Mechanisms of bone and cartilage destruction in rheumatoid arthritis: lessons from the streptococcal cell wall arthritis model in LEW/N rats.

Rheumatoid arthritis is a proliferative and erosive disease which has been described as tumor-like. Streptococcal cell wall-induced arthritis in the LEW/N rat is also tumor-like and closely simulates the features of joint destruction that develop in rheumatoid arthritis. This article discusses the mechanisms of bone and cartilage destruction in streptococcal cell wall arthritis with particular emphasis on the tumor-like behavior of synovial connective tissue cells and the role of cytokines, such as platelet-derived growth factor, transforming growth factor beta and interleukin 1, in regulating this abnormal behavior.