This study investigated the neurotoxic effects of rotenone and 6-hyroxydopamine (6 OHDA), two compounds which have been implicated in Parkinson’s disease (PD). PD is a neurodegenerative disorder that results in the impairment of movement. During the disease process, a group of dopamine-containing cells in the brain region called the Substantia Nigra pars compacta (SNc), degenerate. Whilst genetic factors contribute to approximately 5% of PD cases, the causes of the remaining 95% are unknown. What does seem clear is the pivotal role of mitochondrial dysfunction as observed in post-mortem human tissue. Mitochondrial dysfunction leads to energy depletion and the generation of harmful reactive oxygen species (ROS). However, despite the fact that the involvement of mitochondria in the disease process has been well established, the cellular events that lead to, and result from, mitochondrial dysfunction remain poorly understood. Rotenone and 6 OHDA have been implicated in PD for two reasons: (1) both toxins can relatively selectively kill SNc neurons in animal models of PD, and (2) there is evidence for both compounds having a potential causative role in the etiology of the disease in humans. When 6 OHDA is injected into the brain, or rotenone applied systemically, both toxins cause degeneration of SNc neurons. This ability makes them excellent tools for studying mechanisms of PD in animal models. In addition, both toxins inhibit mitochondrial function. Despite extensive use in models of PD, the mechanisms by which each toxin cause cell damage remains elusive. The first part of this study investigated the acute responses of dopaminergic SNc neurons to rotenone exposure (5 nM – 1 µM). The experiments were conducted on brain slices obtained from rats. Electrophysiological recordings (whole-cell patch-clamp technique) were used to detect activation of specific membrane channels as well as cell firing and changes to the membrane potential. In addition, imaging of several fluorescent dyes sensitive to specific cellular events was carried out. In voltage-clamp experiments, acute rotenone (200 nM – 1 µM) application evoked a concentration-dependent outward current which was mediated by tolbutamide-sensitive KATP channels. The current was associated with a drop in cell input resistance (Rm) and, in current-clamp, membrane hyperpolarization and inhibition of spontaneous action potentials. The mechanisms by which rotenone activates KATP channels is controversial, with some studies suggesting activation by ATP depletion and others by elevated reactive oxygen species (ROS). To address this issue, experiments were conducted with high levels of ATP in the pipette solution. Since the rotenone-induced outward current was unaffected by high ATP levels, it was concluded that KATP channel activation was due to oxidative stress. Indeed, the antioxidant Trolox significantly attenuated the current response. Confirmation of elevated ROS production was obtained by recording increased mitochondrial superoxide production, using the fluorescent dye MitoSOX. In addition, rotenone evoked depolarization of mitochondrial membrane potential (ΔΨm). Measurements of intracellular Ca2+ and Na+ were performed using the fluorescent dyes Fura 2 and SBFI, respectively. Rotenone evoked increases to both [Ca2+]i and [Na+]i in a concentration-dependent manner. The rotenone-induced [Ca2+]i rise was unaffected by blocking KATP channels with Cs+. The elevation of [Ca2+]i is particularly important in relation to cell death, since [Ca2+]i overload is known to activate pathways leading to necrosis and apoptosis. There has been growing interest in the synergistic action of rotenone with other toxins/conditions which also enhance [Ca2+]i. This concept was explored in the present study by testing the relationship between the baseline [Ca2+]i level and the rotenone-induced [Ca2+]i increase. Two approaches were taken. Firstly, baseline [Ca2+]i was deliberately raised by activation of voltage-gated calcium channels. When rotenone was applied in the presence of this raised baseline calcium level, the rotenone-induced [Ca2+]i rise was significantly greater. The second approach involved post-hoc analysis of the relationship between the normal cellular variation in baseline [Ca2+]i and the rotenone-induced [Ca2+]i elevation. This analysis also revealed a dependency of the rotenone-induced [Ca2+]i elevation on the baseline calcium level. From this finding, as well as the observation that rotenone evoked ROS production, Transient Receptor Protein subtype M2 (TRPM2) channels were proposed as the likely underlying mechanism. The potentiation of the rotenone-induced [Ca2+]i rise by an elevation in baseline calcium level can be attributed to the calcium-dependence of ROS-sensitive TRPM2 channels, known to respond with increased channel opening to increased [Ca2+]i. Recent findings from our laboratory have confirmed TRPM2 involvement in rotenone toxicity, since blockade of these channels with ACA reduced the rotenone-induced [Ca2+]i rise (K. Chung, unpublished). Imaging using the fluorescent dye propidium iodide (PI) to label cells with compromised membrane integrity was also conducted in acute midbrain slices. SNc neurons were retrograde-labelled with FluoroGold and then exposed to various toxic insults. The detergent Triton-X100 caused an increase in PI labelling, whilst rotenone and high concentrations of glutamate were ineffective over the period of time investigated (up to 40 min). The second part of this study, also conducted on acute rat midbrain slices, investigated the acute responses of SNc neurons to 6 OHDA (0.2 – 2 mM) exposure. Extracellular recordings of action potential firing were conducted on SNc neurons. 6 OHDA evoked rapid inhibition of firing in a similar manner to dopamine (100 µM). In the presence of D2 dopamine receptor blocker sulpiride, the inhibition of firing evoked by 6 OHDA was delayed, and an initial increase of firing was observed. Blockade of the dopamine transporter with nomifensine reduced the 6 OHDA-induced inhibition of firing, and prevented the persistent inhibition of firing after 6 OHDA washout. For comparison, the response to 6 OHDA of non-dopaminergic neurons in the subthalamic nucleus was also studied. In the subthalamic nucleus, 6 OHDA evoked an increase of spontaneous action potential firing. Rapid application of 6 OHDA (using the picospritz application technique) in voltage-clamp recorded SNc neurons evoked an outward current, similar to that observed after dopamine application. In the presence of sulpiride, 6 OHDA induced an inward current, consistent with the initial increase of firing activity observed in extracellular recordings. Microfluorometric experiments with Fura 2, showed that 6 OHDA evokes an increase in [Ca2+]i. Loading cells with the fluorescent dye Lucifer Yellow enabled visualization of 6 OHDA-induced swelling of the cell body and damage to proximal dendrites. Imaging of SNc neurons loaded with dextran-rhodamine revealed 6 OHDA-induced damage of distal dendrites. The last part of the study was performed on organotypic cultures obtained from slices of the ventral midbrain. These cultures were prepared from newborn transgenic mice expressing green fluorescent protein (GFP) under the tyrosine hydroxylase-promoter. This fluorescent marker enabled easy identification of dopamine-containing cells (including SNc neurons). Only preliminary experiments were carried out using this preparation. GFP-positive neurons did not show the classic membrane hyperpolarization in response to dopamine. For comparison, recordings from GFP-positive SNc neurons in acute slices obtained from