Instituto Nacional Translacional em Medicina INCT TM

Porto Alegre, Brazil

Instituto Nacional Translacional em Medicina INCT TM

Porto Alegre, Brazil
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Longaray-Garcia M.,Grande Rio University | Longaray-Garcia M.,Brazilian National Council for Scientific and Technological Development | Flores J.A.,Grande Rio University | Flores J.A.,Brazilian National Council for Scientific and Technological Development | And 9 more authors.
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology | Year: 2013

Lipoic acid (LA) is a water- and lipid-soluble molecule with capacity to pass through cell membranes and with several antioxidant properties. Previous studies have shown that polymeric nanocapsules with LA favor the protection of this antioxidant, increasing their physical and chemical stability compared to formulations containing free LA. The aim of this study was to evaluate and compare the effect of free LA and LA-nanocapsules on antioxidant enzymes, the concentration of reduced glutathione (GSH) and a by-product of lipid peroxidation (malondialdehyde), as well as the expression of gene coding for different forms of glutathione-S-transferase (GST) in model fish. For this, carp Cyprinus carpio (Cyprinidae) were exposed (i.p.) to different forms of LA (free and in nanocapsules) for different times (48. h, 96. h and 1. week) and the brain, liver and muscle were analyzed. Results indicated that the organs respond differently depending on the time and form in which LA was delivered. After 96. h and 1. week, a better antioxidant response was found generally in the formulation with nanocapsules. The nanocapsule composition showed to be a factor to be considered in future studies, because in some organs and exposure times empty nanocapsules promoted an antioxidant effect and in others a pro-oxidant effect. © 2013.

Seibt K.J.,Grande Rio University | Seibt K.J.,Instituto Nacional Translacional em Medicina INCT TM | Da Luz Oliveira R.,Grande Rio University | Da Luz Oliveira R.,Instituto Nacional Translacional em Medicina INCT TM | And 8 more authors.
Journal of Neural Transmission | Year: 2012

Schizophrenia is a debilitating mental disorder with a global prevalence of 1% and its etiology remains poorly understood. In the current study we investigated the influence of antipsychotic drugs on the effects of MK-801 administration, which is a drug that mimics biochemical changes observed in schizophrenia, on Na+, K+-ATPase activity and some parameters of oxidative stress in zebrafish brain. Our results showed that MK-801 treatment significantly decreased Na+, K+-ATPase activity, and all antipsychotics tested prevented such effects. Acute MK-801 treatment did not alter reactive oxygen/nitrogen species by 2′7′- dichlorofluorscein (H2DCF) oxidation assay, but increased the levels of thiobarbituric acid reactive substances (TBARS), when compared with controls. Some antipsychotics such as sulpiride, olanzapine, and haloperidol prevented the increase of TBARS caused by MK-801. These findings indicate oxidative damage might be a mechanism involved in the decrease of Na+, K+- ATPase activity induced by MK-801. The parameters evaluated in this study had not yet been tested in this animal model using the MK-801, suggesting that zebrafish is an animal model that can contribute for providing information on potential treatments and disease characteristics. © Springer-Verlag 2012.

Sant'Anna M.C.B.,Grande Rio University | de Soares V.M.,Grande Rio University | Seibt K.J.,Grande Rio University | Ghisleni G.,Grande Rio University | And 9 more authors.
Fish Physiology and Biochemistry | Year: 2011

Iron is one the most abundant metals on the earth being essential for living organisms even though its free form can be toxic. The overload of this metal may be related with some disorders, like Alzheimer and Parkinson diseases, and hemochromatosis in the liver. The aim of the present study was to evaluate the effects of iron on acetylcholinesterase (AChE) activity in brain and liver of zebrafish and to investigate the possible correlation with the iron content in these tissues. Different corresponding concentrations of iron were tested using in vitro (0.018, 0.268, and 2.6 mM) and in vivo (1, 15, and 150 mg/l) assays. The in vitro studies showed that iron promoted a significant increase in AChE activity in brain (52%) and liver (53%) at the higher concentration (2.6 mM). In the in vivo assays, a significant increase in this enzyme activity was observed in the presence of 15 mg/l in both, brain (62%) and liver tissue (70%). Semiquantitative RT-PCR did not reveal significant changes in acetylthiocholinesterase mRNA levels. Moreover, we observed that iron content was significantly increased in liver tissue when exposed to 15 (226%) and 150 mg/l (200%). These results indicate that iron can promote significant alterations in AChE activity which probably is not directly related to the iron content in zebrafish tissues. © 2010 Springer Science+Business Media B.V.

Pereira T.C.B.,Grande Rio University | Rico E.P.,Federal University of Rio Grande do Sul | Rosemberg D.B.,Federal University of Rio Grande do Sul | Schirmer H.,Grande Rio University | And 6 more authors.
Zebrafish | Year: 2011

Sirtuins comprise a unique class of NAD+-dependent deacetylases that are key regulators of many physiological processes. They appear to be a potential target set of enzymes for treatment of age-associated diseases and have attracted interest in many research areas involving chemical and cellular investigations to understand them and discover potential ligands. For molecular screening, a cost-effective, easily manipulated, and consolidated model organism is needed, and the zebrafish fits these requirements perfectly. Here, we report the identification of sirtuin-related genes and their expression patterns in nine tissues of adult zebrafish. The investigation identified eight sirtuin-related genes, and their phylogenetic analysis resulted in seven well-resolved terminal clades, corresponding to each sirtuin (SIRT1, 2, 4-7) and two SIRT3 paralogs. Each gene showed a unique expression profile, illustrating a wide tissue distribution of sirtuins in zebrafish. SIRT1, SIRT3, SIRT5, and SIRT6 genes were expressed in all tissues, and SIRT1 exhibited the highest level of expression in all organs. A modulation experiment was performed using resveratrol, and results confirmed to the predicted scenario: altered sirtuin expression levels. Drugs based on sirtuin modulators may be tested using this system and could lead us to more selective and powerful therapies for age-related disorders. © 2011 Mary Ann Liebert, Inc.

Rosemberg D.B.,Federal University of Rio Grande do Sul | Rosemberg D.B.,Instituto Nacional Of Ciencia E Tecnologia Em Excitotoxicidade E Neuroprotecao | Rico E.P.,Federal University of Rio Grande do Sul | Rico E.P.,Instituto Nacional Of Ciencia E Tecnologia Em Excitotoxicidade E Neuroprotecao | And 13 more authors.
PLoS ONE | Year: 2011

The open tank paradigm, also known as novel tank diving test, is a protocol used to evaluate the zebrafish behavior. Several characteristics have been described for this species, including scototaxis, which is the natural preference for dark environments in detriment of bright ones. However, there is no evidence regarding the influence of "natural stimuli" in zebrafish subjected to novelty-based paradigms. In this report, we evaluated the spatio-temporal exploratory activity of the short-fin zebrafish phenotype in the open tank after a short-period confinement into dark/bright environments. A total of 44 animals were individually confined during a 10-min single session into one of three environments: black-painted, white-painted, and transparent cylinders (dark, bright, and transparent groups). Fish were further subjected to the novel tank test and their exploratory profile was recorded during a 15-min trial. The results demonstrated that zebrafish increased their vertical exploratory activity during the first 6-min, where the bright group spent more time and travelled a higher distance in the top area. Interestingly, all behavioral parameters measured for the dark group were similar to the transparent one. These data were confirmed by automated analysis of track and occupancy plots and also demonstrated that zebrafish display a classical homebase formation in the bottom area of the tank. A detailed spatio-temporal study of zebrafish exploratory behavior and the construction of representative ethograms showed that the experimental groups presented significant differences in the first 3-min vs. last 3-min of test. Although the main factors involved in these behavioral responses still remain ambiguous and require further investigation, the current report describes an alternative methodological approach for assessing the zebrafish behavior after a forced exposure to different environments. Additionally, the analysis of ethologically-relevant patterns across time could be a potential phenotyping tool to evaluate the zebrafish exploratory profile in the open tank task. © 2011 Rosemberg et al.

Rosemberg D.B.,Institute Ciencias Basicas da Sau | Rosemberg D.B.,Instituto Nacional em Excitotoxicidade e Neuroprotecao INCT EN | Rico E.P.,Institute Ciencias Basicas da Sau | Rico E.P.,Instituto Nacional em Excitotoxicidade e Neuroprotecao INCT EN | And 10 more authors.
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology | Year: 2010

The nucleoside triphosphate diphosphohydrolase (NTPDase) family cleaves tri- and diphosphonucleosides to monophosphonucleosides and is responsible for terminating purinergic transmission. Since the NTPDase family in zebrafish is poorly understood, here we evaluated the nucleotide hydrolysis in three tissues of adult zebrafish (brain, liver, and heart), confirmed the presence of distinct NTPDase members by a phylogenetic analysis and verified their relative gene expression profiles in the respective tissues. A different profile of ATP and ADP hydrolysis in the brain, liver, and heart as a function of time and protein concentration was observed. Sodium azide (20 mM), ARL 67156 (300 μM) and Suramin (300 μM) differently altered the nucleotide hydrolysis in zebrafish tissues, suggesting the contribution of distinct NTPDase activities. Homology-based searches identified the presence of NTPDase1-6 and NTPDase8 orthologs and the phylogeny also grouped three NTPDase2 and two NTPDase5 paralogs. The deduced amino acid sequences share the apyrase conserved regions, conserved cysteine residues, putative N-glycosylation, phosphorylation, N-acetylation sites, and different numbers of transmembrane domains. RT-PCR experiments revealed the existence of a distinct relative entpd1-6 and entpd8 expression profile in brain, liver, and heart. Taken together, these results indicate that several NTPDase members might contribute to a tight regulation of nucleotide hydrolysis in zebrafish tissues. © 2009 Elsevier Inc. All rights reserved.

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