Navegando por Assunto "Oxidative stress"

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Acesso aberto (Open Access)
Ativação do receptor canabinóide tipo 1 (CB1r) previne o estresse oxidativo cerebral e inibe o comportamento tipo agressivo em Danio rerio (Zebrafish)
(Universidade Federal do Pará, 2022-08-17) PINHEIRO, Emerson Feio; SILVA, Anderson Manoel Herculano Oliveira da; http://lattes.cnpq.br/8407177208423247
Aggression is a set of complex actions that involve several factors of a genetic, neurophysiological, hormonal and behavioral nature. Furthermore, the brain redox state can also influence aggressive behavior in different species. Thus, modulators of this process can influence the expression of aggressive episodes, between them is the Endocannabinoid System that acts as the main neuromodulator of the CNS, in addition to exerting an antioxidant effect in different conditions. However, its participation in the modulation of aggressive-like behavior needs to be better understood. In this context, this study evaluated the role of cannabinoid receptor type 1 (CB1r) in brain redox state and aggressive-like behavior in Danio rerio (Zebrafish). For this, 64 animals were subdivided into groups: (a) Control (n=26), (b) ACEA (n=30) and (c) AM-251 (n=12), all treated with the drugs of interest: (a) Vehicle (NaCl 0.9%); (b) ACEA agonist 1 mg/kg; (c) 1 mg/kg AM-251 antagonist. The animals were isolated in pairs, without physical contact for 24 hours, followed by pre-treatment and after 30 minutes of pharmacokinetics, the fights were filmed for 30 minutes, the individuals were identified as Dominant or Subordinate and the brains were collected for evaluation of the state brain redox of these individuals. Our results demonstrate, for the first time, that the activation of CB1r by the ACEA agonist modulates aggressive-like behavior and, consequently, partially interferes with the establishment of social hierarchy in Zebrafish, through a redox-independent mechanism. We suggest, therefore, that acute treatment targeting CB1r is a useful neuropharmacological tool to elucidate the role of CES in social interaction and aggressive behavior, allowing a translation with numerous pathologies that have aggression as a behavioral disorder.
Acesso aberto (Open Access)
Efeitos do antioxidante tempol nas alterações bioquímicas e estruturais induzidas pela metaloproteinase de matriz 2 no coração
(Universidade Federal do Pará, 2020-09-11) GONÇALVES, Pricila Rodrigues; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390; https://orcid.org/ 0000-0002-3328-5650; PRADO, Alejandro Ferraz do; http://lattes.cnpq.br/7016475842644161; https://orcid.org/ 0000-0001-7495-9837
MMP-2 expression is elevated in many cardiovascular pathologies such as myocardial infarction and heart failure, where tissue remodeling and inflammatory responses are disturbed. Changes in ECM homeostasis can lead to cardiac dysfunction. The most analyzed MMPs in relation to cardiac dysfunction are MMP 2 and MMP-9. ROS inhibitors, as antioxidants, have been shown to reduce the expression of MMP-2 in vascular tissue. Thus, antioxidants with Tempol have great potential to act on these mechanisms. Therefore, we evaluated the activity and purity of rhMMP-2 using the zymogram and SDS-PAGE silver-stained method. The animals were divided into 4 treatment groups. Group 1: received 0.9% saline; group 2: Tempol 18 mg / kg / v.o; group 3: MMP-2 150 ng / kg / i.p; group 4: Tempol 18 mg / kg / v.o + MMP-2 150 ng / kg / i.p; for 4 weeks. At the end of the treatment, the heart was collected for quantification of collagen, quantification of ROS by fluorescence microscopy and immunofluorescence for TNFα and TGF-β. After the analysis, our results showed that rhMMP-2 was pure and active and that there was no difference in the average weight of the animals (P> 0.05). In the group treated withrhMMP-2 and Tempol, there was a decrease in the heart weight / body weight ratio, compared to the control group (P <0.05). Tempol was able to decrease collagen in the heart of animals treated with rhMMP 2. We also saw rhMMP-2 increased ROS in the heart, which was prevented by Tempol. RhMMP-2 also led to an increase in TNF-α and TGF-β in the heart, however TGF-β was reduced by Tempol. In conclusion, rhMMP-2 infusion increased cardiac ROS, which can lead to oxidative stress, with a consequent increase in TNF-α and TGF-β, which can result in a heart with a pro-fibrotic and inflammatory profile. However, Tempol was able to reduce interstitial collagen, inhibit the increase in ROS, TNF-α, TGF-β and increase catalase in the heart. Having Tempol, the potential to inhibit factors that lead to oxidative stress, inflammation and cardiac fibrosis.
