Increase in the activity of lysosomal acid hydrolases in the chondrocytes of arthritic joints of rabbits with experimental allergic arthritis.

Undecalcified cryostat sections of the cartilage-covered ends of the femurs have been prepared from the control and inflamed knees of rabbits with experimental allergic arthritis. The activities of two lysosomal hydrolases, naphthylamidase and beta-glucuronidase, were assayed in the chondrocytes of the articular cartilage in such sections by scanning and integrating microdensitometry. The activities of both enzymes were found to increase significantly in the chondrocytes of the inflamed joints.