EVALUATION OF NORMOTHERMIC ISCHEMIA AND SIMPLE COLD PRESERVATION INJURY IN PIG-KIDNEY BY PROTON NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY

The isolated perfused pig kidney (IPR) model was used to mimick the no n-heart-beating donor situation. This model was performed to assess in itial renal functions after normothermic ischemia, cold flush, and 24 hr cold-storage preservation (CSP) with Euro-Collins and to determine normothermic ischemia and reperfusion impairment by biochemical, histo logical, and proton nuclear magnetic resonance (NMR) spectroscopy anal ysis. Twenty-four pig kidneys were used. There were three experimental groups: Group 1 (G1), control kidneys flushed with cold heparinized s aline and immediately perfused; Group 2 (G2), cold flush followed by 2 4 hr CSP and reperfusion; and Group 3 (G3), 30 min of normothermic isc hemia followed by cold flush and 24 hr CSP and reperfusion. Kidneys we re perfused for 2 hr at 37.5 degrees C for functional evaluation. Perf usate flow rate is significantly different for G3 (P < 0.01). Glomerul ar filtration rate is less in G3 (P < 0.05). Fractional reabsorptions of sodium (FRNa+) and glucose (Glc) excretion in urine are different i n G3 (P < 0.01 and P < 0.05, respectively). Amino acid excretion in NM R spectroscopy was higher in G3 (P < 0.05), Elevated levels of trimeth ylamine-N-oxide (TMAO) and lactate (Lac) were detected by proton NMR s pectroscopy in G2 and particularly G3. A peak is present in G3 and rel ated with poor glomerular and tubular functions and worse histological data. Malondialdehyde tissue level was higher in G3. This study shows that the IPK with proton NMR spectroscopy may be a useful method in t he evaluation of kidneys after cold ischemia and transplantation. This model might be suitable for a variety of experimental protocols, part icularly to improve functional performance after ischemia and reperfus ion. (C) 1997 Academic Press.