In vivo imaging of redox state in mice using EPRI/MRI coimaging

Electron paramagnetic resonance imaging (EPRI) using nitroxide spin probes is a sensitive technique for in vivo measurement of redox state. 1D and 2D EPR imaging has been previously used to map and monitor the change in redox status of various organs in animal models. However, 3D EPR imaging of the change in redox status in vivo with anatomic registration is essential to understand organ specific pathology and disease. In the present work, the nitroxide 3-carbamoyl-2,2,5,5-tetramethyl-1pyrrolidinyl-N-oxyl (3CP) was used to map and monitor the redox state of various organs in living mice using the new EPR/NMR coimaging instrumentation [1]. With rapid scan projection acquisition, we performed 3D mapping of 3CP in living mice every 8 minutes. The NMR coimaging allowed precise slice by slice measurement of the radical reduction and mapping of this metabolism in major organs such as the heart, lungs, liver, bladder and kidneys.