GSTM1 and sickle cell disease: Hemoglobin (HB) has been identified in chondrocytes and is closely associated with cell survival.<h4>Objective</h4>This study aims to investigate the role of HB in condylar cartilage degeneration during the early stage of TMJ OA and evaluate the potential protective effects of hydroxyurea (HU), a therapeutic agent used for sickle cell disease, suggesting its promise as a novel therapeutic strategy against OA.<h4>Methods</h4>The TMJ OA model was established in 6-week-old female rats using unilateral anterior crossbite (UAC).