RESUMO
Neuroinflammation has been associated to neurodegenerative disease development, with evidence suggesting that high levels of proinflammatory cytokines promote neuronal dysfunction and death. Therefore, it is necessary to study new compounds that may be used as adjuvant treatments of neurodegenerative diseases by attenuating the inflammatory response in the central nervous system (CNS). The aim of this study was to utilize the lipopolysaccharide (LPS) induction model of neuroinflammation to evaluate the modulation of inflammation by rosmarinic acid (RA) isolated from Blechnum brasiliense in adult zebrafish. First, we investigated the toxicity and antioxidant properties of fractionated B. brasiliense extract (ethyl acetate fraction- EAF) and the isolated RA in zebrafish embryos. Next, we developed a model of neuroinflammation induction by intraperitoneal (i.p.) injection of LPS to observe the RA modulation of proinflammatory cytokines. The median lethal concentration (LC50) calculated was 185.2 ± 1.24 µg/mL for the ethyl acetate fraction (EAF) and 296.0 ± 1.27 µM for RA. The EAF showed free radical inhibition ranging from 23.09% to 63.44% at concentrations of 10-250 µg/mL. The RA presented a concentration-dependent response ranging from 18.24% to 47.63% at 10-250 µM. Furthermore, the RA reduced LPS induction of TNF-α and IL-1ß levels, with the greatest effect observed 6 h after LPS administration. Thus, the data suggested an anti-inflammatory effect of RA isolated from B. brasiliense and reinforced the utility of the new model of neuroinflammation to test the possible neuroprotective effects of novel drugs or compounds.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Encéfalo/efeitos dos fármacos , Cinamatos/farmacologia , Depsídeos/farmacologia , Gleiquênias/química , Inflamação/tratamento farmacológico , Extratos Vegetais/farmacologia , Peixe-Zebra/imunologia , Animais , Encéfalo/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Inflamação/metabolismo , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Ácido RosmarínicoRESUMO
Stress-related psychiatric disorders are mental conditions that affect mood, cognition and behavior and arise because of the impact of prolonged stress on the central nervous system (CNS). Acetyl-L-carnitine (ALC) is an acetyl ester of L-carnitine that easily crosses the blood-brain barrier and was recently found to be decreased in patients with major depressive disorder. ALC plays a role in energy metabolism and is widely consumed as a nutritional supplement to improve physical performance. In this study, our objective was to evaluate the effects of ALC treatment (0.1â¯mg/L, 10â¯min) for 7 days on behavior and oxidative stress in zebrafish subjected to unpredictable chronic stress (UCS) protocol. Behavioral outcomes were assessed in the novel tank test, and parameters of oxidative status (lipid peroxidation and antioxidant defenses) were evaluated in the brain using colorimetric methods. According to our previous findings, UCS increased anxiety-like behavior and lipid peroxidation, while it decreased non-protein thiol levels and superoxide dismutase activity. However, ALC reversed the anxiety-like behavior and oxidative damage in stressed animals, while it was devoid of effect in control animals. Although our data reinforce the neuroprotective potential of ALC in the treatment of psychiatric disorders related to stress, further investigations are required to clarify its mechanisms of action and confirm its efficacy.
Assuntos
Acetilcarnitina/farmacologia , Antioxidantes/farmacologia , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Acetilcarnitina/uso terapêutico , Animais , Antioxidantes/uso terapêutico , Encéfalo/metabolismo , Feminino , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/metabolismo , Peixe-ZebraRESUMO
Valproic acid (VPA) is an antiepileptic drug (AED) that has the broadest spectrum across all types of seizures and epileptic syndromes. Unfortunately, approximately 30% of epileptic patients are refractory to the classical AED. Metal ions have been frequently incorporated into pharmaceuticals for therapeutic or diagnostic purposes and research. In this preliminary study, we assess the embryo toxicity and the anticonvulsant activity of 4 novel metallodrugs, with Zn+2 and Cu+2, a derivative of valproic acid and the N-donor ligand in an adult zebrafish epileptic seizure model induced by pentylenetetrazole. The most toxic complex was [Cu(Valp)2Bipy], in which the LC50 was 0.22⯵M at 48â¯h post fertilization (HPF) and 0.12⯵M at 96 HPF, followed by [Zn(Valp)2Bipy] (LC50â¯=â¯10⯵M). These same metallodrugs ([Cu(Valp)2Bipy] 10â¯mM/kg and [Zn(Valp)2Bipy] 30â¯mM and 100â¯mM/kg) displayed superior activity, thus reducing the seizure intensity by approximately 20 times compared to sodium valproate (175â¯mM/kg). Overall, [Cu(Valp)2Bipy] showed the best anticonvulsant effects. However, because of the toxicity of copper, [Zn(Valp)2Bipy] is considered the most promising anticonvulsant for future studies.
