Expression and regulation of peroxiredoxin 5 in human osteoarthritis

Reactive oxygen species (ROS) are implicated in the pathogenesis of osteoarthritis (OA). However, little is known about the antioxidant defence system in articular cartilage. We investigated the expression and regulation of peroxiredoxin 5 (PRDX5), a newly discovered thioredoxin peroxidase, in human normal and osteoarthritic cartilage. Our results show that human cartilage constitutively expresses PRDX5. Moreover, the expression is up-regulated in OA. Inflammatory cytokines tumour necrosis factor alpha and interleukin 1 beta contribute to this up-regulation by increasing intracellular ROS production. The present study suggests that PRDX5 may play a protective role against oxidative stress in human cartilage.