Navegando por Assunto "Stresse oxidativo"

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Acesso aberto (Open Access)
Ação da hidroxicloroquina sobre neurônios da retina de embrião de galinha
(Universidade Federal do Pará, 2017-03-22) ROSÁRIO, Aldanete Santos; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978
Hydroxychloroquine (HCQ) is currently used in the treatment of malaria and autoimmune diseases and others therapeutic purposes. However, this drug is known to cause side effects, including producing visual disturbances, which may be irreversible. The mechanisms that produce these visual disorders are not completely known. HCQ - related retinal toxicity may be due to high metabolic rate, being very susceptible to the action of xenobiotics and oxidative damages. Thus, this work aims to evaluate the effects of the HCQ on retinal cells, as well as their possible mechanisms of cytotoxicity. The model used in this work was of cultures of retina cells from chicken embryo. To evaluate cell viability, mitochondrial activity was measured by MTT. The lysosomal function was evaluated by the incorporation rate of the neutral red dye. The levels of reactive species of general oxygen and superoxide anion were evaluated by the CellROX probe and by Nitro Blue Tetrazolium (NBT) and total glutathione levels were quantified using the Ellman reagent. Viability was tested in mixed cultures (glia and neurons) or enriched cultures of neurons and glia after treatment with HCQ and compared with chloroquine (CQ). Cells were exposed to concentrations of 25μM, 50μM and 75μM for 24 hours. The results show that mixed cultures treated with CQ presented a reduction in viability of 36 and 61% at concentrations of 50μM and 75μM, respectively, whereas HCQ did not alter viability at any of the concentrations tested. However, when cultures enriched with glial cells were exposed to HCQ for 24 hours, the concentration of 75μM had a small reduction in cell viability, while that the reduction in neuronal cells was of 20, 33 and 56% at the concentrations of 25μM, 50μM and 75μM, respectively. Even a shorter treatment time (6 hours) there was loss of viability in retinal neurons. The incorporation of neutral red supravital dye was also altered in neuronal cultures treated with HCQ for 24 hours, with reduction of 19 and 32%, compared to the control for the concentrations of 50μM and 75μM, respectively. HCQ significantly reduced the levels of reactive oxygen species produced by the neuronal cells, mainly superoxide anion, 43, 52 and 61% for the concentrations of 25μM, 50μM and 75μM of HCQ in 24 hours of treatment, respectively. In concentrations of 50μM and 75μM of HCQ for 24 for hours, the levels of total glutathione in neuronal cells presented a reduction of 37 and 53%, respectively. When the glial cell conditioned medium was used in neuronal cells for 6 hours after treatment with HCQ, it completely reversed the drug-induced cytotoxicity. When total glutathione levels were measured in culture of glia treated with HCQ for 24 hours no changes were observed. These results suggest cytotoxic action of CQ in mixed culture of chicken embryo retina cells which is not observed in HCQ treatment. However, HCQ showed cytotoxic action when cells are cultured separately, mainly on neurons, which is reversed by some factor released by glial cells in the extracellular environment, and glutathione is a possible candidate to exert this neuroprotective function.
Acesso aberto (Open Access)
Investigação dos efeitos da cafeína e SCH58261 sobre as alterações comportamentais e no estresse oxidativo, e papel dos receptores A2A na potenciação de longo prazo após intoxicação por etanol em padrão binge em ratos fêmeas da adolescência a fase adulta
(Universidade Federal do Pará, 2022-11) PINHEIRO, Bruno Gonçalves; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101
Introduction: Binge consumption of ethanol is an intermittent and episodic pattern of ingestion involved in several brain disorders that affect adolescents, considered more susceptible to damage that persists into adulthood. In the deleterious effects of ethanol, an important intoxication mechanism is the overproduction of adenosine, which causes hyperexcitability in its receptors, generating behavioral changes and oxidative stress. These receptors are antagonized by caffeine, a bioactive compound that can modulate the deleterious overactivation of ethanol. Objective: The aim of this study was to investigate the effects of caffeine administration on behavioral changes related to locomotion, anxiety, cognition and oxidative balance induced by ethanol in the binge drinking pattern during adolescence. In addition, it aims to assess the contribution of A2A receptors in the observed changes, including long-term potentiation (LTP). Material and Methods: Female Wistar rats (35 days old; n = 102) were allocated into six groups: control (distilled water, v.o), ethanol (3 g/kg/day; 3 days on-4 days off, v.o) , caffeine (10 mg/kg/day, v.o), caffeine + ethanol, A2A antagonist SCH58261 (0.1 mg/kg/day, intraperitoneal - i,p) and ethanol + SCH58261. The animals were submitted to open field behavioral tests, object recognition and elevated plus maze. The oxidative biochemistry parameters of trolox equivalent antioxidant capacity (TEAC), glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), nitric oxide (NO), thiobarbituric acid reactive substances (TBARS) in the pre- frontal and hippocampus. LTP recordings in the medial prefrontal cortex (mPFC), ventral (vHip) and dorsal (dHIP) portions of the hippocampus of the control, ethanol, ethanol + SCH58261 and SCH58261 groups were evaluated through electrophysiology. Results: Caffeine prevented ethanol-induced behavioral impairments, including by blocking A2A receptors. In addition, it attenuated the oxidative stress induced by binge drinking by alternative A2A receptor pathways. Blockade of A2A receptors increased LTP levels in mPFC and vHIP, however decreased in dHIP. Conclusion: Caffeine showed neuroprotection in behavioral changes and oxidative stress induced by the binge drinking model in adolescent rats. In addition, blockade of A2A receptors mitigated the observed behavioral changes, with improvement of LTP levels in the prefrontal cortex and hippocampus, which suggests the contribution of this pathway to neuroprotection in deficits induced by ethanol exposure during adolescence.