HNE-binding to Coll II induces changes in chondrocytes morphology, viability and phenotype. Twenty-four-well plates were coated with 0.1 mg/ml human Col II and treated after with HNE at different molar ratios (1:20 to 1:200; Col II:HNE). After several washes, human OA chondrocytes were seeded at 2 × 105 cells/cm2 and incubated up to 48 h. Cell morphology of cultured chondrocytes in untreated Col II (a), HNE-treated Col II at a 1:20 MR (b), and HNE-treated Col II at a 1:200 MR (c) was observed by phase contrast microscopy after hematoxylin and eosin staining (mag. 20 to 40×). (d) Cell viability and caspase-3 activity were determined with MTT assay and commercial kit respectively. (e) Col II protein expression was analyzed in cellular extract by Western blot. ANOVA tests and Bonferroni's multiple comparison were performed to compare each condition. The data are means ± SEM of n = 5. * P < 0.05; **, P < 0.01.