Assuntos
Anticonvulsivantes/farmacologia , Cobre/farmacologia , Teratogênicos/farmacologia , Ácido Valproico/farmacologia , Compostos de Zinco/farmacologia , Animais , Anticonvulsivantes/química , Anticonvulsivantes/toxicidade , Cobre/química , Cobre/toxicidade , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/patologia , Epilepsia/tratamento farmacológico , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Compostos Organometálicos/toxicidade , Pentilenotetrazol , Dados Preliminares , Convulsões/tratamento farmacológico , Teratogênicos/química , Teratogênicos/toxicidade , Ácido Valproico/química , Ácido Valproico/toxicidade , Peixe-Zebra , Compostos de Zinco/química , Compostos de Zinco/toxicidadeRESUMO
Several studies have shown that manipulations to the housing environment modulate susceptibility to stress in laboratory animals, mainly in rodents. Environmental enrichment (EE) is one such manipulation that promotes neuroprotection and neurogenesis, besides affecting behaviors such as drug self-administration. Zebrafish are a popular and useful animal model for behavioral neuroscience studies; however, studies evaluating the impact of housing conditions in this species are scarce. In this study, we verified the effects of EE on behavioral (novel tank test) and biochemical [cortisol and reactive oxygen species (ROS)] parameters in zebrafish submitted to unpredictable chronic stress (UCS). Consistent with our previous findings, UCS increased anxiety-like behavior, cortisol and ROS levels in zebrafish. EE for 21 or 28â days attenuated the effects induced by UCS on behavior and cortisol, and prevented the effects on ROS levels. Our findings reinforce the idea that EE exerts neuromodulatory effects across species, reducing vulnerability to stress and its biochemical impact. Also, these results indicate that zebrafish is a suitable model animal to study the behavioral effects and neurobiological mechanisms related to EE.
Assuntos
Bem-Estar do Animal , Meio Ambiente , Estresse Fisiológico , Peixe-Zebra/fisiologia , Animais , Feminino , Abrigo para Animais , Hidrocortisona/metabolismo , Masculino , Modelos Animais , Distribuição Aleatória , Espécies Reativas de Oxigênio/metabolismoRESUMO
Palicourea genus is chemically and taxonomically close to Psychotria genus, a well-known source of neuroactive alkaloids. It has been previously reported the pharmacological potential of these alkaloids in some targets related to the neurodegenerative process. In this context, this study was carried out in order to evaluate the toxic effects and acetylcholinesterase (AChE) inhibitory potential of Palicourea deflexa fraction of total alkaloids (FTA). P. deflexa FTA was analyzed by means of HPLC-DAD and HRMS-ESI. We performed toxicological screening through Fish Embryo Toxicity (FET) test using zebrafish embryo and abnormal developmental phenotypes were recorded daily. For AChE inhibition, zebrafish brains were used as enzymatic source and formation of thiolate dianion of 5,5'-Dithiobis(2-nitrobenzoic acid) (DTNB) was used to monitor acetylthiocholine hydrolysis. Lineaweaver-Burk double reciprocal plots were used to indicate mode of inhibition. Chemical analysis of the P. deflexa FTA allowed the identification of the main compound as harman-3-carboxylic acid. This fraction was evaluated in vivo for its toxicological effect. The zebrafish embryo test indicated that the FTA has a lethal concentration of 50% (LC50)=72.18µg/mL. Further, the FTA was evaluated for its AChE inhibitory profile, demonstrating an inhibitory concentration of 50% (IC50) of 50.65µg/mL. Lineaweaver-Burk double reciprocal plots indicated a mixed mode of inhibition. It is reported for the first time the toxicological and pharmacological profile of the alkaloid fraction of Palicourea deflexa in zebrafish models.
