Loss of neurons from laminas I-III of the spinal dorsal horn is not required for development of tactile allodynia in the spared nerve injury model of neuropathic pain

Polgar, E., Hughes, D.I. , Arham, A.Z. and Todd, A.J. (2005) Loss of neurons from laminas I-III of the spinal dorsal horn is not required for development of tactile allodynia in the spared nerve injury model of neuropathic pain. Journal of Neuroscience, 25(28), pp. 6658-6666. (doi: 10.1523/JNEUROSCI.1490-05.2005)

Abstract

It has been proposed that death of inhibitory interneurons in the dorsal horn contributes to the neuropathic pain that follows partial nerve injury. In this study, we have used two approaches to test whether there is neuronal death in the dorsal horn in the spared nerve injury (SNI) model. We performed a stereological analysis of the packing density of neurons in laminas I-III 4 weeks after operation and found no reduction on the ipsilateral side compared with that seen on the contralateral side or in sham-operated or naive rats. In addition, we used two markers of apoptosis, terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) staining and immunocytochemical detection of cleaved (activated) caspase-3. Neither of these methods demonstrated apoptotic neurons in the dorsal spinal cord 1 week after operation. Although TUNEL-positive cells were present throughout the gray and white matter at this stage, they were virtually all labeled with antibody against ionized calcium-binding adapter molecule 1, a marker for microglia. All animals that underwent SNI showed clear signs of tactile allodynia affecting the ipsilateral hindpaw. These results suggest that a significant loss of neurons from the dorsal horn is not necessary for the development of tactile allodynia in the SNI model.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hughes, Dr David I and Beresford-Polgar, Dr Erika and Todd, Professor Andrew
• Authors: Polgar, E., Hughes, D.I., Arham, A.Z., and Todd, A.J.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Journal of Neuroscience
• ISSN: 0270-6474
• ISSN (Online): 1529-2401
• Copyright Holders: Copyright © 2005 Society for Neuroscience
• First Published: First published in Journal of Neuroscience 25(28):6658-6666
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher