Osteoarthritis (OA), the prevalent type of arthritis, arises from mechanical wear and inflammatory processes. Platelet-rich plasma (PRP), a derivative of blood enriched with activated platelets, offers a rich mixture of growth factors essential for the repair of cartilage. Twelve rabbits were classified into control negative, OA and treated groups. Induction of arthritis was done by Monoiodoacetate (MIA). Treatment is done with PRP. X-ray, histological study, immunohistochemical investigation, and biochemical measuring were done to investigate arthritis of femorotibial joints and its treatment with PRP. MIA-induced OA is characterized by affection on cartilage with fragmentation, apoptosis of chondrocytes, and loss of matrix. Synovitis is characterized by hyperplasia of lining cells, congestion, extravasation and leucocytic infiltration with increased ESR, CRP and IL-6. The PRP-treated group appeared to preserve the typical structure of both cartilage and synovium. in conclusion We confirm the impact of PRP in the treatment of OA by several scores, Mankin and Krestinsin scores. These scores indicate that PRP may be an efficient method for OA treatment.