The Study Of Protection Of NOS Inhibitor L-NMMA In Articular Cartilage Inmuty

Background: Posttraumatic arthritis after joint injury occurs as a result of the disruption of the matrix components and chondrocyte death. Matrix components can be disrupted by mechanical(primary cartilage injury, residual joint incongruity, residual joint instability )and proteoglycan loss also has been shown to occur after cartilage injury. Until recently, new evidence shows that chondrocyte apoptosis can be stimulated to occur as a result of mechanical injury. Matrix disruption and chondrocyte apoptosis both contribute to the progression of the articular cartilage degeneration.Three classes of articular cartilage injury can be identified based on the type of tissue damageâ‘ cartilage matrix and cell injuries; damage to the joint surface that does not cause visible mechanical disruption of the articular surface; â‘¡chondral fissure,flap tears,or chondral defects; that is,visible mechanical disruption of articular cartilage limited to articular cartilage; â‘¢ osteochondral injuries; that is,visible mechanical disruption of articular cartilage and bone. Especially the matrix, cell and chondral injuries are difficult to diagnosis and treatment in the early phase of posttraumatic osteoarthritis.Nitric Oxide(NO) is a free radical synthesized from L-arginine by NO synthases(NOS).NO plays vital roles in biological responses, including regulation of vascular tone, neurotransmis -sion,anti-viral defense and immune response. The excessive production of nitrc oxide inhibits matrix synthesis, promotes its degradation, inhibits chondrocytes proliferation,adherence, induce chondrocytes apoptosis, promotes chondrocytes necrosis,interfere the message transmission, accelerate matrix collapse. Finally, lead to the articular cartilage...