The senescence-accelerated mouse (SAMP8) is an animal model used in studies of aging. This study was undertaken to investigate the effects of dietary PUFA on longevity (Experiment 1) and serum
lipid concentrations (Experiment 2) in SAMP8 mice. Male mice were fed either an (n-3) PUFA-rich (9 g/100 g
perilla oil) or an (n-6) PUFA-rich (9 g/100 g
safflower oil) diet beginning at 6 wk of age. Experiment 1: The groups did not differ in
body weight gain, but those fed
perilla oil had significantly lower scores of senescence relative to those fed
safflower oil (P<0.05). The mean life span of mice fed
perilla oil was 357+/-21 d and of those fed
safflower oil, 426+/-24 d (P<0.05). Pathological studies revealed that the incidence of
tumors was significantly lower in the
perilla oil group than in the
safflower oil group (P<0.05). Approximately half the mice fed
perilla oil had died after 10 mo, and the direct causes closely connected with death could not be specified. Experiment 2: The serum total
cholesterol, HDL cholesterol,
triglyceride and
phospholipid concentrations were significantly lower in the
perilla oil group than in the
safflower oil group (P<0.01). A marked decrease of serum
HDL cholesterol and
apolipoprotein A-II (
ApoA-II)concentrations in advanced age were observed in the mice fed
perilla oil (P<0.01). Ten-month-old mice fed
perilla oil had a significantly greater ratio of
apolipoprotein A-I (
ApoA-I) to
ApoA-II than those fed
safflower oil. Separation of HDL subfractions revealed that the smaller HDL species were much more abundant than the larger HDL species in both
dietary oil groups. These findings suggest that dietary (n-3) and (n-6) PUFA differ in their effects on serum lipid metabolism which may modulate the mean life span of SAMP8 mice fed each
dietary oil.