Inhibition of adjuvant arthritis in the rat by an oxonate diet: sequential studies

To study the mechanism by which oxonate-induced hyperuricemia inhibits the development of adjuvant arthritis in the rat, we initiated blocking or releasing experiments by changing the oxonate diet of rats at selected times. We were able to define oxonate dietary effects on four specific periods in the development of this experimental arthritis. The inhibition of the primary inflammation at the site of the injection was weak. The inhibition of the secondary reaction was greater than the decrease of the primary inflammation and was more effective when the first two periods (sensitization to antigen and production of immunocompetent cells) were blocked. The reduction in the disease was more marked in the non-injected paw than in the injected paw. Thus, the effect of the oxonate diet is more immunosuppressive than anti-inflammatory. Release of the first period, which provoked an unexpected increase in the severity of the disease, suggests a possible influence of oxonate on pyrimidine metabolism.