Expression of the regeneration-associated protein SPRR1A in primary sensory neurons and spinal cord of the adult mouse following peripheral and central injury

J Comp Neurol, 2009 · DOI: 10.1002/cne.21944 · Published: March 1, 2009

Simple Explanation

This study investigates the expression of SPRR1A, a protein associated with nerve regeneration, in mice following nerve injuries. The research focuses on how SPRR1A expression differs between peripheral and central nerve damage, and examines its presence in various sensory neuron types and spinal cord regions. The researchers induced sciatic nerve, dorsal root, and dorsal column injuries in adult mice. They then used immunocytochemical techniques to observe SPRR1A expression levels and locations in the spinal cord, dorsal root ganglia (DRG), and peripheral nerves. The study found that SPRR1A expression was significantly higher after peripheral nerve injuries compared to central nerve injuries. This suggests SPRR1A plays a more prominent role in the regenerative response of peripheral nerves.

Study Duration

30 days

Participants

44 adult male C57BL/6 mice

Evidence Level

Not specified

Key Findings

1
SPRR1A expression is minimal following injury to the centrally projecting branches of DRG neurons.
2
Following peripheral nerve injury, intense SPRR1A immunoreactivity was observed in the dorsal horn and motoneurons of the spinal cord, in L4/5 DRG neurons and in the injured nerve.
3
SPRR1A was expressed by DRG cells of all sizes and co-localized with classical markers of DRG subpopulations and their primary afferent terminals.

Research Summary

This study characterized SPRR1A expression in the DRG and spinal cord of adult mice following injury to the peripheral and central projections of DRG neurons, finding that SPRR1A induction correlates with regenerative capacity. A time course study comparing expression following transection or crush of the peripheral (sciatic) nerve reveals that the down regulation of SPRR1A expression corresponds with the time course of reinnervation known to occur in these models. SPRR1A becomes de novo expressed by the main subpopulations of DRG neurons following an injury to their peripheral, but not central, projections, supporting the hypothesis that SPRR1A is a regeneration-associated protein.

Practical Implications

Regeneration Marker

SPRR1A can be used as a regeneration-specific marker in CNS and PNS injury studies in mice.

Therapeutic Target

SPRR1A may be a potential therapeutic target for promoting nerve regeneration after injury.

Assessing Interventions

Understanding the time course, extent, and localization of SPRR1A expression following injury may prove useful when assessing interventions aimed at enhancing peripheral nerve regeneration or promoting regeneration following CNS injury.

Study Limitations

1
The study is limited to mice, and the results may not be directly applicable to other species.
2
Further research is needed to fully elucidate the mechanisms by which SPRR1A promotes nerve regeneration.
3
The study focuses on SPRR1A expression, and does not directly assess the functional consequences of SPRR1A induction.

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