Abstract
The right hind leg of each adult rabbit was plaster-immobilized for 2-8 weeks. 1 ml of 4% HRP was directly injected into the articular cavity of the knee joint. After 30 min, the articular cartilage of the distal end of the femur was taken out. The specimens were prefixed with aldehyde, cut into frozen sections, exposed to DAB, and then examined by light and transmission electron microscopy. In the non-treated group, the HRP activity was detected in the matrix throughout the cartilage, and also in chondrocytes in all the layers of the cartilage. In the plaster-immobilized groups, on the other hand, the degree of the HRP penetration was much reduced in depth. With 4 weeks or longer immobilization, the HRP penetration was almost restricted to the surface and the superficial layer of the cartilage. Specimens from the joint without the HRP injection showed no positive reaction. Thus, changes in permeability of the articular cartilage induced by the artificial joint contracture was clearly visualized by light and electron microscopy using HRP as a marker.
