Free radical-induced oxidative stress has been implicated in the pathogenesis of various diseases, including oral diseases such as periodontitis and temporomandibular joint disease. We measured the ESR spectrum or 3D ESR images of the phantom, including 3-carbamoyl-2, 2, 5, 5-tetramethyl-pyrrolidine-1-yloxy (carbamoyl-PROXYL) as nitroxyl spin probe. The limitation of concentration obtained from the ESR spectrum or 3-dimensional ESR images of phantom was estimated at 0.25 mM. We demonstrated slice patterns of ESR-CT images (sagittal section) of 3-methoxycarbonyl-2, 2, 5, 5-tetramethylpyrrolidine-1-oxyl (MC-PROXYL) and carbamoyl-PROXYL in the head region of mice using the in vivo ESR imaging system. By comparison with ESR-CT images of MC-PROXYL, we confirmed the distribution of carbamoylPROXYL in the maxillofacial region of living mice. In vivo ESR imaging could be a powerful technique for non-invasive assessment of the free radical-induced oxidative stress in oral diseases of small animal models.
