Expression of Neurotrophin and Its Trk Receptors During Axonal Regeneration Following Spinal Cord Injury in Larval Lamprey

Neuroscience, 2011 · DOI: 10.1016/j.neuroscience.2011.03.024 · Published: June 2, 2011

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

This study examines how nerve growth factors (neurotrophins) and their receptors (Trk) are expressed in the spinal cord of larval lampreys after spinal cord injury. The study found that after injury, the expression of neurotrophins changes over time, initially decreasing and then returning to normal levels. Additionally, microglia, a type of immune cell in the spinal cord, start expressing neurotrophins after the injury. The expression of Trk receptors also changes, with one type (Trk1) decreasing and another (Trk2) remaining the same or increasing after spinal cord injury.

Study Duration

4 Months

Participants

40 large larval lampreys

Evidence Level

Not specified

Key Findings

1
NT expression was downregulated in neurons close to the transection at 2 weeks post-transection, but returned to control levels by 4 weeks.
2
Trk 1 mRNA expression was downregulated after spinal cord transection, while Trk 2 mRNA expression was either unchanged or increased.
3
Spinal cord injury induces proliferation of macrophage/microglial cells that express neurotrophin.

Research Summary

The study investigates the expression of neurotrophins (NTs) and their Trk receptors in larval lampreys after spinal cord injury (SCI). Results showed that NT expression is initially downregulated near the injury site but recovers over time, with microglia also expressing NTs after injury. Trk1 receptor expression decreases after SCI, while Trk2 remains stable or increases. These findings suggest that endogenous neurotrophins and their receptors play a role in the regenerative response to spinal cord injury in lampreys, with microglia contributing to NT expression.

Practical Implications

Understanding Regeneration

The study can help us better understand how the spinal cord regenerates after injury in lampreys.

Microglia's Role

It sheds light on the role of microglia in expressing neurotrophins and potentially aiding regeneration.

Potential Therapies

The findings may contribute to future therapies for spinal cord injuries by manipulating neurotrophin expression.

Study Limitations

1
The study is limited to larval lampreys, and the findings may not be directly applicable to mammals.
2
The functional significance of the observed changes in neurotrophin and Trk receptor expression requires further investigation.
3
The origin and nature of the lamprey microglia/macrophage cells warrant additional investigation.

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