Iron accumulation in aging: modulation by dietary restriction

Male Fischer 344 rats fed ad libitum or dietary restricted (maintained on 60% of ad libitum food intake) were sacrificed at 6, 12 and 24 months of age. Portions of kidney, liver and brain were removed for total iron content analysis and oxidative stress assessment. Total iron content was measured directly and lipid peroxidation (LPO) was assayed as an index of oxidative stress. Tissue total iron content was shown to increase significantly with age in animals fed ad libitum (AL). At 24 months, these animals showed comparable iron content increases in the liver and kidney, but were significantly greater than measurements found in brain. This age-related iron accumulation, however, was found to be markedly suppressed by dietary restriction (DR) in all tissues. Similarly, LPO measurements increased in an age-related, tissue-specific fashion. At 24 months of age, measurements of LPO in AL rats brain and liver exceeded measurements in kidney. Again, we found DR to markedly suppress age-related LPO in all tissues. Reported here are our findings on the ability of DR to modulate iron status at the tissue level. Consistent with the proposed anti-oxidative mechanism of DR, these findings further suggest that the modulation of tissue total iron content is an important component of that mechanism.