Mice bring hope to the paralysed after they overcome spinal injuries and start walking again

Scientists have been amazed at the speed at which the rodents apparently cure themselves, walking within eight weeks.

They discovered that the animals are able to adjust to their injury by diverting messages from the brain, around the damaged area, to limbs.

This could be a major breakthrough for 2,000 Britons each year who are unable to walk after damaging their spinal cord.

In a few human cases the condition has improved but, until the tests on mice, scientists had no idea why.

The latest study was part-funded by a charity formed by Superman actor Christopher Reeve, who was left paralysed after a riding accident in 1995.

He set up his own research centre, which was carried on by his widow Dana after his death nine years later. Reeve regained sensation in 90 per cent of his body so that he was able to move an index finger, a wrist and thumb.

The experiments on mice were conducted at the University of California, Los Angeles, by Dr Michael Sofroniew, who said: "We were excited to see most of them regained the ability to control their legs within weeks. They walked more slowly and less confidently than before their injury but they still recovered mobility."

The tests showed the messages were being diverted round the damaged area, a system Dr Sofroniew compared to cars on a motorway.

"When there's a traffic accident on the freeway, what do drivers do? They take detours which may not be as direct but still allow drivers to reach their destination," he said.

His tests showed that when the long nerve fibres on the outside of the spinal cord that control walking were damaged, the signals were rerouted to shorter fibres at the cord's centre.

Dr Sofroniew hopes that if drugs can be developed to trigger this rerouting, they could have a huge effect on people left paralysed by spinal cord injury.

The scientist, whose research is published in the journal Nature Medicine, added: "Severe injury to the spinal cord used to mean permanent paralysis.

"What we demonstrate here is that the body can use alternate nerve pathways to deliver instructions that control walking.

"We have identified what appears to be a previously unrecognised mechanism for recovery of function after these kinds of injuries.

"Now we need to understand it better and learn how to exploit it better, working out ways to stimulate this kind of recovery."