Role of Spared Pathways in Locomotor Recovery after Body-Weight-Supported Treadmill Training in Contused Rats

This study investigates how body-weight-supported treadmill training (BWSTT) helps rats recover from spinal cord injuries, focusing on the role of remaining nerve pathways. The goal was to assess locomotor recovery in contused rats after BWSTT, and to study the role of spared pathways in spinal plasticity after BWSTT. The researchers found that BWSTT improved locomotor skills, nerve function, and muscle health in rats with spinal cord contusions. BWSTT-contused animals showed accelerated locomotor recovery, improved H-reflex properties, reduced muscle atrophy, and decreased sprouting of small caliber afferent fibers. The study also showed that the benefits of BWSTT depend on the presence of spared nerve pathways and continued training. This suggests that BWSTT with spared descending pathways leads to neuroplasticity at the lumbar spinal level that is capable of maintaining locomotor activity.

• 1
  BWSTT accelerates locomotor recovery in contused rats, improves H-reflex properties, reduces muscle atrophy, and decreases sprouting of small caliber afferent fibers. BWSTT-contused animals showed accelerated locomotor recovery, improved H-reflex properties, reduced muscle atrophy, and decreased sprouting of small caliber afferent fibers.
• 2
  The benefits of BWSTT rely on spared descending pathways, as transected animals showed no improvement with BWSTT. Transected animals had no effect of BWSTT, indicating that in the absence of spared pathways this training paradigm did not improve function.
• 3
  Continued training is required to maintain the benefits of BWSTT, as discontinuing training led to a reversal of the improvements. Discontinuing training after the transection in the trained contused rats abolished the improved kinematics within 2 weeks and led to a reversal of the improved H-reflex response, increased muscle atrophy, and an increase in primary afferent fiber sprouting.