Naked mole rats—hairless, sausagelike rodents that live in burrows beneath the arid soils of Kenya, Ethiopia and Somalia—have a remarkable ability to resist aging. Scientists are getting closer to understanding why these animals grow old with such grace, and they hope their findings will lead to therapies for staving off age-related ailments.
With a maximum lifespan of about 30 years, the naked mole rat outlives all other rodents by a long shot. It lives about 10 times longer than the similar-size lab mouse and does not show the normal signs of aging such as dementia, menopause, and bone density loss until it's near death (humans start losing bone density in their 30s), says Rochelle Buffenstein, a physiologist at the University of Texas Health Science Center at San Antonio who has spent the past three decades studying the rodents (and admits to having 1,000 of the bald critters living in her lab). What's more, she adds, "We have never seen a single instance of cancer in the lab or in the zoos [where these animals are monitored]."
Buffenstein suspects the mole rat's secret to longevity and good health lies in its proteins. She and her colleagues recently published a study in the Proceedings of the National Academy of Sciences USA showing that proteins in naked mole rat liver cells function much better than mouse liver cells after being exposed to damaging agents such as temperature changes and free radicals (unstable molecules produced by chemical reactions).
Buffenstein speculates that naked mole rat cells may have a large number of proteins that scour cells for damaged proteins and alert other proteins to escort them to the proteasomes. Proteasomes are structures inside all animal cells that break down damaged proteins so that their constituent parts (amino acids) can be recycled to make new proteins.
This quality control system prevents the animals from accumulating crippled proteins throughout their lives, which is key because many aging diseases such as Alzheimer's are believed to be related to such buildups, says study co-author Asish Chaudhuri, a biochemist at the University of Texas Health Science Center at San Antonio.
The next step, says Chaudhuri, is to identify which proteins in naked mole rats (and other long-lived animals) may be the ones that search out damaged proteins and flag them for destruction. If researchers can do that, he says, they may be able to design drugs that activate them, potentially staving off aging-related ills.
Image courtesy of the Barshop Institute for Longevity & Aging Studies at The University of Texas Health Science Center