Histone deacetylase inhibitors block cartilage glycosaminoglycan and collagen loss induced by IL-1α/OSM. Bovine nasal cartilage discs were cultured in the presence or absence of I/O (a combination of IL-1α and oncostatin M (OSM)) and a histone deacetylase inhibitor, either (a) I/O (1 ng/ml IL-1α, 10 ng/ml OSM) with trichostatin A (TSA) or (b) I/O (0.2 ng/ml IL-1α, 2 ng/ml OSM) with sodium butyrate (NaBy). Cartilage was incubated until day 7 and supernates were harvested and replaced with fresh reagents until day 14. Glycosaminoglycan (GAG) release is shown as at day 7 and was assayed using the dimethylmethylene blue method. Collagen release is shown as at day 14 and was measured using an assay for hydroxyproline. Viability was assessed by measuring lactate dehydrogenase in the conditioned medium. Assays were performed at least twice using quadruplicate samples; means ± standard deviations are represented. *P < 0.05, **P < 0.01, ***P < 0.001.