We designed an NMR-compatible bioreactor that allows real-time metabolic measurements of viable rat brain slices under normal conditions and under conditions mimicking hypoxic-ischemic (HI) brain injury. Special emphasis was put on providing physiological temperature in the system, a significant factor in the HI model. 1H NMR spectra were acquired to assess changes in brain metabolites. Peaks of lactic acid, NAA, glutamate, aspartate, and creatine were detected. By acquiring a time series of proton spectra, we observed significantly increased lactate levels over time when switching from normoxia to hypoxia while other metabolites remained stable over the whole experiment.