Dendritic Spine Dynamics after Peripheral Nerve Injury: An Intravital Structural Study

The Journal of Neuroscience, 2020 · DOI: https://doi.org/10.1523/JNEUROSCI.2858-19.2020 · Published: May 27, 2020

Spinal Cord Injury Neurology Pain Management

Simple Explanation

This study investigates how nerve injury affects the structure of nerve cells in the spinal cord, specifically focusing on small protrusions called dendritic spines that are important for communication between neurons. Researchers used a special imaging technique to observe the same nerve cells in mice before and after inducing nerve injury, allowing them to track changes in dendritic spines over time. The study found that nerve injury leads to changes in the dynamics of dendritic spines, suggesting that these structural changes may contribute to the development of neuropathic pain.

Study Duration

7 days

Participants

Male C57/Bl6 Thy1-YFP mice (8- to 10-week-old)

Evidence Level

Level II: Experimental study using animal model

Key Findings

1
Peripheral nerve injury leads to increased fluctuations in the length and width of dendritic spines in the dorsal horn neurons.
2
Nerve injury initially causes a decrease in the elimination of thin-shaped spines, followed by an increase in the formation of mushroom-shaped spines.
3
The increase in mushroom-shaped spine formation and overall density coincides with the onset of maximal pain sensitivity in the animal model.

Research Summary

This study used intravital imaging to profile dendritic spine dynamics in the superficial dorsal horn of mice before and after peripheral nerve injury, providing insights into the structural changes associated with neuropathic pain. The findings reveal a time-dependent relationship between pain sensitivity and dendritic spine dynamics, with increased spine fluctuations and a shift from thin spine elimination to mushroom spine formation after nerve injury. The results suggest that dendritic spine dysgenesis, particularly the increase in mushroom-shaped spines, contributes to the establishment and maintenance of neuropathic pain by stabilizing abnormal structures within spinal nociceptive circuits.

Practical Implications

Potential Therapeutic Target

Dendritic spine dynamics could serve as a structural-based opportunity to investigate mechanisms of pain following injury and disease.

Biomarker for Pain

Dendritic spine remodeling may serve as a pain biomarker.

Understanding Chronic Neurologic Diseases

Malformed dendritic spines occur in a spectrum of chronic neurologic diseases, including epilepsy, stroke, post-traumatic stress disorder, autism spectrum disorder, mental retardation, dementia, and chronic substance abuse or addiction.

Study Limitations

1
The study only investigated cells labeled with Thy1-YFP, a specific marker for neurons.
2
The resolution of the imaging equipment may have limited the ability to detect subtle changes in dendritic spine structure.
3
Additional factors contribute to the pain behavioral outcomes that we observed.

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