Protective effect of steroids on cultured cells damaged by high concentrations of oxygen

Chromosomal aberrations resulting from the exposure of Chinese hamster lung fibroblast cells to 95% oxygen have been used to investigate the protective effect of three steroids. Hydrocortisone had little useful effect. However, dosage of both methylprednisolone and dexamethasone could be increased to a level at which damage by oxygen was reduced to 50% of nuclei compared with 90% damaged in cells unprotected by steroids. There was no appreciable impairment of cell growth. Concentrations of steroids required for this effect were respectively 100 and 10 mumol litre-1, which corresponds to the high dosage regimen currently used to protect the lungs against the effects of endotoxic shock, haemorrhage and other conditions. The steroids did not protect against the depression of cell growth caused by 95% oxygen.