15ΔPGJ2 (15-deoxy-12,14-prostaglandin J2,) represses IL-6 (interleukin-6) and IL-8 (interleukin-8) induced by IL-1α (interleukin-1 alpha). A) Human chondrocytes were treated, in the absence of serum, with 3 μM 15ΔPGJ2 for two hours before being incubated with 100 U/ml IL-1α for 24 hours in the presence of 15ΔPGJ2. A) Immunoblot analysis using IL-6 and IL-8 polyclonal antibodies were performed on conditioned media; B) Quantitation of the inhibition by 15ΔPGJ2 of the IL-6 and IL-8 synthesis was obtained by the densitometric analysis of four Western blots of four independent experiments performed in three different primary cultures. To show the repression by 15ΔPGJ2 the % value referred to the value in IL-1α induced cells (100%) is calculated. Average ± standard deviation is shown. 15ΔPGJ2, 15-deoxy-Δ12,14-prostaglandin J2,; COX-2, cyclooxygenase-2; DGDG, digalactosyldiacylglycerol; IL-1, interleukin-1; IL-6, interleukin-6; IL-8, interleukin-8; MGDG, monogalactosyldiacylglycerol; mPGES, microsomal PGE synthase; NF-kB, nuclear factor-kappaB; P1, cell passage number1; p38, p38 mitogen activated protein kinase; PGE2, prostaglandin E2; TNFα, tumor necrosis factor alpha.