age-matched animals did show a typical hyperpolarizing response to dopamine. GFP-neurons from organotypic cultures also lacked the Ih current – another characteristic feature of SNc neurons in vivo or in acute brain slices. In addition, atypical responses to CNQX (blocker of NMDA receptors) and baclofen (blocker of GABAB receptors) application were identified in GFP-positive neurons. These results demonstrate that the culturing process used in this study alters the functional ‘phenotype’ of dopaminergic neurons, a change which needs to be considered in future studies using this preparation. Chronic exposure of organotypic cultures to low concentration of rotenone (50 nM) evoked a delayed increase of PI labelling indicative of cell death, however technical limitations prevented detection of PI co-localization with GFP was observed. In conclusion, this study identified several key aspects of 6 OHDA and rotenone toxicity in SNc neurons. The most significant novel findings include evidence for ROS activation of KATP channels, presumed involvement of TRPM2 channels in rotenone-induced [Ca2+]i rise, and dopamine-analogous effects of 6 OHDA. The controversial role of KATP channels in neuroprotection was addressed. Findings from this study suggest therapies targeting this channel alone would be of little benefit. The proposed involvement of TRPM2 channels in rotenone-induced [Ca2+]i overload in SNc neurons is particularly interesting as it provides a mechanism for synergism between rotenone and other factors that disrupt [Ca2+]i homeostasis.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Cadmium (Cd) is considered one of the most toxic heavy metals for its ability to affect different tissues, including the brain and the immune system. The molecular mechanisms of toxicity of Cd are not well established, however, it is known that one of the consequences of Cd exposure is the generation of oxidative stress. Conversely, the quercetin, one flavonoid present in various foods performs various therapeutic functions in the body, such as antioxidant activity, anti-inflammatory and neuroprotective action. Thus, the aim of this study was to investigate the effects of quercetin on the behavioral tests, the activity of the enzymes acetylcholinesterase (AChE), Na+, K+-ATPase and the δ-dehydratase aminolevulinic acid (δ-ALA-D), as well as parameters of oxidative stress in the central nervous system of adult male wistar rats exposed to CdCl2. The activities of enzymes AChE, NTPDase and adenosine deaminase (ADA) of peripheral lymphocytes, butyrylcholinesterase (BuChE) in the serum and myeloperoxidase (MPO) in plasma were also measured in the peripheral system of these animals. The rats were exposed to CdCl2 (2.5 mg / kg) and quercetin (5, 25 or 50 mg / kg) by gavage (1 ml/kg) for 45 days. Hence, the animals were divided into eight groups (n = 10-14): saline/control, saline/Querc 5 mg/kg, saline/Querc 25 mg/kg, saline/Querc 50 mg/kg, Cd/ethanol, Cd/Querc 5 mg/kg, Cd/Querc 25 mg/kg and Cd/Querc 50 mg/kg. The groups treated with Cd and quercetin, received the antioxidant quercetin solution after 30 minutes of the administration of Cd solution. At the end of 45 days of the treatment the animals were submitted to training and behavioral tests. After, they were anesthetized by halothane inhalation, and blood collection was performed to set serum, plasma and peripheral lymphocytes apart. Then the animals were euthanized, with part of the brain being removed for analysis of the enzyme δ-ALA-D activity, while the other part of brain was dissected into, cerebral cortex, striatum, cerebellum, hippocampus and hypothalamus, for future enzymatic assays. The results showed that Cd is able to cross the blood brain barrier, therefore, although the amount of Cd accumulated in the different brain structures studied was low, it was significantly higher than in control. Simultaneous treatment of quercetin in Cd exposed animals was ineffective to decrease these levels of Cd. The Cd exposure caused impairment on learning and memory, besides causing an increase in the anxiogenic behavior type. Nevertheless, the treatment with quercetin prevented the undesirable effects caused by exposure to the metal in the anxiety and memory. In relation to enzymatic activities in the brain, it was observed that Cd exposure reduced AChE activity in cerebral cortex and hippocampus, while as activation of the enzyme was observed in hypothalamus. Furthermore, a decrease in the Na+, K+-ATPase enzyme activity in cerebral cortex, hippocampus and hypothalamus was observed, as well as a decrease in the δ-ALA-D activity in total brain of Cd exposed animals. Interestingly, the quercetin co-administration in the Cd exposed animals prevented the changes in the activity of the enzymes AChE and Na+, K+-ATPase in different brain structures, though has not restored the δ-ALA-D enzyme activity. It was also observed an increase in ROS production, in lipid peroxidation, in protein oxidation, the levels of double stranded DNA and changes in the antioxidant system, such as, reduction in the glutathione reductase (GR) activity, levels of total thiols (T-SH) and reduced glutathione (GSH), and an increase in the glutathione S-transferase (GST) enzyme activity in cerebral cortex, hypothalamus and hippocampus of Cd exposed animals. Co-administration of quercetin in Cd exposed rats was able to prevent totally or partially the changes caused by metal exposure in oxidative stress parameters. It is suggested that quercetin is able to reduce the oxidative damage caused by exposure to these metal and subsequently restore the AChE and Na+, K+-ATPase activities, modulating cholinergic neurotransmission and improving cognitive processes. In relation to the peripheral system, there was an increase in the NTPDase, ADA, AChE, BuChE and MPO activities in Cd exposed rats. Based on these results it is possible to infer that the increase in NTPDase activity is a compensatory effect due to the increase in ATP levels in circulation. It is suggested that decreased levels of ACh are available in the circulation due to increase in the peripheral cholinesterase activity. When rats were treated with the quercetin, flavonoid was able to modulate the activities of these enzymes probably due to the anti-inflammatory property of the compound. Accordingly, it is suggested that quercetin prevents or eases the toxicity caused by exposure to metal due to its antioxidant and anti-inflammatory activities. Therefore, it is believed that the flavonoid may be a promising drug in alternative therapies against toxicity induced by the metal in the central nervous system and peripheral system. / O cádmio (Cd) é considerado um dos metais pesados de maior toxicidade devido a sua capacidade de afetar diferentes tecidos, incluindo o encéfalo, bem como o sistema imunológico. Os mecanismos moleculares de toxicidade do Cd ainda não estão bem estabelecidos, contudo, sabe-se que uma das consequências da exposição ao Cd é a geração de estresse oxidativo. Por outro lado, a quercetina, um flavonoide presente em vários alimentos, exerce diversas funções terapêuticas no organismo, como atividade antioxidante, anti-inflamatória e ação neuroprotetora. Sendo assim, o objetivo do presente estudo foi investigar os efeitos da quercetina sobre os testes comportamentais, a atividade das enzimas acetilcolinesterase (AChE), a Na+,K+-ATPase e a δ-desidratase aminolevulinato (δ-ALA-D), bem como os parâmetros de estresse oxidativo no sistema nervoso central de ratos machos wistar adultos expostos ao CdCl2. Também foi avaliada, no sistema periférico destes animais, a atividade das enzimas AChE, NTPDases e