T12-L3 Nerve Transfer-Induced Locomotor Recovery in Rats with Thoracolumbar Contusion: Essential Roles of Sensory...

Area of Science:

• Neuroscience
• Regenerative Medicine
• Spinal Cord Injury Research

Background:

• Locomotor recovery after spinal cord injury (SCI) is a significant clinical challenge.
• Nerve transfer (NT) aims to restore motor control but yields inconsistent outcomes.
• The underlying mechanisms of NT efficacy may involve more than direct motor axon reinnervation.

Purpose of the Study:

• To investigate the role of sensory input in NT-induced locomotor recovery after SCI.
• To explore the impact of timing and adjunct therapies on NT outcomes in different SCI severities.
• To elucidate the neurobiological mechanisms by which NT promotes functional recovery.

Main Methods:

• T12-L3 NT in adult female rats with subacute or chronic mild/moderate T13-L1 thoracolumbar contusion.
• Adjunct therapies for chronic injuries included hMSCs, FGF2, and environmentally enriched housing.
• Assessment of locomotion, nerve root ablation, pharmacological, electrophysiological, and tracing assays were employed.

Main Results:

• NT qualitatively improved locomotion in mild SCI and subacute moderate SCI groups.
• Delayed NT did not significantly improve outcomes in chronic moderate SCI.
• Sensory nerve input was crucial for hindlimb reanimation, and NT enhanced propriospinal networks and neuromodulation.

Conclusions:

• NT-induced locomotor recovery is critically dependent on sensory rerouting and neuroplasticity.
• NT strengthens central neural networks and improves neuromuscular function.
• These findings reveal a novel mechanism for NT and suggest new therapeutic targets for neurotization therapies.