Chondrocyte morphology analysis and actin cytoskeleton. Chondrocytes were incubated as described in Legend 1 and cell morphology was analyzed by fluorescence microscopy using a phalloidin staining and ImageJ analysis. For each condition, the area (a), the Feret's diameter (b), the perimeter (c) and the circularity index (d) of more than 200 cells was measured. Cell cytoskeleton was observed by phalloidin in cultured chondrocytes in untreated Col II (e), HNE-treated Col II at a 1:20 MR (f), and HNE-treated Col II at a 1:200 MR (g). Scale bar, 20 μm. ANOVA tests and Bonferroni's multiple comparison were performed to compare each condition. The data are means ± SEM of n = 4. ** P < 0.01; *** P < 0.001.