adenosina desaminase (ADA) de linfócitos periféricos, butirilcolinesterase (BuChE) do soro e a mieloperoxidase (MPO) do plasma. Os ratos foram expostos ao CdCl2 (2,5 mg/kg) e quercetina (5, 25 ou 50 mg/kg) por gavagem (1ml/kg) durante 45 dias. Para isso, os animais foram distribuídos em oito grupos (n=10-14): salina/controle, salina/Querc 5mg/kg, salina/Querc 25 mg/kg, salina/Querc 50 mg/kg, Cd/etanol, Cd/ Querc 5mg/kg, Cd/Querc 25mg/kg e Cd/Querc 50 mg/kg. Os grupos tratados com Cd e quercetina receberam a solução antioxidante após 30 minutos da administração da solução de Cd. No final do período de 45 dias de tratamento os animais foram submetidos aos treinos e aos testes comportamentais. Posteriormente, foram anestesiados, através da inalação de halotano, e foi realizada a coleta de sangue e separação de soro, plasma e linfócitos periféricos. Em seguida os animais foram submetidos à eutanásia, com parte do encéfalo sendo retirada para a análise da atividade da enzima δ-ALA-D, enquanto que outra parte foi dissecada em córtex cerebral, estriado, cerebelo, hipocampo e hipotálamo, para posteriores ensaios enzimáticos. Os resultados obtidos mostraram que o Cd é capaz de atravessar a barreira hematoencefálica, pois, embora a quantidade de Cd acumulada nas diferentes estruturas encefálicas estudadas tenha sido baixa, ainda assim, foi significativamente maior que o controle. O tratamento concomitante da quercetina nos animais expostos ao Cd foi ineficiente em diminuir estes níveis de Cd. A exposição ao Cd causou prejuízos na aprendizagem e memória, além de causar um aumento no comportamento do tipo ansiogênico. Por outro lado, o tratamento com a quercetina preveniu os efeitos indesejáveis causados pela exposição ao metal na ansiedade e memória. Em relação às atividades enzimáticas no encéfalo, verificou-se que a exposição ao Cd reduziu a atividade da enzima AChE no córtex cerebral e no hipocampo, enquanto que uma ativação da enzima foi observada no hipotálamo. Além disso, observou-se uma diminuição na atividade da enzima Na+, K+-ATPase no córtex cerebral, hipocampo e hipotálamo, bem como uma diminuição na atividade da δ-ALA-D no encéfalo total de animais expostos ao Cd. Interessantemente, a co-administração com a quercetina em animais expostos ao Cd impediu as alterações na atividade das enzimas AChE e Na+, K+-ATPase em diferentes estruturas encefálicas, embora não tenha restaurado a a atividade da enzima δ-ALA-D. Verificou-se, também, um aumento na produção de ROS, na lipoperoxidação, na oxidação de proteínas, nos níveis de DNA dupla fita e alterações no sistema antioxidante, como a diminuição na atividade da enzima glutationa redutase (GR), nos níveis de tióis totais (T-SH) e glutationa reduzida (GSH), e um aumento na atividade da enzima glutationa S-transferase (GST) no córtex cerebral, hipocampo e hipotálamo dos animais expostos ao Cd. A co-administração da quercetina nos ratos expostos ao Cd foi capaz de impedir totalmente ou parcialmente as alterações causadas pela exposição ao metal nos parâmetros do estresse oxidativo. Sugere-se que a quercetina é capaz de diminuir o dano oxidativo causado pela exposição ao metal e, subsequentemente, restaurar a atividade da AChE e Na+, K+-ATPase, modulando, assim, a neurotransmissão colinérgica e melhorando os processos cognitivos. Em relação ao sistema periférico, verificou-se um aumento na atividade das enzimas NTPDase, ADA, AChE, BuChE e MPO nos ratos expostos ao Cd. A partir desse resultado pode-se inferir que o aumento na atividade da NTPDase seja um efeito compensatório devido ao aumento dos níveis de ATP na circulação. Sugere-se que níveis diminuídos de ACh estão disponíveis na circulação devido ao aumento na atividade das colinesterases periféricas. Quando os ratos foram tratados com quercetina o flavonoide foi capaz de modular a atividade dessas enzimas provavelmente devido à propriedade anti-inflamatória do composto. Deste modo, propõe-se que a quercetina previne ou ameniza a toxicidade causada pela exposição ao metal devido a sua atividade antioxidante e anti-inflamatória. Logo, acredita-se que este flavonoide possa ser um fármaco promissor em terapias alternativas contra a toxicidade induzida pelo metal no sistema nervoso central e periférico.

Orientador: Eliana Marisa Ganem / Resumo: Introdução: O parecoxibe, um pró-fármaco hidrolisado à valdecoxibe, é um antagonista da COX-2 com intensa atividade anti-inflamatória e analgésica. Embora muitos estudos tenham sido realizados indicando a eficácia dos antagonistas da COX em aliviar o processo da dor, quase nada foi estudado sobre a toxicidade desses fármacos no neuroeixo. Objetivos: O objetivo desta pesquisa foi avaliar os efeitos que diferentes doses de parecoxibe, administrado pela via subaracnoidea, em punção única, determinariam sobre a medula espinal e as meninges de coelhos. Metodologia: Após aprovação pela Comissão de Ética no Uso de Animais, 30 coelhos adultos jovens, da raça grupo genético de Botucatu, com pesos entre 2510 g e 3560 g, fornecidos pelo Biotério da Faculdade de Medicina de Botucatu, foram randomizados em três grupos: grupo S – solução salina a 0,9%, grupo P4 – parecoxibe (dose: 4 mg) e grupo P8 – parecoxibe (dose: 8 mg). Após a anestesia intravenosa com xilazina e cetamina os animais foram submetidos à punção subaracnoidea guiada por ultrassom, com agulha de Quincke 25G, no espaço entre primeira e a segunda vértebras sacrais e realizada a injeção de uma das soluções previamente sorteadas em volume de 0,4 mL (10 µL por centímetro de medula espinal medida entre a base do crânio e o espaço lombossacral). Após a recuperação da anestesia e por 21 dias, os animais foram avaliados quanto à sensibilidade e à motricidade. Em seguida, foram sacrificados por decapitação e retiradas as porções lomb... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: Parecoxib, a pro-drug that is hydrolyzed to valdecoxib, is a COX-2 antagonist with strong anti-inflammatory and analgesic activity. Although many studies have demonstrated the efficacy of COX antagonists in relieving pain, almost nothing is known about the toxicity of these drugs when administered into the neuraxis. Objectives: The aim of this study was to evaluate the effects of a single injection of different doses of parecoxib into the subarachnoid space on the spinal cord and meninges of rabbits. Methods: After approval by the Ethics Committee on Animal Use, 30 young adult rabbits of the Botucatu genetic group weighing 2,510 to 3,560 g, were randomized into three groups: group S - 0.9% saline; group P4 – parecoxib (dose: 4 mg); group P8 – parecoxib (dose: 8 mg). After intravenous anesthesia with xylazine and ketamine, the animals underwent ultrasound-guided subarachnoid puncture with a Quincke 25G needle in the space between the first and second sacral vertebrae and the injection of one of the previously established solutions was performed in a volume of 0.4 mL (10 µL per cm of spinal cord measured from the skull base to the lumbosacral space). After recovery from anesthesia, the animals were evaluated regarding sensitivity and motor function for 21 days. After this period, the animals were sacrificed by decapitation and the lumbar and sacral portions of the spinal cord and the roots of the cauda equina were removed for histological examination by light micros... (Complete abstract click electronic access below) / Doutor

