Efeito do tratamento de N-acetilcisteína sobre o metabolismo energético e estresse oxidativo no miocárdio de ratos diabéticos
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Data
2017-03-24
Autores
Kaga, Anderson Kiyoshi [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O diabetes mellitus é um grupo heterogêneo de distúrbios no metabolismo energético e consequente estresse oxidativo, fatores importante para o desenvolvimento de complicações diabéticas como cardiomiopatias. A utilização de antioxidantes tem contribuído para melhorar a hiperglicemia e também minimizar as complicações diabéticas. O N-acetilcisteína apresenta ação antioxidante e antihiperglicemiante, sendo capaz de contribuir na terapêutica desta patologia. Este estudo propôs avaliar o metabolismo energético e estresse oxidativo no miocárdio de ratos com diabetes mellitus tipo 1 tratados com N-acetilcisteína. Foram utilizados 32 ratos wistar, com peso corporal ±250g, e 60 dias de idade. Os animais foram distribuídos nos grupos experimentais (n=8): C (normais, controle); NAC (normais, tratados com N-acetilcisteína); DM (diabéticos, não tratados); DM-NAC (diabéticos, tratados com N-acetilcisteína). Os animais receberam ração e água ad libitum. O diabetes mellitus tipo 1 experimental foi induzido através da administração de estreptozotocina através da via intraperitoneal, em dose única, dose de 60mg Kg-1 de peso corporal. Os animais dos grupos NAC e DM-NAC receberam N-acetilcisteína, por via intragástrica com dose de 25mg Kg-1dia-1 durante 37 dias. Durante o período experimental (37 dias) foram avaliados consumo de água e ração. Após o período experimental os animais, em jejum de 12h, foram anestesiados (xilazina e cetamina) e eutanasiados. O sangue e tecido cardíaco (±100mg ventrículo esquerdo) foram coletados e armazenados em freezer -80°C. Os resultados foram analisados por ANOVA One-way seguido do teste de Tukey para comparação das médias. Os testes foram considerados significativos quando p<0.05. A ingesta alimentar e hídrica foi maior (p<0.05) no grupo DM, quando comparado aos demais grupos. Enquanto o peso corporal diminuiu (p<0.05) em animais diabéticos em relação a C e NAC, os quais não diferiram (p>0.05) de DM-NAC. O NAC reduziu (p<0.05) a glicemia nos ratos diabéticos, porém apresentou glicemia maior que os ratos normais (C e NAC). A insulina sérica no grupo DM-NAC esteve aumentada (p<0.05) quando comparada aos ratos do grupo DM. A energia ingerida e o consumo de carboidratos e proteínas aumentou (p<0.05) em ratos diabéticos não tratados (DM) comparativamente aos demais grupos, porém sem diferença significativa (p>0.05) entre C e NAC. A eficiência alimentar em DM foi menor (P<0.05) quando comparada a DM-NAC, os ratos normais (C e NAC) apresentaram valores maiores (P<0.05) que os diabéticos. A concentração cardíaca de proteínas totais e glicogênio em animais diabéticos (DM) foi inferior (p<0.05) aos demais grupos, sendo que o tratamento com NAC melhorou (p<0.05) estes parâmetros. A atividade da fosfofrutoquinase no miocárdio de ratos diabéticos foi recuperada (p<0.05) pela administração de NAC alcançando valores dos grupos obtidos para C e NAC. Não houve diferença estatística na atividade da lactato desidrogenase sérica entre os grupos (p>0.05). O NAC reduziu (p<0.05) a concentração sérica de triacilgliceróis, colesterol total, VLDL-colesterol e LDL-colesterol e aumentou (p<0.05) a concentração de HDL-colesterol em ratos diabéticos em comparação ao grupo DM. O grupo NAC-DM apresentou menor (p<0.05) índice aterogênico em relação ao grupo DM. A atividade da lactato desidrogenase