Glial scar size, inhibitor concentration, and growth of regenerating axons after spinal cord transection

Neural Regen Res, 2012 · DOI: 10.3969/j.issn.1673-5374.2012.20.001 · Published: July 1, 2012

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

This study uses a mathematical model to understand how glial scars and inhibitory molecules affect the regrowth of nerve fibers (axons) after a spinal cord injury. The model simulates the interaction of factors that promote and inhibit axon growth. The simulation considers the size of the glial scar and the concentration of inhibitory molecules released by the scar tissue. It analyzes how these factors impact the speed and success of axonal regeneration. The study found that larger glial scars and higher concentrations of inhibitory molecules slow down axonal growth. Successful axonal regeneration depends on maintaining a balance between growth-promoting and growth-inhibiting factors.

Study Duration

Not specified

Participants

Mouse model of spinal cord transection

Evidence Level

Level 5, Mathematical model study

Key Findings

1
A larger glial scar and a higher release rate of inhibitor resulted in a reduced axonal growth rate.
2
The axonal growth rate depended on the ratio of inhibitor to promoter concentrations at the growth cones.
3
When the average ratio was < 1.5, regenerating axons were able to grow and successfully contact target cells.

Research Summary

This study formulates a mathematical model based on cell chemotaxis and uses a three-dimensional lattice Boltzmann method for numerical simulation to observe the effects of glial scar size and inhibitor concentration on regenerative axonal growth following spinal cord transection. The simulation tests analyze the effects of glial scar size and inhibitor/promoter release rates on axonal growth rate, recording concentrations of inhibitors and promoters at the moving growth cones. The results demonstrate that larger glial scars and higher inhibitor release rates reduce axonal growth rate, and axonal growth rate depends on the ratio of inhibitor to promoter concentrations; a ratio < 1.5 enables successful axonal regeneration and target cell contact.

Practical Implications

Understanding Growth Factor Balance

Maintaining a low ratio of inhibitors to promoters (<1.5) is crucial for successful axonal regeneration after spinal cord injury.

Targeting Glial Scar Size

Reducing the size of the glial scar can promote axonal growth.

Modulating Inhibitor Release

Controlling the release of inhibitory molecules from the glial scar can enhance axonal regeneration.

Study Limitations

1
The study did not analyze secondary injury or apoptosis following neuronal injury.
2
Sprouting mechanisms of remaining neurons were not analyzed.
3
Polymerization of skeleton protein in growth cone of regenerating axons was not analyzed.

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury