Figure 3
The toluidine blue stained histological sections of (a) normal cartilage, (b) the grade 1 cartilage, (c) the grade 2 cartilage, and (d) the grade 3 cartilage. Matrix staining was homogeneously colored by toluidine blue in (a). The reduction in staining was found in (b-d). The long arrows indicate the superficial zone of articular cartilage. The short arrows show the interface between the bone and the cartilage.