Zymosan‐Treated SKG Mice: Assessing Effects of Systemic Inflammation on the Temporomandibular Joint

ABSTRACT Objectives The effects of systemic inflammation on the temporomandibular joint (TMJ) are poorly understood. This study aimed to establish a mouse model to study the effects of systemic inflammation on the TMJ. Materials and Methods SKG mice, a BALB/c strain with spontaneous onset of rheumatoid arthritis‐like symptoms due to a spontaneous point mutation (W163C) in the gene encoding the SH2 domain of ZAP‐70, were treated with zymosan (β‐1,3‐glucan). Synovitis, bone erosion, and cartilage damage in the TMJ were evaluated using established scores for animal models of inflammatory arthritis. Myeloperoxidase‐positive areas and numbers of tartrate‐resistant acid phosphatase (TRAP)‐positive cells were compared between naive and zymosan‐treated SKG mice. Correlations between TMJ inflammation scores and clinical scores for extremities were also assessed. Results There were significant differences in TMJ inflammation scores, including synovitis, bone erosion, and cartilage damage, between naive and high‐dose zymosan‐treated mice. There were significant differences in myeloperoxidase‐positive areas and numbers of TRAP‐positive cells between naive and zymosan‐treated mice. There were significant correlations between TMJ inflammation scores and clinical scores for extremities. Conclusions Systemic administration of zymosan efficiently induces TMJ inflammation in SKG mice. Zymosan‐treated SKG mice offer a useful tool to investigate the effects of systemic inflammation on the TMJ.