Different types of ROS-scavenging enzymes are expressed during cutaneous wound repair

Injury to the skin initiates a series of events including inflammation, new tissue formation, and matrix remodeling. During the early inflammatory phase, polymorphonuclear leukocytes and macrophages infiltrate the wounded tissue. Once activated, they produce large amounts of reactive oxygen species (ROS) as part of their defense mechanism. Although this process is beneficial, increased levels of ROS can inhibit cell migration and proliferation and can even cause severe tissue damage. Therefore, cells must develop strategies for the detoxification of these molecules. To gain insight into the mechanisms which underlie this process, we analyzed the temporal and spatial expression pattern of various ROS-scavenging enzymes during the healing process of full-thickness excisional wounds in mice. Here we demonstrate a strong mRNA expression of two types of superoxide dismutase (SOD), as well as of catalase, and the selenoenzymes glutathione peroxidase (SeGPx) and phospholipid hydroperoxide glutathione peroxidase in normal and wounded skin. Most importantly, mRNA levels of the SODs and of SeGPx increased strongly after skin injury. In situ hybridization and immunofluorescence studies revealed the presence of these transcripts at multiple places in the wound, whereby particularly high expression levels were detected in the hyperproliferative epithelium and the hair follicles at the wound edge. These data suggest an important role of ROS-scavenging enzymes in the detoxification of ROS during cutaneous wound repair.