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 (ATPase) 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 dehydrogenase 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 cells at 20 hours. However, Na(+)/K(+)-ATPase activity was preserved at normal levels with EP4 and LPD over 20 hours. Terbutaline and dbcAMP significantly increased Na(+)/K(+)-ATPase activity in A549 cells preserved with EP4 and LPD solutions for 5 hours. However, we observed no activation in the cells preserved with Euro-Collins solution. We found no significant difference in intracellular cAMP levels after terbutaline challenge among the types of preservation 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 agonists, in alveolar epithelial cells.
Suzuki
S
S
Department of Thoracic Surgery, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan. suzuki@idac.tohoku.ac.jp
Inoue
K
K
Sugita
M
M
Tsubochi
H
H
Kondo
T
T
Fujimura
S
S
D000818:Animals; D002460:Cell Line; D003911:Dextrans / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D006982:Hypertonic Solutions / Q000494:pharmacology*; D008297:Male; D019188:Organ Preservation Solutions / Q000494:pharmacology*; D010710:Phosphates / Q000494:pharmacology; D011239:Prednisolone / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D003911:Dextrans; C087055:Ep4 solution; C037096:Euro-Collins' solution; D006982:Hypertonic Solutions; D019188:Organ Preservation Solutions; D010710:Phosphates; C083290:low potassium dextran glucose solution; D006493:Heparin; D011239:Prednisolone; D000254:Sodium-Potassium-Exchanging ATPase; D005947:Glucose