Experimental model of temporomandibular joint arthritis induced by zymozan in rats and the study of the role of nitric oxide

• Autor(a) principal: HellÃada Vasconcelos Chaves
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFC
• Texto Completo: http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=414
• topic: ArticulaÃÃo temporomandibular; Artrite experimental; Ãxido nÃtrico; Zymosan; SÃndrome de disfunÃÃo da articulaÃÃo temporomandibular; Temporomandibular joint; Experimental arthritis; Nitric oxide; Zymosan; Syndrome of temporomandibular joint dysfunction; FARMACOLOGIA

Temproromandibular disfunction (TMD) is related to a masticatory system disfunction which can include the temporomandibular joint (TMJ), the masticatory muscles and/or other related structures. TMJ inflammatory disorders are one of the major pathology of TMD afecting a great number of patients. Although TMJÂs inflammation and pain are important cinical entities, their mechanisms are poorly understood. The purpose of the study is to propose an experimetnal model of TMJÂs arthritis to study its patophysiological mechanisms and inflammatory mediators such as nitric oxide (NO). Female Wistar rats (160-220 g) were used to the study. To induct TMJÂs arthritis, zymosan 40 microL (Zy: 0,25; 0,5; 1 ou 2 mg) was injected into left TMJ. The animals were sacrified in times 3 h, 6 h, 1, 2, 3, 5, 7, 10 e 21 days. Nitric oxide syntase inhibitors L-NAME (10, 30 e 100 mg/kg i.p.) or 1400W (0,5 e 1 mg/kg s.c.) were administered 30 min before TMJÂs arthritis induction. Leucocyte influx count in the sinovial fluid, vascular permability study using Evans blue dye extravasation, myeloperoxidase assay (MPO), NO production determination using Griess reaction, histopatological analyisis and imunohystochemical for induced NO synthase (iNOS) were utilized as parameters of this sutudy. It was observed that Zy (2 mg) induced significantly increase in leucocyte influx count (p<0,05), Evans blue dyeÂs extravasation (p<0,05), myeloperoxidase activity (p<0,05) and NO dosage (p<0,05) compared with control group 6 h after TMJ arthritis induction. Histopatological analysis of TMJ of Zy injected animals showed inflammatory cell infiltration in synovial membrane (SM), in conective periarticular tissue, in squeletic muscle tissue and thickness of SM in 6 h after TMJ arthritis. On the 10th day after TMJ arthritis, the TMJ remain showing leucocyte infiltration to synovial membrane (SM), to conective periarticular tissue, to squeletic muscle tissue and thickness of SM, as well as fibrosis of SM and articular disc. On the 21st d after TMJ arthritis, it was observed cell influx only to SM, showing, however, thickness of SM and the major fibrosis of SM, articular cartilage, conective periarticular tissue and articular disc. TMJÂs imunohistochemistry reaction for iNOS showed increase iNOSÂs expression in animals with TMJÂs arthritis compared to the control group. L-NAME 100 mg/kg and 1400W 1 mg/kg reduced the increase in leucocyte count in the synovial fluid, the Evans blue dye extravasation, the histopatological alterations, and reduced the iNOS expression after imunohistochemistry reaction for iNOS 6 h after TMJ arthritis. These results sugest that this experimental model can be used to study TMJ arthritis, and that NO can participate in the physiopathological mechanisms of TMD.