A Comparison of Several Parameters of Aging in Drosophila Melanogaster Under Normal and High Oxygen Tension
Previous research by others has suggested that Drosophila, maintained throughout their adult life under high oxygen tension, might provide a model for accelerated aging, at least in regard to lipid peroxidation damage. To test this proposal, adult male Oregon R Drosophila melanogaster were exposed to an atmosphere of 1:1 oxygen-nitrogen. A number of possible effects of excess oxygen and peroxidation damage were investigated. Flies exposed to this oxygen-enriched atmosphere had about a 50% shorter mean lifespan than did flies exposed to normal room air. Similar rates of lipofuscin accumulation were noted in both groups of flies as a function of age. Lipofuscin accumulation is an indication of lipid peroxidation damage. If high oxygen tension were the cause of accelerated aging, then the group exposed to the high oxygen should have accumulated lipofuscin more quickly. Since lipofuscin accumulation was not accelerated by exposure to high oxygen tension the activities of several enzymes, which would be expected to protect the tissues against excess oxygen, were investigated. The most common one, peroxidase, was not detected. Only very low amounts of another, superoxide dismutase, were found. The main protection against high oxygen seems to be afforded by catalase which was present. Flies exposed to room atmosphere were found to have a fairly constant level of catalase activity. Flies exposed to high oxygen were found to have a sharply declining specific activity. The data suggest that high oxygen tension induces a pathological condition resulting in premature death. It does not provide a valid model for accelerated normal aging. The mechanisms that lead to the decline in catalase activity in conditions under which it is expected to increase await further study.
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