FTY720-P enhances cytokine-induced GAG loss. Cartilage explants were treated as indicated for 8 days. Formalin fixed and paraffin embedded explants were then stained with safranin O. (A) untreated; (B) 3 μM FTY720-P; (C) 10 ng/ml IL-1β; (D) 10 ng/ml IL-1β and 3 μM FTY720-P; (E) 100 ng/ml TNF-α; (F) 100 ng/ml TNF-α and 3 μM FTY720-P. The figure shows representative pictures taken from one of 3 independent experiments. (G) GAG depletion was assessed by 1,9-dimethylene blue assay after treatment over 5 days with FTY720-P alone or (H) in the presence of 10 ng/ml IL-1β and 100 ng/ml TNF-α. Data are means ± SEM of 3 independent experiments. *P < 0.05, ** P < 0.01.