Base teórica: O surgimento de bactérias multirresistentes levou a uma renovação no interesse de antigos antimicrobianos, como a polimixina B, medicamento que foi descartado no passado devido sua toxicidade. Nas últimas duas décadas, esse antimicrobiano tornou-se um dos mais importantes agentes terapêuticos para o tratamento de infecções causadas por bactérias multirresistentes; porém, ainda faltam estudos clínicos que avaliem a segurança da polimixina B, especialmente em altas doses. Objetivo: Avaliar eventos adversos graves relacionados à infusão e a falência renal nos pacientes que receberam altas doses de polimixina B intravenosa. Métodos: Realizamos um estudo de coorte retrospectivo, multicêntrico. Incluímos pacientes que receberam > 3mg/kg/ dia ou uma dose total ≥250mg/dia de polimixina B, no período de janeiro de 2013 a dezembro de 2015. Para a avaliação dos eventos relacionados a infusão, foram incluídos pacientes que receberam ≥ 1 dose de polimixina B e para avaliação de falência renal incluiu apenas os pacientes que receberam ≥ 48 horas de polimixina B. Os desfechos principais avaliados foram os eventos adversos graves relacionados à infusão de acordo com os Critérios de Terminologia Comuns para Eventos Adversos (CTCAE v4.0) e a falência renal, utilizamos os critérios RIFLE (Risk, Injury, Failure, Loss and End stage), para categorizar os diferentes graus de lesão renal aguda. As variáveis incluídas no estudo foram as variáveis demográficas (idade, sexo), as variáveis individuais (peso, comorbidades, escore de Charlson), os fatores de gravidade (internação em UTI, uso de vasopressor, uso de bloqueador neuromuscular), outras fármacos nefrotóxicas, dose de polimixina utilizada (total, média diária e em mg/kg/dia), associação com outros medicamentos, e características da infecção (sítio, isolamento microbiológico) foram avaliadas em análise bivariada. Variáveis com P≤0.2 foram incluídas uma a uma, em ordem crescente, em modelo de regressão de COX. Variáveis com P< 0.1 permaneceram no modelo final. Resultados: Foram incluídos 222 pacientes para análise de eventos graves relacionados à infusão. A dose média de polimixina B foi de 3.61± 0.97 mg/kg /dia (dose total media = 268 mg/kg). Ocorreram eventos adversos graves relacionados à infusão em dois pacientes, determinando uma incidência bruta de 0.9% (intervalo de confiança de 95%, 0.2-3.2): um 7 evento classificado como um risco ameaçador a vida (efeito adverso classe IV) ocorreu em um paciente, homem, de 40 anos, internado no Centro de Terapia Intensiva, com fibrose cística, que recebeu 3,3 mg / kg / dia de PMB e desenvolveu dor torácica súbita, dispnéia e hipoxemia, no quarto dia de tratamento e o outro evento adverso grave (classe III), ocorreu em um paciente, homem, 23 anos, internado na enfermaria, com linfoma, que recebeu 3,6 mg / kg / dia de PMB , que apresentou parestesia perioral, tonturas e dispnéia no primeiro dia de tratamento. A falência renal foi analisada em 115 pacientes que receberam ≥ 48 horas de polimixina B e que não estavam em diálise no início do tratamento com Polimixina B; Falência renal foi encontrada em 25 de 115 (21,7%) pacientes expostos as PMB. Nosso estudo identificou que 54 [47,0%] pacientes desenvolveram algum grau de lesão renal aguda, pelos critérios de RIFLE: risco, 15 (27,8%), injúria, 14 (25,9%) e falência, 25 (46,3%) dentro das categorias do RIFLE. Além disso, droga vasoativa, outros fármacos nefrotóxicos e clearance de creatinina foram fatores de risco independentes para falência renal. Nem a dose diária de polimixina B ajustada para o peso corporal, nem a dose diária total foram associadas a falência renal. A mortalidade intra-hospitalar foi de 60% (134 pacientes): 26% (57 pacientes) morreram durante o tratamento e nenhum óbito foi durante a infusão. Conclusão: Altas doses de polimixina B no tratamento de infecções por bactérias gramnegativo apresentaram incidência baixa de eventos adversos agudos no nosso estudo e incidência de nefrotoxicidade elevadas, mas semelhantes a alguns estudos prévios com doses usuais”. Portanto, doses elevadas podem ser testadas em ensaios clínicos, objetivando melhorar os desfechos dos pacientes gravemente doentes com infecções por bactérias multirresistentes e minimizar o surgimento da resistência a polimixina B. / Background: The emergence of multiresistant bacteria has led to a renewal in the interest of old antimicrobials, such as polymyxin B, a drug that has been discarded in the past due to its toxicity. However, at this time, this antimicrobial has become one of the most important therapeutic agents for the treatment of infections caused by multiresistant bacteria but there is still a lack of clinical studies that evaluate the safety of polymyxin B, especially in relation to the use of high doses. This strategy, high doses, may be necessary in the fight against Gramnegative bacteria with a high minimum inhibitory concentration. Patients and methods: A retrospective, multicenter cohort study; the period evaluated was from January 2013 to December 2015, included patients who received > 3mg/kg/day or a total dose of ≥250mg/day of polymyxin B. The study included the evaluation of infusion-related events, patients who received ≥ 1 dose of polymyxin B and patients who received ≥ 48 hours of PMB were included for evaluation of renal failure. Major outcomes were serious adverse events related to infusion according to the Common Terminology Criteria for Adverse Events (CTCAE v4.0) and categorized renal failure by the RIFLE criteria (Risk, Injury, Failure, Loss, End stage). Factors potentially related to nephrotoxicity or mortality in 30 days were: demographic variables (age, sex), individual variables (weight, comorbidities, Charlson score), severity factors (ICU admission, use of vasopressor, use of Neuromuscular blocker), nephrotoxicity (other nephrotoxic drugs), polymyxin dose (total, daily mean and mg / Kg / day), association of drugs and infection characteristics (site and microbiological isolate) were evaluated in bivariate analysis. Variables with P≤0.2 were included one by one, in ascending order, in a Cox regression model. Variables with P <0.1 remained in the final model. Results: Two of 222 patients presented a severe infusion-related adverse event during PMB infusion, resulting in a crude incidence of 0.9% (95% Confidence Interval [CI], 0.2-3.2); one was classified as life-threatening and one classified as severe (crude incidence of each adverse event, 0.45%; 95% CI, 0.08-2.5). The life-threatening adverse effect occurred in an ICU patient (crude incidence among ICU patients, 0.67%; 95% CI, 0.12-3.7), a 40-years old male with cystic fibrosis who used 3.3 mg/kg/day of PMB and developed sudden thoracic pain, dyspnea and hypoxemia, in the fourth day of treatment. The severe adverse effect occurred in a non-ICU patient (crude incidence among non-ICU patients, 1.3%; 95% CI, 0.2-7.2), a 23- years old male with lymphoma exposed to 3.6 mg/kg/day of PMB, who presented perioral 9 paresthesia, dizziness and dyspnea in the first day of treatment. Renal failure was analysed in 115 patients who received ≥48 hours of PMB and who were not previously in dialysis. A total of 54 [47.0%] patients developed any degree of AKI, categorised as Risk [27.8%]; Injury [25.9%] and Failure [46.3%]) and 25 of 115 (21.7%) patients presented renal failure Vasoactive drug, concomitant nephrotoxic drugs and baseline creatinine clearance were independent risk factors for renal failure. Neither PMB daily dose scaled by body weight nor total daily dose were associated with renal failure. In-hospital mortality was 60% (134 patients): 26% (57 patients) occurred during treatment and none during infusion. Conclusion: Results suggest that high dose regimens have similar safety profile of usual doses and could be further tested in clinical trials assessing strategies to improve patients’ outcomes and minimize the emergence of PMB resistance.

