Severed corticospinal axons recover electrophysiologic control of muscle activity after x-ray therapy in lesioned adult spinal cord

Mechanical injury to the adult mammalian spinal cord often results in permanent loss of function below the injury site. This is because the nerve fibers that connect the brain to the spinal cord are severed, and they don't regrow on their own. This study found that using x-ray therapy on the injured spinal cord within a specific time frame after the injury can help the severed nerve fibers regrow. The x-rays modify the environment at the injury site, allowing the nerve fibers to reconnect. When these nerve fibers regrow, they can reestablish connections with the muscles in the hindlimbs, allowing some control of muscle activity to return. This suggests that helping the nerve fibers grow back is enough to restore some function after a spinal cord injury.

• 1
  X-irradiation of sectioned adult rat spinal cord resulted in restitution of structural continuity and regrowth of severed corticospinal axons across and deep into the distal stump.
• 2
  Severed corticospinal axons of transected adult rat spinal cord recover electrophysiologic control of activity of hindlimb muscles innervated by motoneurons distal to the lesion after x-ray therapy of the lesion site.
• 3
  The degree of recovery of control of muscle activity was directly related to the degree of restitution of structural integrity.