Cell proliferation and cytoarchitectural remodeling during spinal cord reconnection in the fresh-water turtle Trachemys dorbignyi

Cell Tissue Res., 2011 · DOI: 10.1007/s00441-011-1173-y · Published: June 1, 2011

Regenerative Medicine Neurology Genetics

Simple Explanation

In fresh-water turtles, spinal cord injury triggers a unique regenerative response. Unlike mammals that form glial scars, turtles develop a cellular bridge composed of regenerating axons and glial cells. This study found increased cell division near the injury site, with new cells associating closely with growing axons. Many of these dividing cells exhibit properties of radial glia, which support and insulate the regenerating nerve fibers. The cellular environment around the injury resembles embryonic tissue, allowing for dynamic cell rearrangements and the initial steps of nerve fiber insulation (myelination), crucial for restoring nerve impulse transmission.

Study Duration

20–30 days

Participants

27 fresh-water turtles (Trachemys dorbignyi)

Evidence Level

Not specified

Key Findings

1
Spinal cord transection induces a significant increase in cell proliferation around the lesion epicenter in turtles.
2
BrdU-tagged cells maintain a close association with regenerating axons, and many of these cells express brain lipid-binding protein (BLBP) and glial fibrillary acidic protein (GFAP).
3
The ultrastructure of the bridge reveals cells resembling immature oligodendrocytes creating an embryonic-like microenvironment supporting and ensheathing regenerating axons.

Research Summary

This study investigates the cellular mechanisms of spinal cord regeneration in fresh-water turtles, focusing on cell proliferation and cytoarchitectural changes following injury. The research demonstrates increased mitotic activity around the injury site, with dividing cells contributing to a glial scaffold that supports axonal regrowth and early remyelination. The findings suggest that radial glia play a crucial role in providing support and sheaths for regenerating axons, creating an embryonic-like environment conducive to neural repair.

Practical Implications

Potential Therapeutic Targets

Identifying the specific molecular signals that stimulate radial glia proliferation and migration could lead to new therapies for spinal cord injuries in mammals.

Understanding the Microenvironment

Further research into the embryonic-like microenvironment created during turtle spinal cord regeneration may reveal factors that promote axonal growth and myelination.

Comparative Neurology

Comparing the regenerative mechanisms in turtles with those in mammals could help identify why mammals have limited regenerative capabilities and suggest strategies to overcome these limitations.

Study Limitations

1
The study focuses on the early stages (20-30 days) of spinal cord regeneration, and long-term outcomes and functional recovery were not fully assessed.
2
The precise origin and lineage of all proliferating cells in the bridge region remain unclear.
3
The study is limited to a single species of turtle, and the findings may not be generalizable to all amniotes.

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