The naked mole rat is considered one of the most unusual mammals in existence due to its remarkable abilities. It has a longer lifespan than any other rodent, living up to 37 years, and can continue to reproduce even as it ages. A recent study, which was published on Feb. 21 in the journal Nature Communications, sheds light on how the naked mole-rat manages to maintain its fertility over time. According to the findings, the naked mole-rat never exhausts its egg cell supply, which challenges the traditional belief that mammals have a limited reserve of egg cells that are established before or shortly after birth and cannot be replenished afterward.
The lead author of the study, Miguel Brieño-Enríquez, who is an assistant professor at Magee-Womens Research Institute and the University of Pittsburgh School of Medicine's Department of Obstetrics, Gynecology, and Reproductive Sciences, stated that naked mole-rats are the most peculiar mammals. According to him, they have the longest lifespan among rodents, rarely develop cancer, do not experience pain like other mammals, reside in subterranean colonies, and only the queen can give birth. However, what he finds most astounding is that they continue to reproduce throughout their lives.
Naked Mole-Rat High Fertility
Unlike many other mammals, naked mole rats do not experience a decline in fertility as they age. However, scientists have not understood the reason for this phenomenon until now. A recent study compared the quantity and mortality rate of egg cells in mice and naked mole rats during various stages of development. Typically, female mammals, such as humans and mice, are born with a finite number of egg cells that deplete naturally over time.
However, the scientists conducting the study discovered that this is not true for naked mole rats. Contrary to most other mammals, female naked mole rats are born without egg cells, but as young pups, they generate an unusually high number of egg cells relative to their body size. Additionally, this reserve of eggs does not diminish over time, unlike in mice, and continues to be replenished throughout the naked mole rats' lives. The researchers observed indications of egg cell production in naked mole rats that were up to 10 years old.
In a statement, Dr. Ned Place, the senior author of the study and a professor at the Cornell University College of Veterinary Medicine, expressed his amazement at the discovery, stating that "this finding is extraordinary." According to Dr. Place, the results of the study challenge the previously established belief, which is almost 70 years old, that female mammals possess a finite number of eggs either before or shortly after birth, with no further additions to their ovarian reserve throughout their lives.
Not only are naked mole-rats (Heterocephalus glaber) the longest-living rodents, they also 'never stop having babies,' according to researchers.
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Reproductive Female Naked Mole to Queen
In addition to adding to the list of unique characteristics of naked mole rats, the scientists believe that these findings may lead to the development of new therapies for humans. Naked mole rats reside in expansive colonies, where only a single dominant female is responsible for breeding. When the dominant female is removed or passes away, subordinate females compete to take her place and become reproductively active, as reported by Live Science.
According to Brieño-Enríquez, "any girl can become a queen." To study the process of transitioning from a subordinate female to a queen, the scientists eliminated non-breeding females from the colony. As a result, precursor egg cells in their ovaries began dividing, indicating that these females were becoming reproductively active in the absence of a queen.
Brieño-Enríquez emphasized the significance of these findings by stating that "if we can understand the mechanism behind this, we may be able to develop new drug targets or techniques to improve human health." Even though humans are living longer lives, menopause continues to occur at the same age. The scientists' goal is to employ the knowledge gained from the study of naked mole rats to help preserve ovary function in later life and extend fertility.
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