Recovery of cells in vitro from the effects hypoxia and hyperoxia

The cytotoxic effect of high, as well as low, oxygen tension of proliferation and metabolism of Low line cells in culture is reversible even after several days of exposure provided the cells are returned to 95% air + 5% CO₂ environment. This suggests that the activity of certain mechanisms within the cells may have been altered or in other ways inhibited by the abnormal environments but are quite rapidly regenerated once the adverse condition is removed. The cells tolerate a low O₂ exposure for at least 20 days while continuous exposure to high O₂ atmosphere results in degeneration and death after 7–10 days. Both glucose utilization and lactic acid production are elevated in cultures exposed to either low or high O₂ tensions, although they are markedly higher in the latter condition. When cell so exposed are returned to an air + 5% CO₂ atmosphere, rate of glucose uptake and lactic acid formation soon approaches that found in control cultures.