Staphylococcal arthritis--effects of superoxide dismutase on infected knee joints of rabbits.

The effect of SOD on staphylococcal arthritis has not been successfully evaluated to date. We developed an animal model to investigate the correlation. Using 16 rabbits divided into four groups, we injected two groups with staphylococcus aureus and the other two with NaCl. One group in each was also injected with SOD. The presence of SOD activity in untreated and infected knee joints of rabbits over a period of 72 hours showed no significant difference. TBA-reactive substances (TBARS) measured in joint fluid and plasma did differ in each of the groups, with the highest values found in animals with septic arthritis treated with SOD. This finding corresponded especially with the histological investigation. Joints of infected animals intra-articularly injected with SOD also showed histologically significantly more inflammation, a higher amount of bacteria in the joint cavity, and more distinct joint damage than joints injected only with bacteria. The mechanisms responsible for this SOD effect remain to be determined.