Simple liver perfusion model for NMR spectroscopic analysis.

We developed a model to study the perfused mouse liver by nuclear magnetic resonance spectroscopy and to sample perfusate as it exited the liver within a vertical-bore spectrometer. The technique consists of rapidly cannulating the portal vein for perfusate inflow, and then suspending the organ in a bath of perfusate. An outlet at the bottom of the NMR tube provides easy access to concentrated samples of the perfusate exiting the liver. A suction outlet located just above the liver removes excess perfusate from the NMR tube. The perfusing medium is oxygenated Krebs-Henseleit buffer perfused at 8 ml/min. We demonstrated excellent P-31 spectra on the mouse liver. The liver energy charge is maintained as reflected in a constant ATP/Pi. We also showed the effects of ischemia and anoxia upon the liver, and correlated these P-31 spectra with biochemical measurements of liver enzyme release. This model was adapted for use in an Oxford wide-bore (89-mm) 8.4 T magnet with a 2-cm NMR tube to study P-31 spectra, liver enzyme and electrolyte release in ischemic and anoxic livers, but it can be used for spectroscopy of any nuclei in any vertical-bore spectrometer.