Figure 3

S1P stimulation induces PGE₂ production from HAC. A): OA chondrocytes were stimulated in vitro with S1P (10 μM) with or without meloxicam (Mel; 1 μM) for 24 h, and levels of PGE₂ in the culture supernatants were subjected to ELISA in triplicate (N = 3 each). B) Expressions of COX-2 were analyzed with western blot (representative results are shown). The intensities of bands detected with COX-2 analysis were calculated according to their relative ratio against GAPDH (N = 5).