0631 Application of in vivo ESR Imaging to Measure Oxidative Stress in Oral Region of Mouse
H. SHOJI, F. YOSHINO, Y. OMORI, and M.-I. LEE, Kanagawa Dental College, Yokosuka, Japan

Objectives: Free radicals have been implicated in the pathogenesis of oral diseases. Regarding as inflammatory oral diseases, free radical-induced oxidative stress could be involved in tissue damage during pathophysiological processes such as periodontitis and tempomandibular joint disease. In the present study, we applied in vivo ESR imaging to measure oxidative stress in oral region of mouse. Methods: Our laboratories have been developed in vivo L-band ESR imaging system in oral region of small animal models. Blood-brain-barrier (BBB) impermeable 3-carbamoyl-2,2,5,5- tetramethyl-pyrrolidine-1-yloxy (carbamoyl-PROXYL) and BBB permeable 3-methoxy carbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-yloxy (MC-PROXYL) were used as nitroxyl spin probe. ICR mice were anesthetized with pentobarbital. After the injection of nitroxyl spin probe via tail vein, the head region of mouse was inserted automatically to resonator the in vivo ESR apparatus. Instrument settings for ESR detection of nitroxyl spin probe were as follows: microwave power, 1 mW; magnetic field, 31.0-34.0 1.2 mT; field modulation width, 0.1 mT; receiver gain, 63-100; time constant, 0.03 sec; field gradient, 1.0 mT/cm. Results: We demonstrated all slice patterns of ESR-CT images in head region of mice. Finally, we succeed to obtain the reconstruction of 3D images of the distribution of carbamoyl-PROXYL in head region non-invasively. Using comparison with ESR-CT images of MC-PROXYL, we confirmed that carbamoyl-PROXYL well distributed in the oral region. Conclusions: These results indicate that high-quality images could be estimate the distribution of radical spin probe in oral region non-invasively. Quantitative ESR imaging analysis by using carbamoyl-PROXYL will be useful for clarifying the reducing status, including oxidative stress, in the oral region. With further advances in ESR imaging instrumentation, this technology holds great promise for non-invasive assessment of free radical induced-oxidative stress in oral region; they lead to great advantage of diagnosis and clinical treatment of oral diseases.

Seq #71 - Oral Tissues, Pharmacology
11:00 AM-12:15 PM, Thursday, 26 June 2003 Svenska Massan Exhibition Hall B

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