Effects of EP4 solution and LPD solution vs euro-collins solution on Na+/K+-ATPase activity in rat alveolar type II cells and human alveolar epithelial cell line A549 cells

Background: Intact alveolar epithelial Na+/K+- adenosinetriphosphatase (ATP ase) function is important in preventing alveolar fluid accumulation after lung transplantation. We examined whether the type of preservation solution used influences Na+/K+-ATPase activity in alveolar epithelial cells. Methods: Rat alveolar type II cells were preserved with EP4, low-potassium dextran (LPD), or Euro-Collins solution at 7 degrees C for 5 and 20 hours. To assess cell toxicity, we measured cell viability and lactate dehydrogena se release. Na+/K+-ATPase activity was measured as ouabain-sensitive ATPase hydrolysis. We also examined the effect of terbutaline (10(-3) mol/liter) and dibutyryl cyclic adenosine monophosphate (dbcAMP) (10(-3) mol/liter) on Na+/K+-ATPase activity in A549 cells preserved for 5 hours. Results: All solutions caused significant damage of rat alveolar type II ce lls at 20 hours. However, Na+/K+-ATPase activity was preserved at normal le vels with EP4 and LPD over 20 hours. Terbutaline and dbcAMP significantly i ncreased Na+/K+-ATPase activity in A549 cells preserved with EP4 and LPD so lutions for 5 hours. However, we observed no activation in the cells preser ved with Euro-Collins solution. We found no significant difference in intra cellular cAMP levels after terbutaline challenge among the types of preserv ation solution. Conclusions: We conclude that extracellular-type solutions such as EP4 and LPD may be preferable for maintaining not only the basal activity but also the ability to activate Na+/K+-ATPase in response to beta-adrenergic agonis ts, in alveolar epithelial cells.