RESUMO
Obesity is characterized by chronic inflammation of low grade. The cholinergic anti-inflammatory pathway favors the reduction of the inflammatory response. In this work the effect of stimulation of the cholinergic anti-inflammatory pathway on SHIRPA behavioral test and mitochondrial respiratory chain activity in obese mice was evaluated. The animals were paired in four groups: saline + control diet; donepezil + control diet; saline + high-fat diet and donepezil + high-fat diet. 5 mg/kg/day orally of donepezil or saline were given 7 days before the beginning of the diet until completing 11 weeks of the experiment. Food intake and body weight were measured. At the end of the experiment the animals were submitted to the SHIRPA behavioral test, soon after they were killed by decapitation, the open abdominal cavity and the mesenteric fat were removed. The hypothalamus, hippocampus, prefrontal cortex, and striatum were removed for evaluation of the mitochondrial respiratory chain. It can be observed that donepezil prevented weight gain and food consumption, as well as a tendency to prevent the accumulation of mesenteric fat in obese animals. There was no behavioral change in obese animals, nor did the influence of donepezil on these parameters. On the other hand, donepezil did not prevent inhibition of complex I activity, prevented the inhibition of complex II, and showed a tendency to prevent IV complex activity inhibited in obesity. With these results it can be concluded that the activation of the cholinergic anti-inflammatory pathway is promising for the alterations found in obesity.
Assuntos
Fármacos Antiobesidade/uso terapêutico , Encéfalo/metabolismo , Donepezila/uso terapêutico , Metabolismo Energético/efeitos dos fármacos , Obesidade/prevenção & controle , Animais , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Masculino , Camundongos , Obesidade/metabolismoRESUMO
Organochalcogens, such as organoselenium and organotellurium compounds, can be neurotoxic to rodents. Since mitochondrial dysfunction plays a pivotal role in neurological disorders, the present study was designed to test the hypothesis that rat brain mitochondrial complexes (I, II, I-III, II-III and IV) could be molecular targets of organochalcogens. The results show that organochalcogens caused statistically significant inhibition of mitochondrial complex I activity, which was prevented by preincubation with NADH and fully blunted by reduced glutathione (GSH). Mitochondrial complex II activity remained unchanged in response to (PhSe)2 treatment. Ebs and (PhTe)2 caused a significant concentration-dependent inhibition of complex II that was also blunted by GSH. Mitochondrial complex IV activity was not modified by organochalcogens. Collectively, Ebs, (PhSe)2 and (PhTe)2 were more effective inhibitors of brain mitochondrial complex I than of complex II, whereas they did not affect complex IV. These observations are consistent with organochalcogens inducing mitochondrial complex I and II inhibition via their thiol-oxidase-like activity, with Ebs, (PhSe)2 and (PhTe)2 effectively oxidising critical thiol groups of these complexes.
Assuntos
Encéfalo/efeitos dos fármacos , Calcogênios/toxicidade , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Membranas Mitocondriais/efeitos dos fármacos , Compostos Organosselênicos/toxicidade , Animais , Encéfalo/enzimologia , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/metabolismo , Masculino , Membranas Mitocondriais/enzimologia , Ratos , Ratos WistarRESUMO
This study was designed to evaluate the effects of bis selenide on Huntington disease (HD)-like signs induced by 3-nitropropionic acid (3-NP) in rats. To this aim, rats were treated for 4 days with bis selenide (5 or 20 mg/kg/day, per oral) 30 min before 3-NP (20 mg/kg/day, intraperitoneally). The body weight gain, locomotor activity, motor coordination, and biochemical parameters in striatal preparations were assessed 24 h after the last injection of 3-NP. The highest dose of bis selenide was effective in protecting against body weight loss and motor coordination deficit induced by 3-NP. The impairment of locomotor activity caused by 3-NP was abolished by bis selenide at both doses. Bis selenide (5 and 20 mg/kg) partially restored succinate dehydrogenase activity inhibited after 3-NP exposure. The dose of 20 mg/kg of bis selenide recovered partially δ-aminolevulinic acid dehydratase activity, and totally Na(+), K(+)-ATPase activity, two sulfhydryl enzymes sensitive to oxidizing agents, which had their activities inhibited by 3-NP. Also, 3-NP led to an increase in protein carbonyl levels and glutathione reductase activity and inhibited catalase activity-alterations that were reversed by bis selenide administration at both doses. The highest dose of bis selenide was effective against the increase of RS levels, the depletion of reduced glutathione content, and the inhibition of glutathione peroxidase activity induced by 3-NP. Bis selenide was not effective against inhibition of SOD activity caused by 3-NP. These findings demonstrate that bis selenide elicited protective effects against HD-like signs induced by 3-NP in rats.
