super-fast-healing spiny mice

Date: 20/10/2012 11:27:13

From: neomyrtus_

ID: 215975

Subject: super-fast-healing spiny mice

http://blogs.discovermagazine.com/notrocketscience/2012/09/26/spiny-mice-flaying-skin-healing-factor/

Spiny mice defend themselves with self-flaying skin and fast healing factors

When Marvel Comics created a short superhero who could heal horrific injuries, perhaps instead of “Wolverine”, they should have named him “African spiny mouse”. These tiny rodents can jettison strips of skin from their own hides when captured by predators, and heal those same wounds with extraordinary speed.

Healing powers are common in the animal world. Salamanders and starfish can regrow lost limbs, while some flatworms can regenerate their bodies from a single cell. But mammals lag behind – while some species can grow back a lost tail, when most of us lose our body parts, we do so permanently. The spiny mice are an exception.

Biologists have noted that these rodents have very weak skin, which seems to slough off easily when they are handled. Led by these anecdotal reports, Ashley Seifert from the University of Florida has studied the skin-shedding ability in greater depth, focusing on two species: Kemp’s spiny mouse (Acomys kempi); and Percival’s spiny mouse (Acomys percivali).

As a first line of defence, the mice have stiff hairs on their backs that act like a hedgehog’s spines. But if they are caught, they struggle vigorously and quickly lose strips of skin. It’s a dramatic strategy. The mice end up with large open wounds, and can lose up to 60 percent of the skin along their backs.

Back in the lab, Seifert discovered why. The spiny mouse’s skin looks superficially similar to that of an ordinary house mouse, but it contains a far greater proportion of follicles—the cradles that hairs grow from—and their associated glands. As a result, they also have less connective tissue, and their skin tears under the smallest forces. For comparison, a house mouse’s skin is around 20 times stronger than a spiny mouse’s, and can absorb 77 times more energy before breaking.

For most mammals, this would be a disaster. The spiny mouse must have some way of controlling infections, and Seifert is now studying its immune system to discover its secrets. But he has already found that it complements its weak skin with extremely fast healing. Its wounds stop bleeding, scab over quickly, and shrink by 64 percent within a day. While a rat would take 5 to 7 days to completely cover a wound with new skin, a spiny mouse can do it in just 3.