Aim: to evaluate the potential effect of apitoxin versus hyaluronic acid in treatment of temporomandibular joint (TMJ) osteoarthritis (OA) in male albino rats through histological examination.

Materials & Methods: Twenty-four rats were separated into three groups (8 rats each): Group I (control group): TMJs with untreated induced arthritis. Group II: with induced TMJs arthritis that were subjected to 50µl intra-articular injection of hyaluronic acid (HA), once a week on days 7, 14, 21 and 28 for 4 weeks. Group III: with induced TMJs arthritis that were subjected to intra-articular injection of bee venom (Apitoxin) solution three times per week for four weeks with dose of 0.5 ml per injection. At the end of the experiment all rats were euthanized, TMJs samples were obtained from different groups. Sections of TMJs specimens were stained with hematoxylin and eosin stain for histopathological examination.

Results: Multiple degenerative histological features were revealed in group I untreated OA rats. In group II treated with intra-articular injection of HA, signs of improvement were observed retaining many of TMJ normal histological structure as thickness of fibrous, proliferative, hypertrophic layers with well organized chondrocytes. While group III treated with apitoxin showed increase in thickness of fibrous layer inspite of the significant retrieval of proliferative and hypertrophic layers of chondrocytes nearly to normal distribution with no empty lacunae.