Assuntos
Acetilcolinesterase/metabolismo , Alcaloides/toxicidade , Inibidores da Colinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Rubiaceae/química , Alcaloides/química , Animais , Encéfalo/enzimologia , Inibidores da Colinesterase/administração & dosagem , Inibidores da Colinesterase/química , Relação Dose-Resposta a Droga , Embrião não Mamífero/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia , Folhas de Planta/química , Peixe-ZebraRESUMO
The understanding of the consequences of chronic treatment with methylphenidate is very important since this psychostimulant is extensively prescribed to preschool age children, and little is known about the mechanisms underlying the persistent changes in behavior and neuronal function related with the use of methylphenidate. In this study, we initially investigate the effect of early chronic treatment with methylphenidate on amino acids profile in cerebrospinal fluid and prefrontal cortex of juvenile rats, as well as on glutamatergic homeostasis, Na(+),K(+)-ATPase function, and balance redox in prefrontal cortex of rats. Wistar rats at early age received intraperitoneal injections of methylphenidate (2.0 mg/kg) or an equivalent volume of 0.9% saline solution (controls), once a day, from the 15th to the 45th day of age. Twenty-four hours after the last injection, the animals were decapitated and the cerebrospinal fluid and prefrontal cortex were obtained. Results showed that methylphenidate altered amino acid profile in cerebrospinal fluid, increasing the levels of glutamate. Glutamate uptake was decreased by methylphenidate administration, but GLAST and GLT-1 were not altered by this treatment. In addition, the astrocyte marker GFAP was not altered by MPH. The activity and immunocontent of catalytic subunits (α1, α2, and α3) of Na(+),K(+)-ATPase were decreased in prefrontal cortex of rats subjected to methylphenidate treatment, as well as changes in α1 and α2 gene expression of catalytic α subunits of Na(+),K(+)-ATPase were also observed. CAT activity was increased and SOD/CAT ratio and sulfhydryl content were decreased in rat prefrontal cortex. Taken together, our results suggest that chronic treatment with methylphenidate at early age induces excitotoxicity, at least in part, due to inhibition of glutamate uptake probably caused by disturbances in the Na(+),K(+)-ATPase function and/or in protein damage observed in the prefrontal cortex.
Assuntos
Ácido Glutâmico/líquido cefalorraquidiano , Homeostase/efeitos dos fármacos , Metilfenidato/farmacologia , Córtex Pré-Frontal/metabolismo , Sistema X-AG de Transporte de Aminoácidos/metabolismo , Animais , Antígenos Nucleares/metabolismo , Domínio Catalítico , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Imuno-Histoquímica , Masculino , Modelos Biológicos , Proteínas do Tecido Nervoso/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/patologia , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
Açai (Euterpe oleracea Mart.), a highly consumed fruit in Amazon, is from a common palm with remarkable antioxidant properties. Because oxidative stress and seizures are intimately linked, this study investigated the potential neuroprotective and anticonvulsant effects of commercial clarified açai juice (EO). EO did not alter spontaneous locomotor activity. Four doses of EO were sufficient to increase latencies to both first myoclonic jerk and first generalized tonic-clonic seizure and significantly decrease the total duration of tonic-clonic seizures caused by pentylenetetrazol administration. Also, electrocortical alterations provoked by pentylenetetrazol were prevented, significantly decreasing amplitude of discharges and frequencies above 50 Hz. EO was also able to completely prevent lipid peroxidation in the cerebral cortex, showing a potent direct scavenging property. These results demonstrate for the first time that E. oleracea significantly protects against seizures and seizure-related oxidative stress, indicating an additional protection for humans who consume this fruit.