Acesso aberto (Open Access)
Efeitos do quelante de ferro, a deferoxamina, sobre as alterações oxidativas e cognitivas induzidas pela dapsona, em modelo animal
(Universidade Federal do Pará, 2020-11-17) MENDES, Paulo Fernando Santos; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390; https://orcid.org/ 0000-0002-3328-5650
Dapsone (DDS) is an antibiotic that works by inhibiting folate synthesis, showing good bacteriostatic action. However, it can lead to severe adverse events such as neurological disorders, methemoglobinemia and hemolysis. These hematological disorders lead to the alteration of iron homeostasis and thereby increase the formation of ROS that can lead to cellular and tissue damage. This change plays an important role in neurodegenerative diseases, whether as a causative and / or intensifying agent in these diseases. In this context, we used an iron chelator, deferoxamine (DFX), to evaluate its effects on the formation of ROS triggered by the increase in free iron induced by the use of DDS. For this, the alteration of iron homeostasis was induced in Swiss mice, using DDS, followed by the administration of DFX. After that, oxidative stress parameters were measured in the hippocampus and plasma, in addition to the measurement of iron levels. Our results showed that DDS decreased TEAC and that DFX treatment was restored. In addition, DDS decreased GSH and DFX treatment was restored. It increased the LPO and the treatment with DFX reduced this effect, increased the concentration of iron and that was reversed by the treatment with DFX. Additionally, the animals were submitted to the Morris water maze, where our results showed that animals treated with DDS showed a reduction in mnemonic capacity and that treatment with DFX was able to inhibit loss. These results suggest that the use of iron chelators may be an alternative to reduce the effects of iron accumulation on the nervous system observed in neurodegenerative diseases.
Acesso aberto (Open Access)
Exposição ao MEHG provoca dano na medula espinhal: percepções a partir da análise proteômica e estresse oxidativo
(Universidade Federal do Pará, 2020-08-27) EIRÓ, Luciana Guimarães; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468; https://orcid.org/ 0000-0003-1486-4013
Methylmercury (MeHg) is considered by the World Health Organization as one of the chemicals of greatest public health concern. Thus, knowing the susceptibility of central nervous system regions and the absence of evidence about the effects on the spinal cord, this study aimed to investigate proteomic and biochemical changes in the spinal cord after MeHg long-term exposure at low doses. For this, male Wistar rats were exposed to a dose of 0.04 mg/kg/day by for 60 days. After that, the proteome was identified with subsequent overrepresentation analysis (ORA). For the oxidative biochemistry, the antioxidant (ACAP, TEAC, GSH) and pro-oxidants (LPO and nitrite ions) parameters were evaluated. The proteomic analysis showed several altered proteins that participate in biological processes, cellular components, and molecular functions. There was an increase in total mercury (Hg) levels in the spinal cord, as well as an increase in LPO and nitrite ions and a reduction in ACAP, TEAC and GSH. Therefore, exposure to low doses of MeHg can trigger oxidative stress associated with changes in the proteomic profile.
