Effect of osmium tetroxide and 198Au in normal and arthritic rabbit knee joints.

Antigen-induced arthritis (AIA) was induced in adult rabbit knee joints, using ovalbumin as antigen. After 4 weeks, intra-articular injections of 0.3 ml 1% osmium tetroxide or 100 muCi 198Au were given. The same injections were also given to normal animals. The animals were observed for up to 12 weeks. In the normal animals, no affection of articular cartilage could be seen by light microscopy. In the arthritic animals, however, severe destruction of articular cartilage was seen. The degree of destruction in the osmium tetroxide-treated animals was similar to or even worse than that of the controls, whereas the 198Au-treated animals showed a lesser degree of destruction than both controls and osmium tetroxide-treated animals. Autoradiograms, using 3H-thymidine, showed affection articular cartilage in all groups, i.e. both normal and arthritic.