کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1910594 1046778 2008 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
In vivo EPR measurement of glutathione in tumor-bearing mice using improved disulfide biradical probe
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی سالمندی
پیش نمایش صفحه اول مقاله
In vivo EPR measurement of glutathione in tumor-bearing mice using improved disulfide biradical probe
چکیده انگلیسی

Disulfide nitroxide biradicals, DNB, have been used for glutathione, GSH, measurements by X-band electron paramagnetic resonance, EPR, in various cells and tissues. In the present paper, the postulated potential use of DNB for EPR detection of GSH in vivo was explored. Isotopic substitution in the structure of the DNB was performed for the enhancement of its EPR spectral properties. 15N substitution in the NO fragment of the DNB decreased the number of EPR spectral lines and resulted in an approximately two-fold increase in the signal-to-noise ratio, SNR. An additional two-fold increase in the SNR was achieved by substitution of the hydrogen atoms with deuterium resulting in narrowing the EPR lines from 1.35 G to 0.95 G. The spectral changes of DNB upon reaction with GSH and cysteine were studied in vitro in a wide range of pHs at room temperature and “body” temperature, 37°C, and the corresponding bimolecular rate constants were calculated. In in vivo experiments the kinetics of the L-band EPR spectral changes after injection of DNB into ovarian xenograft tumors grown in nude mice were measured by L-band EPR spectroscopy, and analyzed in terms of the two main contributing reactions, splitting of the disulfide bond and reduction of the NO fragment. The initial exponential increase of the “monoradical” peak intensity has been used for the calculation of the GSH concentration using the value of the observed rate constant for the reaction of DNB with GSH, kobs (pH 7.1, 37°C) = 2.6 M- 1s- 1. The concentrations of GSH in cisplatin-resistant and cisplatin-sensitive tumors were found to be 3.3 mM and 1.8 mM, respectively, in quantitative agreement with the in vitro data.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 45, Issue 3, 1 August 2008, Pages 312–320
نویسندگان
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