NF-κB-p65 localization and TNF-β expression in human chondrocytes after treatment with IL-1β and/or specific antisense oligonucleotides against NF-κB or with curcumin. (1) Serum-starved primary human chondrocytes were either left untreated (medium) or treated for 1 hour with 10 ng/ml interleukin 1β (IL-1β), or (2) cells were pretreated with 10 ng/ml IL-1β for 1 hour followed by cotreatment with 5 μM curcumin (Cur) for 4 hours, transfected with 0.5 μM sense oligonucleotide (SO) control or antisense oligonucleotide (ASO) against NF-κB in the presence of 10 μl/ml Lipofectin transfection reagent for 24 hours. For immunolabeling, cells were incubated with primary antibodies against nuclear factor κB (NF-κB)-p65 (A) or tumor necrosis factor β (TNF-β) (B), followed by incubation with rhodamine-coupled secondary antibodies and counterstaining with 4′,6-diamidino-2-phenylindole to visualize cell nuclei. Images shown are representative of three different experiments. Original magnification, ×400; bar, 30 nm.