Sure these dirt-dwellers look like a part of the male anatomy with buck-teeth, but their attributes only go up from there (pun?). They survive long periods without oxygen, show insensitivity to pain, and unlike related mice that live 2-4 years, the naked mole-rat lives into its 30s. For humans, that would be a lifespan extension of ~ 400 years. Not impressed? Well they also don't get cancer....ever.
Oxygen Smoxygen
Our brains are damaged after just 3 minutes of oxygen deprivation. This is a concern for heart attacks and strokes, where blood supply to the brain is interrupted. Brain tissue of the naked mole-rat remains functional three times as long as brain tissue of mice, and when oxygen is restored, the brain recovers. With their claustrophobic environment of underground tunnels they've evolved to contend with low oxygen and high carbon dioxide levels. Naked mole-rats protect their brains using the same strategy as infants. Infant humans are more tolerant to oxygen deprivation than adults, and calcium is the culprit. Normally, calcium in our brain helps memories form. But the balance is delicate: too much calcium is damaging. When our brains are oxygen starved, they no longer regulate calcium entry, resulting in too much calcium and brain damage. Researchers discovered that calcium channels in infants close during oxygen deprivation, protecting the brain from calcium overdose in the womb, where the baby gets much less oxygen. After birth, however, oxygen is plentiful, and these channels are replaced by ones that open in response to oxygen deprivation, often leading to cell death. Naked mole-rats retain "infant-style" calcium channels even as adults, which explains their resiliency. These findings provide a new strategy to help victims of heart attack and stroke: design a drug that quickly increases the number of infant-style calcium channels in the brain. This could provide valuable protection during a time when the supply of oxygen-rich blood is stunted.
Our brains are damaged after just 3 minutes of oxygen deprivation. This is a concern for heart attacks and strokes, where blood supply to the brain is interrupted. Brain tissue of the naked mole-rat remains functional three times as long as brain tissue of mice, and when oxygen is restored, the brain recovers. With their claustrophobic environment of underground tunnels they've evolved to contend with low oxygen and high carbon dioxide levels. Naked mole-rats protect their brains using the same strategy as infants. Infant humans are more tolerant to oxygen deprivation than adults, and calcium is the culprit. Normally, calcium in our brain helps memories form. But the balance is delicate: too much calcium is damaging. When our brains are oxygen starved, they no longer regulate calcium entry, resulting in too much calcium and brain damage. Researchers discovered that calcium channels in infants close during oxygen deprivation, protecting the brain from calcium overdose in the womb, where the baby gets much less oxygen. After birth, however, oxygen is plentiful, and these channels are replaced by ones that open in response to oxygen deprivation, often leading to cell death. Naked mole-rats retain "infant-style" calcium channels even as adults, which explains their resiliency. These findings provide a new strategy to help victims of heart attack and stroke: design a drug that quickly increases the number of infant-style calcium channels in the brain. This could provide valuable protection during a time when the supply of oxygen-rich blood is stunted.
Are you a man or a mole-rat?
I recently went on a whiskey distillery tour and the guide asked me to stick my nose in the fermenter and take a whiff (Fermentation: Sugar = CO2 + Delicious Alcohol). I jolted up with my nostrils being pricked by a thousand horseradish-tipped needles. High levels of CO2 can be painful to the eyes and nose due to the formation of acid on the surface of those tissues. A less sadistic experience is the feeling of burping through one’s nose after drinking a coke. Mole-rats are completely insensitive to this and other irritants. The nerve fibers that respond to irritants are less sensitive in naked mole-rats. Importantly, these fibers are responsible for the pain people experience after an injury. Surprisingly, naked mole-rats have these fibers everywhere, but they do not make the neuropeptides usually released because of a gene defect associated with relaying the message of pain. A greater understanding of how this type of pain processing is altered in naked mole-rats has significant implications for the treatment of chronic pain in humans.
Is Joan Rivers a Mole-Rat?
With a recorded lifespan of 32 years, they are the longest-lived rodents known, and remarkably, they are in good health for most of their lives. At an age equivalent to a human age of 92 years, naked mole-rats show unchanged levels of activity and metabolic rate, sustained muscle mass, fat mass, bone density, cardiac health, and brain function. They delay the onset of aging and compress the period of decline into a small fraction of their overall lifespan. These findings of sustained good health are turning current theories of aging on their head. For example, the widely accepted "oxidative stress theory of aging" attributes our decline in function to damage caused by reactive oxygen species. In much the same way that oxygen causes your car to rust, cell membranes, proteins, and DNA are also damaged. Over time, we "rust", which causes our bodies to slowly malfunction. Surprisingly, naked mole-rats also show high levels of rust at an early age, yet cellular function is not impaired. Another aging theory is that the length of an organism’s DNA ends (telomeres), is a marker of aging. As our cells divide, the ends of our chromosomes get shorter and shorter, eventually chewing into genes required for cellular function. But the naked mole-rat has short telomeres, similar to those of humans. Thus, the telomere theory is unlikely to explain their longevity. Where's the fountain of youth?!
Rat for the cure
The naked mole-rat doesn't get cancer. Scientists have blasted these critters with cancer causing radiation and no tumors develop. Some real jerks even altered their DNA to produce aggressive tumors. Again; nothing! But the jerks did notice something intriguing. The cancerous cells didn't die, they just stopped dividing. It seems as though the naked mole-rat is very good at recognizing abnormal cells, neutralizing cell overgrowth, and repairing DNA. The genome of the naked mole-rat has unveiled novel insights into why they are impervious to cancer. Given that cancer is one of the largest contributors to mortality in elderly humans, these cancer prevention pathways may contribute substantially to the longevity of naked mole-rats.
They sure are ugly, but we are slowly recognizing the beauty from within. Research on this fascinating animal will do so much. If I'm ever saved from brain damage, pain, cancer, or even aging because of these critters, I'll be the guy in the naked mole-rat mobile with the naked mole-rat tattoo on the way to PetSmart to buy a dozen naked mole-rats....to be my pets!!!
