Local injection of growth hormone for temporomandibular joint osteoarthritis

Abstract

Purpose: Osteoarthritis (OA) of the temporomandibular joint (TMJ) elicits cartilage and subchondral bone defects. Growth hor- mone (GH) promotes chondrocyte growth. The aim of this study was to evaluate the efficacy of intra-articular injections of GH to treat TMJ-OA. Materials and Methods: Monosodium iodoacetate (MIA) was used to induce OA in the TMJs of rats. After confirming the induc- tion of OA, recombinant human GH was injected into the articular cavities of rats. Concentrations of GH and IGF-1 were measured in the blood and synovial fluid, and OA grades of cartilage and subchondral bone degradation were recorded by histological exam- ination and micro-computed tomography. Results: MIA-induced OA in the rat TMJ upregulated insulin-like growth factor-1 (IGF-1) rather than GH levels. GH and IGF-1 con- centrations were increased after local injection of GH, compared with controls. Locally injected GH lowered osteoarthritic scores in the cartilage and subchondral bone of the TMJ. Conclusion: Intra-articular injection of GH improved OA scores in rat TMJs in both cartilage and subchondral bone of the condyles without affecting condylar bone growth. These results suggest that intra-articular injection of human GH could be a suitable treat- ment option for TMJ-OA patients in the future.