Ostoarthritis is characterized by chronic degradation of articular cartilage in the afflicted joints. Histochemical and biochemical findings suggest that increased levels of lysosomal enzymes are associated with the breakdown of sulfated proteoglycans, the principal extracellular constituents lost during the early stages of the disease. Arylsulfatases A and B, in particular, have been shown to be elevated in the articular cartilage derived from individuals with osteoarthritis. Studies conducted in tissue culture have indicated that vitamin C simultaneously inhibited arylsulfatase activities and stabilized newly synthesized sulfated proteoglycans in the cell layer of human chondrocytes derived from both normal and osteoarthritic articular cartilage. If ascorbic acid could act similarly in vivo, then it might be possible to use this natural compound therapeutically in early stages of degenerative joint disease. Guinea pigs, like man, cannot synthesize Vitamin C endogenously. To test the effect of vitamin C on the development of osteoarthritis, a surgical lesion will be created in the right knee joints of animals maintained on various levels of dietary vitamin C. The development of osteoarthritis in the operated knees will be monitored by sacrificing animals at various time intervals and examining the articular cartilage for gross and microscopic changes. In addition, the cartilage will be analyzed for arylsulfatase activities and proteoglycan content. The pathological changes in knees of animals on highly enriched and minimal vitamin C diets will be compared with a view to discerning at what level ascorbic acid may be of benefit in the treatment of osteoarthritis.
