Transection of Preganglionic Axons Leads to CNS Neuronal Plasticity Followed by Survival and Target Reinnervation

Auton Neurosci, 2013 · DOI: 10.1016/j.autneu.2013.07.002 · Published: December 1, 2013

Simple Explanation

This study investigates how sympathetic preganglionic neurons in the spinal cord change after their axons are cut, specifically focusing on the impact on the superior cervical ganglion (SCG). Researchers examined the levels of BDNF and its receptor TrkB in the spinal cord, noting changes in protein expression after the injury. The study found that while there were initial decreases in neuron size and ChAT expression, the neurons largely recovered over time without significant cell death. Alterations in BDNF and TrkB might have contributed to this survival and recovery, as well as the reinnervation of the SCG.

Study Duration

16 weeks

Participants

Young adult (3 months of age) female Sprague Dawley rats

Evidence Level

Not specified

Key Findings

1
Significant decrease in soma volume and reduced soma expression of choline acetyltransferase (ChAT) in the intermediolateral cell column (IML) of T1 spinal cord were observed at 1 week.
2
Protein levels of BDNF and/or full length TrkB in the spinal cord were increased throughout the survival period.
3
ChAT-ir axons and ChAT protein remained decreased in the SCG at 16 weeks, but were increased compared to the 10 week time point.

Research Summary

The study examined the effects of cervical sympathetic trunk (CST) transection on sympathetic preganglionic neurons, focusing on changes in ChAT expression, soma size, and the presence of ATF3 in the IML. Results showed a transient decrease in ChAT expression and cell volume at 1 week, followed by recovery to control values and a decline in ATF3 neurons. The alterations in BDNF and TrkB may have played a role in the recovery of ChAT expression and neuroprotection in the IML and may have served to facilitate the reinnervation of the SCG.

Practical Implications

Understanding neuronal response to injury

The study provides insights into how CNS neurons respond to peripheral axon injury, highlighting the transient nature of some changes and the potential for recovery.

Role of BDNF and TrkB

The findings suggest that BDNF and TrkB play a crucial role in neuronal survival, recovery, and reinnervation after injury, potentially informing therapeutic strategies.

Slow reinnervation process

The research indicates that reinnervation of the SCG is a slow process, which has implications for understanding the functional recovery after nerve injuries.

Study Limitations

1
The study was conducted on female Sprague Dawley rats, so the results may not be generalizable to other species or sexes.
2
The study focused primarily on protein expression and did not investigate the underlying molecular mechanisms in detail.
3
The reinnervation of the SCG was not fully complete at the end of the 16 week survival period, limiting the conclusions about long-term recovery.

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