Naked mole rats reveal biological secrets of lifelong fertility

Fertility declines with age in most feminine mammals, however bare mole rats can develop new eggs as adults, enabling them to stay fertile all through their lives

By Christa Lesté-Lasserre

Unlike most mammals, feminine bare mole rats develop new eggs all through their whole lives – a discovering that might result in enhancements in human infertility analysis.

“This animal is the opportunity to think about and develop new techniques or potential targets for making new drugs, because their [reproductive] cells have the same program that we have in mice and humans, but they’re behaving differently,” says Miguel Angel Brieño-Enríquez on the University of Pittsburgh in Pennsylvania.

Native to East Africa, bare mole rats (Heterocephalus glaber) dwell for as much as 37 years and kind underground colonies with social constructions just like these of bees, together with a single queen that produces offspring for her whole life. By distinction, mice solely dwell for about 4 years and their fertility begins dropping when they’re solely 9 months previous.

Curious about these variations in reproductive lifespans, Brieño-Enríquez and his colleagues regarded on the ovaries of bare mole rats underneath a microscope when the animals have been 1, 5, 8, 15, 28 and 90 days previous. They used superior staining and testing methods to establish the completely different sorts of cells they noticed. In specific, they have been on the lookout for germ cells that may divide and mature into oocytes – or eggs – by means of a course of often called oogenesis.

In people, mice and different mammals, oogenesis solely happens earlier than delivery and, in some species, shortly afterwards, leaving new child females with a restricted lifetime provide of eggs. Those eggs regularly die over time, resulting in diminished fertility with age.

In the bare mole rats, although, Brieño-Enríquez and his colleagues discovered giant numbers of germ cells at each stage of life they examined, with numbers steadily rising all through the primary week of life. At 8 days previous, the bare mole rats had a median of 1.5 million egg cells – 95 instances greater than 8-day-old mice, says Brieño-Enríquez.

The researchers then grew ovary sections of younger animals of their laboratories and noticed ongoing oogenesis. Combined with the group’s earlier discovery of germ cells even in 10-year-old mole rats, the observations counsel that bare mole rats can frequently replenish their egg provide.

Because any younger feminine mole rat can grow to be the colony’s subsequent queen, the researchers then examined the employee females’ potential fertility by eradicating 3-year-old females from their colonies and putting them in particular person cages with a male for 4 weeks. The animals grew to become fertile like queens, says Brieño-Enríquez. Investigations underneath the microscope confirmed that employee females have germ cells of their ovaries, however oogenesis solely begins when the employee transitions to a queen.

The research gives “very useful insight”, which will definitely be “a substantial contribution to the field”, says Scott Sills on the Center for Advanced Genetics in California. “If this could be transformed into a clinical application [for humans], then not only would it have a very meaningful role in infertility practice, but it would basically reset the whole paradigm for how we treat menopause,” he says. “Symptomatic menopause would no longer be hostage to [hormone] replacement therapy.”

But how precisely that data can translate into contributions to human drugs stays to be seen, says Aspasia Destouni at Aristotle University of Thessaloniki in Greece. “I see this as an exciting opportunity to manipulate a new model organism that has more accessible samples [for human reproduction research],” she says. “But we have to be cautious about the excitement level, because people might think that this is an answer to menopause… but clearly, they’re not there yet.”

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