Quantitative criteria for evaluating the early development of osteoarthritis and the effect of diclofenac sodium.

In assessing the possible efficacy of drugs for the treatment of osteoarthritis (OA), it may be helpful to have a model, in animals, of the early development of the disease prior to the expression of secondary phenomena. It is also necessary that such effects are quantifiable. To this end, the natural development of OA in the STR/ORT mouse has been investigated. It has been shown that very early events in the development of the disease are disturbances in the activity of chondrocytic glucose 6-phosphate dehydrogenase, the initial step in the pentose-phosphate pathway, and in the orientation of the proteoglycans of the matrix of the articular cartilage. The study has been done by reference to the effect of diclofenac sodium, which previously has been reported to retard the destruction of articular cartilage. The results appear to indicate that these markers may provide quantitative measures for assessing potential therapeutic agents.