Pearson W, Orth MW, Karrow NA, Lindinger MI. Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada. AJVR 2008 Dec 69 12 1560-8 Objective-To test the hypothesis that simulated digests of Biota orientalis (BO) and a dietary nutraceutical (DN; composed of mussel, shark cartilage, abalone, and BO seed lipid extract) inhibit prostaglandin E(2) (PGE(2)), nitric oxide (NO), and glycosaminoglycan (GAG) production in interleukin (IL)-1-stimulated cartilage explants. Sample Population-Cartilage tissue from 12 pigs. Procedures-Articular cartilage explants were conditioned with a simulated digest of BO (BO(sim)) or DN (DN(sim)) at concentrations of 0, 0.06, or 0.18 mg/mL or indomethacin (INDO(sim); 0 or 0.02 mg/mL) for 72 hours. Control explants received digest vehicle only. Explants were or were not stimulated with recombinant human-IL-1beta (10 or 0 ng/mL) during the final 48 hours of culture. Concentrations of PGE(2), GAG, and NO in media samples (mPGE(2),mGAG, and mNO concentrations, respectively) were analyzed, and explant tissue was stained fluorochromatically to determine chondrocyte viability. Treatment effects during the final 48-hour culture period were analyzed. Results-IL-1 increased mPGE(2), mGAG, and mNO concentrations in control explants without adversely affecting cell viability. Treatment with INDO(sim) blocked PGE(2) production and increased mNO concentration in IL-1-stimulated and unstimulated explants and increased mGAG concentration in unstimulated explants. Treatment with DN(sim) (0.06 and 0.18 mg/mL) reduced mPGE(2) concentration in IL-1-stimulated and unstimulated explants, reduced mNO concentration in IL-1-stimulated explants, and increased mNO concentration in unstimulated explants. Treatment with 0.18 mg of DN(sim)/mL increased cell viability in the presence of IL-1. In IL-1-stimulated explants, BO(sim) (0.06 and 0.18 mg/mL) reduced mPGE(2) concentration, but 0.18 mg of BO(sim)/mL increased cell viability. Conclusions and Clinical Relevance-Effects of IL-1 on cartilage explants in vitro were modulated by DN(sim) and BO(sim).