Thermal burn injury induced myeloperoxidase changes in murine obesity model

Abstract

Inflammatory response due to thermal burn injury was assessed in murine obesity model. Multimodal non invasive imaging of the myeloperoxidase activity was determined for the purpose. Myeloperoxidase (MPO), an inflammatory heme protein is present in myeloid cells‐ neutrophils, microglia, and macrophages, and utilizes hydrogen peroxide to generate reactive oxygen species. We earlier demonstrated using multimodal fluorescence imaging, infiltration of the peritoneal macrophages at the site of burn injury. Here, we determined the changes in MPO activity as a response to burn injury using C57BL/6NTac mice placed under high fat or regular diet. The in vivo MPO activity was detected by whole body luminescence imaging 15 minutes after i.p injection of luminol. luminol a redox‐sensitive compound emits blue luminescence upon exposure to oxidizing agents, and established to have unique specificity to MPO in vivo. We show significant increase in MPO activity as a result of neutrophil activation at the burn injury. Robust activation, deduced from the MPO activity, was observed in the lymph nodes of the murine model that went through the high‐fat diet regime. These real‐time monitoring methodologies of MPO activity detection by in vivo imaging will greatly enhance the understanding of the early phase of immune response to a burn injury and aid in development of better treatments.