UW Researchers Study of African Spiny Mice Reveals First Documented Case of Tissue Regeneration in Mammals

September 26, 2012
This Kemp’s spiny mouse is one of two species of African spiny mice that shed its skin and hair as a protective measure. Along with colleagues from the University of Florida and the University of Nairobi, Jacob Goheen, an assistant professor in UW’s Department of Zoology and Physiology, and the Department of Botany, documented that it is the first mammal that can regenerate skin tissue. The research appears in the Sept. 27 issue of Nature. (Photo: Jacob Goheen)

Sometimes, science can be more serendipitous than scheduled. Just ask Jacob Goheen.

Goheen, an assistant professor in the University of Wyoming Department of Zoology and Physiology, and the Department of Botany, was part of a research team that recently discovered the first documented case of a mammal -- in this case, African spiny mice -- regenerating tissue after shedding its skin.

A study on the subject -- which Goheen helped formulate, write and edit -- appears in the Sept. 27 issue of Nature, an international weekly journal of science.

“A lot of times, there are surprises in research. We stumbled on this trait by accident when we were trapping small mammals for a different project on the ecology of African savannas. At the beginning of this work, I couldn’t have anticipated that we would capture this mouse that has regenerative capabilities similar to some lizards,” Goheen says. “This has not been described before in a mammal. Something similar happens with lizards and salamanders (their tails grow back) or with limbs re-growing in insects and spiders.”

The discovery came about purely by accident. Goheen has studied large mammal populations, such as elephants, giraffes and zebras in central Kenya, for the past decade. Specifically, he examines how ecosystems change when these species are removed from the equation.

To simulate that dynamic on a smaller level, Goheen and colleagues constructed electrified fences to exclude these large mammals, and then sampled miniature mammals to tag and study. These smaller mammals included African spiny mice, elephant shrews and gerbils.

In 2008, Goheen picked up a spiny mouse by the scruff of the neck after trapping it. Its hair and skin shed easily, which allowed the rodent to escape. Goheen immediately understood the similarity to when a predator captures a lizard by the tail, which breaks off and allows the reptile to escape a predator. A lizard’s tail eventually grows back, and so did the skin and hair follicles of spiny mice.

“It was very interesting,” says Goheen, who is in his third year as a faculty member at UW. “I couldn’t think of another mammal that could do this. It could have future implications for scar-healing in humans.”

Goheen researched the regenerative abilities in two species of African spiny mice (Kemp’s spiny mice and Percival’s spiny mice), which are native to Kenya’s savannas. Spiny mice are noted for their bare, scaly tails, and their fur coats have unusually stiff hairs that function similar to the spines a hedgehog uses for protection.

Goheen observed that, after the mouse’s wound healed, its skin and hair follicles grew back quickly in a matter of days. More significantly, regeneration occurred without scarring.

“There’s definitely a genetic signal, because we find it (skin regeneration) in two species that are very closely related,” Goheen says. “Why it evolved in this genus and not any other is anyone’s guess. That’s a mystery.”

Goheen described the discovery as an “example of serendipity in the field.” He also sees the research as significant because it was an interdisciplinary collaboration between developmental biologists and ecologists.

After his initial observations, Goheen says he had no idea how to document the findings. He contacted Ashley Seifert, a post-doctoral Fellow who specializes in developmental biology at the University of Florida. Seifert conducted previous studies of tissue regeneration in salamanders and ended up being the lead writer on the Nature paper.

“Science is not only about finding something interesting, but knowing when you find something interesting,” Goheen says.

Further study revealed that African spiny mice can regenerate skin tissue and hair on their ears, which had only been previously documented in rabbits, Goheen says.

“These findings are significant because they demonstrate skin shedding as a novel behavior in a wild population of rodents. In response to these drastic injuries, Acomys (spiny mice) can heal their wounds very rapidly and with little scarring,” says Seifert, who also is a visiting professor at the University of Nairobi’s Department of Veterinary Anatomy and Physiology. “These mice appear to have enhanced regenerative ability relative to other rodents. The fact that they can regenerate several types of tissue in their ears presents these animals as a potential fruitful model for research in regenerative medicine.”

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