Fertility in most female mammals declines with age, but naked mole rats can develop new eggs as adults, thus maintaining fertility throughout their lives.
life
February 21, 2023
Naked mole rat in the lab UPMC
Unlike most mammals, female naked mole rats develop new eggs throughout their lives. This finding could lead to improvements in human fertility research.
“This animal is an opportunity to think and develop new technologies and potential targets for making new drugs. [reproductive] Cells have the same programs as mice and humans, but they behave differently,” says Miguel Angel Brieño-Enríquez of the University of Pittsburgh in Pennsylvania.
Naked mole rat native to East Africa (Heterocephalus glaber) live up to 37 years and form underground colonies with a social structure similar to that of honeybees. In contrast, mice have a lifespan of about 4 years and begin to decline in fertility at 9 months of age.
Intrigued by these differences in reproductive lifespan, Briño Enriquez and his colleagues microscopically examined the ovaries of naked mole rats at 1, 5, 8, 15, 28, and 90 days of age. They used advanced staining and testing techniques to identify the different types of cells they saw. In particular, they sought germ cells that could divide and mature into oocytes (or eggs) through a process known as oogenesis.
In humans, mice, and other mammals, oogenesis occurs only before birth, and in some species soon thereafter, with a limited life-long supply of eggs in newborn females. These eggs gradually die over time, and fertility declines with age.
However, Brieño-Enríquez and his colleagues found large numbers of germ cells in naked mole rats at all stages of life they tested, with numbers steadily increasing throughout the first week of life. According to Brienho-Henriquez, naked mole rats had an average of 1.5 million egg cells at eight days of age. That’s 95 times more than he is in an eight-day-old rat.
The researchers then grew ovarian slices from young animals in the lab to observe ongoing oogenesis. Together with the discovery of germ cells in 10-year-old mole rats, this observation suggests that naked mole rats can continuously replenish their egg supply.
Since any young female mole rat could become the next queen of the colony, the researchers next removed the three-year-old females from the colony and placed them in individual cages with the males for four weeks to allow them to work. We tested the fertility potential of ant females. The animal became fertile like a queen, says Brienho Henriquez. Microscopic examination has shown that female worker ants have germ cells in their ovaries, but oogenesis only begins when the worker transitions to the queen bee.
The study provides “very useful insights” and it will certainly be a “substantial contribution to the field,” says Scott Sills of the Center for Advanced Genetics in California. if it can change to [for humans]Not only would that play a very meaningful role in fertility treatment, but it would fundamentally reset the whole paradigm about how menopause is treated,” he says. It will no longer be a hostage. [hormone] replacement therapy. “
But how exactly that information translates into contributions to human medicine remains to be seen, says Aspasia Destouni of the Aristotle University of Thessaloniki, Greece. “I think this is an exciting opportunity to work with new model organisms with more accessible samples. [for human reproduction research]”But people may think this is the answer to menopause, so we have to be careful with arousal levels…but clearly, they’re not there yet.”
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