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Naked mole rat could hold key to women giving birth at any age

The breakthrough opens the door to 'eternal fertility'

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A naked mole rat. (John Brighenti via Wikimedia Commons)

By Mark Waghorn via SWNS

The naked mole rat could hold the key to women giving birth at any age - because females produce eggs their whole lives.

The female of the species produces eggs throughout her life - contradicting the common-held doctrine that female mammals have a finite number.

Researchers said the breakthrough offers hope for new treatments for couples struggling to start a family.

It also opens the door to 'eternal fertility' - with moms having children in their 60s or even 70s, experts said.

The bizarre-looking rodent's remarkable ability may also lead to a cure for ovarian cancer - one of the deadliest forms of the disease.

Dr. Miguel Brieno-Enriquez, a gynaecologist at the University of Pittsburgh and a lead author of the study, said: "Naked mole-rats are the weirdest mammals.

"They're the longest-lived rodent, they almost never get cancer, they don't feel pain like other mammals, they live in underground colonies - and only the queen can have babies.

"But to me, the most amazing thing is they never stop having babies - they don’t have a drop in fertility as they age. We want to understand how they do this."

Naked Mole-rat (2011) by Mehgan Murphy. Original from Smithsonian's National Zoo. Digitally enhanced by rawpixel. (Wikimedia Commons)

Their large buck teeth and wrinkled, hairless bodies put them among the least cute animals on the planet.

But they can survive over 30 years thanks to a remarkable resistance to age-related diseases.

Naked mole-rat queens also breed right through old age - avoiding waning fertility by preserving their 'ovarian reserve.'

Dr. Brieno-Enríquez added: "There are three possibilities for how they do this. They are born with a lot of egg cells, not as many of these cells die, or they continue to create more egg cells after birth.

"My favourite hypothesis is that they use a cocktail of all three."

The team compared ovaries from naked mole rats with those of mice across different stages of development - and indeed identified evidence of all three.

Despite their similar sizes, mice live for four years at most and start to show a drop in fertility by nine months.

The study found lower death rates of egg cells - and hence exceptionally large numbers - in naked mole rats.

For example, at eight days old, a female has an average of 1.5 million - about 95 times more than a mouse of the same age.

Most remarkably, production or 'oogenesis' happens post-natally. Egg precursor cells were actively dividing in three-month-old animals.

They were also found in 10-year-old animals - suggesting it continues throughout their lives.

Professor Ned Place, of Cornell University, New York, and a senior author of the study, said: "This finding is extraordinary.

"It challenges the dogma that was established nearly 70 years ago, which stated female mammals are endowed with a finite number of eggs before or shortly after birth, without any additions being made to the ovarian reserve thereafter."

Naked mole rats live in colonies of several dozen to hundreds of individuals.

Like bees or ants, colony members divvy up tasks, including providing defence, digging tunnels, caring for young and collecting food.

Only the single dominant female in a colony can breed, and she suppresses reproduction in other females to maintain her queenly status.

Dr. Brieno-Enriquez said: "Unlike bees or ants, a female naked mole-rat is not born a queen.

"When the queen dies or is removed from the colony, subordinate females compete to take her place and become reproductively activated. Any girl can become a queen."

The researchers shed fresh light on the phenomenon by removing three-year-old 'new queens' from the colony to prompt reproductive activation.

Non-breeding subordinates had egg precursor cells in their ovaries - but the cells started dividing only after a transition to queen.

Dr. Brieno-Enriquez added: "This is important because if we can figure out how they're able to do this, we might be able to develop new drug targets or techniques to help human health.

"Even though humans are living longer, menopause still happens at the same age. We hope to use what we are learning from the naked mole-rat to protect ovary function later in life and prolong fertility.

"But the ovary is more than just a baby factory. Ovary health influences cancer risk, heart health and even lifespan.

"Better understanding of the ovary could help us find ways to improve overall health."

Septuagenarians claim to have already given birth, most notably India's Erramatti Mangayamma, who reportedly welcomed twins in September 2019 aged 74.

Her success was achieved through IVF, heralded as one of the greatest medical breakthroughs of the last century.

Experts have predicted women giving birth in their 50s or 60s might end up being routine within the next three decades.

Recent research also found naked mole rats have different dialects - just like humans.

German scientists said they chirp, squeak, twitter or even grunt to one another - with a variety of sounds unique to each community.

Naked mole rats live in hostile desert regions underground and have to work together to get their food.

The challenging lifestyle has made them one of the most communicative creatures in the world.

Over millions of years of evolution, the critters have cast off things which use their energy - such as fur.

They use their distinctive, elastic 'baggy' skin to squeeze through tunnels.

The slightly unsightly creature has fascinated medical experts for decades. It is cancer resistant - and has the lowest metabolic rate of any mammal.

Evolution has shut down everything that is not absolutely necessary – including extra nerve receptors so it can't feel pain.

Doctors believe the naked mole rat holds the key to combating a host of diseases.

The study is published in Nature Communications.

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