Oxidative stress, senescence and mediterranean diet effects on osteoarthritis

Osteoarthritis is a joint disorder characterized by a progressive degradation of joint cartilage. Cartilage is a connective tissue consisting of a extracellular matrix (ECM) of collagen fibres and elastic fibres embedded in a rubber-like substance. The ECM is produced by chondrocytes, which remain embedded in the same matrix they produced. Cartilage degeneration is a consequence of chondrocyte hypertrophy, characterized by wrong synthesis of ECM and by high expression of proteolytic enzymes. The ECM is made up of type II collagen (COL2), negatively charged proteoglycans, water and some other minor components including some glycoproteins and non-collagenous proteins. Osteoarthritis can be induced by several cause, among them mechanical joint injury, ageing and diet and metabolism. Foods contain anti-oxidant and pro-oxidant compounds, which affect cell signalling by stimulating inflammation and senescence of articular cells. In this chapter, we describe the effects of pro-oxidant agents on chondrocyte senescence and in turn on osteoarthritis onset.