Biochemical and Histological Evaluation of different intra-articular injections as therapy for Temporomandibular Joint Osteoarthritis in Rats

Introduction: Temporomandibular joint (TMJ) osteoarthritis is usually treated by intraarticular injection of medications.Intra-articular hyaluronic acid (HA) injection reduces friction and stress on the joint cartilage through lubrication, chondro-protection and proteoglycans synthesis.Platelet Rich Plasma (PRP) with its high concentration of growth factors plays a great role in joint repair through enhancing osteo-inductivity, and chondrogenic differentiation.This study aims at comparing intra-articular injection of combination of hyaluronic acid and platelet rich plasma to intra-articular injection of each of them alone.Materials and Methods: 24 young adult male 250-300 grams albino rats were used in the current study divided randomly into 4 groups: Group 1 (control) in which animals were left without treatment.Group 2 which was subdivided into 3 study groups, in Group 2A: the animals received 2 doses of HA, in Group 2B: the animals received 2 doses of PRP, and in Group 2C: the animals received 2 doses of combined PRP and HA.After 28 days, the animals were sacrificed and histological analysis was performed.Synovial fluid Samples were extracted before each intraarticular injection, the concentration of vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2) were detected and statistically analyzed.Results: Group 2C showed superior findings to the other 2 study groups regarding fibrocartilage and bone regeneration, while Group 2B was superior to group 2A regarding the study parameters. Conclusion:Intra-articular injection of combination of PRP and HA is superior to intraarticular injection of HA or PRP alone for the treatment of TMJ osteoarthritis in rats.