ABSTRACT
Some of the biochemical indices relevant to the "free radical theory" of aging have been assessed in mice subjected to chronic low-dose whole-body irradiation. Radiation exposure results in enhanced accumulation of the lipofuscins in brain, heart, and intestine. In these animals, the degree of lipoperoxidation in liver was greatly increased, as were the free activities of acid phosphatase and cathespin, indicating damage to lysosomal membranes. The activity of SOD in brain and liver 20,000g post-mitochondrial supernatants was lower in the irradiated mice. All these changes arising from chronic whole-body irradiation are similar to those observed during aging and are effectively prevented by dietary supplementation with BHT. These observations lend considerable support to the "free radical theory" of aging.
Subject(s)
Aging , Butylated Hydroxytoluene/pharmacology , Lipofuscin/metabolism , Pigments, Biological/metabolism , Whole-Body Irradiation , Acid Phosphatase/metabolism , Animals , Brain/metabolism , Cathepsins/metabolism , Diet , Female , Gamma Rays , Lipid Peroxides/metabolism , Liver/metabolism , Mice , Myocardium/metabolismABSTRACT
The effects of chronic diet restriction in mice on some biochemical parameters related to aging have been investigated. Restriction of food intake to about one-half of the ad libitum consumption resulted in a significantly decreased growth rate immediately after weaning. In the experimental mice killed after different periods on a restricted diet up to 12 months, in vitro lipoperoxidation, the percent free activities of lysosomal enzymes and the accumulation of lipofuscins in tissues such as brain and heart were lower in comparison to those of the control animals. The superoxide dismutase activity in liver and brain did not show any consistent variations due to diet restrictions. These beneficial influences of decreased food intake on some free radical-mediated cellular damage may underlie its reported effects on longevity, in conformity with the free radical theory of aging.
Subject(s)
Aging , Food Deprivation , Animals , Brain/enzymology , Brain/metabolism , Female , Lipid Peroxides/metabolism , Lipofuscin/metabolism , Liver/enzymology , Lysosomes/enzymology , Mice , Myocardium/metabolism , Superoxide Dismutase/metabolismABSTRACT
An investigation was undertaken to study the effect of dietary protein level on some age-related biochemical processes in mice. Weanling mice were fed a laboratory diet containing protein at 6, 12 or 24% and adequate in all other nutrients, for up to 52 weeks. Although the rate of gain in body weight of the animals between 3 and 6 weeks was related to the dietary level of protein, the final body weights of mice in different groups were not significantly different. Lipid peroxidation in liver homogenate, free activities of some lysosomal enzymes of brain, liver and intestine, and the accumulation of lipofuscin pigments showed an increase with the dietary level of protein. On the other hand, the activity of superoxide dismutase in liver showed an inverse relationship to the protein level of the diet. The findings are discussed in relation to the free-radical theory of ageing.
