Fish that regenerate their spinal cords could hold the key to helping paralysed humans walk again.
Scientists believe they have uncovered the secret key to spinal cord regeneration, thanks to zebra fish.
In a zebra fish, the process of regeneration includes a “bridge” being formed between the two ends when its spinal cord is broken and after eight weeks the damage is completely repaired.
The secret to this process, scientists believe, is a protein called connective tissue growth factor A (CTGFA).
It was identified in a molecular “fishing expedition” conducted by researchers as they randomly searched for genes whose activity changed after spinal cord injury.
CTGFA appeared to play a lead role in building the bridge of nerve tissue. When its gene was deleted, the fish were no longer able to repair their spinal cords.
People also have a version of the protein, but human spinal cords are unable to regenerate like those of zebra fish.
However, when human CTGFA was applied to sites of spinal injury in zebra fish, it had a dramatic effect.
Why the protein does not seem to work the same magic on humans is still being investigated.
Healing is more complex in mammals, partly because of the formation of scar tissue. The team now plans to study the effect of CTGFA in mice.
Other proteins secreted by zebra fish after a spinal cord injury may also be important, say the scientists.
Co-author Professor Kenneth Poss, director of the Regeneration Next initiative at Duke University, said: “Given the limited number of successful therapies available today for repairing lost tissues, we need to look to animals like zebra fish for new clues..
“I don’t think CTGF is the complete answer, but it’s a great thing to have in hand to inform new ways to think about the real challenge of trying to improve regeneration.”