Hypoxia/reoxygenation injury in liver: Kupffer cells are much more vulnerable to reoxygenation than to hypoxia.

Cell injury due to hypoxia and reoxygenation was studied in primary cultured rat Kupffer cells. Under hypoxic conditions only 20% of the cells had lost their viability after 12 h of incubation. In contrast, almost complete losses of cell viability were observed when reoxygenation was performed after 2, 4 or 6 h of hypoxia. The time-course of reoxygenation injury in Kupffer cells was characterized by a lag phase of 2 h during which no difference between reoxygenated and hypoxically incubated cells was apparent; during the next 4 h, there was an increase of up to 100% in the amount of nonviable cells in the reoxygenated cultures. These results indicate that Kupffer cells were much more vulnerable to reoxygenation than to hypoxia. The time-course of cell damage upon hypoxia/reoxygenation may indicate a self-destruction mechanism caused by an oxygen-triggered activation of these cells.