The mechanism of joint destruction in osteoarthritis and rheumatoid arthritis.

风湿性关节炎（RA）是一种难以治愈的疾病。虽然类风湿性关节炎被认为是一种自身免疫性疾病，但其病因仍不清楚。因此，RA给医生带来了诊断和治疗上的困难。在这里，我们显示了强有力的证据表明，RA并不像以前认为的那样主要涉及滑膜，这可能会允许在未来开发针对该疾病的特异性治疗方法。关节损伤发展的第一个事件是滑膜细胞的增殖以及滑膜组织基质中的炎症和血管新生。随着疾病的进展，增生的滑膜组织在关节软骨上延伸，并从关节表面向下侵蚀并包括软骨下骨。最终，患者的小关节和大关节被破坏、变形和强直。

Rheumatoid arthritis (RA) is an enigmatic and incurable disease. Although RA is considered to be an autoimmune disease, its aetiology remains unknown. Therefore, RA presents both diagnostic and therapeutic difficulties to the physician. Here we show strong evidence that RA does not primarily involve the synovial membrane as previously believed, which may allow for the development of a specific treatment for the disease in the future.It is generally accepted that RA is a chronic inflammatory disease of synovium. The first events in the development of articular damage is the proliferation of synovial cells together with inflammation and vascular neoformation in stroma of synovial tissue. As the disease progresses, the proliferating synovial tissue extends over the articular cartilage and erodes from the joint surface down to and including the subchondral bone. Eventually, small and large joints of patients are destroyed, deformed and ankylosed.