Smithsonian.com

Photo: Marcel Burkhard

Like salamanders, newts and other amphibians, the African spiny mouse can regrow toetips, seal holes in its ears, and regenerate missing skin, bone muscles and nerves without any trace of scar tissue, making it a stand-out example among mammals.

The spiny mouse achieves this regeneration feat thanks to its unique gene expression. But new research shows that tissue regeneration may not be so uncommon in mammals as scientists once thought. As Scientific American’s Ferris Jabr writes, the mammalian genome conceals a latent ability to regrow damaged body parts.

To form new skin, grow fresh tails and seal up ear-holes without scarring, spiny mice use a blastema-like cell—a mass of cells typical in newts and salamanders. These cells revert to an immature, undifferentiated state so that they can assume the form of any number of different kinds of tissues to become a new limb. The researchers observed in the spiny mice, “You could see a conveyor belt of new hair follicles growing in the ear and undifferentiated cells—all the hallmarks of regeneration seemed to be there.”

Part of the reason these mice can regenerate tissue, past studies showed, is that they do not express a particular gene called p21. Scientists can already revert normal mouse muscle cells to a blastema-like state that mirrors the spiny mouse’s natural abilities by temporarily knocking out two tumor-suppressing genes. Jabr continues:

Extending the logic of these findings, p21 and other genes may suppress latent regenerative abilities in typical mice and indeed in most mammals. Learning to precisely control these genes at will opens the prospect of healing injuries in people by restoring our lost power of tissue regeneration. African spiny mice now offer scientists new opportunities to investigate such possibilities.

Ideas like regrowing limbs lost in car wrecks, regenerating fingertips nicked off in kitchen mishaps or bypassing scar tissue from burn wounds remain firmly in the realm of the scifi. But spiny mice hint at a future for mammalian and, thus, human tissue regrowth.

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Patient, Heal Thyself