Glucose modulates cell death due to normobaric hyperoxia by maintaining cellular ATP

Abstract

To determine whether glucose depletion is a principal determinant of hyperoxic cell death in vitro, human lung epithelial-like cells (A549) were exposed to hyperoxia (95% O2) in either 10, 30, or 50 ml of medium (Ham’s F-12K). Glucose was depleted in the medium after 36, 60, or 96 h, respectively. Medium lactate dehydrogenase (LDH) activity increased only after glucose was depleted. To confirm that glucose depletion was critical to cell death, cells exposed to 95% O2were supplemented with glucose at regular intervals to reestablish initial medium glucose concentrations. Other cells received no supplements. Without supplementation, glucose was depleted within 48 h, followed within 12 h by an almost complete loss of cell ATP and elevated medium LDH activity. Glucose-supplemented cells appeared normal microscopically and did not release LDH activity despite an extracellular pH of 6.5 due to fermentation. Additional experiments at sea-level pressure confirmed that glucose supplementation prevents extensive cell death in hyperoxia in cultured A549 cells.