Nervous Tissue Stiffens Postinjury

Biophysical Journal, 2020 · DOI: https://doi.org/10.1016/j.bpj.2019.09.050 · Published: January 21, 2020

Neurology Biomechanics Regenerative Medicine & Stem Cells

Simple Explanation

Zebrafish have remarkable regenerative abilities, including the capacity to recover fully from spinal cord injuries, unlike humans who suffer irreversible neuron loss and permanent paralysis. Glial cells in zebrafish play a crucial role in spinal cord repair by forming a 'glial bridge' that guides the regrowth of axons and creation of new neurons. A recent study found that spinal cord tissue stiffens significantly after injury in zebrafish, suggesting that this stiffening does not impede regeneration, challenging the idea that softening the tissue is necessary for repair.

Study Duration

Not specified

Participants

Zebrafish

Evidence Level

Not specified

Key Findings

1
Gray matter in the spinal cord is approximately twice as stiff as white matter in both healthy and injured states.
2
White matter stiffness near the injury site doubles 2-4 weeks post-transection, eventually returning to baseline levels after 6 weeks.
3
Myelin density is a key microstructural determinant that can be confidently linked to the mechanical stiffness of nervous tissue.

Research Summary

This article discusses a study on zebrafish spinal cord injury and repair, focusing on the biochemomechanical microenvironment changes following transection. The key finding is that spinal cord tissue stiffness increases significantly after injury but does not impede regeneration, suggesting that softening the glial scar may not be necessary for spinal cord repair in humans. The study emphasizes the importance of understanding the interplay between mechanical and biochemical factors in promoting successful spinal cord regeneration.

Practical Implications

Challenging Existing Paradigms

The finding that increased stiffness does not inhibit regeneration challenges the idea that softening glial scars is essential for spinal cord repair.

Focus on Comprehensive Solutions

Successful spinal cord repair likely requires a multifaceted approach that considers both mechanical and biochemical factors.

Advancing Neuromechanics Research

Further research is needed to understand the complex interplay between chemical composition and mechanical properties in the nervous system to improve treatment strategies.

Study Limitations

1
The correlations between microstructural composition and nervous tissue stiffness are not one-to-one, making it difficult to pinpoint specific factors.
2
The range of reported stiffness values varies hugely due to differences in sample preparation, sample size, testing method, and tissue microstructure.
3
Our understanding of neuronal mechanosensitivity is still in its infancy.

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