Acesso aberto (Open Access)
Intestinal intraluminal injection of glutamine increases trolox total equivalent antioxidant capacity (TEAC) in hepatic ischemia-reperfusion
(Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia, 2006) SALOMÃO, Alberto Bicudo; NASCIMENTO, José Eduardo de Aguilar Siqueira do; PERCÁRIO, Sandro; GARCIA, Victor Cezar Sano; MARQUES, Nicole Ribeiro; DIAS, Claudia Cristina Gomes de Oliveira
PURPOSE: To evaluate the effects of intraluminal injection of glutamine on the serum trolox equivalent antioxidant capacity in an experimental model of ischemia-reperfusion of the liver observing the applicability of modifications on the original assay method. METHODS: Thirty Wistar rats underwent laparotomy to perform a 20 cm blind sac of small bowel and occlusion of the hepatic hilo for 30 minutes and reperfusion for 5 minutes. Into the gut sac it was injected glutamine (glutamine group, n=10) or distilled water (control group, n=10). Ten other animals (sham group) underwent laparotomy without artery occlusion. Blood samples were collected for trolox equivalent antioxidant capacity assays in different temperature conditions, reagent quantities and time for spectrophotometer readings. RESULTS: Total antioxidant capacity was significantly greater in glutamine group than in both control group (1,60[1,55-1,77] vs 1,44[1,27-1,53]) and sham group (1,60[1,55-1,77] vs 1,48[1,45-1,59]). CONCLUSION: Glutamine enhanced serum antioxidant capacity. The assay technique consistently reflected the changes in the antioxidant defenses in this experimental model.
Acesso aberto (Open Access)
Suplementação alimentar com açaí (Euterpe oleracea) como potencial modulador das defesas antioxidantes e dano oxidativo em zebrafish (Danio rerio)
(Universidade Federal do Pará, 2024-04-25) NASCIMENTO, Géssica Amorim do; AMADO, Lilian Lund; http://lattes.cnpq.br/3382900147208081; HTTPS://ORCID.ORG/0000-0001-7693-8191; VALENTIN, Fernanda Nogueira; http://lattes.cnpq.br/5323991664296959; https://orcid.org/0000-0002-8279-3758
Diets enriched with Amazonian açaí (E. oleracea) provide great nutritional and therapeutic health benefits, related to the presence of bioactive compounds. The pulp of the açaí fruit is high in anthocyanins, plant pigments that have anti- inflammatory and antioxidant properties. The use of D. rerio (Teleostei: Cyprinidae) as an animal model in bioassays is important for evaluating possible molecular alterations caused by the pro-oxidants present in the cells, with direct applications in other fish and can also be extrapolated to humans, due to the genetic homology of 70% of the genome. The aim of this study was to characterize the effects of dietary supplementation with freeze-dried açaí pulp (AÇL), testing different concentrations of anthocyanins, as a potential modulator of the antioxidant defence system in D. rerio. The study was carried out in the Ecotoxicology section of LAPMAR at UFPA/Belém. A total of 40 D. rerio specimens were organized into: control group (CTR) - standard diet only; and according to the value of the standard diet, the amounts for supplementation in treatment were calculated T1 - standard diet and supplementation of 10% AÇL; T2 - standard diet and supplementation of 25% AÇL; T3 - standard diet and supplementation of 50% AÇL. Water physicochemical parameters, siphoning and partial water changes were analyzed over the course of 5 days. At the end of the 120-hour experiment, the fish were collected, euthanized by cryoanesthesia, biometrically measured, weighed and stored at -80 ºC in an ultrafreezer. Subsequently, the whole animals were homogenized, followed by the quantification of total proteins and measurements of biochemical biomarkers of oxidative stress: total antioxidant capacity (TACC), glutamate cysteine ligase (GCL), reduced glutathione (GSH), glutathione reductase (GR), glutathione s- transferase (GST) and lipoperoxidation (LPO). The results were analyzed by means of comparisons between independent groups with a quantitative response variable, using the non-parametric Kruskal-Wallis test, with a significance level of 5%. Of the physicochemical parameters evaluated, ammonia levels were the only ones monitored that showed a significant difference (p < 0.05) in the T3 - 50% AÇL treatment at the last analysis time. There was no statistically significant difference (p>0.005) for the biometric data and also for the biomarkers between the sample groups. The results indicate that the supplementary supply of açaí for longer periods can promote a neutralization of pro-oxidant agents in the cells. This supplementation can be considered a natural alternative to increase resistance to stress in the face of pro-oxidant conditions in the body, establishing chemoprotection strategies for human and animal health.