Superoxide dismutase activity is significantly lower in end-stage osteoarthritic cartilage than non-osteoarthritic cartilage.

Recent studies have shown that superoxide dismutase 1 (SOD1), SOD2, and SOD3 are significantly decreased in human osteoarthritic cartilage. SOD activity is a marker that can be used to comprehensively evaluate the enzymatic capacities of SOD1, SOD2, and SOD3; however, the trend of SOD activity in end-stage osteoarthritic tissues remains unknown. In the present study, we found that SOD activity in end-stage osteoarthritic synovium of the knee was significantly lower than that in control synovium without the influence of age. The SOD activity was significantly lower in the end-stage knee osteoarthritic cartilage than in the control, but a weak negative correlation was observed between aging and SOD activity. However, SOD activity in end-stage hip osteoarthritic cartilage was significantly lower than that in control cartilage without the influence of aging. The relationship between osteoarthritis and SOD activity was stronger than the relationship between aging and SOD activity. These results indicate that direct regulation of SOD activity in joint tissues may lead to suppression of osteoarthritis progression.