Effect of oxygen tension, pH, and IL-1β on glyosaminoglycan (GAG) release from equine articular chondrocytes in the absence or presence of resveratrol or N-acetylcysteine. Equine articular chondrocytes were cultured in 3D alginate beads for 48 h in <1, 2, 5, or 21% O2 at pH 7.2 (A), pH 6.2 (B), pH 7.2 plus 10 ng/ml IL-1β (C) or pH 6.2 plus 10 ng/ml IL-1β (D) in the absence or presence of N-acetylcysteine (2 mM) or resveratrol (10 µM). GAG release was measured in media using the dimethylmethylene blue (DMMB) assay. Bar charts represent mean±SEM, n=3. *P<0.05 versus control (time=0, 5%O2, pH 7.2).