RESUMO
The effect of alpha-tocopherol pretreatment (6 mg/100 g body wt/day, orally for a period of 90 days) on mitochondrial electron transport in myocardial infarction induced by isoproterenol (20 mg/100 g body wt, subcutaneously for two days) was studied in rats. A significant decrease was observed in the activities of isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, NADH dehydrogenase and cytochrome oxidase in heart mitochondria of isoproterenol administered rats. The cytochrome content and the oxidation of succinate in state 3 and state 4 decreased significantly in the cardiac mitochondria treatment. In alpha-tocopherol pretreated rats, the activities of TCA cycle enzymes, concentration of cytochromes and the oxidation of succinate in state 3 and state 4 were retained at near normal values, following isoproterenol administration.
Assuntos
Animais , Ciclo do Ácido Cítrico/efeitos dos fármacos , Citocromos/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Isoproterenol , Peroxidação de Lipídeos/efeitos dos fármacos , Peróxidos Lipídicos/metabolismo , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Infarto do Miocárdio/induzido quimicamente , Ratos , Ratos Wistar , Valores de Referência , Vitamina E/farmacologiaRESUMO
The effect of alpha-tocopherol pretreatment on lipid peroxidation and antioxidant status in isoproterenol induced myocardial infarction was studied in rats. Isoproterenol administered rats showed a significant increase in lipid peroxides in serum, heart and aorta. A significant increase in serum iron level with a significant decrease in iron binding capacity was also observed. The levels of antioxidants such as ceruloplasmin, glutathione and the activities of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase decreased significantly in isoproterenol administered rats when compared to control. The activity of Na+K+ATPase decreased significantly and the activity of Ca2+ATPase increased significantly in heart and aorta of isoproterenol administered rats. alpha-tocopherol pretreated rats maintained the levels of antioxidants, membrane bound enzymes and activities of antioxidant enzymes near normal, on isoproterenol administration, thus establishing its effect as an antioxidant.
Assuntos
Animais , Antioxidantes/farmacologia , Radicais Livres/metabolismo , Isoproterenol/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Infarto do Miocárdio/induzido quimicamente , Oxirredutases/efeitos dos fármacos , Ratos , Ratos Wistar , Vitamina E/farmacologiaRESUMO
The effect of alpha-tocopherol (6 mg/100 g body wt, orally, daily for 90 days) pretreatment in isoproterenol (20 mg/100 g body wt, subcutaneously, twice at an interval of two days at the end of the alpha-tocopherol pretreatment) induced myocardial infarction was studied in rats. Isoproterenol administered rats showed electrocardiographic changes suggestive of myocardial infarction with marked ST segment elevation, Q waves appearance and a significant increase in heart rate. In isoproterenol administered rats, a significant decrease was observed in the activities of marker enzymes such as aspartate amino transferase, alanine amino transferase, lactate dehydrogenase and creatine kinase in heart and aorta with a significant increase in their activities in serum. The levels of lipid peroxides in terms of "TBA reactants" increased significantly in serum, heart and aorta on isoproterenol administration. The histology of heart and aorta showed marked fragmentation of muscle fibres and necrotic lesions in isoproterenol administered rats. alpha-Tocopherol pretreated rats showed a near normal ECG pattern, levels of lipid peroxides, activities of marker enzymes and a near normal histology of heart and aorta on isoproterenol administration.