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Six experimental groups of young (7-month-old) and aged (24-32-month-old) rats, underwent different dietary manipulations (i.e. dietary restriction and/or a vitamin E-depleted diet), and their liver mitochondria were assayed for several antioxidants and peroxidation markers. Glutathione levels were affected both by age and dietary treatment. Coenzyme Q9 and C0Q10 showed the highest levels in the oldest rats where ageing, as well as other oxidative stresses, could induce ubiquinone biosynthesis.

We have investigated the susceptibility to peroxidation of erythrocytes from young, adult and old ad libitum (AL) fed, as well as from adult and old food restricted rats, measuring the rate of hemolysis under controlled peroxidative condition. Food restriction has been applied on an every-other-day (EOD) schedule starting from the age of 3.5 months. The oxidation of red blood cells by molecular oxygen was performed in an aqueous suspension using the azo-compound 2-2'-azo-bis-(2-amidinopropane)hydrochloride (AAPH) as the free radical initiator. Several parameters were calculated from the time-dependent curve of AAPH induced hemolysis. The time required to achieve 50% hemolysis decreased with aging and this decrease was prevented by food restriction. The lag time, which reflects the capacity of the cell to buffer free radicals, was longer in young than in old AL fed animals also this impairment was almost completely prevented in EOD fed animals. The same beneficial effect of food restriction was observed considering the maximal amount of hemolysis attained with the dose of AAPH applied and the time necessary to reach this level. The general picture emerging from the present study is that erythrocyte membranes from EOD fed rats are better protected, than those from AL fed ones, against damages caused by peroxidation. This effect may be due to a difference in the chemical composition of the erythrocyte membranes as it was found in other organs.

Diet restriction, prolonging the lifespan of rodents, represents an interesting model for gerontological studies. We analyzed the activity of antioxidant enzymes, Superoxide Dismutase, Catalase and Glutathione Peroxidase in erythrocytes from young, old and old food restricted Wistar rats. Diet restriction was applied feeding the animals on every-other-day schedule starting from the age of 3.5 months. The age-dependent decrease of Catalase and Glutathione Peroxidase activities was prevented by food restriction, whereas Superoxide Dismutase activity was not influenced either by aging and dietary intervention. Present results support the hypothesis that diet restriction increases the protection of cell structure against the peroxidative damage, preserving the activity of antioxidant enzymes.

The microviscosity of cerebellar membranes from female Wistar rats during aging and subsequent to diet restriction has been investigated. Diet restriction was applied feeding the animals on every-other-day schedule starting from the age of 3.5 months. Undernutrition increased the lifespan of the animals and retarded the appearance of the age-dependent increase of microviscosity of cerebellar membranes.