Functional recovery of stepping in rats after a complete neonatal spinal cord transection is not due to regrowth across the lesion site

This research investigates how rats regain stepping ability after a complete spinal cord injury at a young age. Unlike adult rats with similar injuries, neonatal rats can recover significant stepping function. The study aimed to determine if this recovery is due to the spinal cord re-growing across the injury or changes in the spinal cord circuitry. The researchers cut the spinal cords of rat pups and then trained some of them to walk on a treadmill. They used special dyes to track nerve pathways and see if any nerves had re-grown across the injury. They also re-injured some rats' spinal cords to see if it affected their stepping ability. The study found no evidence of nerve re-growth across the injury. The improved stepping ability seems to be due to changes within the spinal cord itself, allowing it to control stepping without input from the brain. This is an important step in understanding how to improve recovery after spinal cord injuries.

• 1
  Stepping performance was significantly better in spinal cord transected rats trained on a treadmill compared to non-trained rats, indicating that training enhances locomotor ability after neonatal spinal cord injury.
• 2
  Anterograde and retrograde tracing experiments showed no evidence of corticospinal or rubrospinal tract axons regenerating or reconnecting across the spinal cord transection site.
• 3
  Re-transection of the spinal cord at or rostral to the original transection site did not affect the stepping ability of trained rats, further supporting the conclusion that regeneration across the lesion does not contribute to functional recovery.