The suppressive effect of gelatin-conjugated superoxide dismutase on disease development and severity of collagen-induced arthritis in mice.

We studied the effect of superoxide dismutase (SOD) on murine collagen-induced arthritis (CIA), an animal model of human rheumatoid arthritis (RA). Among SOD derivatives studied, only gelatin-SOD conjugate which has prolonged half life in vivo was effective to suppress the development of CIA, while native SOD or gelatin carrier alone was ineffective. Interestingly, pyran polymer-conjugated SOD which also has a long half life showed no suppressive effect on the disease. No significant effect on immune response against type II collagen (CII) was found in any of the experimental groups. In addition, induction of suppressor cells was not detected in spleen or lymph node cells of the gelatin-SOD-treated group. Therefore, these results suggest that oxygen radicals may have an important role in the effector phase of the immune response to manifest this chronic autoimmune polyarthritis. Thus, the use of appropriate antioxidants for the treatment of human RA may be rationalized.