INFLUENCE OF MOUSE PERITONEAL-MACROPHAGES ON CARTILAGE MATRIX AND INTEGRINS IN-VITRO

The problem of cartilage breakdown in rheumatoid arthritis can partial ly be studied using in vitro techniques. Among the numerous models, or ganoid (high density) cultures have proved to be quite suited for thes e purposes. Chondroblasts/chondrocytes, obtained by cultivating precar tilage cells of limb buds from day-12 mouse embryos, were cocultivated with mouse peritoneal macrophages in high-density or monolayer cultur es. The result was an extensive breakdown of the cartilage matrix. Num erous chondrocytes detached from the matrix and became fibroblast-like cells. Immunomorphological methods showed that collagen type II, fibr onectin and several integrins (beta 1-, alpha 3-, and alpha 5 beta 1 t ypes) disappeared from the surface of chondrocytes. These pathological findings in cartilage tissue could be due to degradative products of macrophages and also chondrocytes. The in vitro model introduced here should be useful for studying matrix components and the turnover of ma trix receptors of cartilage tissue in vivo under pathological conditio ns.