no tecido cardíaco de ratos não demonstrou diferença estatística entre os grupos. No miocárdio de ratos diabéticos a atividade piruvato desidrogenase diminuiu (p>0.05), e o NAC melhorou (p>0.05) em DM-NAC, porém sem alcançar os valores obtidos em ratos normais (C e NAC). A administração de NAC foi capaz de melhorar (p>0.05) atividade de β-hidroxiacil-CoA desidrogenase e citrato sintase no tecido cardíaco dos ratos diabéticos (DM-NAC). A relação da atividade da lactato desidrogenase/citrato sintase foi menor (p<0.05) no grupo DM que em outros, os quais não diferiram significativamente. Não houve diferença significativa na relação β-hidroxiacil-CoA desidrogenase/citrato sintase. A atividade da superóxido dismutase no miocárdio reduziu no grupo DM, enquanto os grupos que receberam NAC (NAC e DM-NAC) demonstraram valores intermediários entre C e DM. O NAC aumentou (p<0.05) a atividade cardíaca da catalase em ratos diabéticos, atingindo valores próximos aos grupos C e NAC. A atividade da glutationa peroxidase no tecido cardíaco aumentou no grupo DM-NAC em relação a DM, mas não diferiu (p>0.05) quando comparada ao grupo C e NAC. A concentração cardíaca de glutationa total e GSH diminuiu (p<0.05) em DM quando comparada com outros grupos. O grupo DM mostrou maiores valores para hidroperóxido de lipídeo no miocárdio, enquanto a administração de NAC melhorou este valor (p<0.05). O tratamento com NAC normalizou (p<0.05) a relação do hidroperóxido de lipídeo com as enzimas antioxidantes em ratos diabéticos. Diante dos resultados obtidos pode-se concluir que o DM1 promoveu alterações metabólicas em cardiomiócitos, favorecendo a oxidação de ácidos graxos em detrimento da oxidação de glicose com estresse oxidativo levando as disfunções cardíacas. A administração de NAC pode ser uma alternativa terapêutica, pois reverteu a desregulação do metabolismo energético induzido pelo DM1 no músculo cardíaco através do seu efeito antiabetogênico, controlando a glicemia e consequentemente atenuou o estresse oxidativo. O NAC melhorou os parâmetros nutricionais e normalizou o perfil lipídico e o índice aterogênico.
Diabetes mellitus is a heterogeneous group of disturbances in energy metabolism and consequent oxidative stress, important factors for the development of diabetic complications such as cardiomyopathies. The use of antioxidants has contributed to improve hyperglycemia and also minimize diabetic complications. N-acetylcysteine has antioxidant and antihyperglycemic action, being able to contribute to the therapeutics of this pathology. This study aimed to evaluate the energetic metabolism and oxidative stress in the myocardium of rats with type 1 diabetes mellitus treated with N-acetylcysteine. 32 male wistar rats, with ±250g body weigth, 60 days old were distributed in groups (n=8): C (normal, control); NAC (normal, treated with N-acetylcysteine); DM (diabetic, untreated); DM-NAC (diabetic, treated with N-acetylcysteine). The rats received water and a rodent chow ad libitum. Experimental type 1 diabetes mellitus was induced by streptozotocin (60mg Kg-1 body weight, single dose, i.p.). Animals of the group NAC and DM-NAC received N-acetylcysteine (25mg Kg-1 day-1) by gavage for 37 days. During the experimental period (37 days), food and water intake were evaluated. After this period the animals, in a 12h fast, were anesthetized (xylasin and ketamin) and euthanized. Blood and cardiac tissue (±100mg, left ventricle) were collected and stored in a freezer -80°C. Results were analyzed by One-way ANOVA followed by Tukey test for comparison of means. The results were considered significant