Inflammatory pain assessment in the arthritis of the temporomandibular joint in rats: A comparison between two phlogistic agents

• Published in: Journal of pharmacological and toxicological methods Vol. 88; no. Pt 1; pp. 100 - 108
• Main Authors: de Araújo, Joana Cláudia Bezerra, Gondim, Delane Viana, Cavalcante, André Luiz Cunha, Lisboa, Mario Roberto Pontes, de Castro Brito, Gerly Anne, Vale, Mariana Lima
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2017
• Subjects: Animals; Arthritis - chemically induced; Arthritis - diagnosis; Arthritis - pathology; Arthritis - physiopathology; Carrageenan - pharmacology; Disease Models, Animal; Hyperalgesia - chemically induced; Hyperalgesia - pathology; Hyperalgesia - physiopathology; Injections, Intra-Articular; Macrophages - drug effects; Macrophages - pathology; Male; Microglia - drug effects; Microglia - pathology; Nociception - drug effects; Nociception - physiology; Pain - chemically induced; Pain - pathology; Pain - physiopathology; Pain Measurement - methods; Rats; Rats, Sprague-Dawley; Rats, Wistar; Temporomandibular Joint Disorders - chemically induced; Temporomandibular Joint Disorders - pathology; Temporomandibular Joint Disorders - physiopathology; Trigeminal Ganglion - cytology; Trigeminal Ganglion - drug effects; Zymosan - pharmacology
• ISSN: 1056-8719; 1873-488X
• DOI: 10.1016/j.vascn.2017.08.001

Temporomandibular joint (TMJ) disorders are a group of conditions that result in TMJ pain, which frequently limits basic daily activities. Experimental models that allow the study of the mechanisms underlying these inflammatory and pain conditions are of great clinical relevance. The aim of this study was to evaluate nociception, inflammation and participation of the macrophage/microglia cells in the arthritis of the TMJ induced by two phlogistic agents. 84 rats were divided into 2 groups: Zy, which received zymosan intra-articularly, or Cg, which received carrageenan intra-articularly. Mechanical nociception, total leukocyte influx to the synovial fluid and histopathological analyses were evaluated in the TMJ. The participation of macrophage/microglia located in trigeminal ganglia (TG) and in the subnucleus caudalis (V-SnC) was assessed immunohistochemically. Both agents induced mechanical hyperalgesia 6h after the induction, but a more persistent algesic state was perceived in the Cg group, which lasted for 120h. Even though both groups presented increased leukocyte influx, the Zy-group presented a more intense influx. Zymosan recruited resident macrophage in the trigeminal ganglia 24h after the injection. In the V-SnC, the group Cg presented a more prolonged immunolabeling pattern in comparison with the group Zy. It can be concluded that zymosan induced a more intense infiltrate and peripheral nervous changes, while Cg lead to a moderate TMJ inflammation with prominent changes in the V-SnC.