Heterocephalus glaber, also known as the naked mole rat
It’s no secret that the naked mole-rat — that wrinkled, nearly hairless rodent with long protruding teeth — isn’t the most attractive animal on the planet.
But these creatures make up for their lack of beauty with a series of extraordinary features that have drawn the attention of zoologists and medical researchers around the world.
Despite its small size (which varies from 7.6 to 33 cm), the naked mole rat lives, on average, 30 years. the rodent is resistant to chronic diseasesincluding diabetes, and has a remarkable reproductive system.
They also benefit the environment by acting as “ecosystem engineers” and increasing soil biodiversity by digging the burrows where they make their nests.
Immune to pain and aging, these strange-looking creatures have fascinated scientists for a long time. Now, research reveals they may hold the key to understanding a range of human conditions, such as cancer and aging.
Historically, we’ve studied rats and mice to understand the secrets of human biology. But scientists believe that the naked mole rat has special advantages for medical research.
The scientific name of the species – Heterocephalus glaber – essentially means “bald thing with different head“.
The naked mole rat is native to the warm, tropical environments of northeast Africa. In their natural environment, they live in large underground colonies, forming a labyrinth of tunnels and chambers that extends over an area corresponding to several football fields.
The harsh conditions in which naked mole rats live, with low levels of oxygen, could be an indication of some of the unusual characteristics of their species.
unique biology
The biology of the species is incredibly unique. Naked mole rats are considered “extremophiles“, that is, they can survive in extreme environments underground, according to researcher Ewan St. John Smith, who studies the sensory nervous system at the University of Cambridge in the UK.
One of its most striking features is that it is hard to say exactly the age of a naked mole rat, as its signs of physical decline are limited.
While humans may become increasingly wrinkled, gray, or susceptible to chronic disease, “the common signs of aging expected in most mammals really don’t seem to happen” in these rodents. Heart function, body composition, bone quality or metabolism do not change significantly.
At the University of Cambridge, Smith’s team maintains five colonies. “I have kept my animals in Cambridge for 10 years and I have never had one that simply died of natural causes,” says Smith. He says that, in captivity, fights between rodents are usually the main cause of death.
It’s a very different picture from common causes of death in humans. “One out of every two humans is likely to get cancer,” according to Smith. “Rats and mice are similarly likely to develop cancer, but nude mole rats almost never get the disease – it’s very rare.”
How do you escape illness?
Why the naked mole rat escapes cancer it’s still a mystery.
One theory is that naked mole rats have a particularly effective form of anti-cancer mechanism called cellular senescence — an evolutionary adaptation that prevents injured cells from dividing out of control and developing cancer. Another theory suggests that these rodents secrete a “super sugar” complex that prevents cells from agglomerating and forming tumors.
The most recent research focuses on their bodies’ own conditions that prevent cells from multiplying carcinogenic. Experts at the University of Cambridge indicate that interactions with the naked mole rat’s internal microenvironment — the complex system of cells and molecules surrounding a cell, including the immune system — prevent disease rather than an inherent cancer-resistant mechanism.
In an experiment at the University of Cambridge, researchers analyzed 79 different cell lines grown in tissues from the intestine, kidney, pancreas, lung and skin of 11 individual naked mole rats. The scientists infected the cells with viruses modified to introduce cancer-causing genes.
To their surprise, the cells of the infected naked mole rats began to multiply rapidly. This confirmed that it is the rodent’s body environment that prevents the development of cancer and not a feature at the cellular level.
Painless
But perhaps the strangest characteristic of the naked mole rat is its insensitivity to pain. “It is likely the result of an evolutionary adaptation to the [seu] environment with high level of carbon dioxide,” explains Smith.
The air that these rodents breathe is richer in CO2 than the air in the atmosphere. If this exhaled air is trapped in underground tunnels, the CO2 content builds up.
For most mammals, this would be a problem. “Carbon dioxide reacts with water to form an acid, called carbonic acid, which can activate the nerves to cause pain“, says the scientist.
In many inflammatory diseases, such as rheumatoid arthritis, areas of tissue swelling can often become acidic and cause pain. But “the naked mole rat does not feel the acid as something painfulo, not in the way that lemon juice or vinegar sprinkled over cut skin causes pain,” explains Smith.
He studied the molecular basis for this tolerance and identified a gene that causes the acid to act as an anesthetic rather than an activator of the naked mole rat’s sensory nerves.
The importance and difficulties of studies
As extraordinary as naked mole rats are, biologically speaking, they are not the simplest species to observe, which means that relatively few research groups all over the world study this amazing species.
In addition to the reproduction logistics of hot and humid environments, the life cycle of a naked mole rat is longer than that of rats or mice.
For this reason, Smith created the Naked Mole Rat Initiative, to collaborate with experts in other fields of medicine, such as cancer treatment, and use his animals to support new lines of research.
Colonies of Smith’s naked mole rats, if they live to their full natural age, are likely to will go beyond the investigator’s career.
There may also be other benefits to researching these highly unusual animals, some of which can hardly be predicted. Smith uses PCR tests to detect covid-19 as an example.
“The reason PCR tests work is because they use an enzyme that was extracted from a species of bacteria that lives in Yellowstone Park’s thermal vents. [nos Estados Unidos]”, he explains. “Living at high temperatures means that the bacteria’s enzymes have evolved to be stable under high temperatures, when biological reactions happen most quickly.”
“If no study biology under extreme conditionswe end up missing some things”, concludes Smith.
