Fig. 3. Effects of passage number on cartilage markers in isolated rabbit chondrocytes. Study of passage number effects on biofunctional behaviour of isolated healthy or diseased chondrocytes to optimize scaffold seeding before animal experiments. (A) Collagen I, II and heparan sulfate (Col I, Col II and HS, respectively) expression and localization in isolated rabbit chondrocytes. (B) Collagen I, II and heparan sulfate expression and localization in rabbit chondrocytes after 2 passages. (C) Collagen I, II and heparan sulfate expression and localization in rabbit chondrocytes after 5 passages. (D) Quantification of percentage of fluorescent area from immunofluorescence images obtained for collagen I, II, and heparan sulfate (n = 4 per passage); data are represented as mean ± SEM. Significant differences between the groups: ***p < 0.001. (E) Collagen I and II expression in PGA scaffolds seeded with rabbit chondrocytes at passage 2. All images were obtained via epifluorescence microscopy (20× magnification).