Posted by: Prospector PJ10 JUL 2013
A subterranean rodent with no fur and baggy skin could hold an important clue to cancer treatment and prevention.
The naked mole rat (Heterocephalus glaber) never suffers from cancer, yet when high molecular weight hyaluronan (HMW-HA) is removed from its skin it becomes susceptible to the disease. A study published online in Nature on 19 June 2013 proposed that the sugar, which is involved in tissue repair and found in high concentrations in the rat’s skin, protects against cancer.
But this is not the only reason why H glaber is interesting. A lack of substance P is thought to be responsible for the rat’s insensitivity to certain types of pain stimulus. The naked mole rat responds to mechanical pain but is insensitive to stimuli such as capsaicin and acid. The lack of sensitivity could be an adaptation to living in underground tunnels, where carbon dioxide levels can reach 10 per cent and would form carbonic acid on damp membranes.
Naked mole rats also enjoy unusual longevity for small rodents. They can live for up to 30 years, in sharp contrast to mice, for example, which live for no longer than four years. The mole rat’s long life is thought to be due to an ability to reduce its metabolism significantly when food is scarce, which reduces ageing-induced damage from oxidative stress.
H glaber is the only mammalian thermoconformer, that is, an animal unable to regulate its body temperature. When it is cold the rats huddle together for warmth or bask in the sun-warmed shallower parts of their burrow. And if the temperature rises, they retreat to the deeper, cooler parts of their tunnel system.
The naked mole rat is one of only two eusocial mammals. Their social structure is similar to that found in bees and ants, with only one female (the queen) and a small number of males involved in reproduction, while the rest of the colony are sterile workers.
The Damaraland mole rat is the only other eusocial mammal.