Figure 5.

Insulin growth factor (IGF) stimulates local replenishment of cartilage. Articular cartilage explants were cultured with either oncostatin M plus tumour necrosis factor (OSM + TNF) or vehicle for 7, 11, and 17 days. Subsequently, cartilage explants were paraffin-embedded and stained for aggrecan content as described in Materials and methods. Aggrecan is completely depleted from the tissue at 7, 11, and 17 days. Other cultures were treated with either OSM + TNF or vehicle for 7, 11, and 17 days followed by stimulation with either IGF or vehicle control for 14 days. Subsequently, cartilage explants were paraffin-embedded and stained for aggrecan content as described in Materials and methods. As a control experiment, articular cartilage explants were cultured for 21 days with vehicle, OSM + TNF, IGF, or metabolically inactive (MI) control for 21 days as controls (lower panel). W/O, without stimulation.