title: In vivo spin trapping of nitric oxide from animal tumors.
abstract: Spin trapping/electron paramagnetic resonance (EPR) spectroscopy allows specific detection of nitric oxide (NO) generation, in vivo. However, in order to detect an EPR signal in living organism, usually a stimulation of immune system with LPS is used to achieve higher than physiological NO levels. Here, we report non-invasive spin trapping of NO in tumors of non-treated, living animals. EPR spectroscopy was performed at S-band to detect NO in Cloudman S91 melanoma tumors growing in the tail of living, syngeneic hosts-DBA/2 mice. Iron (II) N-(dithiocarboxy)sarcosine Fe2+(DTCS)(2) was used as the spin trap. The results were confirmed by X-band ex vivo study. A characteristic three-line spectrum of NO-Fe(DTCS)(2) (A(N)=13 G) was observed (n=4, out of total n=6) in non-treated tumors and in tumors of animals treated with l-arginine. Substrate availability did not limit the detection of NO by spin trapping. Half-life time of the NO-Fe(DTCS)(2) in tumor tissue was about 60 min. The feasibility of non-invasive spin trapping/EPR spectroscopic detection of NO generated in tumor tissue in living animals, without additional activation of the immune system, was demonstrated for the first time.
authors.affiliation: Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Pustelny
authors.forename: Joanna
authors.initials: J
authors.lastname: Bielanska
authors.forename: Przemyslaw M
authors.initials: PM
authors.lastname: Plonka
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Rosen
authors.forename: Martyna
authors.initials: M
authors.lastname: Elas
mesh_terms: D000818:Animals; D004578:Electron Spin Resonance Spectroscopy; D005849:Gerbillinae; D008546:Melanoma, Experimental / Q000378:metabolism*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism*; D013113:Spin Labels
chemical_list: D013113:Spin Labels; D009569:Nitric Oxide