Can an injured spinal cord ever heal itself?
If a salamander’s spinal cord is severed, gradually the nerves controlling the animal’s lower body will magically regenerate – leaving no lasting evidence of the trauma.
Unfortunately, the same cannot be said of humans.
In humans, a major impediment to the re-growth and repair of the injured spinal cord is the scar that forms at the site of injury. The proteins comprising the scar actually block nerve growth: in the case of the injured salamander, its spinal cord would heal without a scar.Arthur Brown, PhD, is approaching the problem of spinal cord injuries from a different angle. He has pinpointed a protein that controls the expression of key genes, which determine the spinal cord’s ability to heal and re-grow. Called SOX9, this protein acts as a kind of construction foreman, who coordinates the formation of unwanted scar tissue, which impedes spinal cord regeneration, following injury. Controlling two different ‘work crews’, the SOX9 enzyme executes two functions detrimental to nerve recovery: 1) increasing activity of genes that build a ‘brick wall’ inhibiting nerve re-growth; and 2) decreasing activity of genes that construct the ‘scaffold’ upon which damaged nerves re-grow and thrive.
Brown’s team is the only one in the world known to be attacking the problem of spinal cord injury by trying to change the expression of genes. Ultimately, Brown hopes his discovery will lead to the development of a drug that will actually change the composition of the scar tissue that forms after spinal cord injury, thereby promoting regeneration of damaged nerves.