Reactive oxygen species (ROS) play an important role in chondrocyte catabolic activity leading to cell death and matrixcomponents breakdown.Intra-articularcorticosteroid injections such as hydrocortisone sodium succinate have been used to control pain and inflammation associated with arthritis and new treatment of arthritis, platelet-rich plasma. Compare the biological and traditional treatment of arthritis in stallion and its effect on fertility. In the present study twelve horses were grouped into three groups according to type of treatment of arthritis used in the study. First group (n=3) with signs of arthritis and treated with intra-articular injection of hydrocortisone sodium succinate 100 mg, 2nd group (n=6) with signs of arthritis and treated with platelets rich plasma (PRP) injection, 3rd group (n=3)as control group without arthritis and injected with saline.Synovial fluid samples were collected after treatment, to estimate some oxidants (lipid peroxide,malondialdehyde (MDA) and antioxidant parameters glutathione reduced (GRH), Catalase (CAT) and glutathione peroxidase(GPX).The hydrocortisone sodium succinate showed mild decrease in MDA level with significant increase in CAT, GR and GPX. Intra-articular PRP showed a significant decrease in MDA level with significant increase in antioxidant activity (CAT, GR and GPX)