The sensitivity to hyperbaric oxygen of human diploid fibroblasts during ageing in vitro

The effect of hyperbaric oxygen on human diploid fibroblasts, WI-38, at various passages was examined. Their colony-forming ability deteriorates on exposure to hyperbaric oxygen. The cellular injury is not due to the high pressure per se, but to oxygen toxicity, since compressed nitrogen has no effect on the cells. When the cells beyond mid-40 population doublings (lifespan completed more than about 75%) are exposed to 50 atm of oxygen, there is a great decrease in the efficiency of the colony formation. A double exposure to 75 atm of oxygen inhibits the growth of the late passage cells more strongly than that of the early passage cells. These results suggest that the late passage cells are more sensitive to oxygen than the early passage cells.