Int J Oral Biol.  2016 Sep;41(3):125-131. 10.11620/IJOB.2016.41.3.125.

Participation of IL-1β in temporomandibular nociception in rats with CFA-induced inflammation

• Ju JS
• Choi SH
• Kim HJ
• Son JY
• Ahn DK

• KMID: 2354200
• DOI: http://doi.org/10.11620/IJOB.2016.41.3.125

Abstract

The aim of the present study was to develop an animal model for evaluation of temporomandibular (TMJ) nociception under TMJ inflammation. We also investigated the participation of IL-1β in inflammation-induced TMJ nociception. Experiments were carried out using male Sprague-Dawley rats. Intra-articular injection of 3% formalin was administered to evaluate hyperalgesia 3 days after CFA injection. Intra-articular injection of 3% formalin did not produce nociceptive behavior in normal rats. Although intra-articular injection of 3 doses of CFA produced TMJ inflammation, only 1:3 diluted CFA produced hyperalgesia when formalin was injected intra-articularly 3 days after CFA injection. Co-administration of IL-1 receptor inhibitor with formalin into the TMJ cavity 3 days after CFA injection was performed. Co-administration of IL-1 receptor inhibitor significantly inhibited formalin-induced hyperalgesia in rats with CFA-induced TMJ inflammation. These results suggested that intra-articular injection of formalin produced hyperalgesia under chronic TMJ inflammation. Moreover, IL-1β plays an important role in TMJ hyperalgesia under chronic inflammation and blockade of IL-1β is a potential therapeutic target for inflammatory TMJ pain.

Keyword

IL-1β; TMJ; nociception; CFA; formalin behavior test

MeSH Terms

Animals
Formaldehyde
Humans
Hyperalgesia
Inflammation*
Injections, Intra-Articular
Interleukin-1
Male
Models, Animal
Nociception*
Rats*
Rats, Sprague-Dawley
Temporomandibular Joint
Formaldehyde
Interleukin-1