The effect of oxygen tension on rat hepatocytes in short-term culture

Cell viability, cytochrome P-450 content, cell respiration, and lipid peroxidation were all investigated as a function of oxygen tension in adult rat hepatocytes in short-term culture (less than 9 h). The various oxygen tensions used in this study were obtained by equilibrating culture medium with air, air + nitrogen, or air + oxygen. Cell viability, as assessed by trypan blue exclusion, was significantly greater at all time points tested when hepatocytes were cultured in Ham's F12 medium containing 132 microM O2, as compared to medium equilibrated with air (220 microM O2) or air + oxygen (298 microM O2). Cells cultured in 220 microM O2 (air) also exhibited a gradual loss of cytochrome P-450, so that by 9 h of incubation less than 60% of the active material remained. This loss of P-450 was minimized when cells were cultured in 163 microM O2 and abolished when cells were cultured in 132 microM O2. The 132 microM O2 exposure conditions also maintained cell respiration at the 1 h incubation values, whereas there was a continuous loss in cell respiration over time when the cells were cultured in either 220 microM O2 (air) or 298 microM O2 (air:O2). These cytotoxicity findings may be related to oxidative cell damage inasmuch as it was additionally demonstrated that lipid peroxidation (as measured by malondieldehyde equivalents) was consistantly lower in hepatocytes cultured in air:N2 as compared to air or air:O2. These results suggest that hepatocyte culture in low oxygen tension improves not only cell viability but also maintains other functional characteristics of the cell.