Retarding effect of dietary restriction on the accumulation of 8-hydroxy-2'-deoxyguanosine in organs of Fischer 344 rats during aging.

An age-related accumulation in rats of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, and the effect of dietary restriction on the accumulation of 8-OHdG were examined. The 8-OHdG concentrations of nuclear DNA in organs of ad libitum fed rats were similar in young and middle age, but increased significantly in kidney at 24 months of age, in heart and liver at 27 months of age, and in brain at 30 months of age. The 8-OHdG concentration in dietary-restricted rats showed no changes in any organ up to 30 months of age and then was increased at 33 months of age. Dietary restriction retarded the onset of the age-related increase in 8-OHdG concentration, although it did not reduce the concentration in young and middle age. These results suggest that the effect of dietary restriction on the extension of life-span in rats might be related to a reduction in oxidative damage.