when p<0.05. Food and water intake were higher (p<0.05) in the DM group, when compared to the other groups. While body weight decreased (p<0.05) in diabetic animals related to C and NAC, which did not differ (p>0.05) DM-NAC. NAC increased (p<0.05) glycemia in diabetic rats, but presented higher glycemia than normal rats (C and NAC). Serum insulin in DM-NAC group was increased (p<0.05) when compared to DM group rats. Energy intake and carbohydrate and protein consumption increased (p<0.05) in untreated diabetic rats (DM) compared to the other groups, but without significant difference (p>0.05) between C and NAC. Alimentary efficiency in DM was lower (p<0.05) when compared to DM-NAC, normal rats (C and NAC) had higher values (p<0.05) than diabetics. Cardiac concentration of total proteins and glycogen in diabetic animals (DM) were decreased (p<0.05) to the other groups, and treatment with NAC improved (p<0.05) these parameters. Phosphofructokinase activity in myocardium of diabetic rats was recovered (p<0.05) by the administration of NAC reaching values of the groups C and NAC. There was no statistical difference in serum lactate dehydrogenase activity between the groups (p>0.05). NAC decreased serum concentration of triacylglycerols, total cholesterol, VLDL-cholesterol and LDL-cholesterol (p<0.05) and increased HDL-cholesterol concentration in diabetic rats compared to the DM group (p<0.05). NAC-DM group had a lower (p<0.05) atherogenic index than the DM group. Lactate dehydrogenase activity in rat heart tissue did not show statistical difference (p>0.05) between the groups. In myocardium of diabetic rats pyruvate dehydrogenase activity decreased (p<0.05), and NAC improved (p<0.05) in DM-NAC, but did not reach values obtained in normal rats (C and NAC). NAC administration was able to improve (p>0.05) β-hydroxyl-CoA dehydrogenase activity and citrate synthase in cardiac tissue of diabetic rats (DM-NAC). The ratio Lactate dehydrogenase/citrate synthase was lower (p<0.05) in DM group than others, which did not differ significantly. There was no significant difference in ratio β-hydroxyl-CoA dehydrogenase/citrate synthase. Superoxide dismutase activity in myocardium was reduced (p<0.05) in DM, whereas groups receiving NAC (NAC and DM-NAC) demonstrated intermediate values between C and DM. NAC increased (p<0.05) cardiac catalase activity in diabetic rats, reaching values close to the C and NAC groups. Glutathione peroxidase activity in myocardium increased in DM-NAC group compared to DM, but did not differ (p>0.05) when compared to group C and NAC. The cardiac concentration of total glutathione and reduced glutathione activity decreased (p<0.05) in DM when compared to the other groups. DM group showed higher values for lipid hydroperoxide in myocardium, while the administration of NAC improved this value (p<0.05). NAC treatment normalized (p<0.05) the relationship between lipid hydroperoxide and activity antioxidants enzymes in diabetic rats. In view of the obtained results it can be concluded that type 1 diabetes mellitus promoted metabolic alterations in cardiomyocytes, favoring the oxidation of fatty acids in detriment of oxidation of glucose with oxidative stress leading to cardiac dysfunction. NAC administration may be a therapeutic alternative, since it reversed the deregulation of the energy metabolism induced by the DM1 in the cardiac muscle through its antidiabetogenic effect, controlling the glycemia and consequently attenuated the oxidative stress. NAC improved the nutritional parameters and normalized the lipid profile and the atherogenic index.
