a significant reduction in brain sulfhydryl content in zebrafish subjected to EtOH withdrawal. Therefore, Cef treatment in conjunction with EtOH withdrawal induced anxiolytic-like effects due to possible neuromodulation of glutamatergic transporters, potentially through mitigation of oxidative stress.
Assuntos
Ansiedade/metabolismo , Encéfalo/metabolismo , Ceftriaxona/uso terapêutico , Etanol/efeitos adversos , Ácido Glutâmico/metabolismo , Síndrome de Abstinência a Substâncias/metabolismo , Consumo de Bebidas Alcoólicas/efeitos adversos , Consumo de Bebidas Alcoólicas/psicologia , Animais , Ansiedade/tratamento farmacológico , Ansiedade/psicologia , Encéfalo/efeitos dos fármacos , Ceftriaxona/farmacologia , Etanol/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Síndrome de Abstinência a Substâncias/prevenção & controle , Síndrome de Abstinência a Substâncias/psicologia , Peixe-ZebraRESUMO
Binge drinking is characterized by excessive alcohol consumption in a short period of time and is associated with a poor quality of life. Zebrafish are commonly used to investigate neurochemical, behavioral, and genetic parameters associated with ethanol (EtOH) exposure. However, few studies have used zebrafish as a model to investigate binge EtOH exposure. In order to elucidate the potential neurobehavioral impairments evoked by binge EtOH exposure in zebrafish, animals were immersed in 1.4% EtOH for 30â¯min three consecutive times with intervals of one week. Neurobehavioral parameters were analyzed immediately following the third exposure, as well as 2 and 9â¯days later. Brain choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were reduced 9â¯days after the treatment. Thiobarbituric acid-reactive species and dichlorodihydrofluorescein levels were increased immediately after the treatment, but both returned to normal levels 2â¯days after the treatment. Catalase and glutathione reductase were impaired 2 and 9â¯days after the treatment. No alteration was observed in superoxide dismutase and glutathione peroxidase activities. EtOH treatment did not alter brain expression of inflammatory genes such as il-1ß, il-10, and tnf-α. Zebrafish displayed anxiolytic-like behavior immediately after the last exposure, though there was no behavioral alteration observed 9â¯days after the treatment. Therefore, binge EtOH exposure in zebrafish leads to long lasting brain cholinergic alteration, probably related to oxidative stress immediately after the exposure, which is independent of classical inflammatory markers.
Assuntos
Etanol/administração & dosagem , Comportamento Exploratório/efeitos dos fármacos , Peixe-Zebra/fisiologia , Acetilcolinesterase/metabolismo , Animais , Comportamento Animal , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Colina O-Acetiltransferase/metabolismo , Etanol/farmacologiaRESUMO
Binge drinking is defined as the infrequent consumption of excessive doses of alcohol in a short period of time. Zebrafish is a reliable model to investigate ethanol consumption impact on the CNS, including reward signaling like dopaminergic neurotransmission system. The aim of this study was to evaluate zebrafish brain dopaminergic parameters after intermittent weekly ethanol exposure (WEE), which mimics binge drinking. Thus, adult zebrafish were exposed to ethanol (1.4% v/v) for 30â¯min, once a week for three consecutive weeks. The groups were divided according to different time points after the third exposure and name as follow: immediately (WEEI), two days (WEE-2), and nine days (WEE-9) after last exposure to ethanol. Brain dopaminergic function was assessed by the activity of the dopamine transporters (DAT); monoamine oxidase (MAO) activity; dopamine and noradrenaline levels by chromatography. The WEE-I and WEE-2 groups presented a significant increase in DAT activity. The MAO activity was decreased for WEE-2 and WEE-9 groups. The WEE-2 and WEE-9 groups presented an increase in brain dopamine levels, while noradrenaline levels were not affected. Therefore, dopaminergic parameters are still altered two and nine days after the last ethanol exposure in this binge experimental model, resulting in a modulatory event in this neurotransmission pathway.