Neuropatia é a complicação mais comum e mais debilitante da Diabetes Mellitus, a longo prazo presente em mais de 50% dos pacientes que possuem a doença. A hiperglicemia induz estresse oxidativo nos neurônios de diabéticos acarretando a ativação de múltiplas vias bioquímicas, as quais são potenciais alvos terapêuticos para a neuropatia diabética. Está claro que compostos carbonil reativos são mediadores glicotóxicos do estresse oxidativo através da formação de produtos finais de glicação avançada como resultado direto da hiperglicemia. Metilglioxal e glicolaldeído são compostos carbonil reativos inevitavelmente produzidos pelo metabolismo, os quais são encontrados em maior quantidade em situações de hiperglicemia. Recentemente, tem sido dada muita atenção para o envolvimento de espécies reativas na toxicidade do metilglioxal e do glicolaldeído, e tem-se demonstrado que essas glicotoxinas têm potencial para induzir estresse oxidativo, parar o crescimento celular e promover morte por apoptose ou necrose. O metilglioxal e o glicolaldeído interagem com grupamentos sulfidril de moléculas de glutationa e de enzimas, inibindo sua atividade; entretanto, os mecanismos moleculares relacionados aos efeitos tóxicos dessas glicotoxinas e as vias pelas quais elas levam a formação de espécies reativas não estão completamente elucidados. Neste estudo nós buscamos esclarecer a relação entre o metabolismo do metilglioxal e do glicolaldeído e a produção de espécies reativas, e investigamos as possíveis rotas de morte celular envolvidas. Utilizamos a linhagem celular de neuroblastoma humano SH-SY5Y diferenciada, pois este é um modelo neuronal bem caracterizado para estudos de compostos neurotóxicos. Nós avaliamos a produção de espécies reativas induzida por metilglioxal e glicolaldeído através da técnica da diclorofluoresceína, e avaliamos, também, seus efeitos sob o conteúdo de glutationa celular. Além disso, investigamos a ativação das caspase-3, -8 e -9 e a contribuição de diferentes sistemas peroxidases (glutationa-redutase e a tioredoxina-redutase), na defesa neuronal contra essas glicotoxinas. Como resultados encontramos que o tratamento com ambas glicotoxinas rapidamente provocou um aumento na produção de espécies reativas e diminuição do conteúdo de glutationa, com concomitante ativação das caspases-8 e -9 e, posteriormente, também houve ativação da caspase-3 pelo tratamento com metilglioxal. Vimos que a tioredoxina-redutase possui um papel mais importante na defesa celular contra a toxicidade do metilglioxal do que contra o glicolaldeído, enquanto que a glutationa-redutase tem papel semelhante na defesa celular contra ambas glicotoxinas. Nossos resultados demonstraram que o estresse oxidativo é um importante mecanismo da toxicidade do metilglioxal e do glicolaldeído nas células diferenciadas SHSY5Y e, que enzimas redutoras de grupamentos sulfidril contribuem de diferentes formas na defesa celular contra cada uma dessas glicotoxinas. / Neuropathy is the most common and debilitating complication of Diabetes Mellitus present in more than 50% of the patients with long-standing disease. Hyperglycemia induces oxidative stress in neurons from diabetic patients and results in activation of multiple biochemical pathways. These activated pathways are a major source of damage and are potential therapeutic targets in diabetic neuropathy. A large body of evidence has implicated reactive carbonyl compounds as glycotoxic mediators of oxidative stress by forming advanced glycation endproducts as a direct result of hyperglycemia. Methylglyoxal and glycolaldehyde are reactive carbonil compounds inevitably produced by the metabolism, but they are found in increased rates under hyperglycemia condition. Recently, the attention has been focused on the involvement of reactive species in methylglyoxal and glycolaldehyde toxicities, resulting in oxidative stress and leading to cell growth arrest, apoptotic or necrosis death. These glycotoxins interact with sulfhydryl-groups of glutathione molecules enzymes, inhibiting their activity; however, the molecular mechanism underlying methylglyoxal and glycolaldehyde cytotoxic effects and reactive species generation are not fully understood. In this study we have pursued to establish the role of methylglyoxal and glycolaldehyde metabolisms and reactive species production, and have looked for the possible death routes involved with the toxic effects of these glycotoxins. Here we used the differentiated human neuroblastoma SH-SY5Y cells as neuronal experimental model to investigate the pathological effects of various neurotoxic compounds. We have evaluated the methylglyoxal and glycolaldehyde capacity to reactive species generation by dichlorofluorescein assay and their effects upon cellular glutathione content. Also, we have assessed the caspase-3, -8 and -9 activation and the contribution of different peroxidases systems (glutathione reductase and thioredoxin reductase) in the neuronal defense against methylglyoxal and glycolaldehyde cytotoxicities. We found that both glycotoxins promptly provoke reactive species generation and decrease the cell glutathione content, as well induce caspase-8 and -9 activation. Later caspase-3 activation was found in methylglyoxal treatment. We demonstrate that thioredoxin reductase has a most important role in cell defense against methylglyoxal toxicity than against glycolaldehyde, meanwhile there is no difference in the glutathione reductase role. Our results show that oxidative stress is an important mechanism in the methylglyoxal and glycolaldehyde toxicities and sulfhydryl reductases contributes differently in the cellular defense against these glycotoxins.