Assuntos
Ataxia/tratamento farmacológico , Corpo Estriado/efeitos dos fármacos , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Doença de Huntington/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Neurotoxinas/antagonistas & inibidores , Nitrocompostos/antagonistas & inibidores , Compostos Organosselênicos/uso terapêutico , Propionatos/antagonistas & inibidores , Animais , Ataxia/enzimologia , Corpo Estriado/enzimologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Comportamento Exploratório/efeitos dos fármacos , Glutationa/metabolismo , Masculino , Estrutura Molecular , Proteínas do Tecido Nervoso/análise , Fármacos Neuroprotetores/administração & dosagem , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Neurotoxinas/toxicidade , Nitrocompostos/toxicidade , Compostos Organosselênicos/administração & dosagem , Compostos Organosselênicos/química , Compostos Organosselênicos/farmacologia , Propionatos/toxicidade , Carbonilação Proteica/efeitos dos fármacos , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Teste de Desempenho do Rota-Rod , Succinato Desidrogenase/antagonistas & inibidores , Aumento de Peso/efeitos dos fármacosRESUMO
The vitamin E derivative (+)α-tocopheryl succinate (α-TOS) exerts pro-apoptotic effects in a wide range of tumors and is well tolerated by normal tissues. Previous studies point to a mitochondrial involvement in the action mechanism; however, the early steps have not been fully elucidated. In a model of acute promyelocytic leukemia (APL) derived from hCG-PML-RARα transgenic mice, we demonstrated that α-TOS is as effective as arsenic trioxide or all-trans retinoic acid, the current gold standards of therapy. We also demonstrated that α-TOS induces an early dissipation of the mitochondrial membrane potential in APL cells and studies with isolated mitochondria revealed that this action may result from the inhibition of mitochondrial respiratory chain complex I. Moreover, α-TOS promoted accumulation of reactive oxygen species hours before mitochondrial cytochrome c release and caspases activation. Therefore, an in vivo antileukemic action and a novel mitochondrial target were revealed for α-TOS, as well as mitochondrial respiratory complex I was highlighted as potential target for anticancer therapy.
Assuntos
Arsenicais/uso terapêutico , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Leucemia Promielocítica Aguda/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Óxidos/uso terapêutico , Tretinoína/uso terapêutico , alfa-Tocoferol/farmacologia , alfa-Tocoferol/uso terapêutico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Apoptose/efeitos dos fármacos , Trióxido de Arsênio , Caspases/metabolismo , Linhagem Celular Tumoral , Citocromos c/metabolismo , Modelos Animais de Doenças , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Humanos , Leucemia Promielocítica Aguda/mortalidade , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Transgênicos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Estabilidade Proteica/efeitos dos fármacos , Ratos , Espécies Reativas de Oxigênio/metabolismo , Transplante IsogênicoRESUMO
The pathophysiology of gastritis involves an imbalance between gastric acid attack and mucosal defence. In addition, the gastric mucosal injury results in adenosine triphosphate (ATP) depletion leading to mitochondrial dysfunction. Several studies have shown the association of mitochondrial disorders with gastrointestinal dysfunction. In the present study, we investigated the activity of mitochondrial respiratory chain complexes activity in the stomach of rats with gastritis induced by indomethacin (IDM) and treated with omeprazole (OM), N-acetylcysteine (NAC) and the gastrin-releasing peptide receptor (GRPR) antagonist RC-3095. Adult male Wistar rats were pre-treated for 7 days with OM, NAC, RC-3095, combination of OM plus RC-3095, OM plus NAC and water (control). The animals were then submitted to fasting for 24 hr; IDM was administered. The rats were killed 6 hr later, and the stomachs were used for evaluation of macroscopic damage and respiratory chain activity. Our results showed that complex I and IV activities were not affected by administration of IDM. On the other hand, complex II and III activities were inhibited. In addition, OM plus RC-3095 and OM plus NAC did not reverse complex II activity inhibition. However, the complex III activity inhibition was reversed only with the combined use of OM plus RC-3095 and OM plus NAC. Our results are in agreement with previous studies indicating mitochondrial dysfunction in the pathophysiology of gastrointestinal tract disease and we suggest that GRPR antagonism might be a novel therapeutic strategy in gastritis.
