Biologists have solved one of the mysteries of naked mole rats, model animals used to study problems of aging and cancer. Unlike other mammals, females of these animals can bear offspring throughout their lives, up to old age. The reason is that eggs do not die in women’s ovaries during life and continue to be produced until old age, according to the study. published in the journal Nature Communication.
One of the unsolved mysteries of naked mole-rats, which still astonish biologists, is their ability to bear and give birth to offspring, which, unlike all other mammalian species, including humans, does not diminish with age.
“Naked diggers are the strangest creatures. They are the longest-lived rodents, they almost never get cancer, they don’t feel pain like other mammals, they live underground in colonies, and only the queen can have offspring. But for me, the most amazing thing is that they never stop giving birth – their fertility does not decline with age,” said Miguel Brieno-Enriquez of the University of Pittsburgh School of Medicine. .
Females of most mammals are born with a finite number of eggs, which are produced in the ovaries in a process called oogenesis. As the number of eggs decreases over time (some leave during ovulation, most simply die), female fertility decreases with age. Digging females, on the contrary, can bear young until old age, before eating until they are 30 years old and older. “There are three ways to do it. They are born with a large number of eggs, not all eggs die or they continue to create new eggs after birth,” the author explained.
The study showed that in the case of excavators, all three mechanisms work.
In their work, the scientists compared the ovaries of naked mole-rats and mice, whose life expectancy rarely reaches four years, and whose fertility declines from the age of 9 months, at different stages of development. It turned out that in female mole rats at the age of 8 days, an average of 1.5 million ova are present in the ovaries, which is 95 times more than in female mice of the same age.
Importantly, oogenesis in female mole-rats continues throughout life: so-called germinal notches have divided in the ovaries of 3-month-old females and have been found in the ovaries of 10-month-old animals. years. “This is an incredible discovery. It breaks the 70-year-old dogma that female mammals are endowed with a limited number of eggs before or shortly after birth,” said co-author Ned Place of Cornell University.
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