Fig. 4.

Histological findings in the femur and tibia, and OARSI scores. (A) Undamaged femoral condylar Safranin O staining was observed in Group A with loss of chondrocytes and proteoglycans. Group B showed a cartilage layer and some Safranin O staining. Group C showed erosion and thinning of the cartilage layer. No peeling of the transplanted cartilage sheet or uninitiated parts were observed in Group B. Safranin O staining of the normal tibia and loss of chondrocytes and proteoglycans were observed in Group A, as seen in the femur. Compared with the femur in Group B, although the cartilage layer remained, slight erosion was observed and this tissue did not stain with Safranin O in Group A. In Group C, erosion and thinning of the cartilage layer were observed (×20, scale bar = 50 μm). Immunostaining of the femur showed collagen type II staining in all intact cartilage, but collagen type I staining was observed only in the superficial regions of cartilage in normal, Group A, and Group B. Immunostaining of the tibia showed both collagen type I and collagen type II staining (×20, scale bar = 50 μm). (B) The OARSI score for the femur differed significantly between Groups B and C but not between Groups A and B, or Groups A and C (*p < 0.05, Group B vs C; p > 0.05, Group A vs B, and Group A vs C). The OARSI score for the tibia did not differ significantly between the three groups.