Assuntos
Acetilcisteína/farmacologia , Antiulcerosos/farmacologia , Bombesina/análogos & derivados , Complexo II de Transporte de Elétrons/metabolismo , Gastrite/metabolismo , Omeprazol/farmacologia , Fragmentos de Peptídeos/farmacologia , Receptores da Bombesina/antagonistas & inibidores , Acetilcisteína/uso terapêutico , Animais , Anti-Inflamatórios não Esteroides/toxicidade , Antiulcerosos/uso terapêutico , Bombesina/farmacologia , Bombesina/uso terapêutico , Quimioterapia Combinada , Transporte de Elétrons/efeitos dos fármacos , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Mucosa Gástrica/metabolismo , Gastrite/patologia , Gastrite/prevenção & controle , Indometacina/toxicidade , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , Omeprazol/uso terapêutico , Fragmentos de Peptídeos/uso terapêutico , Inibidores da Bomba de Prótons/farmacologia , Inibidores da Bomba de Prótons/uso terapêutico , Ratos , Ratos Wistar , Índice de Gravidade de Doença , Estômago/efeitos dos fármacos , Estômago/patologia , Úlcera Gástrica/prevenção & controleRESUMO
Malathion is a pesticide used on a large scale and with high potential risk for human exposure. However, it is reasonable to hypothesize that while the malathion is metabolizing reactive oxygen species (ROS) can be generated and subsequently there is onset of an oxidative stress in central nervous system (CNS) structures: hippocampus, cortex, striatum and cerebellum of intoxicated rats due to mitochondrial respiratory chain disfunctions. The present study was therefore undertaken to evaluate malathion-induced lipid peroxidation (LPO), superoxide production from sub-mitochondrial particles and the activity of complexes II and IV of the mitochondrial respiratory chain. Malathion was administered in doses of 25, 50, 100 and 150 mg malathion/kg. After malathion administration LPO increased in hippocampus and striatum. This was accompanied by an increase in the formation of superoxide in submitochondrial particles in the hippocampus. Complex IV suffered significant inhibition of its activity. We could demonstrate in this study that malathion induces oxidative stress and it could be due to inactivation of mitochondrial respiratory complexes.
Assuntos
Encéfalo/efeitos dos fármacos , Respiração Celular/fisiologia , Inseticidas/farmacologia , Malation/farmacologia , Mitocôndrias/metabolismo , Estresse Oxidativo , Animais , Encéfalo/anatomia & histologia , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Peroxidação de Lipídeos , Masculino , Ratos , Ratos Wistar , Superóxidos/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Ethylmalonic aciduria is a common finding in patients affected by short-chain acyl-CoA dehydrogenase (SCAD) deficiency and other diseases characterized by encephalopathy, muscular symptomatology, and lactic acidemia. Considering that the pathophysiological mechanisms of these disorders are practically unknown and that lactic acidosis suggest an impairment of energy production, the objective of the present work was to investigate the in vitro effect of ethylmalonic acid (EMA), at concentrations varying from 0.25 to 5.0 mM, on important parameters of energy metabolism in human skeletal muscle, such as the activities of the respiratory chain complexes and of creatine kinase, which are responsible for most of the ATP produced and transferred inside the cell. We verified that EMA significantly inhibited the activity of complex I-III at concentrations as low as 0.25 mM, complex II-III at 1 mM and higher concentrations, and complex II at the concentration of 5 mM. In contrast, complex IV was not inhibited by the acid. Finally, we observed that the activity of creatine kinase was significantly inhibited by EMA at the concentrations of 1 and 5 mM. These results suggest that EMA compromises energy metabolism in human skeletal muscle. In case the in vitro effects detected in the present study also occur in vivo, it is tempting to speculate that they may contribute, at least in part, to explain the hypotonia/myopathy, as well as the increased concentrations of lactic acid present in the patients affected by illnesses in which EMA accumulates.
Assuntos
Acidose Láctica/metabolismo , Creatina Quinase/metabolismo , Complexo de Proteínas da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Malonatos/farmacologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/enzimologia , Trifosfato de Adenosina/metabolismo , Adolescente , Adulto , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Técnicas In VitroRESUMO
Methylmalonic acidemia is an inherited metabolic disorder biochemically characterized by tissue accumulation of methylmalonic acid (MMA) and clinically by progressive neurological deterioration and kidney failure, whose pathophysiology is so far poorly established. Previous studies have shown that MMA inhibits complex II of the respiratory chain in rat cerebral cortex, although no inhibition of complexes I-V was found in bovine heart. Therefore, in the present study we investigated the in vitro effect of 2.5mM MMA on the activity of complexes I-III, II, II-III and IV in striatum, hippocampus, heart, liver and kidney homogenates from young rats. We observed that MMA caused a significant inhibition of complex II activity in striatum and hippocampus (15-20%) at low concentrations of succinate in the medium, but not in the peripheral tissues. We also verified that the inhibitory property of MMA only occurred after exposing brain homogenates for at least 10 min with the acid, suggesting that this inhibition was mediated by indirect mechanisms. Simultaneous preincubation with the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME) and catalase (CAT) plus superoxide dismutase (SOD) did not prevent MMA-induced inhibition of complex II, suggesting that common reactive oxygen (superoxide, hydrogen peroxide and hydroxyl radical) and nitric (nitric oxide) species were not involved in this effect. In addition, complex II-III (20-35%) was also inhibited by MMA in all tissues tested, and complex I-III only in the kidney (53%) and liver (38%). In contrast, complex IV activity was not changed by MMA in all tissues studied. These results indicate that MMA differentially affects the activity of the respiratory chain pending on the tissues studied, being striatum and hippocampus more vulnerable to its effect. In case our in vitro data are confirmed in vivo in tissues from methylmalonic acidemic patients, it is feasible that that the present findings may be related to the pathophysiology of the tissue damage characteristic of these patients.
