Identification of Differential Fibrocartilage Degradation Between Sexes in a Burn-Synovectomy Temporomandibular Osteoarthritis Mouse Model.

Abstract

BACKGROUND: Temporomandibular joint osteoarthritis is a degenerative disease with a higher prevalence in women, yet its sex-specific mechanisms remain unclear. This study investigates fibrocartilage degradation in a burn-synovectomy TMJ OA mouse model, hypothesizing that female mice exhibit greater cartilage degradation due to differential inflammatory responses. METHODS: PRG4-CreERT2; Ai9 mice (12-week-old males and females) underwent burn-synovectomy injuries and were euthanized at 1, 3, and 9 weeks for histological and immunofluorescence analyses. PRG4 and MMP-13 expression were assessed to evaluate fibrocartilage integrity and degradation. Statistical significance was determined using ANOVA and post hoc testing. RESULTS: Female mice showed significantly higher Osteoarthritis Research Society International (OARSI) scores and MMP-13/PRG4 ratios at later time points, indicating sustained degradation. PRG4 expression increased similarly in both sexes in all time points, but MMP-13 expression was significantly higher in females at 9 weeks, suggesting heightened cartilage catabolism. CONCLUSION: This study highlights sex-based differences in TMJ OA progression, reinforcing the importance of targeted therapeutic strategies. The burn-synovectomy model effectively replicates TMJ OA pathology, making it a valuable tool for future research.