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Chronic Constriction of the Sciatic Nerve and Pain Hypersensitivity Testing in Rats
Published on: March 13, 2012
Spinal glial activation contributes to postoperative mechanical hypersensitivity in the rat
Hideaki Obata1, James C Eisenach, Hesham Hussain
1Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
The Journal of Pain
|November 1, 2006
Summary
Hind paw incision causes mechanical hypersensitivity due to spinal cord glial activation. Inhibiting spinal astrocytes, a type of glial cell, significantly reduces this pain, suggesting them as a potential therapeutic target.
Area of Science:
- Neuroscience
- Pain Research
- Cell Biology
Background:
- Peripheral nerve injury and inflammation activate spinal cord glia (microglia and astrocytes).
- This glial activation is known to contribute to behavioral hypersensitivity.
- The specific role of spinal glia in mechanical hypersensitivity following hind paw incision remained uninvestigated.
Purpose of the Study:
- To investigate the contribution of spinal cord glia to mechanical hypersensitivity after hind paw incision.
- To examine the temporal profile of spinal microglia and astrocyte activation post-incision.
- To determine if inhibiting glial activation can alleviate mechanical hypersensitivity.
Main Methods:
- Unilateral plantar hind paw incision was performed on male Sprague-Dawley rats.
- Mechanical hypersensitivity was assessed using von Frey filaments.
- Spinal cord microglia and astrocyte activation was measured via immunohistochemistry at multiple time points.
- The glial activation inhibitor fluorocitrate was administered intrathecally to assess its effect.
Main Results:
- Hind paw incision induced mechanical hypersensitivity and ipsilateral spinal astrocyte activation within 24 hours.
- Both microglia and astrocytes showed maximal activation 3 days post-incision.
- Intrathecal administration of fluorocitrate dose-dependently reduced mechanical hypersensitivity when given 24 hours after incision.
Conclusions:
- Spinal cord glial activation, particularly astrocytes within 24 hours of incision, contributes to mechanical hypersensitivity after hind paw incision.
- Inhibiting spinal cord glia effectively alleviates this hypersensitivity.
- Spinal cord astrocytes represent a potential novel therapeutic target for managing postoperative pain.
