Effects of Intra-articular Infiltration of Proteoglycan 4 / Lubricin in Temporomandibular Joint Osteoarthritis: An Experimental Study

Objective : The proposed research aims to evaluate the histopathological effects of intra-articular administration of recombinant human proteoglycan 4 (rhPRG4) on articular cartilage and articular disc in an experimental model of induced temporomandibular joint osteoarthritis (TMJ-OA) in rabbits. Materials and Methods: An experimental study was conducted on twenty-four rabbits’ TMJs, distributed in: 1) TMJ-C, control group consisting of 4 healthy TMJs; 2) TMJ-OA, group consisting of 5 TMJs with OA; 3) TMJ-OA-WT, group consisting of 5 untreated TMJ-OAs; 4) rhPRG4-30, group consisting of 5 ATM with OA treated with lubricin 30 μg /ml; and 5) rhPRG4-100, group consisting of 5 ATM with OA treated with lubricin 100 μg/ml. A histopathological analysis was performed, considering the mandibular condyle, articular disc, and mandibular fossa, comparing the groups. In addition, a quantitative comparative analysis was performed using the Osteoarthritis Research Society International (OARSI) scale. The Kruskal-Wallis and Dunn's post hoc tests were used for statistical analysis, considering a statistical significance of p < 0.05. Results: Descriptive histological analysis of TMJ joint tissue reveals key differences between healthy, osteoarthritic, and rhPRG4-treated joints. The analysis also suggests beneficial treatment effects with intra-articular infiltration of rhPRG4, reducing the severity of osteoarthritis. Conclusions : Intra-articular infiltration of rhPRG4 in TMJ-OA has a cartilage and articular disc repair effect, reducing the severity of osteoarthritis and promoting a more organized cartilage structure, with slightly better results at the 30 μg/ml concentration. Clinical Relevance: Intra-articular infiltration of rhPRG4 is proposed as a new therapeutic alternative in TMJ-OA, enhancing joint tissue regeneration.