¹H-nuclear magnetic resonance deoxymyoglobin signal as indicator of intracellular oxygenation in myocardium

We report in this study that the intracellular oxygenation state is measurable with the ¹H nuclear magnetic resonance signal of the proximal histidine N(δ)H proton of deoxymyoglobin. The signal appears in a clear spectral region of the ¹H spectrum and is sensitive to various hypoxic and ischemic conditions. In perfused heart, the deoxymyoglobin's response to tissue oxygenation precedes the one reflected in the ³¹P phosphocreatine or ATP signals, suggesting that oxidative energy metabolism is still sufficient even when the myoglobin is partially saturated with oxygen. Our method offers then a unique way to observe tissue oxygenation and its interaction in localized tissue region in vivo.