Sensitivity of cultured mammalian cells to oxidative stress: adaptation to repeated exposures of hyperbaric oxygen.

Four established cell lines (mouse neuroblastoma, N2A; Chinese hamster lung, V79; Chinese hamster ovary, CHO; and rabbit kidney, RK13) were made O2-tolerant by repetitive exposure to hyperbaric oxygen (HBO). The cultures were exposed to 100% O2 at pressures ranging from 6 to 10 ATA for time periods up to 3 h, and the surviving cells were regrown to monolayer confluency and reexposed; by the end of three cycles of treatment these cells were tolerant to exposures of 10 ATA O2 for greater than 5 h. The development of O2 tolerance was measured by enzyme and morphologic indices. Results showed that all of the cell lines tested could be made O2 resistant. However, qualitative differences were found. RK13 cells were more resistant to HBO than the other cell types tested. The technique provides a powerful adjunct to current methods that study the effects of oxidative stress in mammalian cells. The ability to generate O2-resistant cells in only 3-4 wk provides a considerable time savings over published efforts (12-20 mo.). In addition, rapid screening of various cell lines may lead to discovery of O2-resistant cell types which will provide insight into the factors inherent in the development of oxygen tolerance.