Diabetes mellitus is a heterogeneous group of disturbances in energy metabolism and consequent oxidative stress, important factors for the development of diabetic complications such as cardiomyopathies. The use of antioxidants has contributed to improve hyperglycemia and also minimize diabetic complications. N-acetylcysteine has antioxidant and antihyperglycemic action, being able to contribute to the therapeutics of this pathology. This study aimed to evaluate the energetic metabolism and oxidative stress in the myocardium of rats with type 1 diabetes mellitus treated with N-acetylcysteine. 32 male wistar rats, with ±250g body weigth, 60 days old were distributed in groups (n=8): C (normal, control); NAC (normal, treated with N-acetylcysteine); DM (diabetic, untreated); DM-NAC (diabetic, treated with N-acetylcysteine). The rats received water and a rodent chow ad libitum. Experimental type 1 diabetes mellitus was induced by streptozotocin (60mg Kg-1 body weight, single dose, i.p.). Animals of the group NAC and DM-NAC received N-acetylcysteine (25mg Kg-1 day-1) by gavage for 37 days. During the experimental period (37 days), food and water intake were evaluated. After this period the animals, in a 12h fast, were anesthetized (xylasin and ketamin) and euthanized. Blood and cardiac tissue (±100mg, left ventricle) were collected and stored in a freezer -80°C. Results were analyzed by One-way ANOVA followed by Tukey test for comparison of means. The results were considered significant when p<0.05. Food and water intake were higher (p<0.05) in the DM group, when compared to the other groups. While body weight decreased (p<0.05) in diabetic animals related to C and NAC, which did not differ (p>0.05) DM-NAC. NAC increased (p<0.05) glycemia in diabetic rats, but presented higher glycemia than normal rats (C and NAC). Serum insulin in DM-NAC group was increased (p<0.05) when compared to DM group rats. Energy intake and carbohydrate and protein consumption increased (p<0.05) in untreated diabetic rats (DM) compared to the other groups, but without significant difference (p>0.05) between C and NAC. Alimentary efficiency in DM was lower (p<0.05) when compared to DM-NAC, normal rats (C and NAC) had higher values (p<0.05) than diabetics. Cardiac concentration of total proteins and glycogen in diabetic animals (DM) were decreased (p<0.05) to the other groups, and treatment with NAC improved (p<0.05) these parameters. Phosphofructokinase activity in myocardium of diabetic rats was recovered (p<0.05) by the administration of NAC reaching values of the groups C and NAC. There was no statistical difference in serum lactate dehydrogenase activity between the groups (p>0.05). NAC decreased serum concentration of triacylglycerols, total cholesterol, VLDL-cholesterol and LDL-cholesterol (p<0.05) and increased HDL-cholesterol concentration in diabetic rats compared to the DM group (p<0.05). NAC-DM group had a lower (p<0.05) atherogenic index than the DM group. Lactate dehydrogenase activity in rat heart tissue did not show statistical difference (p>0.05) between the groups. In myocardium of diabetic rats pyruvate dehydrogenase activity decreased (p<0.05), and NAC improved (p<0.05) in DM-NAC, but did not reach values obtained in normal rats (C and NAC). NAC administration was able to improve (p>0.05) β-hydroxyl-CoA dehydrogenase activity and citrate synthase in cardiac tissue of diabetic rats (DM-NAC). The ratio Lactate dehydrogenase/citrate synthase was lower (p<0.05) in DM group than others, which did not differ significantly. There was no significant difference in ratio β-hydroxyl-CoA dehydrogenase/citrate synthase. Superoxide dismutase activity in myocardium was reduced (p<0.05) in DM, whereas groups receiving NAC (NAC and DM-NAC) demonstrated intermediate values between C and DM. NAC increased (p<0.05) cardiac catalase activity in diabetic rats, reaching values close to the C and NAC groups. Glutathione peroxidase activity in myocardium increased in DM-NAC group compared to DM, but did not differ (p>0.05) when compared to group C and NAC. The cardiac concentration of total glutathione and reduced glutathione activity decreased (p<0.05) in DM when compared to the other groups. DM group showed higher values for lipid hydroperoxide in myocardium, while the administration of NAC improved this value (p<0.05). NAC treatment normalized (p<0.05) the relationship between lipid hydroperoxide and activity antioxidants enzymes in diabetic rats. In view of the obtained results it can be concluded that type 1 diabetes mellitus promoted metabolic alterations in cardiomyocytes, favoring the oxidation of fatty acids in detriment of oxidation of glucose with oxidative stress leading to cardiac dysfunction. NAC administration may be a therapeutic alternative, since it reversed the deregulation of the energy metabolism induced by the DM1 in the cardiac muscle through its antidiabetogenic effect, controlling the glycemia and consequently attenuated the oxidative stress. NAC improved the nutritional parameters and normalized the lipid profile and the atherogenic index.
Descrição
Palavras-chave
Metabolismo energético, Estresse oxidativo, Antioxidantes, Diabetes mellitus tipo 1, Miocárdio, N-acetilcisteína