title: A quantitative method to assess muscle tissue oxygenation in vivo by monitoring 1H nuclear magnetic resonance myoglobin resonances.
abstract: A nuclear magnetic resonance (NMR) method was implemented to assess in vivo oxygenation levels by a quantitative determination of the 1H NMR myoglobin (Mb) resonances. The proximal His-F8 NdeltaH at 70-90 ppm and Val-E11 gammaCH3 resonance at -2.8 ppm, reflecting deoxygenated (deoxy-Mb) and oxygenated (met-Mb) states, were alternately recorded. The method was developed in vitro choosing a couple of NMR sequences that could each maximize the signal-to-noise ratio (SNR) while avoiding baseline rolling and suppressing the water signal. Two quantitative calibration methods were implemented for deoxy- and met-Mb samples (0.1-1 mM), respectively. The respective limit of detection (LOD) and limit of quantification (LOQ) were 0.015 and 0.05 mM for met-Mb and 0.013 and 0.042 mM for deoxy-Mb. Sequences and calibration curves were employed in vivo in Arenicola marina to obtain, for the first time, an accurate measurement of oxy- and deoxy-Mb actual concentrations. In Arenicola, the peaks at approximately 87 and -2.7 ppm, reflecting the deoxy- and oxy-Mb states, respectively, were alternately recorded during increasing hypoxia. The deoxy-Mb concentrations were obtained from the calibration curve. The oxy-Mb concentrations were calculated from the calibration of met-Mb because it was proved that oxy- and met-Mb gave the same NMR molar response. From oxy- and deoxy-Mb concentrations, the intracellular oxygen partial pressure (PiO2) trend was determined.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università di Milano, Segrate, Milano 20090, Italy. maristella.gussoni@unimi.it
authors.forename: Maristella
authors.initials: M
authors.lastname: Gussoni
authors.forename: Mauro A
authors.initials: MA
authors.lastname: Cremonini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Vezzoli
authors.forename: Fulvia
authors.initials: F
authors.lastname: Greco
authors.forename: Lucia
authors.initials: L
authors.lastname: Zetta
mesh_terms: D000818:Animals; D019069:Cell Respiration; D000860:Hypoxia; D018482:Muscle, Skeletal / Q000378:metabolism*; D009211:Myoglobin / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010101:Oxygen Consumption / Q000502:physiology*; D011077:Polychaeta / Q000378:metabolism
chemical_list: D009211:Myoglobin