The effects of idebenone on the superoxide dismutase, catalase and glutathione peroxidase activities in liver and brain homogenates, as well as in brain synaptosomal and mitochondrial fractions

Abstract

The cerebral cortex and liver of 20 female CFY rats of 21 months of age (at killing), kept in conventional housing conditions, were studied. Ten animals received placebo (5% gum arabic solution) and 10 other rats received 50 mg/kg body weight/day idebenone suspended in the gum arabic, through a gastric tube for 5 weeks (except Sundays). Liver and brain homogenates were obtained by homogenization of tissue pieces (10 mg/ml) in 0.32 M sucrose solution. Synaptosomal and mitochondrial fractions of the brain cortex were prepared by using established methods of density gradient centrifugation, pooling together the brains of two animals for each experiment. Protein contents of the samples were measured by means of a modified folin-phenol method. Superoxide dismutase (SOD), catalase (CA) and glutathione peroxidase (GP) activities were measured by using established biochemical methods. The activities were compared in the placebo and verum groups on a protein weight basis. The SOD activity increased slightly (but not significantly) in the total brain homogenate, whereas both the mitochondrial and synaptosomal fractions of the cortex displayed significant increases of this enzyme activity (28.5 and 16.3% respectively). SOD and CA activities decreased in the liver homogenate and all other parameters remained invariate both in the brain and its subfractions, except CA in the synaptosomal fraction where a slight decrease occured (−15.6%).