This opens up the possibility of various types of treatment

Dr James Fawcett, Cambridge University

Lead researcher Dr James Fawcett, of the Cambridge University Centre for Brain Repair, said: "Repairing spinal cords will involve several treatments being used together. This new technique is the basis for one of these treatments."

Cord injury affects 1,000 patients per year in the UK and 10,000 in the USA. The average age of injury is 19, but patients have an almost normal life expectancy.

On-going research and the high-profile case of paralysed actor Christopher Reeve has generated widespread interest and expectation.

Indeed, some scientists claim that in five to 10 years, it may be possible to partially repair spinal injuries.

However, the key to treating these disabling conditions is finding a way to make the damaged nerve fibres regenerate.

Permanent damage

A major problem facing neurologists is that damage to the brain and spinal cord is permanent, and is not reversed by normal healing processes.

The damaged nerve fibres do not re-grow, meaning communication with other nerve cells is lost. This leads to the paralysis and loss of sensation that devastates the lives of patients.

Dr Fawcett said that one of the reasons why regeneration fails is because scar tissue forms at the injury site.

This tissue produces particular molecules that block nerve fibre regeneration. The researchers found a way to remove this block by using a bacterial enzyme called chondroitinase.

The enzyme breaks down some of the molecules that cause the problem. The benefits of this treatment have previously been shown in tissue culture experiments.

However, the new work marks the first time the treatment has been used to promote nerve regeneration through the injured central nervous system (CNS).

The enzyme was injected into rats with injured spinal cords. Subsequent tests on the rats indicated that they had reclaimed much lost neurological function.

Dr Fawcett and his group hope their techniques could be applied to humans.

He said: "This is the first demonstration that treatment with chondroitinase can promote neurological recovery after injury.

"This opens up the possibility of various types of treatment aimed at the enzyme being useful for patients with spinal injuries and other CNS injuries."

Currently, patients do not receive treatment to promote nerve regeneration after cord injury. The research was financed by the charity Action Research.