In Vivo Electron Paramagnetic Resonance Detects Oxidative Stress in Skeletal Muscle After Burn Trauma

Electron paramagnetic resonance (EPR) is a magnetic resonance-based technique that detects species with unpaired electrons such as free radicals (organic or inorganic) and transition metal ions. The development of low frequency (1200 MHz and below) EPR spectrometers has led to the in vivo application of the technique in a variety of animal models. Often, EPR may also be complementary to nuclear magnetic resonance (NMR). For assessing oxidative damage after burn trauma, in vivo EPR using nitroxides is complementary to NMR since NMR cannot measure redox status and reactive oxygen species (ROS), while EPR can. Here, for the first time, we report tissue partial pressure of oxygen (pO2), redox status and ROS measurement by in vivo EPR in intact proximal skeletal muscle tissue following burn trauma in mice. The potential significance of our findings includes the in vivo non-invasive nature of the EPR measurements, which can serve to follow tissue pathology and to monitor the effectiveness of antioxidant agents in order to alleviate the symptoms of severe burn trauma. The development and application of in vivo EPR oximetry in the clinical management of burn injury alongside NMR might also prove to be very useful.