Hideo Utsumi

In Vivo Esr Studies of Antioxidant Activity on Free Radical Reaction in Living Mice Under Oxidative Stress

In vivo antioxidant activity seems to be quite complicate due to multiple interaction with biomaterials and differs from results by in vitro experiments. In vivo estimation of antioxidant activity is performed by measuring TBA reactive substances in blood or hydrocarbon gases in breath, but these systems do not measure free radical reaction but the final products of oxidative reaction. In the present study, we applied in vivo ESR to evaluate antioxidant activity by monitoring the redox reaction of nitroxide radical and clearly found that the nitroxide is very susceptible to oxidative stress in vivo and quite useful to evaluate antioxidant activity non-invasively.

In vivo ESR measurements of free radical reactions in living mice

In vivo ESR measurements were carried out to estimate free radical reactions in living mice using nitroxyl radicals as probes. The ESR signal of nitroxyl radical which was intravenously or intramuscularly injected to living female ddY mice decreased gradually by reducing to the corresponding hydroxylamine. The reduction rate was enhanced by oxidative stress, and pre-treatment of antioxidants suppressed the enhancement of signal decay. Oral administration of carbon tetrachloride enhanced signal decay in upper abdomen but not in thorax. These results indicated that free radicals, which can reduce nitroxyl radical, were produced in the upper abdomen by oral administration of carbon tetrachloride.

In Vivo ESR Studies on Pharmacokinetics and Metabolism of Parenteral Lipid Emulsion in Living Mice

AbstractPurpose. We applied non-invasive and real-time method with in vivo ESR spectroscopy to determining pharmacokinetics and metabolism of lipid emulsion as a drug carrier in living mice. Methods. A spin-labeled triglyceride (SL-TG) was newly synthesized and lipid emulsion containing SL-TG was prepared. In vivo ESR spectra in mice were observed after intravenous administration of the lipid emulsion. Results. In vivo ESR spectra consisted of three components, coinciding with the in vitro spectra of SL-TG particles, free and immobilized fatty acids. The amount of the components depended on both the observing domain and the period after administration. In the chest, all three components were observed, while SL-TG particle was lacking in the abdomen. The half-life of the lipid particles in the chest was 2 hr. Conclusions. Non-invasive and real-time analysis of drug carriers in living animal is successfully accomplished using an in vivo ESR method.