Assuntos
Transporte de Elétrons/fisiologia , Inibidores Enzimáticos/metabolismo , Ácido Metilmalônico/metabolismo , Animais , Bovinos , Córtex Cerebral/enzimologia , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Rim/enzimologia , Fígado/enzimologia , Miocárdio/enzimologia , Ratos , Ratos Wistar , Extratos de Tecidos/metabolismoRESUMO
Changes in mitochondrial integrity, reactive oxygen species release and Ca2+ handling are proposed to be involved in the pathogenesis of many neurological disorders including methylmalonic acidaemia and Huntington's disease, which exhibit partial mitochondrial respiratory inhibition. In this report, we studied the mechanisms by which the respiratory chain complex II inhibitors malonate, methylmalonate and 3-nitropropionate affect rat brain mitochondrial function and neuronal survival. All three compounds, at concentrations which inhibit respiration by 50%, induced mitochondrial inner membrane permeabilization when in the presence of micromolar Ca2+ concentrations. ADP, cyclosporin A and catalase prevented or delayed this effect, indicating it is mediated by reactive oxygen species and mitochondrial permeability transition (PT). PT induced by malonate was also present in mitochondria isolated from liver and kidney, but required more significant respiratory inhibition. In brain, PT promoted by complex II inhibition was stimulated by increasing Ca2+ cycling and absent when mitochondria were pre-loaded with Ca2+ or when Ca2+ uptake was prevented. In addition to isolated mitochondria, we determined the effect of methylmalonate on cultured PC12 cells and freshly prepared rat brain slices. Methylmalonate promoted cell death in striatal slices and PC12 cells, in a manner attenuated by cyclosporin A and bongkrekate, and unrelated to impairment of energy metabolism. We propose that under conditions in which mitochondrial complex II is partially inhibited in the CNS, neuronal cell death involves the induction of PT.
Assuntos
Antimicina A/análogos & derivados , Encéfalo/citologia , Cálcio/farmacologia , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Mitocôndrias/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Animais , Antimicina A/farmacologia , Ácido Bongcréquico/farmacologia , Calcimicina/farmacologia , Catalase/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Ciclosporinas/farmacologia , Relação Dose-Resposta a Droga , Interações Medicamentosas , Inibidores Enzimáticos/farmacologia , Feminino , Técnicas In Vitro , Ionóforos/farmacologia , Malonatos/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Ácido Metilmalônico/farmacologia , Mitocôndrias/metabolismo , NADP/metabolismo , Neurônios/citologia , Nitrocompostos , Consumo de Oxigênio/efeitos dos fármacos , Células PC12 , Permeabilidade/efeitos dos fármacos , Propionatos/farmacologia , Ratos , Rotenona/farmacologia , Tacrolimo/farmacologia , Sais de Tetrazólio , Tiazóis , Desacopladores/farmacologiaRESUMO
Intracellular calcium homeostasis is important for cell survival. However, increase in mitochondrial calcium (Ca2+m) induces opening of permeability transition pore (PTP), mitochondrial dysfunction and apoptosis. Since alterations of intracellular Ca2+ and reactive oxygen species (ROS) generation are involved in cell death, they might be involved in neurodegenerative processes such as Huntington's disease (HD). HD is characterized by the inhibition of complex II of respiratory chain and increase in ROS production. In this report, we studied the correlation between the inhibitor of the complex II, 3-nitropropionic acid (3NP), Ca2+ metabolism, apoptosis and behavioural alterations. We showed that 3NP (1 mm) is able to release Ca2+m, as neither Thapsigargin (TAP, 2 microm) nor free-calcium medium affected its effect. PTP inhibitors and antioxidants inhibited this process, suggesting an increase in ROS generation and PTP opening. In addition, 3NP (0.1 mm) also induces apoptotic cell death. Behavioural changes in animals treated with 3NP (20 mg/kg/day for 4 days) were also attenuated by pre- and co-treatment with vitamin E (VE, 20 mg/kg/day). Taken together, our results show that complex II inhibition could involve Ca2+m release, oxidative stress and cell death that may precede motor alterations in neurodegenerative processes such as HD.