Chronic food restriction modulates the advance of senescence in the senescence accelerated mouse (SAM).

The effects of chronic food restriction on grading scores of senescence, deposition of senile amyloid (ASSAM), mean life span and 10th decile were investigated by using animal models for accelerated senescence (SAM-P/1) and for normal aging (SAM-R/1). The experimental groups consisted of control (ad libitum fed), 80% (fed 80% of control intake), and 60% (fed 60% of control intake) groups. The grading score of SAM-P/1 mice was significantly improved in the 60% group, but not in the 80% group, compared to the control group. The grading score of SAM-R/1 mice, however, was significantly less than that in the control group in both the 60 and 80% groups. In SAM-P/1 mice liver, skin and testis, the severity of senile amyloid deposition was significantly less with 40% food restriction (60% group) than in the control group. A restriction of 20% (80% group) had no influence on amyloid deposition. A definite tendency to prolong mean life span (24.3%) and 10th decile (65.9%, mean life span of the last 10th of survivors of a group) was observed in the 60% group of SAM-P/1 mice, but the changes were not statistically significant. In the 80% group of SAM-P/1 mice and also in either restriction group of SAM-R/1 mice, however, such a tendency was not evident. These results indicate that 40% food restriction modulates the advance of senescence in these mice.