Type II collagen-induced arthritis. A morphologic and biochemical study of articular cartilage

Articular cartilage was obtained from type II collagen-induced arthritic rat joints. Transmission electron microscopy showed a gradual degeneration of chondrocytes, disorganization of the collagenous extracellular matrix, and formation of microscars. Biochemical analyses indicated that type II collagen was the only collagen present and that it was normal in regard to hydroxylation of lysine and glycosylation of hydroxylysine. Analyses of the proteoglycan in the extracellular matrix revealed a 50% loss of chondroitin sulfate and keratan sulfate.