Oxidative Stress-Induced Metabolic Changes in Mouse C2C12 Myotubes Studied with High-Resolution ¹³C, ¹H, and ³¹P NMR Spectroscopy

In this study, stress in relation to slaughter was investigated in a model system by the use of ¹³C, ¹H, and ³¹P nuclear magnetic resonance (NMR) spectroscopy for elucidating changes in the metabolites in C2C12 myotubes exposed to H₂O₂-induced stress. Oxidative stress resulted in lower levels of several metabolites, mainly amino acids; however, higher levels of alanine were apparent in the ¹³C spectra after incubation with [¹³C₁]glucose. In the ¹³C spectra [¹³C₃]lactate tended to increase after exposure to increasing concentrations of H₂O₂; conversely, a tendency to lower levels of the unlabeled (¹²C) lactate were identified in the ¹H spectra after stress exposure. These data indicate an increase in de novo synthesis of alanine, concomitant with a release of lactate from the myotubes to the medium at oxidative stress conditions. The changes in the metabolite levels could possibly be useful as markers for meat quality traits.