[en] Purpose: Osteoarthritis (OA) is an important cause of pain and disability in the ageing population. Angiogenesis and inflammation are closely integrated process in OA and may contribute to its pathogenesis, as well as, affect disease progression and pain. Chondroitin sulfate (CS) is a symptomatic slow acting drug for OA and there is strong evidence suggesting that CS may also be a structure disease modifying osteoarthritis drug. The mechanisms underlying these effects remain poorly understood. This work aimed to demonstrate the relation between inflammation and angiogenesis of synovium and to study the effect of CS on synovium angiogenesis.