Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus

<p>Abstract</p> <p>Background</p> <p>Glial cells have been shown to directly participate to the genesis and maintenance of chronic pain in both the sensory ganglia and the central nervous system (CNS). Indeed, glial cell activation has been reported in both the dorsal r...

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Main Authors: Jasmin Luc, Magni Giulia, Zanardelli Matteo, Ceruti Stefania, Villa Giovanni, Ohara Peter T, Abbracchio Maria P
Format: Article
Language:English
Published: SAGE Publishing 2010-12-01
Series:Molecular Pain
Online Access:http://www.molecularpain.com/content/6/1/89
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author Jasmin Luc
Magni Giulia
Zanardelli Matteo
Ceruti Stefania
Villa Giovanni
Ohara Peter T
Abbracchio Maria P
author_facet Jasmin Luc
Magni Giulia
Zanardelli Matteo
Ceruti Stefania
Villa Giovanni
Ohara Peter T
Abbracchio Maria P
author_sort Jasmin Luc
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Glial cells have been shown to directly participate to the genesis and maintenance of chronic pain in both the sensory ganglia and the central nervous system (CNS). Indeed, glial cell activation has been reported in both the dorsal root ganglia and the spinal cord following injury or inflammation of the sciatic nerve, but no data are currently available in animal models of trigeminal sensitization. Therefore, in the present study, we evaluated glial cell activation in the trigeminal-spinal system following injection of the Complete Freund's Adjuvant (CFA) into the temporomandibular joint, which generates inflammatory pain and trigeminal hypersensitivity.</p> <p>Results</p> <p>CFA-injected animals showed ipsilateral mechanical allodynia and temporomandibular joint edema, accompanied in the trigeminal ganglion by a strong increase in the number of GFAP-positive satellite glial cells encircling neurons and by the activation of resident macrophages. Seventy-two hours after CFA injection, activated microglial cells were observed in the ipsilateral trigeminal subnucleus caudalis and in the cervical dorsal horn, with a significant up-regulation of Iba1 immunoreactivity, but no signs of reactive astrogliosis were detected in the same areas. Since the purinergic system has been implicated in the activation of microglial cells during neuropathic pain, we have also evaluated the expression of the microglial-specific P2Y<sub>12 </sub>receptor subtype. No upregulation of this receptor was detected following induction of TMJ inflammation, suggesting that any possible role of P2Y<sub>12 </sub>in this paradigm of inflammatory pain does not involve changes in receptor expression.</p> <p>Conclusions</p> <p>Our data indicate that specific glial cell populations become activated in both the trigeminal ganglia and the CNS following induction of temporomandibular joint inflammation, and suggest that they might represent innovative targets for controlling pain during trigeminal nerve sensitization.</p>
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spelling doaj.art-1a6de694694a4859807fb9ed02798edc2022-12-21T22:10:00ZengSAGE PublishingMolecular Pain1744-80692010-12-01618910.1186/1744-8069-6-89Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleusJasmin LucMagni GiuliaZanardelli MatteoCeruti StefaniaVilla GiovanniOhara Peter TAbbracchio Maria P<p>Abstract</p> <p>Background</p> <p>Glial cells have been shown to directly participate to the genesis and maintenance of chronic pain in both the sensory ganglia and the central nervous system (CNS). Indeed, glial cell activation has been reported in both the dorsal root ganglia and the spinal cord following injury or inflammation of the sciatic nerve, but no data are currently available in animal models of trigeminal sensitization. Therefore, in the present study, we evaluated glial cell activation in the trigeminal-spinal system following injection of the Complete Freund's Adjuvant (CFA) into the temporomandibular joint, which generates inflammatory pain and trigeminal hypersensitivity.</p> <p>Results</p> <p>CFA-injected animals showed ipsilateral mechanical allodynia and temporomandibular joint edema, accompanied in the trigeminal ganglion by a strong increase in the number of GFAP-positive satellite glial cells encircling neurons and by the activation of resident macrophages. Seventy-two hours after CFA injection, activated microglial cells were observed in the ipsilateral trigeminal subnucleus caudalis and in the cervical dorsal horn, with a significant up-regulation of Iba1 immunoreactivity, but no signs of reactive astrogliosis were detected in the same areas. Since the purinergic system has been implicated in the activation of microglial cells during neuropathic pain, we have also evaluated the expression of the microglial-specific P2Y<sub>12 </sub>receptor subtype. No upregulation of this receptor was detected following induction of TMJ inflammation, suggesting that any possible role of P2Y<sub>12 </sub>in this paradigm of inflammatory pain does not involve changes in receptor expression.</p> <p>Conclusions</p> <p>Our data indicate that specific glial cell populations become activated in both the trigeminal ganglia and the CNS following induction of temporomandibular joint inflammation, and suggest that they might represent innovative targets for controlling pain during trigeminal nerve sensitization.</p>http://www.molecularpain.com/content/6/1/89
spellingShingle Jasmin Luc
Magni Giulia
Zanardelli Matteo
Ceruti Stefania
Villa Giovanni
Ohara Peter T
Abbracchio Maria P
Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
Molecular Pain
title Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
title_full Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
title_fullStr Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
title_full_unstemmed Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
title_short Temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
title_sort temporomandibular joint inflammation activates glial and immune cells in both the trigeminal ganglia and in the spinal trigeminal nucleus
url http://www.molecularpain.com/content/6/1/89
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