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of this study was to investigate if myelinogenesis is related to the mechanism by which diphenyl ditelluride [(PhTe)2] causes toxicity in rat pups. The present study was performed to examine whether the behavioral performance is related to demyelination process induced by (PhTe)2 in rat pups. acetilcholinesterase (AChE) activity was carried out in cerebral cortex of rat pups since studies have demonstrated that demyelinating events interfere with the activity of this enzyme. Rat pups received a single subcutaneous injection of (PhTe)2 (0,25 μmol/kg) or vehicle (canola oil) at 14th post natal day (PND). From day 1 to 7 (PND 15 to 21) after exposure, negative geotaxis, forelimb support and open field tests were performed in pups. Rat pups were euthanized daily (from day 1 to 7) immediately after the behavioral tests. The cerebral density of myelin and histological analysis were performed. The appearance of classic signs of toxicity, behavioral alterations and demyelination of CNS was dependent of the time after (PhTe)2 exposure to rat pups. Neuronal damage, revealed by histological analysis, and the increase in AChE activity occurred at 4th and 5th day after (PhTe)2 exposure, which is coincident with the critical period of demyelination. In conclusion, exposure to (PhTe)2 induced an impairment of developmental behavioral, neurotoxicity and demyelination in the central nervous system of rat pups. / O objetivo geral deste estudo foi investigar se a mielinogênese está envolvida no mecanismo pelo qual o ditelureto de difenila [(PhTe)2] exerce toxicidade em filhotes de ratos. O presente estudo avaliou a performance comportamental durante o desenvolvimento pós-natal está relacionada ao processo de desmielinização induzida por (PhTe)2 em filhotes de ratos Wistar. A atividade da acetilcolinesterase (AChE) foi realizada no córtex cerebral dos filhotes de ratos, uma vez que estudos têm demonstrado que os eventos desmielinizantes podem interferir na atividade desta enzima. Os filhotes de ratos receberam uma única injeção subcutânea de (PhTe)2 (0,25 μmol/kg) ou veículo (óleo de canola) no 14º dia pós-natal (PND). E após a exposição ao (PhTe)2, a performance comportamental dos animais foi avaliada nos testes da geotaxia negativa, da sustentação na barra e do campo aberto, estes ensaios foram realizados do 1º ao 7º dia (PND 15 a 21) após a injeção do composto. Diariamente e imediatamente após estes testes comportamentais, os filhotes foram submetidos à eutanásia (do 1º ao 7° dia), e as amostras de tecidos recolhidas para a quantificação da densidade de mielina encefálica e análises histológicas. O aparecimento de sinais clássicos de toxicidade, alterações comportamentais e desmielinização do sistema nervoso central (SNC) foi dependente do tempo após a exposição ao (PhTe)2 em filhotes de ratos. O dano neuronal, revelado pela análise histológica, e o aumento na atividade da AChE ocorreu nos dias 4 e 5 após a exposição ao (PhTe)2, que é coincidente com o período crítico de desmielinização. Em conclusão, a exposição ao (PhTe)2 induz um prejuízo no desenvolvimento, neurotoxicidade e desmielinização do SNC de filhotes de ratos.

Submitted by Isabela Leite Ferraz Cabral (isabelalferraz@hotmail.com) on 2018-04-19T13:07:04Z No. of bitstreams: 1 Isabela Leite Ferraz (após a defesa).pdf: 2321770 bytes, checksum: 6bfabab6d5e2449baea610ec9c7969ec (MD5) / Approved for entry into archive by Luciana Pizzani null (luciana@btu.unesp.br) on 2018-04-19T17:32:17Z (GMT) No. of bitstreams: 1 cabral_ilf_dr_bot.pdf: 2321770 bytes, checksum: 6bfabab6d5e2449baea610ec9c7969ec (MD5) / Made available in DSpace on 2018-04-19T17:32:17Z (GMT). No. of bitstreams: 1 cabral_ilf_dr_bot.pdf: 2321770 bytes, checksum: 6bfabab6d5e2449baea610ec9c7969ec (MD5) Previous issue date: 2018-02-21 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Justificativa e objetivo: o hábito de tatuar o corpo faz parte da cultura de muitos povos no mundo. A partir do início dos anos 1990, passou a ser utilizada por alguns grupos sociais e em faixa etária determinada como uma forma de arte no corpo. Os pigmentos podem conter componentes orgânicos e inorgânicos, metais e solventes. Há grande variação na composição química destes, o que dá origem às diferentes cores. Pouco se conhece sobre as possíveis implicações da introdução de uma agulha para realização de anestesia regional sobre uma pele tatuada. Alguns autores questionam se o pigmento contido na tatuagem pode desencadear aracnoidite química. Estudo experimental determinou infiltrado inflamatório linfoplasmacitário perivascular nas meninges de coelhos, 6 meses após punção subaracnoidea sobre pele tatuada. O objetivo desta pesquisa foi avaliar se a punção subaracnoidea realizada sobre a pele tatuada de coelhos ocasiona alterações histológicas precoces nas meninges. Material e Métodos: após a aprovação da Comissão de Ética e Pesquisa no Uso de Animais, foram utilizados 28 coelhos adultos jovens, da raça Grupo Genético de Botucatu, com pesos entre 3300 e 5400g e comprimento de medula espinal (espaço medido entre a base do crânio e o espaço lombossacral) entre 38 e 41 cm, fornecidos pelo Biotério da Faculdade de Medicina de Botucatu. Os animais foram divididos em 2 grupos (G): G1- punção subaracnoidea sobre tatuagem e injeção de solução salina a 0,9% e G2 - punção subaracnoidea sobre pele não tatuada e injeção de solução salina a 0,9%. Após anestesia venosa com xilazina e cetamina, os animais de G1 foram tatuados e, após 30 dias, sob a mesma anestesia, foi realizada a abordagem do espaço subaracnoideo, com agulha de Quincke 22G 21/2”, no espaço intervertebral entre a primeira e a segunda vértebra sacral, guiada por ultrassom. Os animais de G1 e G2 receberam as soluções correspondentes em volume de 5 μL por centímetro de medula espinal (aproximadamente 0,2 mL). Os animais foram avaliados clinicamente quanto à sensibilidade e à motricidade por 30 dias, após os quais foram sacrificados e retiradas as porções lombar e sacral da medula espinhal para exame histológico por microscopia óptica. Resultados: onze animais (78,6%) de G1 apresentaram lesões histológicas focais na pia-máter e aracnoide. Nos animais de G2 não foram encontradas alterações histológicas no tecido nervoso, nos vasos sanguíneos ou nas meninges. Conclusão: são precoces as alterações histológicas meníngeas desencadeadas pela introdução do pigmento da tatuagem após punção subaracnoidea. / Background: body tattooing is cultural for many people around the world. Since the early 1990s, it began to be used by some social groups and some age groups as a body art. The pigments may contain organic and inorganic components, metals and solvents. There is a great variation in the chemical composition of these pigments and that is why they produce different colors. We don’t know the possible implications of introducing a needle for performing regional anesthesia on a tattooed skin. Some authors question whether the pigment contained in the tattoo can trigger chemical arachnoiditis. One experimental study showed perivascular lymphoplasmacytic inflammatory infiltrate in rabbit meninges, 6 months after subarachnoid puncture on tattooed skin. The aim of this study was to evaluate if the subarachnoid puncture performed on the tattooed skin of rabbits already causes early histological changes in the meninges. Material and Methods: after Ethics Committee’s approval, it was used 28 young adult rabbits from Botucatu’s genetic group. The rabbits weights were between 3000 and 4500g and the length of spine (space measured from the base of the skull to lumbosacral space) were between 38 and 