Long descending cervical propriospinal neurons differ from thoracic propriospinal neurons in response to low thoracic spinal injury

BMC Neuroscience, 2010 · DOI: 10.1186/1471-2202-11-148 · Published: November 23, 2010

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

This study investigates how different types of spinal cord neurons (LDPT) respond to injury, comparing them to other spinal neurons (TPS) and supraspinal neurons (SSN). Researchers analyzed gene expression in LDPT neurons after spinal cord injury to understand their regenerative capacity. The findings revealed that LDPT neurons down-regulate many genes after injury, unlike TPS neurons which show an up-regulation. This suggests LDPT neurons enter a state of dormancy rather than actively regenerating. The research also found distinct differences between uninjured LDPT and TPS neurons, which may explain their different responses to spinal cord injury. These insights could help develop targeted therapies for different types of spinal neurons to promote regeneration.

Study Duration

3-days to 1-month

Participants

36 female hooded Long-Evans rats

Evidence Level

Not specified

Key Findings

1
LDPT neurons exhibit a broad down-regulation of genes related to growth factors and axonal regeneration early after a low thoracic spinal cord injury.
2
Unlike TPS neurons, LDPT neurons do not show a significant cell death response over the first month post-injury.
3
Uninjured TPS and LDPT neurons have significant phenotypic differences, which may contribute to their differing post-axotomy responses.

Research Summary

This study examines the intrinsic response of long descending propriospinal tract (LDPT) neurons to axotomy following a low thoracic spinal cord injury (SCI) in rats, comparing their response to short thoracic propriospinal (TPS) neurons. The results indicate a broad overall down-regulation in genes related to neurotrophic factors, growth factor receptors, and axonal regeneration in LDPT neurons after SCI, contrasting with the regenerative response observed in TPS neurons. Phenotypic differences exist between uninjured TPS and LDPT neurons that may partly explain the differences in their post-axotomy responses, suggesting different therapeutic approaches are needed for each population.

Practical Implications

Targeted Therapies

Different approaches are needed to enhance the capacity for each population of propriospinal neuron to survive and undergo successful axonal regeneration after SCI.

Neurotrophic Factor Selection

GDNF may not be the optimal neurotrophic agent for LDPT neurons after thoracic axotomy, but LIF, CNTF, BDNF, and NT-3 might be beneficial.

Inflammation Role

An inflammatory response may play an important role in the ability of CNS neurons to mount a regenerative response.

Study Limitations

1
The study focused on a specific time frame (up to one month) post-injury, limiting understanding of long-term effects.
2
The use of Fluorogold (FG) for retrograde labeling might have cytotoxic effects, although the study argues against this.
3
The distance between the axotomy site and the LDPT neuron cell bodies may influence the observed response.

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