Comparison of the efficacy of intra-articular injections of hyaluronic acid and lactoferrin in mono-iodoacetateinduced temporomandibular joint osteoarthritis: A histomorphometric, immunohistochemistry, and micro-computed tomography analysis

OBJECTIVES: This study aims to evaluate the efficacy of highmolecular-weight hyaluronic acid (HMWHA) and lactoferrin (LF) injections on temporomandibular joint (TMJ) cartilage and subchondral bone in mono-iodoacetate (MIA)-induced temporomandibular joint osteoarthritis model in rats. MATERIALS AND METHODS: In this in vivo study, a total of 24 rats were divided into three groups as follows: saline group (Group 1), HMWHA group (Group 2), and LF group (Group 3) including eight rats in each group. The intra-articular injections were administered once a week for three weeks after osteoarthritis was induced. All animals were euthanized 28 days after induction of osteoarthritis, and TMJs were harvested for histomorphometric, immunohistochemical, and micro-computed tomography (CT) analysis. RESULTS: There was no significant difference between the HMWHA and LF groups in terms of the histomorphometric and immunohistochemical analysis results (p>0.05). According to the micro-CT analysis, the LF group had the highest mean bone volume fraction (74.9±0.5) and trabecular thickness (0.122±0.002), while the saline group had the lowest mean values (55.0±0.3 and 0.071±0.002, respectively) (p<0.001). There was no significant difference between the HMWHA and LF groups according to the micro-CT analysis (p>0.05). Both groups had better healing effects than the saline group in all analyses. CONCLUSION: Lactoferrin has a healing effect at least as much as HMWHA in MIA-induced TMJ osteoarthritis. We suggest that LF may be evaluated in future clinical studies as a promising agent in the treatment of osteoarthritis.