FUNCTIONAL AND BIOCHEMICAL EVALUATION OF THE PRESERVED LUNG IN A RAT MODEL

Lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) activ ities and total protein concentrations were examined in the postrinsin g solutions from rat lungs preserved in phosphate-buffered saline (PBS ), Euro-Collins (E-C) solution, or low-potassium E-C solution for 8 h at 4 degrees C, 10 degrees C, or 20 degrees C. The LDH and AST activit ies were higher when the organs were preserved in PBS for 8 h at 20 de grees C than at 4 degrees C or 10 degrees C, while the total protein c oncentration did not differ according to the temperature or solution. The activities mere also higher when the lungs were preserved in Euro- Collins (E-C) solution than in PBS or the low-potassium E-C solution. On examining pulmonary functions utilizing an ex vivo reperfusion mode l, the lungs preserved at 20 degrees C showed poorer gas exchange than those preserved at 4 degrees C or 10 degrees C. Moreover, the organs preserved in E-C solution showed poorer function than those preserved in any other solution. These findings suggest that some enzymatic acti vities in the postrinsing solution could be indicators of lung viabili ty after preservation.