reductase induction increases early
survival and decreases lipofuscin accumulation in aging frogs.
Journal of Neuroscience Research. 34(2):233-42, 1993 Feb 1.
Brain catalase was continuously depleted throughout the life
span starting with a large population of initially young and old frogs. Free
radical-related parameters were measured in the brain tissue
once per year after 2.5, 14.5, and 26.5 months of experimentation.
Brain lipofuscin accumulation was observed after 14.5 and
26.5 months, and survival was continuously followed during 33 months. The age
of the animal did not decrease endogenous antioxidants nor increase tissue
peroxidation either in cross-sectional or longitudinal comparisons.
Continuous catalase depletion similarly affected young and old animals,
inducing glutathione reductase, tending to
decrease oxidized glutathione/reduced
glutathione (GSSG/GSH) ratio, decreasing lipofuscin
accumulation in the brain, and increasing survival from 46%
to 91% after 14.5 months. At 26.5 months of experimentation the loss of the
induction in catalase-depleted animals was accompanied by
the presence of higher lipofuscin deposits than in controls and was followed
by a great increase in mortality rate. Even though the maximal life span (7
years) was the same in the control and treated animals which were already old
(4.2 years) at the beginning of the experiment, the treated animals showed a
strong reduction in the rates of early death. It is proposed that the
maintenance of a high antioxidant/prooxidant balance in the vertebrate
brain greatly increases the probability of the individual to
reach the final segments of its species-specific life span.
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