Assuntos
Anticonvulsivantes/farmacologia , Antioxidantes/farmacologia , Euterpe , Pentilenotetrazol/farmacologia , Convulsões/tratamento farmacológico , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Euterpe/metabolismo , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologiaRESUMO
Cadmium (Cd) is a known hepato- and nephrotoxic pollutant and zinc (Zn) metalloproteins are important targets of Cd. Hence, the administration of Zn may mitigate Cd toxic effects. However, the interaction of Cd and Zn has been little investigated in the brain. Previously, we reported a protective effect of Zn on mortality caused by Cd in rats. Here, we tested whether the protective effect of Zn could be related to changes in brain Zn-proteins, metallothionein (MT) and δ-aminolevulinate dehydratse (δ-ALA-D). Male adult rats were daily administered for 10 days with Zn (2 mg kg-1), Cd (0.25 and 1 mg kg-1) and 0.25 mg kg-1 of Cd plus Zn and 1 mg kg-1 of Cd plus Zn. The body weight loss, food intake deprivation, and mortality occurred in 1 mg kg-1 of Cd, but Zn co-administration did mitigate these effects. The brain Zn content was not modified by treatment with Cd, whereas cerebral Cd levels increased in animals exposed to Cd. The administration of 0.25 mg kg-1 of Cd (with or without Zn) induced lipid peroxidation and decreased MT concentration, but 2 mg kg-1 of Zn and 1 mg kg-1 of Cd did not change these parameters. Brain δ-ALA-D was not modified by Cd and/or Zn treatments. Since the co-administration of Zn did not attenuate the changes induced by Cd in the brain, our results suggest that the protective effect of Zn on impairments caused by Cd in animal status is weakly related to a cerebral interaction of these metals.
RESUMO
Reactive zinc (Zn) is crucial for neuronal signaling and is largely distributed within presynaptic vesicles of some axon terminals of distinct vertebrates. However, the distribution of reactive Zn throughout the central nervous system (CNS) is not fully explored. We performed a topographical study of CNS structures containing reactive Zn in the adult zebrafish (Danio rerio). Slices of CNS from zebrafish were stained by Neo-Timm and/or cresyl violet. The Zn specificity of Neo-Timm was evaluated with Zn chelants, N,N,N',N'-Tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), sodium diethyldithiocarbamate (DEDTC), Zn sulfide washing solution, and hydrochloric acid (HCl). Unfixed slices were also immersed in the fluorescent Zn probe (zinpyr-1). Yellow-to-brown-to-black granules were revealed by Neo-Timm in the zebrafish CNS. Telencephalon exhibited slightly stained regions, while rhombencephalic structures showed high levels of staining. Although stained granules were found on the cell bodies, rhombencephalic structures showed a neuropil staining profile. The TPEN produced a mild reduction in Neo-Timm staining, while HCl and mainly DEDTC abolished the staining, indicating a large Zn content. This result was also confirmed by the application of a Zn probe. The present topographical study revealed reactive Zn throughout the CNS in adult zebrafish that should be considered in future investigation of Zn in the brain on a larger scale.
Assuntos
Sistema Nervoso Central/metabolismo , Peixe-Zebra/metabolismo , Zinco/metabolismo , Animais , Ditiocarb , Etilenodiaminas , Feminino , Fluoresceínas , MasculinoRESUMO
Pentylenetetrazole (PTZ) is a common convulsant agent used in animal models to investigate the mechanisms of seizures. Although adult zebrafish have been recently used to study epileptic seizures, a thorough characterization of the PTZ-induced seizures in this animal model is missing. The goal of this study was to perform a detailed temporal behavior profile characterization of PTZ-induced seizure in adult zebrafish. The behavioral profile during 20 min of PTZ immersion (5, 7.5, 10, and 15 mM) was characterized by stages defined as scores: (0) short swim, (1) increased swimming activity and high frequency of opercular movement, (2) erratic movements, (3) circular movements, (4) clonic seizure-like behavior, (5) fall to the bottom of the tank and tonic seizure-like behavior, (6) death. Animals exposed to distinct PTZ concentrations presented different seizure profiles, intensities and latencies to reach all scores. Only animals immersed into 15 mM PTZ showed an increased time to return to the normal behavior (score 0), after exposure. Total mortality rate at 10 and 15 mM were 33% and 50%, respectively. Considering all behavioral parameters, 5, 7.5, 10, and 15 mM PTZ, induced seizures with low, intermediate, and high severity, respectively. Pretreatment with diazepam (DZP) significantly attenuated seizure severity. Finally, the brain PTZ levels in adult zebrafish immersed into the chemoconvulsant solution at 5 and 10 mM were comparable to those described for the rodent model, with a peak after a 20-min of exposure. The PTZ brain levels observed after 2.5-min PTZ exposure and after 60-min removal from exposure were similar. Altogether, our results showed a detailed temporal behavioral characterization of a PTZ epileptic seizure model in adult zebrafish. These behavioral analyses and the simple method for PTZ quantification could be considered as important tools for future investigations and translational research.