The African mouse that could hold the key to healing wounds without scar tissue by regenerating its own damaged skin
African spiny mouse is first mammal found capable of regrowing its own skinCould provide a new model for wound healing and tissue regeneration in people
11:16 GMT, 27 September 2012
The mouse that can heal itself: This rodent can shed its skin and fur to allow it to escape the grasp of predators
A small African mammal with an unusual ability to regrow damaged tissues could be the key to the next breakthrough in regenerative medicine, say scientists.
Salamanders have long been studied for their ability to regrow lost limbs. However, amphibian biology is so different from human biology that experts have found it difficult to translate their findings into medical therapies for humans.
But the African spiny mouse is a mammal and therefore far closer on an evolutionary scale to ourselves.
Study leader Ashley Seifert, from the University of Florida, said: 'The African spiny mouse appears to regenerate ear tissue in much the way that a salamander regrows a limb that has been lost to a predator.
'Skin, hair follicles, cartilage – it all comes back.'
He said that the genes that direct regeneration in salamanders are probably switched off in mammals, but have been switched back on in the African mice. Locating this mechanism could have exciting potential for wound healing in people.
In most mammals the gap created by a wound is filled by scar tissue. However, it lacks the functionality of the original tissue and has low elasticity. Internal scar tissue can prevent organs from working properly.
Seifert was studying scar-free healing in amphibians when a colleague told him that a small rodent he had observed in Africa seemed capable of autotomy, a defense mechanism whereby the animal self-amputates a body part to escape a predator.
'Autotomy in skinks, geckos and some salamanders is well known,' Seifert said.
'But it is very rare in mammals, and so far we’ve only seen it in a few rodents that can jettison their tail.'
The spiny mice A. kempi (a) and A. percivali (b) possess stiff, spine-like hairs. (c) shows A. kempi after loss of dorsal skin. (d) and (f) show scab formation while (e) shows the wound is not visible
Seifert travelled to Nairobi, Kenya, where he documented the first known case of skin autotomy in a mammal. But it was how the animals’ injuries appeared to be healing that really got his attention.
He used a tiny biopsy punch, half a centimetre across to puncture holes in the ears of the mice to see if they would regenerate.
'The results were astonishing,' he said.
'The various tissues in the ear grew back through formation of blastema-like structures – the same sort of biological process that a salamander uses to regenerate a severed limb.'
Professor Ken Muneoka, from Tulane University agrees that Seifert’s findings are important.
'It could represent a new model system for skin wound healing and tissue regeneration in humans,' he said.
While regrowing whole limbs may seem the work of science fiction, scientists have already grown bladders in the laboratory as well as transplant stem-cell seeded wind pipes.
The latest study has been published in the journal Nature.