NEURAL RECONNECTION IN THE TRANSECTED SPINAL CORD OF THE FRESH-WATER TURTLE Trachemys dorbignyi

J Comp Neurol, 2009 · DOI: 10.1002/cne.22061 · Published: July 10, 2009

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

This research shows that freshwater turtles can reconnect their spinal cords after complete transection, leading to some recovery of motor functions. The reconnection involves the formation of a cellular bridge made of glial cells that supports the transit of regenerating axons across the injury site. Unlike mammals, turtles do not develop a glial scar that inhibits axon regrowth, and a significant number of axons are able to cross the lesion.

Study Duration

24 hours to 120 days

Participants

25 fresh-water turtles (Trachemys dorbignyi)

Evidence Level

Not specified

Key Findings

1
Some turtles regained the ability to perform stepping locomotion after spinal cord transection, although slower than normal.
2
Axons regrowing across the severed spinal cord region were observed in all injured turtles, originating mainly from sensory neurons.
3
The absence of a glial scar and the presence of a cellular scaffold of BLBP and GFAP positive cells facilitate axon regeneration in turtles.

Research Summary

This study demonstrates that fresh-water turtles can reconnect their completely transected spinal cord leading to some degree of recovery of the motor functions lost after injury. The reconnection involves the formation of a glial cell scaffold that supports axonal regrowth across the lesion site, with a major contingent of axons originating from sensory neurons. Unlike mammals, turtles do not form a glial scar, and the study suggests that these endogenous repair mechanisms could provide insights into novel strategies for spinal cord repair in humans.

Practical Implications

Potential therapeutic targets

Identifying the specific molecules involved in glial cell scaffolding and axon guidance in turtles could reveal therapeutic targets for promoting spinal cord regeneration in mammals.

Drug development

The absence of a glial scar in turtles suggests that drugs targeting glial scar formation may not be necessary for promoting regeneration and may even be detrimental.

Model for studying regeneration

The fresh-water turtle provides a new animal model for studying spinal cord repair mechanisms that are not present in mammals.

Study Limitations

1
The study only examined a limited number of turtles.
2
Functional recovery was incomplete, suggesting that not all nerve tracts were fully restored.
3
The study did not explore the potential regeneration of long supraspinal tracts.

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