IL-1β Suppresses the Formation of Osteoclasts by Increasing OPG Production via an Autocrine Mechanism Involving Celecoxib-Related Prostaglandins in Chondrocytes

Figure 5

Effect of conditioned medium from IL-1β-treated and -untreated chondrocytes on the formation of osteoclast-like cells. Cells were cultured in DMEM containing 10% FBS with or without 100 U/mL IL-1β for 7 or 28 days. The culture medium was changed to DMEM containing 2% FBS without IL-1β, and the cells were cultured for 24 h. The culture medium was collected and diluted with an equal volume of DMEM containing 2% FBS, supplemented with 50 ng/mL soluble RANKL, and then used as conditioned medium. RAW264.7 cells, an osteoclast precursor, were cultured in conditioned media from IL-1β-treated and -untreated (control) chondrocytes for up to 7 days, and then stained using a TRAP and alkaline phosphatase double-staining kit.