Fig. 5

Hematoxylin eosin (5A, 5B) and alcian blue staining (5C) of articular cartilage samples. The cartilage shows a normal appearance, the surface is smooth, chondrocytes are present throughout, and the matrix staining is homogeneous in the control knee (5A). The superficial and intermediate layers of cartilage are lost, and matrix vertical fissures reach the deep radial zone in this sample corresponding to an ulcer at the weight bearing area from an OA knee in animals subjected to meniscal root injury and partial meniscectomy (5 B, C). Cellularity is diminished and the normal pattern of distribution in columns is lost. Cartilage matrix is loss with delamination and excavation of superficial and mid layer (5B, C). Marked structural abnormalities and hypocellularity are also evident. Matrix staining intensity is severely reduced (× 20)