Stress deprivation enhances manganese superoxide dismutase expression in the rat patellar tendon

Manganese superoxide dismutase (Mn-SOD) is a key antioxidant enzyme that prevents reactive oxygen species (ROS) damage to biological tissues. Although Mn-SOD has been investigated for a variety of cells, little is known about its expression in the tendon, particularly in the stress-deprived condition. The present study demonstrated that Mn-SOD is excessively expressed in the cultured fibroblasts derived from the stress-deprived patellar tendon in the rat using subtractive hybridization analysis. In addition, we confirmed that the expression of Mn-SOD is up-regulated in the stress-deprived patellar tendon in vivo at both the mRNA and protein levels. These results suggest that Mn-SOD may play a role in regulating ROS and matrix degradation involving mechanical deterioration of the stress-deprived tendon tissue.