Ibuprofen (Advil) is a propionic acid derivate and nonsteroidal anti-inflammatory drug (NSAID) with anti-inflammatory, analgesic, and antipyretic effects. Ibuprofen inhibits the activity of cyclo-oxygenase I and II, resulting in a decreased formation of precursors of prostaglandins and thromboxanes.

In the adult female Sprague-Dawley rat model induced by the HRHF method, Ibuprofen treats arthritis and early cartilage degeneration by inhibiting serum C1 and 2C as well as collagen degradation and synthesis.

Within cells, Ibuprofen inhibits the cyclooxygenases COX-1 and COX-2, and the conversion of arachidonic acid into prostaglandin H2 (PGH2). In prostate tumor cells, Ibuprofen can suppress the activation of NF-κB and IKKα.

Radiochemical enzyme assays for COX-1 and COX-2: 10 μL of purified COX-1 (0.7-0.8 μg) or COX-2 (3.0 units, 0.3μg) is activated with 50 μL of cofactor solution [l-epinephrine (1.3 mg/mL), reduced glutathione (0.3 mg/mL), and hematin (1.3 mg/mL) in oxygen-free Tris-HCl buffer (pH 8.0)]. The enzyme solution (60 μL) is added to Ibuprofen solutions or DMSO (20 μL) after [14C]arachidonic acid is added in 0.2 mL eight-strip test tubes and preincubated 10 minutes on ice. Samples are incubated for 15 minutes at 37 °C, after which the reaction is terminated by addition of 10 μL of 2 M HCl and 5 μL of carrier solution (PGE2 and PGF2α, 0.2 μg/mL of each in EtOH). The unmetabolized arachidonic acid is separated from the prostaglandin products by column chromatography and eluted with n-hexane-dioxane-glacial acetic acid (70:30:1). The prostaglandin products are then eluted with EtOAc-MeOH (85:15), and the samples are counted in a Packard scintillation spectrometer. IC50 values are obtained by linear regression analysis.

Each cell line is incubated with Ibuprofen of various concentrations for 48 hours. Cell survival is estimated by the MTT assay, and cell death is determined by Hoechst staining used to distinguish between intact cell nuclei and fragmented nuclei undergoing cell death. Cells are lysed and analyzed by western blotting for detection of the p75NTR protein.(Only for Reference)