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

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.