Antioxidant enzyme peroxiredoxin 5 is upregulated in degenerative human tendon

Peroxiredoxin 5 (PRDX5) is a novel thioredoxin peroxidase recently identifi ed in a variety of human cells and tissues, which is considered to play an important role in oxidative stress protection mechanisms. However, little i s known about its expression in tendon degeneration, a common and disabling condition that primarily affects older people, in which oxidative stress m ay be implicated. The present study demonstrated that normal human tendon e xpresses PRDX5 and its expression is significantly increased in degenerativ e tendon. In addition, we have localized PRDX5 to fibroblasts in normal ten don and to both fibroblasts and endothelial cells in degenerate tendon. The differential expression of PRDX5 in normal and degenerate tendon shows tha t a thioredoxin peroxidase with antioxidant properties is upregulated under pathophysiological conditions and suggests that oxidative stress may be in volved in the pathogenesis of tendon degeneration. PRDX5 may play a protect ive role against oxidative stress during this pathophysiological process. ( C) 2001 Academic Press.