41 cm provided by the Medical Center of Botucatu Medical School. The animals were divided into 2 groups (G): in G1 group there was a subarachnoid puncture on tattooing and injection of 0.9% saline solution while in G2 group there was a subarachnoid puncture on non-tattooed skin and injection of 0.9% saline solution. After venous anesthesia with xylazine and ketamine, the G1 animals were tattooed. After 30 days, under the same anesthesia, the subarachnoid space were accessed, with Quincke's Needle 22G 21/2” , in the intervertebral space between the first and second sacral vertebra. All the procedure was ultrasound guided. The rabbits of G1 and G2 groups received the corresponding volume solutions of 5 μl per centimeter of spinal cord (approximately 0.2 mL). The animals were clinically assessed for sensitivity and motor function for 30 days. After that, they were sacrificed and the lumbar and sacral portions of the spinal cord were removed for histological examination by light microscopy. Results: eleven animals (78.6%) of G1 group had focal histological lesions in the pia mater and arachnoid. No histological changes were found in nervous tissue, blood vessels or meninges on G2 group. Conclusions: early meningeal histological changes are triggered by introduction of tattoo pigment into central nervous system after subarachnoid puncture. / FAPESP - Proc 2014/24053-9

Orientador: Eliana Marisa Ganem / Resumo: Justificativa e objetivo: o hábito de tatuar o corpo faz parte da cultura de muitos povos no mundo. A partir do início dos anos 1990, passou a ser utilizada por alguns grupos sociais e em faixa etária determinada como uma forma de arte no corpo. Os pigmentos podem conter componentes orgânicos e inorgânicos, metais e solventes. Há grande variação na composição química destes, o que dá origem às diferentes cores. Pouco se conhece sobre as possíveis implicações da introdução de uma agulha para realização de anestesia regional sobre uma pele tatuada. Alguns autores questionam se o pigmento contido na tatuagem pode desencadear aracnoidite química. Estudo experimental determinou infiltrado inflamatório linfoplasmacitário perivascular nas meninges de coelhos, 6 meses após punção subaracnoidea sobre pele tatuada. O objetivo desta pesquisa foi avaliar se a punção subaracnoidea realizada sobre a pele tatuada de coelhos ocasiona alterações histológicas precoces nas meninges. Material e Métodos: após a aprovação da Comissão de Ética e Pesquisa no Uso de Animais, foram utilizados 28 coelhos adultos jovens, da raça Grupo Genético de Botucatu, com pesos entre 3300 e 5400g e comprimento de medula espinal (espaço medido entre a base do crânio e o espaço lombossacral) entre 38 e 41 cm, fornecidos pelo Biotério da Faculdade de Medicina de Botucatu. Os animais foram divididos em 2 grupos (G): G1- punção subaracnoidea sobre tatuagem e injeção de solução salina a 0,9% e G2 - punção subaracnoidea s... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: body tattooing is cultural for many people around the world. Since the early 1990s, it began to be used by some social groups and some age groups as a body art. The pigments may contain organic and inorganic components, metals and solvents. There is a great variation in the chemical composition of these pigments and that is why they produce different colors. We don’t know the possible implications of introducing a needle for performing regional anesthesia on a tattooed skin. Some authors question whether the pigment contained in the tattoo can trigger chemical arachnoiditis. One experimental study showed perivascular lymphoplasmacytic inflammatory infiltrate in rabbit meninges, 6 months after subarachnoid puncture on tattooed skin. The aim of this study was to evaluate if the subarachnoid puncture performed on the tattooed skin of rabbits already causes early histological changes in the meninges. Material and Methods: after Ethics Committee’s approval, it was used 28 young adult rabbits from Botucatu’s genetic group. The rabbits weights were between 3000 and 4500g and the length of spine (space measured from the base of the skull to lumbosacral space) were between 38 and 41 cm provided by the Medical Center of Botucatu Medical School. The animals were divided into 2 groups (G): in G1 group there was a subarachnoid puncture on tattooing and injection of 0.9% saline solution while in G2 group there was a subarachnoid puncture on non-tattooed skin and injection of 0.... (Complete abstract click electronic access below) / Doutor

Orientador: Antonio Francisco Godinho / Resumo: Nas últimas décadas os níveis de contaminação ambiental por metais pesados e inseticidas vêm aumentando significativamente, acompanhando exponencialmente o rápido e crescente desenvolvimento industrial levando à exposição simultânea a vários agentes químicos com ação sobre o sistema nervoso central (SNC). Sob o ponto de vista toxicológico, co-exposição a substâncias químicas tende a piorar de forma qualitativa e quantitativa os danos produzidos e a irreversibilidade dos processos de neurotoxicidade. Um dos mais prevalentes tipos de desordens sobre o SNC é o da ansiedade. O objetivo deste trabalho foi estudar a co-exposição gestacional ao metal pesado cádmio (Cd) e ao inseticida organofosforado dimetoato (DM) e sua influência sobre o comportamento de ansiedade na prole de ratos em desenvolvimento. Fêmeas prenhes foram expostas durante toda a gestação, por via oral, a solução de Cd (10mg/l), DM (4mg/kg, gavage) e Cd+DM. Após o nascimento dos filhotes foram avaliados: desenvolvimento físico e sensório-motor dos filhotes durante os primeiros dias de idade e o comportamento de ansiedade nas idades de 30 e 80 dias, utilizando arena de campo aberto (ACA), labirinto em cruz elevado (LCE) e caixa claro-escura (CCE). Também foram quantificadoso Cd e o DM tecidual e a atividade da enzima acetilcolinesterase (AChE) sanguínea e cerebral. Os resultados obtidos mostram que: a co-exposição aos agentes alterou o desenvolvimento físico dos filhotes; Cd, DM e Cd+DM aumentaram a ansiedade da pro... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the last decades the levels of environmental contamination by heavy metals and insecticides increased significantly, following exponentially the fast and crescent industrial development leading to the simultaneous exposition to some chemical agents with action on the central nervous system (SNC). Under the toxicological point of view, co-exposure enhances qualitatively and quantitatively the damages produced and the irreversibility of the neurotoxicity processes. One of the most prevalent types of disorders on the SNC is the anxiety. The objective of this work was to study the gestational co-exposure to heavy metal cadmium (Cd) and organophosphate insecticide dimethoate (DM), and its influences on anxiety behavior of rats offspring during its development. Pregnant females were exposed during gestational period, by oral view, to the Cd solution (10 mg/l), DM (4 mg/kg, gavage), or Cd+DM. After birth were evaluated: offspring's physical and sensory-motor development in the first days of age, and anxiety behavior in the ages of 30 and 80 days, using open field arena (OF), elevated plus maze (EPM) and light-dark box (LDB) apparatus. Also were quantified Cd and DM in tissues and activity of the acetylcholinesterase enzyme (AChE) in blood and brain. The obtained results show that: co-exposition to chemical agents modified the physical development of the young rats; Cd, DM and Cd+DM increased the anxiety of the offspring in the young and adult age however, the increase of anxiety ... (Complete abstract click electronic access below) / Mestre

