Scientists explain why naked mole-rats' longevity contradicts accepted aging theory

FEBRUARY 10, 2020

by Missouri University of Science and Technology

Dr. Chen Hou and his research collaborators have found an answer to the decades-old question of why naked mole-rats with high oxidative damage live 10 times longer than mice of comparative weight.

"The long lifespan of the East African naked mole-rats raises one of the most serious paradoxes in the study of aging," says Hou, an associate professor of biological sciences at Missouri S&T. "And geriatric researchers are asking if the oxidative stress theory is dead."

The widely accepted theory of aging is based on a negative correlation between oxidative stress and animal lifespan. This theory posits that aging occurs because of accumulated cellular damage caused by the byproducts of oxidative metabolism—or the way we burn oxygen to produce energy. When a certain threshold of oxidative damage is reached, animals will die.

"We've observed the correlation between damage level and lifespan is the dynamic process of damage accumulation, which is largely determined by the animal's growth and metabolism," says Hou. "Besides offering a simple explanation to the 'naked mole-rats paradox' that has puzzled scientists for years, our results provide a starting point for new comparative aging studies."

To explain the contradiction, the researchers developed a data-based theoretical model that estimates oxidative damage accumulation with age. Their model highlights a tradeoff between the metabolic energy cost of growth versus damage repair. The tested hypothesis is if animals expend too much energy on growth, less will be available to repair their oxidative damage, which will accumulate. It also suggests that high metabolism leads to faster damage accumulation.

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