T12-L3 Nerve Transfer-Induced Locomotor Recovery in Rats with Thoracolumbar Contusion: Essential Roles of Sensory Input Rerouting and Central Neuroplasticity

Cells, 2023 · DOI: 10.3390/cells12242804 · Published: December 8, 2023

Spinal Cord Injury Neurology Neuroplasticity

Simple Explanation

This study explores nerve transfer (NT) as a method to improve motor function after spinal cord injury (SCI) in rats. The procedure involves connecting a functional nerve to a paralyzed nerve root to restore motor control. The researchers hypothesized that the effectiveness of nerve transfer relies on more than just reconnecting motor axons. They investigated the role of sensory nerve regrowth and central neuroplasticity in improving locomotion. The study found that nerve transfer, particularly when performed within a specific timeframe that supports sensory nerve regrowth, significantly improved hindlimb movement in rats with spinal cord injuries.

Study Duration

12 weeks

Participants

Adult female Sprague Dawley rats (230–250 g)

Evidence Level

Not specified

Key Findings

1
T12-L3 nerve transfer (NT) qualitatively improved locomotion in rats with mild thoracolumbar contusion (SCImi) and in animals with subacute moderate contusion (SCImo).
2
Ablation of the T12 dorsal/sensory root determined that the T12-L3 sensory input played a key role in hindlimb reanimation.
3
NT strengthened the integrity of the propriospinal network, serotonergic neuromodulation, and the neuromuscular junction.

Research Summary

This study investigates the efficacy of T12-L3 nerve transfer (NT) in promoting locomotor recovery in rats with thoracolumbar spinal cord injury (SCI). The researchers explore the roles of sensory input rerouting and central neuroplasticity in NT-induced neurological reinstatement. The findings indicate that NT, when performed within a specific time window optimal for sensory nerve regrowth, significantly improves hindlimb function in rats with both mild and moderate SCI. Ablation studies further highlight the crucial role of sensory input in hindlimb reanimation. Electrophysiological and pharmacological assays reveal that NT strengthens the integrity of the propriospinal network and enhances serotonergic neuromodulation, contributing to locomotor recovery. This research provides valuable insights into the mechanisms underlying NT and offers potential targets for innovative neurotization therapies.

Practical Implications

Therapeutic Development

Findings can be targeted for development of innovative neurotization therapies.

Clinical Application

NT can be additively or synergistically applied in combination with other promising therapeutic strategies.

Understanding Recovery

NT possesses desirable potential to engender new neurocircuitry and neuroplasticity to induce recovery neurobiology-based repairs

Study Limitations

1
The absence of investigation into the post-SCI locomotor effect of T12 ventral root-only versus T12 dorsal root-alone neurotization.
2
Lack of measurement of intraspinal cord collateral sprouting of T12-L3 proprioceptive neurites compared to other sensory fibers.
3
The absence of specific molecular or genetic tactics to block the propriospinal network for assessing its role in T12-L3 NT-reanimated locomotion.

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