Fig. 2.

Normal and OCD chondrogenic pellets produced the larger amount of safranin O-stained proteoglycans compared with SONK pellets (a–c, red). Lipid vacuoles were observed in normal and OCD chondrocytes after adipogenic induction (a and b, red). Calcium depositions were induced by osteogenic treatments in normal cartilage- and OCD-derived cells (a and b, brown). On the other hand, neither adipogenesis nor osteogenesis was induced in SONK-derived cells (c). The Bern pellet histology score was higher in normal and OCD pellets than in SONK pellets (d). Staining density of oil red O and von Kossa was lower in SONK-derived cells than in normal and OCD chondrocytes after the treatment of adipogenic and osteogenic induction (e and f). Bars, 100 μm. *p < 0.05