Dietary restriction induces microcytic change and shortened life span of erythrocytes without anemia in mice.

Dietary restriction is well known to increase mean and maximal life span in rodents and other species, although the mechanisms remain unclear. To investigate the effects of dietary restriction on erythrocyte cellular life span, mice were fed 40% restricted diet and erythrocyte properties were examined. At the end of the 8th week of a feeding period, erythrocytes in the restricted mice showed strikingly shorter life span than those in the unrestricted mice (restricted; T1/2 = 15.4 +/- 1.1 days, unrestricted; T1/2 = 18.9 +/- 1.2 days). However, the restricted mice never showed anemic conditions although they had microcytes, in addition. Significant increase in the erythrocyte count was observed in the restricted mice. These results strongly suggest that increased erythropoiesis should exist in the restricted mice, and that some unknown biophysical significance made shortened erythrocyte life span in mice fed restricted amount of diet.