Underground Supermodels: no cancer, ever, no pain, resistant to poisons, super long lives, young forever!
OK, OK, it's just the naked mole-rats. But 'what can a twentysomething naked mole-rat tell us about fighting pain, cancer, and aging?' Naked mole rats don't get cancer, ever. They don't experience pain from many sources, are highly resistant to pollution from heavy metals, carbon dioxide, plant poisons and a wide variety of chemicals. Yet, they live an astonishing 30-some year lifespans, and are physiologically young
for most of that time.
'Naked mole-rats, unlike other mammals, tolerate variable body temperatures, attributed to their lack of an insulatory layer of fur. Their pink skin is hairless except for sparse, whisker-like strands that crisscross the body to form a sensitive sensory array that helps them navigate in the dark. Both the naked mole-rat’s skin and its upper respiratory tract are completely insensitive to chemical irritants such as acids and capsaicin, the spicy ingredient in chili peppers. Most surprisingly, they can survive periods of oxygen deprivation that would cause irreversible brain damage in other mammals, and they are also resistant to a broad spectrum of other stressors, such as the plant toxins and heavy metals found in the soils in which they live. Unlike other mammals, they never get cancer, and this maintenance of genomic integrity, even as elderly mole-rats, most likely contributes to their extraordinarily long life span. In contrast to similar-size mice that only live 2–4 years, naked mole-rats can survive and thrive, maintaining normal function and reproduction, into their 30s.'
'Unlike mice, which very commonly develop tumors, naked mole-rats have never been found to naturally have cancer. Moreover, subjecting mole-rats to ionizing radiation does not induce much DNA damage, as seen in other animals, nor does it result in tumors, even 5 years later. Attempts to turn naked mole-rat cells cancerous via injection of oncogenes have also failed, whereas similar methods using human, mouse, and even cattle cells results in conversion to highly aggressive and invasive cancer-forming cells.6 Instead of starting to proliferate in an uncontrolled manner, transformed naked mole-rat cells immediately stop dividing, though they do not die.7 Similarly, naked mole-rat cells treated with a toxin or simply housed under suboptimal conditions immediately stop dividing until conditions improve.'
'Although naked mole-rats are the size of a mouse, weighing only about 35–65 grams, in captivity these rodents live 9 times longer. With a recorded maximum lifespan of 32 years, they are the longest-lived rodents known.10 And remarkably, they appear able to maintain 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, as well as sustained muscle mass, fat mass, bone density, cardiac health, and neuron number. These clear indications of both attenuated and delayed physiological aging are also accompanied by the maintenance of protein quality and gene expression levels.
Some of the oldest naked mole-rats (>26 years; equivalent to humans >105 years old) do begin to show signs of muscle loss, osteoarthritis, and cardiac dysfunction, demonstrating that mole-rats do, eventually, age like other animals. Somehow 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 surprising given that the naked mole-rat is an exception to many of the current theories of why we age. For example, the widely accepted oxidative stress theory of aging attributes the gradual decline in function to damage caused by the free radicals or reactive oxygen species formed as an inevitable by-product of oxygen respiration. In much the same way that oxygen causes metal to rust when exposed to the elements, cell membranes, proteins, and DNA are damaged by the gas, and this accumulating damage, so goes the theory, causes physiological systems to malfunction. Naked mole-rats in captivity, however, show very high levels of oxidative damage at an early age, yet cellular function is not impaired, and the animals are able to tolerate these high levels of oxidative damage for more than 20 years.'