Neuropatia é a complicação mais comum e mais debilitante da Diabetes Mellitus, a longo prazo presente em mais de 50% dos pacientes que possuem a doença. A hiperglicemia induz estresse oxidativo nos neurônios de diabéticos acarretando a ativação de múltiplas vias bioquímicas, as quais são potenciais alvos terapêuticos para a neuropatia diabética. Está claro que compostos carbonil reativos são mediadores glicotóxicos do estresse oxidativo através da formação de produtos finais de glicação avançada como resultado direto da hiperglicemia. Metilglioxal e glicolaldeído são compostos carbonil reativos inevitavelmente produzidos pelo metabolismo, os quais são encontrados em maior quantidade em situações de hiperglicemia. Recentemente, tem sido dada muita atenção para o envolvimento de espécies reativas na toxicidade do metilglioxal e do glicolaldeído, e tem-se demonstrado que essas glicotoxinas têm potencial para induzir estresse oxidativo, parar o crescimento celular e promover morte por apoptose ou necrose. O metilglioxal e o glicolaldeído interagem com grupamentos sulfidril de moléculas de glutationa e de enzimas, inibindo sua atividade; entretanto, os mecanismos moleculares relacionados aos efeitos tóxicos dessas glicotoxinas e as vias pelas quais elas levam a formação de espécies reativas não estão completamente elucidados. Neste estudo nós buscamos esclarecer a relação entre o metabolismo do metilglioxal e do glicolaldeído e a produção de espécies reativas, e investigamos as possíveis rotas de morte celular envolvidas. Utilizamos a linhagem celular de neuroblastoma humano SH-SY5Y diferenciada, pois este é um modelo neuronal bem caracterizado para estudos de compostos neurotóxicos. Nós avaliamos a produção de espécies reativas induzida por metilglioxal e glicolaldeído através da técnica da diclorofluoresceína, e avaliamos, também, seus efeitos sob o conteúdo de glutationa celular. Além disso, investigamos a ativação das caspase-3, -8 e -9 e a contribuição de diferentes sistemas peroxidases (glutationa-redutase e a tioredoxina-redutase), na defesa neuronal contra essas glicotoxinas. Como resultados encontramos que o tratamento com ambas glicotoxinas rapidamente provocou um aumento na produção de espécies reativas e diminuição do conteúdo de glutationa, com concomitante ativação das caspases-8 e -9 e, posteriormente, também houve ativação da caspase-3 pelo tratamento com metilglioxal. Vimos que a tioredoxina-redutase possui um papel mais importante na defesa celular contra a toxicidade do metilglioxal do que contra o glicolaldeído, enquanto que a glutationa-redutase tem papel semelhante na defesa celular contra ambas glicotoxinas. Nossos resultados demonstraram que o estresse oxidativo é um importante mecanismo da toxicidade do metilglioxal e do glicolaldeído nas células diferenciadas SHSY5Y e, que enzimas redutoras de grupamentos sulfidril contribuem de diferentes formas na defesa celular contra cada uma dessas glicotoxinas. / Neuropathy is the most common and debilitating complication of Diabetes Mellitus present in more than 50% of the patients with long-standing disease. Hyperglycemia induces oxidative stress in neurons from diabetic patients and results in activation of multiple biochemical pathways. These activated pathways are a major source of damage and are potential therapeutic targets in diabetic neuropathy. A large body of evidence has implicated reactive carbonyl compounds as glycotoxic mediators of oxidative stress by forming advanced glycation endproducts as a direct result of hyperglycemia. Methylglyoxal and glycolaldehyde are reactive carbonil compounds inevitably produced by the metabolism, but they are found in increased rates under hyperglycemia condition. Recently, the attention has been focused on the involvement of reactive species in methylglyoxal and glycolaldehyde toxicities, resulting in oxidative stress and leading to cell growth arrest, apoptotic or necrosis death. These glycotoxins interact with sulfhydryl-groups of glutathione molecules enzymes, inhibiting their activity; however, the molecular mechanism underlying methylglyoxal and glycolaldehyde cytotoxic effects and reactive species generation are not fully understood. In this study we have pursued to establish the role of methylglyoxal and glycolaldehyde metabolisms and reactive species production, and have looked for the possible death routes involved with the toxic effects of these glycotoxins. Here we used the differentiated human neuroblastoma SH-SY5Y cells as neuronal experimental model to investigate the pathological effects of various neurotoxic compounds. We have evaluated the methylglyoxal and glycolaldehyde capacity to reactive species generation by dichlorofluorescein assay and their effects upon cellular glutathione content. Also, we have assessed the caspase-3, -8 and -9 activation and the contribution of different peroxidases systems (glutathione reductase and thioredoxin reductase) in the neuronal defense against methylglyoxal and glycolaldehyde cytotoxicities. We found that both glycotoxins promptly provoke reactive species generation and decrease the cell glutathione content, as well induce caspase-8 and -9 activation. Later caspase-3 activation was found in methylglyoxal treatment. We demonstrate that thioredoxin reductase has a most important role in cell defense against methylglyoxal toxicity than against glycolaldehyde, meanwhile there is no difference in the glutathione reductase role. Our results show that oxidative stress is an important mechanism in the methylglyoxal and glycolaldehyde toxicities and sulfhydryl reductases contributes differently in the cellular defense against these glycotoxins.